2021/05/16 更新

写真a

アマノ タツロウ
天野 達郎
AMANO Tatsuro
所属
教育研究院 人文社会科学系 教育学系列 准教授
教育学部 保健体育・スポーツ科学講座 准教授
職名
准教授
外部リンク

学位

  • 学術 ( 2014年3月   神戸大学 )

  • 学術 ( 2011年3月   神戸大学 )

  • 発達科学 ( 2009年3月   神戸大学 )

研究キーワード

  • エレクトロポレーション

  • イオントフォレーシス

  • 経皮ドラッグデリバリー

  • マイクロニードル

  • スポーツ栄養

  • 皮膚血流

  • 子ども

  • 脱水

  • マラソン

  • 暑熱順化

  • 運動トレーニング

  • 体温調節

  • 熱中症

  • エクリン汗腺

研究分野

  • ライフサイエンス / 体育、身体教育学

  • ライフサイエンス / スポーツ科学

  • ライフサイエンス / 栄養学、健康科学

  • ライフサイエンス / 生理学

経歴(researchmap)

  • 新潟大学   研究推進機構   研究教授

    2020年9月 - 現在

      詳細を見る

  • 新潟大学   人文社会科学系(教育学部)

    2016年4月 - 現在

      詳細を見る

  • 神戸大学   発達科学部   博士研究員

    2014年4月 - 2016年3月

      詳細を見る

  • 学術振興会特別研究員(DC2)

    2012年4月 - 2014年3月

      詳細を見る

経歴

  • 新潟大学   教育学部 保健体育・スポーツ科学講座   准教授

    2016年4月 - 現在

学歴

  • 神戸大学大学院   人間発達環境学研究科 博士後期課程

    2011年4月 - 2014年3月

      詳細を見る

  • 神戸大学大学院   人間発達環境学研究科 博士前期課程

    2009年4月 - 2011年3月

      詳細を見る

  • 神戸大学   Faculty of Human Development

    2004年4月 - 2009年3月

      詳細を見る

所属学協会

  • 国際環境人間工学会

    2011年7月 - 現在

      詳細を見る

  • 日本体力医学会

    2009年4月 - 現在

      詳細を見る

 

論文

  • Effects of short-term heat acclimation on whole-body heat exchange and local nitric oxide synthase- and cyclooxygenase-dependent heat loss responses in exercising older men. 国際誌

    Naoto Fujii, Gregory W McGarr, Sean R Notley, Pierre Boulay, Ronald J Sigal, Tatsuro Amano, Takeshi Nishiyasu, Martin P Poirier, Glen P Kenny

    Experimental physiology   2020年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? Does short-term heat acclimation enhance whole-body evaporative heat loss and augment nitric oxide synthase (NOS)-dependent cutaneous vasodilatation and NOS- and cyclooxygenase (COX)-dependent sweating, in exercising older men? What is the main finding and its importance? Our preliminary data (n = 8) demonstrated that short-term heat acclimation improved whole-body evaporative heat loss, but it did not influence the effects of NOS and/or COX inhibition on cutaneous vasodilatation or sweating in older men during an exercise-heat stress. These outcomes might imply that although short-term heat acclimation enhances heat dissipation in older men, it does not modulate NOS- and COX-dependent control of cutaneous vasodilatation or sweating on the forearm. ABSTRACT: Ageing is associated with decrements in whole-body heat loss (evaporative + dry heat exchange), which might stem from alterations in nitric oxide synthase (NOS)- and cyclooxygenase (COX)-dependent cutaneous vasodilatation and sweating. We evaluated whether short-term heat acclimation would (i) enhance whole-body heat loss primarily by increasing evaporative heat loss, and (ii) augment NOS-dependent cutaneous vasodilatation and NOS- and COX-dependent sweating, in exercising older men. Eight older men [mean (SD) age, 59 (8) years] completed a calorimetry and microdialysis trial before and after 7 days of exercise-heat acclimation. For the calorimetry trials, whole-body evaporative and dry heat exchange were assessed using direct calorimetry during 30 min bouts of cycling at light, moderate and vigorous metabolic heat productions (150, 200 and 250 W/m2 , respectively) in dry heat (40°C, 20% relative humidity). For the microdialysis trials, local cutaneous vascular conductance and sweat rate were assessed during 60 min exercise in the heat (35°C, 20% relative humidity) at four dorsal forearm skin sites treated with lactated Ringer solution (control), NOS inhibitor, COX inhibitor or combined NOS and COX inhibitors, via microdialysis. Evaporative heat loss during moderate (P = 0.036) and vigorous (P = 0.021) exercise increased after acclimation. Inhibition of NOS alone reduced cutaneous vascular conductance to a similar extent before and after acclimation (P < 0.040), whereas separate and combined NOS and COX inhibition had no significant effects on sweating relative to the control site (P = 0.745). Our preliminary results might suggest that short-term heat acclimation improves evaporative heat loss, but does not significantly modulate the contributions of NOS or COX to cutaneous vasodilatation or sweating on the forearm in older men during an exercise-heat stress.

    DOI: 10.1113/EP089025

    PubMed

    researchmap

  • TRPV4 channel blockade does not modulate skin vasodilation and sweating during hyperthermia or cutaneous post-occlusive reactive and thermal hyperemia. 査読 国際誌

    Naoto Fujii, Glen P Kenny, Gregory W McGarr, Tatsuro Amano, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    American journal of physiology. Regulatory, integrative and comparative physiology   2020年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Transient receptor potential vanilloid 4 (TRPV4) channels exist on vascular endothelial cells and eccrine sweat gland secretory cells in human skin. Here, we assessed if TRPV4 channels contribute to cutaneous vasodilation and sweating during whole-body passive heat stress (protocol 1) and to cutaneous vasodilation during post-occlusive reactive hyperemia and local thermal hyperemia (protocol 2). Intradermal microdialysis was employed to locally deliver pharmacological agents to forearm skin sites where cutaneous vascular conductance (CVC) and sweat rate were assessed. In protocol 1 (twelve young adults), CVC and sweat rate were increased by passive whole-body heating resulting in a body core temperature elevation of 1.2±0.1ºC. The elevated CVC and sweat rate assessed at sites treated with TRPV4 channel antagonist (either 200 µM HC-067047 or 125 µM GSK2193874) were not different from the vehicle control site (5 % dimethyl sulfoxide). After whole-body heating, a TRPV4 channel agonist (100 µM GSK1016790A) was administered to each skin site, eliciting elevations in CVC. Relative to control, this response was partly attenuated by both TRPV4 channel antagonists, confirming drug efficacy. In protocol 2 (ten young adults), CVC was increased following a 5-min arterial occlusion and during local heating from 33 to 42ºC. These responses did not differ between the control and the TRPV4 channel antagonist sites (200 µM HC-067047). We show that TRPV4 channels are not required for regulating cutaneous vasodilation or sweating during a whole-body passive heat stress. Further, they are not required for regulating cutaneous vasodilation during post-occlusive reactive hyperemia and local thermal hyperemia.

    DOI: 10.1152/ajpregu.00123.2020

    PubMed

    researchmap

  • Caffeine Exacerbates Hyperventilation and Reductions in Cerebral Blood Flow in Physically Fit Males Exercising in the Heat. 査読 国際誌

    Naoto Fujii, Tomomi Fujimoto, Yinhang Cao, Kohei Dobashi, Ryoko Matsutake, Tatsuro Amano, Koichi Wanatabe, Takeshi Nishiyasu

    Medicine and science in sports and exercise   2020年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    INTRODUCTION: Caffeine is an exercise performance enhancer widely used by individuals engaged in training or competition under heat-stressed conditions. Caffeine ingestion during exercise in the heat is believed to be safe, since it does not greatly affect body temperature responses, heart rate or body fluid status. However, it remains unknown whether caffeine affects hyperthermia-induced hyperventilation or reductions in the cerebral blood flow index. We tested the hypothesis that under conditions inducing severe hyperthermia, caffeine exacerbates hyperthermia-induced hyperventilation and reduces the cerebral blood flow index during exercise. METHODS: Using a randomized, single-blind, crossover design, twelve physically active healthy young males (23±2 years) consumed a moderate dose of caffeine (5 mg/kg) or placebo in the heat (37°C). Approximately 60 min after the ingestion, they cycled for ~45 min at a workload equal to ~55% of their pre-determined peak oxygen uptake (moderate intensity) until their core temperature increased to 2.0°C above its pre-exercise baseline level. RESULTS: In both trials, ventilation increased and the cerebral blood flow index assessed by middle cerebral artery mean blood velocity decreased as core temperature rose during exercise (P<0.05), indicating that hyperthermia-induced hyperventilation and lowering of the cerebral blood flow index occurred. When core temperature was elevated by 1.5°C or more (P<0.05), ventilation was higher and the cerebral blood flow index was lower throughout the caffeine trial than the placebo trial (P<0.05). CONCLUSION: A moderate dose of caffeine exacerbates hyperthermia-induced hyperventilation and reductions in the cerebral blood flow index during exercise in the heat with severe hyperthermia.

    DOI: 10.1249/MSS.0000000000002537

    PubMed

    researchmap

  • The sweat glands maximum ion reabsorption rates following heat acclimation in healthy older adults. 査読 国際誌

    N Gerrett, T Amano, Y Inoue, N Kondo

    Experimental physiology   2020年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question to this study? Do the sweat glands maximum ion reabsorption rates increase following heat acclimation in healthy older individuals and is this associated with elevated aldosterone concentrations? What is the main finding and its importance? Sweat glands maximum ion reabsorption rates improved heterogeneously across body sites, which occurred without any changes in aldosterone concentration following a controlled hyperthermic heat acclimation protocol in healthy older individuals. ABSTRACT: We examined whether the eccrine sweat glands ion reabsorption rates improved following heat acclimation (HA) in older individuals. Ten healthy older adults (>65 yrs) completed a controlled hyperthermic (+0.9˚C rectal temperature, Tre ) HA protocol for 9 non-consecutive days. Participants completed a passive heat stress test (lower leg 42˚C water submersion) pre-HA and post-HA to assess physiological regulation of sweat glands ions reabsorption at the chest, forearm and thigh. The maximum ion reabsorption rate was defined as the inflection point in the slope of the relation between galvanic skin conductance and sweat rate (SR). We explored the responses again after a 7-day decay. During passive heating, the Tb thresholds for sweat onset on the chest and forearm were lowered after HA (P < 0.05). However, neither sweat sensitivity (i.e. the slope), the SR at a given Tre , nor gross sweat loss improved after HA (P > 0.05). Any changes observed were lost during the decay. Pilocarpine-induced sudomotor responses to iontophoresis did not change after HA (P ≥ 0.801). Maximum ion reabsorption rate was only enhanced at the chest (P = 0.001) despite unaltered aldosterone concentration after HA. The data suggests that this adaptation is lost after 7-days decay. The HA protocol employed in the present study induced partial adaptive sudomotor responses. Eccrine sweat glands ion reabsorption rates improved heterogeneously across the skin sites. It is likely that aldosterone secretion did not alter the chest sweat ion reabsorption rates observed in the older adults. This article is protected by copyright. All rights reserved.

    DOI: 10.1113/EP088486

    PubMed

    researchmap

  • Effects of L-type voltage-gated Ca2+ channel blockade on cholinergic and thermal sweating in habitually trained and untrained men. 査読 国際誌

    Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yumi Okamoto, Yoshimitsu Inoue, Narihiko Kondo

    American journal of physiology. Regulatory, integrative and comparative physiology   2020年9月

     詳細を見る

    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We evaluated the hypothesis that the activation of L-type voltage-gated Ca2+ channels contribute to exercise training-induced augmentation in cholinergic sweating. On separate days, 10 habitually trained and 10 untrained men participated in two experimental protocols. Prior to each protocol, we administered 1% verapamil (Verapamil, L-type voltage-gated Ca2+ channel blocker) and saline (Control) at forearm skin sites on both arms via transdermal iontophoresis. In Protocol 1, we administered low (0.001%) and high (1%) doses of pilocarpine at both the verapamil-treated and untreated forearm sites. In protocol 2, participants were passively heated by immersing their limbs in hot water (43°C) until rectal temperature increased by 1.0°C above baseline resting levels. Sweat rate at all forearm sites were continuously measured throughout both protocols. Pilocarpine-induced sweating in Control was higher in trained than in untrained men for both concentrations of pilocarpine (both P≤0.001). Pilocarpine-induced sweating at the low dose site was attenuated at the Verapamil versus Control site in both groups (both P≤0.004), albeit the reduction was greater in trained as compared to untrained men (P=0.005). The verapamil-mediated reduction in sweating remained intact at the high dose pilocarpine site in the untrained (P=0.004) but not the trained men (P=0.180). Sweating did not differ between Control and Verapamil sites with increases in rectal temperature in both groups (interaction, P=0.571). We show that activation of L-type voltage-gated Ca2+ channels modulates sweat production in habitually trained men induced by a low dose of pilocarpine. However, no effect on sweating was observed during passive heating in either group.

    DOI: 10.1152/ajpregu.00167.2020

    PubMed

    researchmap

  • Ageing augments β-adrenergic cutaneous vasodilatation differently in men and women, with no effect on β-adrenergic sweating. 査読 国際誌

    Naoto Fujii, Gregory W McGarr, Tatsuro Amano, Ronald J Sigal, Pierre Boulay, Takeshi Nishiyasu, Glen P Kenny

    Experimental physiology   2020年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? β-Adrenergic receptor activation modulates cutaneous vasodilatation and sweating in young adults. In this study, we assessed whether age-related differences in β-adrenergic regulation of these responses exist and whether they differ between men and women. What is the main finding and its importance? We showed that ageing augmented β-adrenergic cutaneous vasodilatation, although the pattern of response differed between men and women. Ageing had no effect on β-adrenergic sweating in men or women. Our findings advance our understanding of age-related changes in the regulation of cutaneous vasodilatation and sweating and provide new directions for research on the significance of enhanced β-adrenergic cutaneous vasodilatation in older adults. ABSTRACT: β-Adrenergic receptor agonists, such as isoprenaline, can induce cutaneous vasodilatation and sweating in young adults. Given that cutaneous vasodilatation and sweating responses to whole-body heating and to pharmacological agonists, such as acetylcholine, ATP and nicotine, can differ in older adults, we assessed whether ageing also modulates β-adrenergic cutaneous vasodilatation and sweating and whether responses differ between men and women. In the context of the latter, prior reports showed that the effects of ageing on cutaneous vasodilatation (evoked with ATP and nicotine) and sweating (stimulated by acetylcholine) were sex dependent. Thus, in the present study, we assessed the role of β-adrenergic receptor activation on forearm cutaneous vasodilatation and sweating in 11 young men (24 ± 4 years of age), 11 young women (23 ± 5 years of age), 11 older men (61 ± 8 years of age) and 11 older women (60 ± 8 years of age). Initially, a high dose (100 µm) of isoprenaline was administered via intradermal microdialysis for 5 min to induce maximal β-adrenergic sweating. Approximately 60 min after the washout period, three incremental doses of isoprenaline were administered (1, 10 and 100 µm, each for 25 min) to assess dose-dependent cutaneous vasodilatation. Isoprenaline-mediated cutaneous vasodilatation was greater in both older men and older women relative to their young counterparts. Augmented cutaneous vasodilatory responses were observed at 1 and 10 µm in women and at 100 µm in men. Isoprenaline-mediated sweating was unaffected by ageing, regardless of sex. We show that ageing augments β-adrenergic cutaneous vasodilatation differently in men and women, without influencing β-adrenergic sweating.

    DOI: 10.1113/EP088583

    PubMed

    researchmap

  • Does the iontophoretic application of bretylium tosylate modulate sweating during exercise in the heat in habitually trained and untrained men? 査読 国際誌

    Tatsuro Amano, Shin Sekihara, Naoto Fujii, Glen P Kenny, Yoshimitsu Inoue, Narihiko Kondo

    Experimental physiology   2020年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? Does the administration of the adrenergic presynaptic release inhibitor bretylium tosylate modulate sweating during exercise in the heat, and does this response differ between habitually trained and untrained men? What is the main finding and its importance? Iontophoretic administration of bretylium tosylate attenuates sweating during exercise in the heat in habitually trained and untrained men. However, a greater reduction occurred in trained men. The findings demonstrate a role for cutaneous adrenergic nerves in the regulation of eccrine sweating during exercise in the heat and highlight a need to advance our understanding of neural control of human eccrine sweat gland activity. ABSTRACT: We recently reported an influence of cutaneous adrenergic nerves on eccrine sweat production in habitually trained men performing an incremental exercise bout in non-heat stress conditions. Based on an assumption that increasing heat stress induces cholinergic modulation of sweating, we evaluated the hypothesis that the contribution of cutaneous adrenergic nerves on sweating would be attenuated during exercise in the heat. Twenty young habitually trained and untrained men (n = 10/group) underwent three successive bouts of 15 min of light-, moderate- and vigorous-intensity cycling (equivalent to 30, 50, and 70% of peak oxygen uptake (


    V
    ̇



    O
    2

    peak


    ) respectively), each separated by a 15 min recovery while wearing a perfusion suit perfused with warm water (43°C). Sweat rate (ventilated capsule) was measured continuously at two bilateral forearm skin sites treated with 10 mm bretylium tosylate (an inhibitor of neurotransmitter release from adrenergic nerve terminals) and saline (control) via transdermal iontophoresis. A greater sweat rate was measured during vigorous exercise only in trained as compared to untrained men (P = 0.014). In both groups, sweating was reduced at the bretylium tosylate versus control sites, albeit the magnitude of reduction was greater in the trained men (P ≤ 0.024). These results suggest that cutaneous adrenergic nerves modulate sweating during exercise performed under a whole-body heat stress, albeit a more robust response occurs in trained men. While it is accepted that a cholinergic mechanism plays a primary role in the regulation of sweating during an exercise-heat stress, our findings highlight the need for additional studies aimed at understanding the neural control of human eccrine sweating.

    DOI: 10.1113/EP088797

    PubMed

    researchmap

  • Does α1-adrenergic receptor blockade modulate sweating during incremental exercise in young endurance-trained men? 査読 国際誌

    Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yoshimitsu Inoue, Narihiko Kondo

    European journal of applied physiology120 ( 5 ) 1123 - 1129   2020年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: Human eccrine sweat glands respond to α1-adrenergic receptor agonists. We recently reported that adrenergic mechanisms contribute to sweating in endurance-trained men during an incremental exercise to volitional fatigue. However, it remains unclear if this response is mediated by α1-adrenergic receptor activation. METHODS: Twelve endurance-trained men performed an incremental cycling bout until exhaustion while wearing a water-perfused suit to clamp skin temperature at ~ 34 °C. Bilateral forearm sweat rates were measured wherein the distal area was treated with either 1% terazosin (α1-adrenergic receptor antagonist) or saline solution on the opposite limb (Control) via transdermal iontophoresis. We also measured proximal bilateral forearm sweat rate in untreated sites to confirm that no between-limb differences in forearm sweat rate occurred. Once sweat rate returned to pre-exercise resting levels at ~ 20 min postexercise, 0.25% phenylephrine (α1-adrenergic receptor agonist) was iontophoretically administered to skin to verify α1-adrenergic receptor blockade. RESULTS: Sweat rates at the proximal untreated right and left forearm sites were similar during exercise (interaction, P = 0.581). Similarly, no effect of terazosin on sweat rate was measured relative to control site (interaction, P = 0.848). Postexercise administration of phenylephrine increased sweat rate at the control site (0.08 ± 0.09 mg cm-2 min-1), which was suppressed by ~ 90% at the terazosin-treated site (0.01 ± 0.02 mg cm-2 min-1) (P = 0.026), confirming that α1-adrenergic receptor blockade was intact. CONCLUSION: Our findings demonstrate that α1-adrenergic receptors located at eccrine sweat glands do not contribute to eccrine sweating during incremental exercise in young endurance-trained men.

    DOI: 10.1007/s00421-020-04351-3

    PubMed

    researchmap

  • Regional influence of nitric oxide on cutaneous vasodilatation and sweating during exercise-heat stress in young men. 査読 国際誌

    Madison D Schmidt, Gregory W McGarr, Caroline M Muia, Naoto Fujii, Tatsuro Amano, Glen P Kenny

    Experimental physiology105 ( 5 ) 773 - 782   2020年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? Do regional differences exist in nitric oxide synthase (NOS)-dependent cutaneous vasodilatation and sweating during exercise-heat stress in young men. What is the main finding and its importance? Exercise-induced increases in cutaneous vasodilatation and sweating were greater on the chest and upper back compared to the forearm, although the NOS contribution to cutaneous vasodilatation was similar across all regions. Conversely, there was a greater NOS-dependent rate of change in sweating on the chest compared to the forearm, with a similar trend on the back. ABSTRACT: While it is established that nitric oxide synthase (NOS) is an important modulator of forearm cutaneous vasodilatation and sweating during an exercise-heat stress in young men, it remains unclear if regional differences exist in this response. In 15 habitually active young men (24 ± 4 (SD) years), cutaneous vascular conductance (CVC) and local sweat rate (LSR) were assessed at three body regions. On each of the dorsal forearm, chest and upper-back (trapezius), sites were continuously perfused with either (1) lactated Ringer solution (control) or (2) 10 Mm Nω -nitro-l-arginine (l-NNA, NOS inhibitor), via microdialysis. Participants rested in the heat (35°C) for ∼75 min, followed by 60 min of semi-recumbent cycling performed at a fixed rate of heat production of 200 W m-2 (equivalent to ∼42%


    V
    ̇



    O
    2

    peak


    ). During exercise, the chest and upper-back regions showed higher CVC and LSR responses relative to the forearm (all P < 0.05). Within each region, l-NNA attenuated CVC and LSR relative to control (all P < 0.05). However, the NOS contribution was not different across regions for the rate of change and plateau for CVC or for the LSR plateau (all P > 0.05). Conversely, there was a greater NOS contribution to the rate of change for LSR at the chest relative to the forearm (P < 0.05) with a similar trend for the back. In habitually active young men, NOS-dependent cutaneous vasodilatation was similar across regions while the NOS contribution to LSR was greater on the chest relative to the forearm. These findings advance our understanding of the mechanisms influencing regional variations in cutaneous vasodilatation and sweating during an exercise-heat stress.

    DOI: 10.1113/EP088388

    PubMed

    researchmap

  • Effects of Casein Hydrolysate Ingestion on Thermoregulatory Responses in Healthy Adults during Exercise in Heated Conditions: A Randomized Crossover Trial. 査読 国際誌

    Yasuyuki Sakata, Chikako Yoshida, Yuka Fujiki, Yutaka Matsunaga, Hirohiko Nakamura, Takashi Shimizu, Yasuhiro Takeda, Tatsuro Amano

    Nutrients12 ( 3 )   2020年3月

     詳細を見る

    担当区分:最終著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Food ingestion has been shown to affect thermoregulation during exercise, while the impact of protein degradant consumption remains unclear. We investigated the effects of casein hydrolysate ingestion on thermoregulatory responses during exercise in the heat. In a randomized, placebo-controlled, double-blind, crossover trial, five men and five women consumed either 5 g of casein hydrolysate or placebo. Thirty minutes after ingestion, participants cycled at 60% VO2max until voluntary exhaustion wearing a hot-water (43 °C) circulation suit. Exercise time to exhaustion, body core temperature, forearm sweat rate, and forearm cutaneous vascular conductance did not differ different between the conditions. However, chest sweat rate and mean skin temperature increased upon casein hydrolysate ingestion compared with placebo during exercise. Increased chest sweat rate upon casein hydrolysate ingestion was associated with elevated sudomotor sensitivity to increasing body core temperature, but not the temperature threshold for initiating sweating. A positive correlation was found between chest sweat rate and plasma total amino acid concentration during exercise. These results suggest that casein hydrolysate ingestion enhances sweating heterogeneously by increasing peripheral sensitivity of the chest's sweating mechanism and elevating skin temperature during exercise in the heat. However, the physiological link between plasma amino acid concentration and sweat rate remains unclear.

    DOI: 10.3390/nu12030867

    PubMed

    researchmap

  • NO-mediated activation of KATP channels contributes to cutaneous thermal hyperemia in young adults. 査読 国際誌

    Naoto Fujii, Gregory W McGarr, Glen P Kenny, Tatsuro Amano, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    American journal of physiology. Regulatory, integrative and comparative physiology318 ( 2 ) R390-R398   2020年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Local skin heating to 42°C causes cutaneous thermal hyperemia largely via nitric oxide (NO) synthase (NOS)-related mechanisms. We assessed the hypothesis that ATP-sensitive K+ (KATP) channels interact with NOS to mediate cutaneous thermal hyperemia. In 13 young adults (6 women, 7 men), cutaneous vascular conductance (CVC) was measured at four intradermal microdialysis sites that were continuously perfused with 1) lactated Ringer solution (control), 2) 5 mM glibenclamide (KATP channel blocker), 3) 20 mM NG-nitro-l-arginine methyl ester (NOS inhibitor), or 4) a combination of KATP channel blocker and NOS inhibitor. Local skin heating to 42°C was administered at all four treatment sites to elicit cutaneous thermal hyperemia. Thirty minutes after the local heating, 1.25 mM pinacidil (KATP channel opener) and subsequently 25 mM sodium nitroprusside (NO donor) were administered to three of the four sites (each 25-30 min). The local heating-induced prolonged elevation in CVC was attenuated by glibenclamide (19%), but the transient initial peak was not. However, glibenclamide had no effect on the prolonged elevation in CVC in the presence of NOS inhibition. Pinacidil caused an elevation in CVC, but this response was abolished at the glibenclamide-treated skin site, demonstrating its effectiveness as a KATP channel blocker. The pinacidil-induced increase in CVC was unaffected by NOS inhibition, whereas the increase in CVC elicited by sodium nitroprusside was partly (15%) inhibited by glibenclamide. In summary, we showed an interactive effect of KATP channels and NOS for the plateau of cutaneous thermal hyperemia. This interplay may reflect a vascular smooth muscle cell KATP channel activation by NO.

    DOI: 10.1152/ajpregu.00176.2019

    PubMed

    researchmap

  • Regional contributions of nitric oxide synthase to cholinergic cutaneous vasodilatation and sweating in young men. 査読 国際誌

    Gregory W McGarr, Reem Ghassa, Naoto Fujii, Tatsuro Amano, Glen P Kenny

    Experimental physiology105 ( 2 ) 236 - 243   2020年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? We evaluated whether regional variations exist in NO-dependent cutaneous vasodilatation and sweating during cholinergic stimulation. What is the main finding and its importance? Peak cutaneous vasodilatation and sweating were greater on the torso than the forearm. Furthermore, we found that NO was an important modulator of cholinergic cutaneous vasodilatation, but not sweating, across body regions, with a greater contribution of NO to cutaneous vasodilatation in the limb compared with the torso. These findings advance our understanding of the mechanisms influencing regional variations in cutaneous vasodilator and sweating responses to pharmacological stimulation. ABSTRACT: Regional variations in cutaneous vasodilatation and sweating exist across the body. Nitric oxide (NO) is an important modulator of these heat loss responses in the forearm. However, whether regional differences in NO-dependent cutaneous vasodilatation and sweating exist remain uncertain. In 14 habitually active young men (23 ± 4 years of age), cutaneous vascular conductance (CVC%max ) and local sweat rates were assessed at six skin sites. On each of the dorsal forearm, chest and upper back (trapezius), sites were continuously perfused with either lactated Ringer solution (control) or 10 mm Nω -nitro-l-arginine (l-NNA; an NO synthase inhibitor) dissolved in Ringer solution, via microdialysis. At all sites, cutaneous vasodilatation and sweating were induced by co-administration of the cholinergic agonist methacholine (1, 10, 100, 1000 and 2000 mm; 25 min per dose) followed by 50 mm sodium nitroprusside (20-25 min) to induce maximal vasodilatation. The l-NNA attenuated CVC%max relative to the control conditions for all regions (all P < 0.05), and NO-dependent vasodilatation was greater at the forearm compared with the back and chest (both P < 0.05). Furthermore, maximal vasodilatation was higher at the back and chest relative to the forearm (both P < 0.05). Conversely, l-NNA had negligible effects on sweating across the body (all P > 0.05). Peak local sweat rate was higher at the back relative to the forearm (P < 0.05), with a similar trend observed for the chest. In habitually active young men, NO-dependent cholinergic cutaneous vasodilatation varied across the body, and the contribution to cholinergic sweating was negligible. These findings advance our understanding of the mechanisms influencing regional variations in cutaneous vasodilatation and sweating during pharmacological stimulation.

    DOI: 10.1113/EP088295

    PubMed

    researchmap

  • Nicotinic receptors modulate skin perfusion during normothermia, and have a limited role in skin vasodilatation and sweating during hyperthermia. 査読 国際誌

    Naoto Fujii, Tatsuro Amano, Glen P Kenny, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    Experimental physiology104 ( 12 ) 1808 - 1818   2019年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? What is the role of nicotinic receptors in the regulation of normothermic cutaneous blood flow and cutaneous vasodilatation and sweating during whole-body heating induced following resting in a non-heat-stress condition? What is the main finding and its importance? Nicotinic receptors modulated cutaneous vascular tone during rest in a non-heat-stress condition and in the early stage of heating, but they had a limited role in mediating cutaneous vasodilatation when core temperature increased >0.4°C. Further, the contribution of nicotinic receptors to sweating was negligible during whole-body heating. Our findings provide new insights into the role of nicotinic receptors in end-organ function of skin vasculature and sweat glands in humans. ABSTRACT: Nicotinic receptors are present in human skin including cutaneous vessels and eccrine sweat glands as well as peripheral nerves. We tested the hypothesis that nicotinic receptors do not contribute to the control of cutaneous vascular tone in the normothermic state, but are involved in mediating cutaneous vasodilatation and sweating during a whole-body passive heat stress in humans. We first performed a nicotinic receptor blocker verification protocol in six young adults (one female) wherein increases in cutaneous vascular conductance and sweating elicited by 10 mm nicotine were blocked by administration of 500 µm hexamethonium to confirm effective blockade. Thereafter, 12 young males participated in a passive heating protocol. After an instrumentation period in a non-heat-stress condition, participants rested for a 10 min baseline period. Thereafter, oesophageal temperature was increased by 1.0°C using water-perfusion suits. Cutaneous vascular conductance, sweat rate, active sweat gland density and sweat output per individual gland were assessed with and without 500 µm hexamethonium administered via intradermal microdialysis. Hexamethonium reduced cutaneous vascular conductance by 22-34% during normothermia and the early stage of heating. However, this effect was diminished as oesophageal temperature increased >0.4°C. Active sweat gland density was reduced by hexamethonium when oesophageal temperature was elevated by 0.4-0.6°C above baseline resting. However, this was paralleled by a marginal increase in sweat gland output. Consequently, sweat rate remained unchanged. We showed that nicotinic receptors modulate cutaneous perfusion during normothermia and the early stage of heating, but not when core temperature increases >0.4°C. Additionally, they play a limited role in mediating sweating during heating.

    DOI: 10.1113/EP088072

    PubMed

    researchmap

  • Contribution of nitric oxide synthase to cutaneous vasodilatation and sweating in men of black-African and Caucasian descent during exercise in the heat. 査読 国際誌

    Caroline M Muia, Gregory W McGarr, Madison D Schmidt, Naoto Fujii, Tatsuro Amano, Glen P Kenny

    Experimental physiology104 ( 12 ) 1762 - 1768   2019年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? Nitric oxide modulates cutaneous vasodilatation and sweating during exercise-induced heat stress in young men. However, it remains uncertain whether these effects are reduced in black-African descendants, who commonly demonstrate reduced nitric oxide bioavailability. Therefore, we assessed whether black-African descendants display reduced nitric oxide-dependent cutaneous vasodilatation and sweating compared with Caucasians in these conditions. What is the main finding and its importance? Nitric oxide-dependent cutaneous vasodilatation and sweating were similar between groups, indicating that reduced nitric oxide bioavailability in black-African descendants does not attenuate these heat-loss responses during an exercise-induced heat stress. ABSTRACT: Men of black-African descent are at an increased risk of heat-related illness relative to their Caucasian counterparts. This might be attributable, in part, to reduced cutaneous nitric oxide (NO) bioavailability in this population, which might alter local cutaneous vasodilatation and sweating. To evaluate this, we compared these heat-loss responses in young men (18-30 years of age) of black-African (n = 10) and Caucasian (n = 10) descent during rest, exercise and recovery in the heat. Participants were matched for physical characteristics and fitness, and they were all born and raised in the same temperate environment (i.e. Canada; second generation and higher). Both groups rested for 10 min and then performed 50 min of moderate-intensity exercise at 200 W m-2 , followed by 30 min of recovery in hot, dry heat (35°C, 20% relative humidity). Local cutaneous vascular conductance (CVC%max ) and sweat rate (SR) were measured at two forearm skin sites treated with either lactated Ringer solution (control) or 10 mm NG -nitro-l-arginine methyl ester (l-NAME, a nitric oxide (NO) synthase inhibitor). l-NAME significantly reduced CVC%max throughout rest, exercise and recovery in both groups (both P < 0.001). However, there were no significant main effects for the contribution of NO to CVC%max between groups (all P > 0.500). l-NAME significantly reduced local SR in both groups (both P < 0.050). The contribution of NO to SR was similar between groups such that l-NAME reduced SR relative to control at 40 and 50 min into exercise (both P < 0.05). We demonstrate that ethnicity per se does not influence NO-dependent cutaneous vasodilatation and sweating in healthy young men of black-African and Caucasian descent during exercise in dry heat.

    DOI: 10.1113/EP088115

    PubMed

    researchmap

  • 朝食をモデルとした食事摂取が若年女性の体温調節反応に及ぼす影響 査読

    米浪 直子, 池田 麻友美, 一之瀬 智子, 大上 安奈, 天野 達郎, 上田 博之, 近藤 徳彦, 井上 芳光

    日本生理人類学会誌24 ( 4 ) 131 - 138   2019年11月

     詳細を見る

    記述言語:日本語   出版者・発行元:日本生理人類学会  

    researchmap

  • Effects of isomaltulose ingestion on postexercise hydration state and heat loss responses in young men. 査読 国際共著 国際誌

    Tatsuro Amano, Yuki Sugiyama, Junya Okumura, Naoto Fujii, Glen P Kenny, Takeshi Nishiyasu, Yoshimitsu Inoue, Narihiko Kondo, Katsumi Sasagawa, Yasuaki Enoki, Daisuke Maejima

    Experimental Physiology104 ( 10 ) 1494 - 1504   2019年10月

     詳細を見る

    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    NEW FINDINGS: What is the central question of this study? What are the effects of isomaltulose, an ingredient in carbohydrate-electrolyte beverages to maintain glycaemia and attenuate the risk of dehydration during exercise heat stress, on postexercise rehydration and physiological heat loss responses? What is the main finding and its importance? Consumption of a 6.5% isomaltulose-electrolyte beverage following exercise heat stress restored hydration following a 2 h recovery as compared to a 2% solution or water only. While the 6.5% isomaltulose-electrolytes increased plasma volume and plasma osmolality, which are known to modulate postexercise heat loss, sweating and cutaneous vascular responses did not differ between conditions. Consequently, ingestion beverages containing 6.5% isomaltulose-electrolytes enhanced postexercise rehydration without affecting heat loss responses. ABSTRACT: Isomaltulose is a disaccharide carbohydrate widely used during exercise to maintain glycaemia and hydration. We investigated the effects of ingesting a beverage containing isomaltulose and electrolytes on postexercise hydration state and physiological heat loss responses. In a randomized, single-blind cross-over design, 10 young healthy men were hypohydrated by performing up to three 30 min successive moderate-intensity (50% heart rate reserve) bouts of cycling, each separated by 10 min, while wearing a water-perfusion suit heated to 45°C. The protocol continued until a 2% reduction in body mass was achieved. Thereafter, participants performed a final 15 min moderate-intensity exercise bout followed by a 2 h recovery. Following cessation of exercise, participants ingested a beverage consisting of (i) water only (Water), (ii) 2% isomaltulose (CHO-2%), or (iii) 6.5% isomaltulose (CHO-6.5%) equal to the volume of 2% body mass loss within the first 30 min of the recovery. Changes in plasma volume (ΔPV) after fluid ingestion were greater for CHO-6.5% compared with CHO-2% (120 min postexercise) and Water (90 and 120 min) (all P ≤ 0.040). Plasma osmolality remained elevated with CHO-6.5% compared with consumption of the other beverages at 30 and 90 min postexercise (all P ≤ 0.050). Urine output tended to be reduced with CHO-6.5% compared to other fluid conditions (main effect, P = 0.069). Rectal and mean skin temperatures, chest sweat rate and cutaneous perfusion did not differ between conditions (all P > 0.05). In conclusion, compared with CHO-2% and Water, consuming a beverage consisting of CHO-6.5% and electrolytes during recovery under heat stress enhances PV recovery without modulating physiological heat loss responses.

    DOI: 10.1113/EP087843

    PubMed

    researchmap

  • Evidence for TRPV4 channel induced skin vasodilatation through NOS, COX, and KCa channel mechanisms with no effect on sweat rate in humans. 査読 国際誌

    Naoto Fujii, Glen P Kenny, Tatsuro Amano, Yasushi Honda, Narihiko Kondo, Takeshi Nishiyasu

    European journal of pharmacology858   172462 - 172462   2019年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Transient receptor potential vanilloid 4 (TRPV4) channels exist in the endothelial cells of cutaneous blood vessels and the secretory cells of eccrine sweat glands. We assessed if exogenous TRPV4 channel activation elicits cutaneous vasodilatation and sweating in humans in vivo, and if so, whether this response is mediated by nitric oxide synthase (NOS)- cyclooxygenase (COX)- and/or Ca2+-sensitive K+ (KCa) channel-related mechanisms. In ten healthy young adults (24±2 years, 5 women), cutaneous vascular conductance and sweat rate were assessed at four dorsal forearm skin sites continuously treated with either: 1) lactated Ringer's solution (Control), 2) 20 mM L-NAME, a non-selective NOS inhibitor, 3) 10 mM ketorolac, a non-selective COX inhibitor, or 4) 50 mM TEA, a non-selective KCa channel blocker. A potent and selective TRPV4 channel agonist, GSK1016790 A (GSK101), was administered to each skin site in a dose-dependent manner (1, 10, 100, 1000 μM each for ≥30min) via intradermal microdialysis. Administration of 100 and 1000 μM GSK101 increased cutaneous vascular conductance from pre-infusion level at the Control site (48±12 and 57±9%max, respectively, P≤0.004). This response was markedly (53-83%) attenuated by NOS inhibition, COX inhibition, or KCa channel blockade (all P≤0.037), except KCa channel blockade had no effect during 1000 μM GSK101 administration. GSK101 did not influence sweat rate regardless of skin site. We showed that in human skin in vivo, exogenous activation of TRPV4 channels mediates cutaneous vasodilatation, but not sweating through NOS, COX, and KCa channel mechanisms.

    DOI: 10.1016/j.ejphar.2019.172462

    PubMed

    researchmap

  • The influence of local skin temperature on the sweat glands maximum ion reabsorption rate 査読

    N. Gerrett, T. Amano, G. Havenith, Y. Inoue, Narihiko Kondo

    EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY119 ( 3 ) 685 - 695   2019年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    PurposeChanges in mean skin temperature (T-sk) have been shown to modify the maximum rate of sweat ion reabsorption. This study aims to extend this knowledge by investigating if modifications could also be caused by local T-sk.MethodsThe influence of local T-sk on the sweat gland maximum ion reabsorption rates was investigated in ten healthy volunteers (three female and seven male; 20.81.2years, 60.47.7kg, 169.4 +/- 10.4cm) during passive heating (water-perfused suit and lower leg water immersion). In two separate trials, in a randomized order, one forearm was always manipulated to 33 degrees C (Neutral), whilst the other was manipulated to either 30 degrees C (Cool) or 36 degrees C (Warm) using water-perfused patches. Oesophageal temperature (T-es), forearm T-sk, sweat rate (SR), galvanic skin conductance (GSC) and salivary aldosterone concentrations were measured. The sweat gland maximum ion reabsorption rates were identified using the SR threshold for an increasing GSC.ResultsThermal [T-es and body temperature (T-b)] and non-thermal responses (aldosterone) were similar across all conditions (p>0.05). A temperature-dependent response for the sweat gland maximum ion reabsorption rates was evident between 30 degrees C (0.18 +/- 0.10mg/cm(2)/min) and 36 degrees C (0.28 +/- 0.14mg/cm(2)/min, d=0.88, p<0.05), but not for 33 degrees C (0.22 +/- 0.12mg/cm(2)/min), d=0.44 and d=0.36, p>0.05.Conclusion The data indicate that small variations in local T-sk may not affect the sweat gland maximum ion reabsorption rates but when the local T-sk increases by >6 degrees C, ion reabsorption rates also increase.

    DOI: 10.1007/s00421-018-04059-5

    Web of Science

    researchmap

  • Effect of ice slushy ingestion and cold water immersion on thermoregulatory behavior. 査読 国際誌

    Hui C Choo, Jeremiah J Peiffer, João P Lopes-Silva, Ricardo N O Mesquita, Tatsuro Amano, Narihiko Kondo, Chris R Abbiss

    PloS one14 ( 2 ) e0212966   2019年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Two studies were conducted to examine the effects of ice slushy ingestion (ICE) and cold water immersion (CWI) on thermoregulatory and sweat responses during constant (study 1) and self-paced (study 2) exercise. In study 1, 11 men cycled at 40-50% of peak aerobic power for 60 min (33.2 ± 0.3°C, 45.9 ± 0.5% relative humidity, RH). In study 2, 11 men cycled for 60 min at perceived exertion (RPE) equivalent to 15 (33.9 ± 0.2°C and 42.5 ± 3.9%RH). In both studies, each trial was preceded by 30 min of CWI (~22°C), ICE or no cooling (CON). Rectal temperature (Tre), skin temperature (Tsk), thermal sensation, and sweat responses were measured. In study 1, ICE decreased Tre-Tsk gradient versus CON (p = 0.005) during first 5 min of exercise, while CWI increased Tre-Tsk gradient versus CON and ICE for up to 20 min during the exercise (p<0.05). In study 2, thermal sensation was lower in CWI versus CON and ICE for up to 35-40 min during the exercise (p<0.05). ICE reduced thermal sensation versus CON during the first 20 min of exercise (p<0.05). In study 2, CWI improved mean power output (MPO) by ~8 W, compared with CON only (p = 0.024). In both studies, CWI (p<0.001) and ICE (p = 0.019) delayed sweating by 1-5 min but did not change the body temperature sweating threshold, compared with CON (both p>0.05). Increased Tre-Tsk gradient by CWI improved MPO while ICE reduced Tre but did not confer any ergogenic effect. Both precooling treatments attenuated the thermal efferent signals until a specific body temperature threshold was reached.

    DOI: 10.1371/journal.pone.0212966

    PubMed

    researchmap

  • β-Adrenergic receptor blockade does not modify non-thermal sweating during static exercise and following muscle ischemia in habitually trained individuals. 査読 国際誌

    Tatsuro Amano, Anna Igarashi, Naoto Fujii, Daichi Hiramatsu, Yoshimitsu Inoue, Narihiko Kondo

    European journal of applied physiology118 ( 12 ) 2669 - 2677   2018年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: This study investigated the influence of β-adrenergic receptor blockade on sweating during bilateral static knee extension (KE) and lateral isometric handgrip (IH) exercises followed by post-exercise muscle ischemia (PEMI) in habitually trained individuals. METHOD: Ten habitually trained men (maximum oxygen uptake, 57.1 ± 3.4 ml kg-1 min-1) were mildly heated by increasing their skin temperature, and bilateral KE or lateral IH exercises at an intensity of 60% maximum voluntary contraction were subsequently performed for 1 min, followed by PEMI to stimulate muscle metaboreceptors for 2 min. Sweat rates were measured on the bilateral forearms (KE) or thighs (IH) transdermally administered with 1% propranolol (propranolol, a non-selective β-adrenergic receptor inhibitor) or saline (control) via iontophoresis. RESULTS: Relative to the pre-exercise baseline values, IH exercise (P = 0.038) followed by PEMI (P = 0.041) similarly increased sweat rates on the thighs at both control and propranolol sites (baseline, 0.05 ± 0.04 vs. 0.05 ± 0.04; IH, 0.14 ± 0.12 vs. 0.15 ± 0.14; PEMI, 0.14 ± 0.16 vs. 0.14 ± 0.16 mg cm-2 min-1). KE increased sweat rates on the forearms (P = 0.001) at both control and propranolol sites similarly (baseline, 0.02 ± 0.03 vs. 0.02 ± 0.03; KE, 0.21 ± 0.19 vs. 0.20 ± 0.18), whereas PEMI did not significantly induce sweating at these sites (P = 0.260) (0.09 ± 0.12 and 0.10 ± 0.12 mg cm-2 min-1, respectively). CONCLUSION: These results suggest that non-thermal drives induced by static exercise and PEMI do not elicit β-adrenergic sweating in habitually trained individuals even when the non-thermal drives are originated from leg(s) under the conditions in the present study.

    DOI: 10.1007/s00421-018-3993-x

    PubMed

    researchmap

  • Cutaneous adrenergic nerve blockade attenuates sweating during incremental exercise in habitually trained men. 査読 国際誌

    Tatsuro Amano, Naoto Fujii, Yoshimitsu Inoue, Narihiko Kondo

    Journal of applied physiology (Bethesda, Md. : 1985)125 ( 4 ) 1041 - 1050   2018年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    It remains unknown whether cutaneous adrenergic nerves functionally contribute to sweat production during exercise. This study examined whether cutaneous adrenergic nerve blockade attenuates sweating during incremental exercise, specifically in habitually trained individuals. Accordingly, 10 habitually trained and 10 untrained males (V̇o2max: 56.7 ± 5.4 and 38.9 ± 6.7 ml·kg-1·min-1, respectively; P < 0.001) performed incremental semirecumbent cycling (20 W/min) until exhaustion. Sweat rates (ventilated capsule) were measured at two bilateral forearm skin sites on which either 10 mM bretylium tosylate (BT) (an inhibitor of neurotransmitter release from sympathetic adrenergic nerve terminals) or saline (Control) was transdermally administered via iontophoresis. BT treatment delayed sweating onset in both groups (∼0.66 min; P = 0.001) and suppressed the sweat rate relative to the Control treatment at ≥70% relative total exercise time in trained individuals (each 10% increment; all P ≤ 0.009) but not in untrained counterparts ( P = 0.122, interaction between relative time × treatment). Changes in total sweat production at the BT site relative to the Control site were greater in trained individuals than in untrained counterparts (area under the curve, -0.86 ± 0.67 and -0.22 ± 0.39 mg/cm2, respectively; P = 0.023). In conclusion, we demonstrated that cutaneous adrenergic nerves do modulate sweating during incremental exercise, which appeared to be more apparent in habitually trained men (e.g., ≥70% maximum workload). Although our results indicated that habitual exercise training may augment neural adrenergic sweat production during incremental exercise, additional studies are required to confirm this possibility. NEW & NOTEWORTHY We demonstrated for the first time that cutaneous adrenergic nerves do modulate sweating during high-intensity exercise in humans (≥70% maximum workload). In addition, neural adrenergic sweating appeared to be greater in habitually trained individuals than in untrained counterparts, although further studies are necessary to confirm such a possibility. Nonetheless, the observations presented herein advance our understanding on human thermoregulation while providing new evidence for the neutral mediation of adrenergic sweating during exercise.

    DOI: 10.1152/japplphysiol.00370.2018

    PubMed

    researchmap

  • Influence of dietary nitrate supplementation on local sweating and cutaneous vascular responses during exercise in a hot environment. 査読 国際誌

    Tatsuro Amano, Dai Okushima, Brynmor C Breese, Stephen J Bailey, Shunsaku Koga, Narihiko Kondo

    European journal of applied physiology118 ( 8 ) 1579 - 1588   2018年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: We investigated the influence of inorganic nitrate ([Formula: see text]) supplementation on local sweating and cutaneous vascular responses during exercise in hot conditions. METHOD: Eight healthy, young subjects were assigned in a randomized, double-blind, crossover design to receive [Formula: see text]-rich beetroot (BR) juice (140 mL/day, containing ~ 8 mmol of [Formula: see text]) and [Formula: see text]-depleted placebo (PL) juice (140 mL/day, containing ~ 0.003 mmol of [Formula: see text]) for 3 days. On day 3 of supplementation, subjects cycled at an intensity corresponding to 55% of [Formula: see text]O2max for 30 min in hot conditions (30 °C, 50% relative humidity). Chest and forearm sweat rate (SR) and skin blood flow (SkBF), were measured continuously. Cutaneous vascular conductance (CVC) was calculated by SkBF/mean arterial pressure (MAP). RESULTS: Prior to exercise, plasma [Formula: see text] (21 ± 6 and 581 ± 161 µM) and nitrite ([Formula: see text], 87 ± 28 and 336 ± 156 nM) concentrations were higher after BR compared to PL supplementation (P ≤ 0.011, n = 6). Oesophageal, mean skin, and mean body temperatures during exercise were not different between conditions. In addition, BR supplementation did not affect SR, SkBF, and CVC during exercise. A lower MAP was found after 30 min of exercise following BR supplementation (112 ± 6 and 103 ± 6 mmHg for PL and BR, respectively, P = 0.021). CONCLUSION: These results suggest that inorganic [Formula: see text] supplementation, which increases the potential for O2-independent NO production, does not affect local sweating and cutaneous vascular responses, but attenuates blood pressure in young healthy subjects exercising in a hot environment.

    DOI: 10.1007/s00421-018-3889-9

    PubMed

    researchmap

  • The effects of exercise and passive heating on the sweat glands ion reabsorption rates. 査読 国際誌

    Nicola Gerrett, Tatsuro Amano, Yoshimitsu Inoue, George Havenith, Narihiko Kondo

    Physiological reports6 ( 5 )   2018年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The sweat glands maximum ion reabsorption rates were investigated (n = 12, 21.7 ± 3.0 years, 59.4 ± 9.8 kg, 166.9 ± 10.4 cm and 47.1 ± 7.5 mL/kg/min) during two separate endogenous protocols; cycling at 30% (LEX) and 60% VO2max (MEX) and one exogenous trial; passive heating (PH) (43°C water lower leg immersion) in 27°C, 50%RH. Oesophageal temperature (Tes ), skin temperature (Tsk ), and forearm, chest and lower back sweat rate (SR) and galvanic skin conductance (GSC) were measured. Salivary aldosterone was measured pre-and postheating (n = 3). Using the ∆SR threshold for an increasing ∆GSC to identify maximum sweat ion reabsorption rate revealed higher reabsorption rates during MEX compared to PH (mean of all regions: 0.63 ± 0.28 vs. 0.44 ± 0.3 mg/cm2 /min, P < 0.05). It was not possible to identify the ion reabsorption rate during LEX for some participants. Tes and mean Tsk were different between conditions but mean body temperature (Tb ) and local Tsk (forearm, chest and back) were similar (P > 0.05). Aldosterone increased more during MEX (72.8 ± 36.6 pg/mL) compared to PH (39.2 ± 17.5 pg/mL) and LEX (1.8 ± 9.7 pg/mL). The back had a higher threshold than the forearm (P < 0.05) but it was similar to the chest (P > 0.05) (mean of all conditions; 0.64 ± 0.33, 0.42 ± 0.25, 0.54 ± 0.3 mg/cm2 /min, respectively). Although the differences between conditions may be influenced by thermal or nonthermal mechanism, our results indicate a possibility that the sweat glands maximum ion reabsorption rates may be different between exercise and passive heating without mediating skin regional differences.

    DOI: 10.14814/phy2.13619

    PubMed

    researchmap

  • Do nitric oxide synthase and cyclooxygenase contribute to sweating response during passive heating in endurance-trained athletes? 査読 国際誌

    Tatsuro Amano, Naoto Fujii, Glen P Kenny, Yoshimitsu Inoue, Narihiko Kondo

    Physiological reports5 ( 17 )   2017年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The aim of our study was to determine if habitual endurance training can influence the relative contribution of nitric oxide synthase (NOS) and cyclooxygenase (COX) in the regulation of sweating during a passive heat stress in young adults. Ten trained athletes and nine untrained counterparts were passively heated until oral temperature (as estimated by sublingual temperature, Tor) increased by 1.5°C above baseline resting. Forearm sweat rate (ventilated capsule) was measured at three skin sites continuously perfused with either lactated Ringer's solution (Control), 10 mmol/L N
    G
    -nitro-L-arginine methyl ester (L-NAME, non-selective NOS inhibitor), or 10 mmol/L ketorolac (Ketorolac, non-selective COX inhibitor) via intradermal microdialysis. Sweat rate was averaged for each 0.3°C increase in Tor Sweat rate at the L-NAME site was lower than Control following a 0.9 and 1.2°C increase in Tor in both groups (all P ≤ 0.05). Relative to the Control site, NOS-inhibition reduced sweating similarly between the groups (P = 0.51). Sweat rate at the Ketorolac site was not different from the Control at any levels of Tor in both groups (P > 0.05). Nevertheless, a greater sweat rate was measured at the end of heating in the trained as compared to the untrained individuals (P ≤ 0.05). We show that NOS contributes similarly to sweating in both trained and untrained individuals during a passive heat stress. Further, no effect of COX on sweating was measured for either group. The greater sweat production observed in endurance-trained athletes is likely mediated by factors other than NOS- and COX-dependent mechanisms.

    DOI: 10.14814/phy2.13403

    PubMed

    researchmap

  • Evidence for β-adrenergic modulation of sweating during incremental exercise in habitually trained males. 査読 国際誌

    Tatsuro Amano, Yosuke Shitara, Naoto Fujii, Yoshimitsu Inoue, Narihiko Kondo

    Journal of applied physiology (Bethesda, Md. : 1985)123 ( 1 ) 182 - 189   2017年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The aim of the present study was to determine the β-adrenergic contribution to sweating during incremental exercise in habitually trained males. Nine habitually trained and 11 untrained males performed incremental cycling until exhaustion (20 W/min). Bilateral forearm sweat rates (ventilated capsule) were measured at two skin sites that were transdermally administered via iontophoresis with either 1% propranolol (Propranolol, a nonselective β-adrenergic receptor antagonist) or saline (Control). The sweat rate was evaluated as a function of both relative (percentage of maximum workload) and absolute exercise intensities. The sweat rate at the Propranolol site was lower than the control during exercise at 80 (0.57 ± 0.21 and 0.45 ± 0.19 mg·cm-2·min-1 for Control and Propranolol, respectively) and 90% (0.74 ± 0.22 and 0.65 ± 0.17 mg·cm-2·min-1, respectively) of maximum workload in trained males (all P < 0.05). By contrast, no between-site differences in sweat rates were observed in untrained counterparts (all P > 0.05). At the same absolute intensity, higher sweat rates on the control site were observed in trained males relative to the untrained during exercise at 160 (0.23 ± 0.20 and 0.04 ± 0.05 mg·cm-2·min-1 for trained and untrained, respectively) and 180 W (0.40 ± 0.20 and 0.13 ± 0.13 mg·cm-2·min-1, respectively) (all P < 0.05), whereas this between-group difference was not observed at the Propranolol site (all P > 0.05). We show that the β-adrenergic mechanism does modulate sweating during exercise at a submaximal high relative intensity in habitually trained males. The β-adrenergic mechanism may in part contribute to the greater sweat production in habitually trained males than in untrained counterparts during exercise.NEW & NOTEWORTHY We demonstrated for the first time that the β-adrenergic mechanism does modulate sweating (i.e., β-adrenergic sweating) during exercise using a localized β-adrenoceptor blockade in humans in vivo. β-Adrenergic sweating was evident in habitually trained individuals during exercise at a submaximal high relative intensity (80-90% maximal work). This observation advances our understanding of human thermoregulation during exercise and of the mechanism that underlies sweat gland adaptation to habitual exercise training.

    DOI: 10.1152/japplphysiol.00220.2017

    PubMed

    researchmap

  • Maximum rate of sweat ions reabsorption during exercise with regional differences, sex, and exercise training. 査読 国際誌

    Tatsuro Amano, Megumi Hirose, Kana Konishi, Nicola Gerrett, Hiroyuki Ueda, Narihiko Kondo, Yoshimitsu Inoue

    European journal of applied physiology117 ( 7 ) 1317 - 1327   2017年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    PURPOSE: It is recently reported that determining sweat rate (SR) threshold for increasing galvanic skin conductance (GSC) would represent a maximum rate of sweat ion reabsorption in sweat glands. We evaluate the maximum rate of sweat ion reabsorption over skin regions, sex, and long-term exercise training by using the threshold analysis in the present study. METHODS: Ten males (2 untrained, 4 sprinters, and 4 distance runners) and 12 females (5 untrained, 4 sprinters, and 3 distance runners) conducted graded cycling exercise for 45 min at low, middle, and high exercise intensities (heart rate 100-110, 120-130, and 140-150 beats/min, respectively) for 10, 15, and 20 min, respectively, at 30 °C and 50% relative humidity. Comparisons were made between males and females and among untrained individuals, distance runners, and sprinters on the back and forearm. RESULTS: SR threshold for increasing GSC on back was significantly higher than that of forearm (P < 0.05) without any sex differences (back 0.70 ± 0.08 and 0.61 ± 0.04, forearm 0.40 ± 0.05 and 0.45 ± 0.06 mg/cm2/min for males and females, respectively). Distance runners and sprinters showed higher SR threshold for increasing GSC than that of untrained subjects on back (P < 0.05) but not on forearm (back 0.45 ± 0.06, 0.83 ± 0.06, and 0.70 ± 0.04, forearm 0.33 ± 0.04, 0.49 ± 0.02, and 0.39 ± 0.07 mg/cm2/min for untrained subjects, distance runners, and sprinters, respectively). CONCLUSION: These results suggest that the maximum sweat ion reabsorption rate on the back is higher than that of forearm without sex differences. Furthermore, exercise training in distance runners and sprinters improves the maximum sweat ion reabsorption rate on the back.

    DOI: 10.1007/s00421-017-3619-8

    PubMed

    researchmap

  • The effect of dietary nitrate supplementation on the spatial heterogeneity of quadriceps deoxygenation during heavy-intensity cycling 査読 国際誌

    Brynmor C. Breese, David C. Poole, Dai Okushima, Stephen J. Bailey, Andrew M. Jones, Narihiko Kondo, Tatsuro Amano, Shunsaku Koga

    PHYSIOLOGICAL REPORTS5 ( 14 )   2017年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    This study investigated the influence of dietary inorganic nitrate supplementation on pulmonary and muscle deoxyhemoglobin/myoglobin (i.e. deoxy [Hb+Mb]) kinetics during submaximal cycling exercise. In a randomized, placebo-controlled, cross-over study, eight healthy and physically active male subjects completed two step cycle tests at a work rate equivalent to 50% of the difference between the gas exchange threshold and peak over separate 4-day supplementation periods with NO(BR; providing 8.4mmol NO and NO depleted (placebo; PLA) beetroot juice. Pulmonary was measured breath-by-breath and time-resolved near-infrared spectroscopy was utilized to quantify absolute deoxy [Hb+Mb] and total [Hb+Mb] within the rectus femoris, vastus lateralis, and vastus medialis. There were no significant differences (P>0.05) in the primary deoxy [Hb+Mb] mean response time or amplitude between the PLA and BR trials at each muscle site. BR significantly increased the mean (three-site) end-exercise deoxy [Hb+Mb] witha tendency to increase the mean (three-site) area under the curve for total [Hb + Mb] responses . The mml:mover accent="true"VO2 slow component reduction after BR supplementation (PLA: 0.27 +/- 0.07 vs. BR: 0.23 +/- 0.08Lmin(-1), P=0.07) correlated inversely with the mean increases in deoxy [Hb+Mb] and total [Hb+Mb] across the three muscle regions (r(2)=0.62 and 0.66, P<0.05). Dietary supplementation increased O-2 diffusive conductance across locomotor muscles in association with improved mml:mover accent="true VO2 dynamics during heavy-intensity cycling transitions.

    DOI: 10.14814/phy2.13340

    Web of Science

    PubMed

    researchmap

  • Mechanisms of nicotine-induced cutaneous vasodilation and sweating in young adults: roles for KCa, KATP, and KV channels, nitric oxide, and prostanoids. 査読 国際誌

    Naoto Fujii, Jeffrey C Louie, Brendan D McNeely, Tatsuro Amano, Takeshi Nishiyasu, Glen P Kenny

    Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme42 ( 5 ) 470 - 478   2017年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We evaluated the influence of K+ channels (i.e., Ca2+-activated K+ (KCa), ATP-sensitive K+ (KATP), and voltage-gated K+ (KV) channels) and key enzymes (nitric oxide synthase (NOS) and cyclooxygenase (COX)) on nicotine-induced cutaneous vasodilation and sweating. Using intradermal microdialysis, we evaluated forearm cutaneous vascular conductance (CVC) and sweat rate in 2 separate protocols. In protocol 1 (n = 10), 4 separate sites were infused with (i) lactated Ringer (Control), (ii) 50 mmol·L-1 tetraethylammonium (KCa channel blocker), (iii) 5 mmol·L-1 glybenclamide (KATP channel blocker), and (iv) 10 mmol·L-1 4-aminopyridine (KV channel blocker). In protocol 2 (n = 10), 4 sites were infused with (i) lactated Ringer (Control), (ii) 10 mmol·L-1 Nω-nitro-l-arginine (NOS inhibitor), (iii) 10 mmol·L-1 ketorolac (COX inhibitor), or (iv) a combination of NOS+COX inhibitors. At all sites, nicotine was infused in a dose-dependent manner (1.2, 3.6, 11, 33, and 100 mmol·L-1; each for 25 min). Nicotine-induced increase in CVC was attenuated by the KCa, KATP, and KV channel blockers, whereas nicotine-induced increase in sweat rate was reduced by the KCa and KV channel blockers (P ≤ 0.05). COX inhibitor augmented nicotine-induced increase in CVC (P ≤ 0.05), which was absent when NOS inhibitor was co-administered (P > 0.05). In addition, our secondrary experiment (n = 7) demonstrated that muscarinic receptor blockade with 58 μmol·L-1 atropine sulfate salt monohydrate abolished nicotine-induced increases in CVC (1.2-11 mmol·L-1) and sweating (all doses). We show that under a normothermic resting state: (i) KCa, KATP, and KV channels contribute to nicotinic cutaneous vasodilation, (ii) inhibition of COX augments nicotinic cutaneous vasodilation likely through NOS-dependent mechanism(s), and (iii) KCa and KV channels contribute to nicotinic sweating.

    DOI: 10.1139/apnm-2016-0615

    PubMed

    researchmap

  • Individual variations in nitric oxide synthase-dependent sweating in young and older males during exercise in the heat: role of aerobic power. 査読 国際誌

    Tatsuro Amano, Naoto Fujii, Jeffrey C Louie, Robert D Meade, Glen P Kenny

    Physiological reports5 ( 6 )   2017年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We evaluated the association between aerobic power (defined by peak oxygen consumption; VO2peak) and the contribution of nitric oxide synthase (NOS) to the sweating response in young and older individuals during exercise in the heat. Data from 44 young (24 ± 1 years) and 48 older (61 ± 2 years) males with mean VO2peak of 47.8 ± 2.4 (range, 28.0-62.3) and 39.1 ± 2.3 (range, 26.4-55.7) mLO2 kg-1 min-1, respectively, were compiled from our prior studies. Participants performed two 15- to 30-min bouts of exercise at a fixed rate of metabolic heat production of 400 or 500 W, each separated by 15-20 min recovery in the heat (35°C, relative humidity of 20%). Forearm sweat rate (ventilated capsule technique) was measured at two skin sites that were continuously and simultaneously administered with lactated Ringers solution (Control) or 10 mmol/L N
    G
    -nitro-L-arginine methyl ester (L-NAME, nonselective NOS inhibitor) via intradermal microdialysis. Sweat rate during the final 5 min of each exercise bout was lower with L-NAME compared to the Control in both groups (all P < 0.05). The magnitude of the attenuation in sweat rate induced by L-NAME compared to the Control was not correlated with VO2peak (all P ≥ 0.46) while this attenuation was negatively correlated with the sweat rate at the Control in both groups and in both exercise bouts (all P < 0.01, R ≤ -0.43). These results suggest that NOS-dependent sweating is not associated with aerobic power per se, while it becomes evident in individuals who produce larger sweat rates during exercise irrespective of age.

    DOI: 10.14814/phy2.13208

    PubMed

    researchmap

  • Sweating responses to isometric hand-grip exercise and forearm muscle metaboreflex in prepubertal children and elderly 査読 国際誌

    Tatsuro Amano, Seiko Kai, Michi Nakajima, Tomoko Ichinose-Kuwahara, Nicola Gerrett, Narihiko Kondo, Yoshimitsu Inoue

    EXPERIMENTAL PHYSIOLOGY102 ( 2 ) 214 - 227   2017年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    The purpose of the present study was to investigate sweating responses to isometric hand-grip (IH) exercise andmuscle metaboreflex in prepubertal children and the elderly. In hot conditions (ambient temperature, 35 degrees C; relative humidity, 45%), 13 healthy young adults, 10 prepubertal children and 10 elderly subjects (aged 20.4 +/- 1.2, 11.4 +/- 0.5 and 63.5 +/- 3.1 years, respectively) repeated a three hand-grip exercise protocol that consisted of 1 min IH exercise at 15, 30 or 45% of maximal voluntary contraction (MVC) followed by 2 min postexercise forearm occlusion. Local sweat rates (SRs) on the forehead, chest, forearm, thigh and palm were continuously measured (ventilated capsule method). The forehead SR in prepubertal children during IH exercise at 45% MVC was significantly lower than that of young adults (0.26 +/- 0.22 and 0.08 +/- 0.15 mg cm(-2) min(-1) for young adults and children, respectively; P < 0.05) but not of the elderly at any exercise intensities. The SR on the chest (0.22 +/- 0.22 and -0.01 +/- 0.05 mg cm(-2) min(-1) for young adults and children, respectively), forearm (0.14 +/- 0.12 and 0.03 +/- 0.04 mg cm(-2) min(-1)) and thigh (0.13 +/- 0.10 and 0.02 +/- 0.03 mg cm(-2) min(-1)) during postexercise occlusion at 45% MVC was significantly lower in children than in young adults (P < 0.05). Elderly subjects showed a significantly lower SR on the forearm (0.04 +/- 0.04 and 0.01 +/- 0.02 mg cm(-2) min(-1) for young adults and elderly, respectively) and thigh (0.07 +/- 0.07 and 0.01 +/- 0.03 mg cm(-2) min(-1)) at 15% MVC and on the thigh at 45% MVC (0.13 +/- 0.10 and 0.04 +/- 0.04 mg cm-2 min-1) during postexercise occlusion compared with young adults (P< 0.05). These results suggest that sweating responses to IH exercise and muscle metaboreflex were underdeveloped in prepubertal children and that ageing attenuates the response to the muscle metaboreflex in a way that is not consistent across the body.

    DOI: 10.1113/EP085908

    Web of Science

    PubMed

    researchmap

  • Intradermal administration of endothelin-1 attenuates endothelium-dependent and -independent cutaneous vasodilation via Rho kinase in young adults 査読

    Naoto Fujii, Tatsuro Amano, Lyra Halili, Jeffrey C. Louie, Sarah Y. Zhang, Brendan D. McNeely, Glen P. Kenny

    AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY312 ( 1 ) R23 - R30   2017年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    We recently showed that intradermal administration of endothelin-1 diminished endothelium-dependent and -independent cutaneous vasodilation. We evaluated the hypothesis that Rho kinase may be a mediator of this response. We also sought to evaluate if endothelin-1 increases sweating. In 12 adults (25 +/- 6 yr), we measured cutaneous vascular conductance (CVC) and sweating during 1) endothelium-dependent vasodilation induced via administration of incremental doses of methacholine (0.25, 5, 100, and 2,000 mM each for 25 min) and 2) endothelium-independent vasodilation induced via administration of 50 mM sodium nitroprusside (20-25 min). Responses were evaluated at four skin sites treated with either 1) lactated Ringer solution (Control), 2) 400 nM endothelin-1, 3) 3 mM HA-1077 (Rho kinase inhibitor), or 4) endothelin-1 + HA-1077. Pharmacological agents were intradermally administered via micro-dialysis. Relative to the Control site, endothelin-1 attenuated endothelium-dependent vasodilation (CVC at 2,000 mM methacholine, 80 +/- 10 vs. 56 +/- 15% max, P < 0.01); however, this response was not detected when the Rho kinase inhibitor was simultaneously administered (CVC at 2,000 mM methacholine for Rho kinase inhibitor vs. endothelin-1 + Rho kinase inhibitor sites: 73 +/- 9 vs. 72 +/- 11% max, P > 0.05). Endothelium-independent vasodilation was attenuated by endothelin-1 compared with the Control site (CVC, 92 +/- 13 vs. 70 +/- 14% max, P < 0.01). However, in the presence of Rho kinase inhibition, endothelin-1 did not affect endotheliumin-dependent vasodilation (CVC at Rho kinase inhibitor vs. endothelin-1 + Rho kinase inhibitor sites: 81 +/- 9 vs. 86 +/- 10% max, P > 0.05). There was no between-site difference in sweating throughout (P > 0.05). We show that in young adults, Rho kinase is an important mediator of the endothelin-1-mediated attenuation of endothelium-dependent and -independent cutaneous vasodilation, and that endothelin-1 does not increase sweating.

    DOI: 10.1152/ajpregu.00368.2016

    Web of Science

    researchmap

  • Greater (V)over dotO(2peak) is correlated with greater skeletal muscle deoxygenation amplitude and hemoglobin concentration within individual muscles during ramp-incremental cycle exercise 査読

    Dai Okushima, David C. Poole, Thomas J. Barstow, Harry B. Rossiter, Narihiko Kondo, T. Scott Bowen, Tatsuro Amano, Shunsaku Koga

    PHYSIOLOGICAL REPORTS4 ( 23 )   2016年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    It is axiomatic that greater aerobic fitness ((V)over dotO(2peak)) derives from enhanced perfusive and diffusive O-2 conductances across active muscles. However, it remains unknown how these conductances might be reflected by regional differences in fractional O-2 extraction (i.e., deoxy [Hb+Mb] and tissue O-2 saturation [StO2]) and diffusive O-2 potential (i.e., total[Hb+Mb]) among muscles spatially heterogeneous in blood flow, fiber type, and recruitment (vastus lateralis, VL; rectus femoris, RF). Using quantitative time-resolved near-infrared spectroscopy during ramp cycling in 24 young participants ((V)over dotO(2peak) range: similar to 37.4-66.4 mL kg(-1) min(-1)), we tested the hypotheses that (1) deoxy [Hb+Mb] and total[Hb+Mb] at (V)over dotO(2peak) would be positively correlated with (V)over dotO(2peak) in both VL and RF muscles; (2) the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) during submaximal exercise would not differ among subjects differing in (V)over dotO(2peak). Peak deoxy [Hb+Mb] and StO2 correlated with (V)over dotO(2peak) for both VL (r = 0.44 and -0.51) and RF (r = 0.49 and -0.49), whereas for total[Hb+Mb] this was true only for RF (r = 0.45). Baseline deoxy[Hb+Mb] and StO2 correlated with (V)over dotO(2peak) only for RF (r = -0.50 and 0.54). In addition, the deoxy[Hb+Mb] slopes were not affected by aerobic fitness. In conclusion, while the pattern of deoxygenation (the deoxy[Hb+Mb] slopes) did not differ between fitness groups the capacity to deoxygenate [Hb+Mb] (index of maximal fractional O-2 extraction) correlated significantly with (V)over dotO(2peak) in both RF and VL muscles. However, only in the RF did total [Hb+Mb] (index of diffusive O-2 potential) relate to fitness.

    DOI: 10.14814/phy2.13065

    Web of Science

    researchmap

  • Sex differences in age-related changes on peripheral warm and cold innocuous thermal sensitivity 査読

    Yoshimitsu Inoue, Nicola Gerrett, Tomoko Ichinose-Kuwahara, Yasue Umino, Saeko Kiuchi, Tatsuro Amano, Hiroyuki Ueda, George Havenith, Narihiko Kondo

    PHYSIOLOGY & BEHAVIOR164   86 - 92   2016年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Cutaneous thermal sensitivity to a warm and cold stimulus was compared amongst 12 older (OF, 65.2 +/- 1.0 year) and 29 younger (YF, 21.6 +/- 0.2 years) female participants, and 17 older (OM, 66.2 +/- 1.5 years) and 13 younger (YM, 21.2 +/- 0.4 years) male participants to examine the effects of ageing and sex. In a neutral condition (27.5 degrees C, 50% RH) during rest, warm and cold thermal sensitivity was measured on eight body regions (forehead, chest, back, forearm, hand, thigh, calf, and foot). Using the method of limits, a thermal stimulator was applied to the skin at an adapting temperature and either increased or decreased at a constant rate (0.3 degrees C/s) until the participants detected the temperature with a push button. Thermal sensitivity declined with ageing to both a cold (older: 1468.6 +/- 744.7 W/m(2), younger: 869.8 +/- 654.7 W/m(2), p < 0.001) and warm (older: 2127.0 +/- 12083 W/m(2), younger: 1301.7 +/- 1055.2 W/m(2), p < 0.001) innocuous stimulus. YF and OF were more sensitive than YM and OM to both a warm and cold stimulus (p < 0.05). There was no interaction between age and sex suggesting that whilst thermal sensitivity decreases with age the decrease is similar between the sexes (p > 0.05). There was an interaction between temperatures, age and location and it seemed that cold thermal sensitivity was more homogenous for young and older participants however warm thermal sensitivity was more heterogeneous especially in the younger participants (p < 0.05). Although the pattern was not similar between ages or sexes it was evident that the forehead was the most sensitive region to a warm and cold stimulus. Interestingly the decline in sensitivity observed with ageing occurred for all locations but was attenuated at the forehead in both males and females (p > 0.05). (C) 2016 Elsevier Inc All rights reserved.

    DOI: 10.1016/j.physbeh.2016.05.045

    Web of Science

    researchmap

  • Effect of stride frequency on thermoregulatory responses during endurance running in distance runners 査読

    Tatsuro Amano, Masaki Ishitobi, Yukio Ogura, Yoshimitsu Inoue, Shunsaku Koga, Takeshi Nishiyasu, Narihiko Kondo

    JOURNAL OF THERMAL BIOLOGY61   61 - 66   2016年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    Changing stride frequency may influence oxygen uptake and heart rate during running as a function of running economy and central command. This study investigated the influence of stride frequency manipulation on thermoregulatory responses during endurance running. Seven healthy endurance runners ran on a treadmill at a velocity of 15 km/h for 60 min in a controlled environmental chamber (ambient temperature 27 degrees C and relative humidity 50%), and stride frequency was manipulated. Stride frequency was intermittently manipulated by increasing and decreasing frequency by 10% from the pre-determined preferred frequency. These periods of increase or decrease were separated by free frequency running in the order of free stride frequency, stride frequency manipulation (increase or decrease), free stride frequency, and stride frequency manipulation (increase or decrease) for 15 min each. The increased and decreased stride frequencies were 110% and 91% of the free running frequency, respectively (196 +/- 6, 162 +/- 5, and 178 +/- 5 steps/min, respectively, P < 0.01). Compared to the control, stride frequency manipulation did not affect rectal temperature, heart rate, or the rate of perceived exhaustion during running. Whole-body sweat loss increased significantly when stride frequency was manipulated (1.48 +/- 0.11 and 1.57 +/- 0.11 kg for control and manipulated stride frequencies, respectively, P < 0.05), but stride frequency had a small effect on sweat loss overall (Cohen's d=0.31). A higher mean skin temperature was also observed under mixed frequency conditions compared to that in the control (P < 0.05). While the precise mechanisms underlying these changes remain unknown (e.g. running economy or central command), our results suggest that manipulation of stride frequency does not have a large effect on sweat loss or other physiological variables, but does increase mean skin temperature during endurance running. (C) 2016 Published by Elsevier Ltd.

    DOI: 10.1016/j.jtherbio.2016.08.005

    Web of Science

    researchmap

  • Influence of forearm muscle metaboreceptor activation on sweating and cutaneous vascular responses during dynamic exercise 査読

    Tatsuro Amano, Masashi Ichinose, Yoshimitsu Inoue, Takeshi Nishiyasu, Shunsaku Koga, Glen P. Kenny, Narihiko Kondo

    AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY310 ( 11 ) R1332 - R1339   2016年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    We examined whether the sustained activation of metaboreceptor in forearm during cycling exercise can modulate sweating and cutaneous vasodilation. On separate days, 12 young participants performed a 1.5-min isometric handgrip exercise at 40% maximal voluntary contraction followed by 1) 9-min forearm ischemia (Occlusion, to activate metaboreceptor) or 2) no ischemia (Control) in thermoneutral conditions (27(circle)C, 50%) with mean skin temperature clamped at 34(circle)C. Thirty seconds after the handgrip exercise, participants cycled for 13.5 min at 40% VO2 max. For Occlusion, forearm ischemia was maintained for 9 min followed by no ischemia thereafter. Local sweat rate (SR, ventilated capsule) and cutaneous vascular conductance (CVC, laser-Doppler perfusion units/ mean arterial pressure) on the contralateral nonischemic arm as well as esophageal and skin temperatures were measured continuously. The period of ischemia in the early stages of exercise increased SR (+ 0.03 mg(.)cm (-2) (.) min (-1), P < 0.05) but not CVC (P > 0.05) above Control levels. No differences were measured in the esophageal temperature at which onset of sweating (Control 37.19 +/- 0.09 vs. Occlusion 37.07 +/- 0.09(circle)C) or CVC (Control 37.21 +/- 0.08 vs. Occlusion 37.08 +/- 0.10(circle)C) as well as slopes for these responses (all P > 0.05). However, a greater elevation in SR occurred thereafter such that SR was significantly elevated at the end of the ischemic period relative to Control (0.37 +/- 0.05 vs. 0.23 +/- 0.05 mg(.)cm (-2.)min (- 1), respectively, P < 0.05) despite no differences in esophageal temperature. We conclude that the activation of forearm muscle metaboreceptor can modulate sweating, but not CVC, during cycling exercise without affecting the core temperature-SR relationship.

    DOI: 10.1152/ajpregu.00545.2015

    Web of Science

    researchmap

  • Determination of the maximum rate of eccrine sweat glands' ion reabsorption using the galvanic skin conductance to local sweat rate relationship 査読

    Tatsuro Amano, Nicola Gerrett, Yoshimitsu Inoue, Takeshi Nishiyasu, George Havenith, Narihiko Kondo

    EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY116 ( 2 ) 281 - 290   2016年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Purpose The purpose of the present study was to develop and describe a simple method to evaluate the rate of ion reabsorption of eccrine sweat glands in human using the measurement of galvanic skin conductance (GSC) and local sweating rate (SR). This purpose was investigated by comparing the SR threshold for increasing GSC with following two criteria of sweat ion reabsorption in earlier studies such as (1) the SR threshold for increasing sweat ion was at approximately 0.2-0.5 mg/cm(2)/min and (2) exercise heat acclimation improved the sweat ion reabsorption ability and would increase the criteria 1.Methods Seven healthy non-heat-acclimated male subjects received passive heat treatment both before and after 7 days of cycling in hot conditions (50 % maximum oxygen uptake, 60 min/day, ambient temperature 32 degrees C, and 50 % relative humidity).Results Subjects became partially heat-acclimated, as evidenced by the decreased end-exercise heart rate (p < 0.01), rate of perceived exhaustion (p < 0.01), and oesophageal temperature (p = 0.07), without alterations in whole-body sweat loss, from the first to the last day of training. As hypothesized, we confirmed that the SR threshold for increasing GSC was near the predicted SR during passive heating before exercise heat acclimation, and increased significantly after training (0.19 +/- 0.09-0.32 +/- 0.10 mg/cm(2)/min, p < 0.05).Conclusions The reproducibility of sweat ion reabsorption by the eccrine glands in the present study suggests that the relationship between GSC and SR can serve as a new index for assessing the maximum rate of sweat ion reabsorption of eccrine sweat glands in humans.

    DOI: 10.1007/s00421-015-3275-9

    Web of Science

    researchmap

  • The Spatial Distribution of Absolute Skeletal Muscle Deoxygenation During Ramp-Incremental Exercise Is Not Influenced by Hypoxia 査読

    T. Scott Bowen, Shunsaku Koga, Tatsuro Amano, Narihiko Kondo, Harry B. Rossiter

    OXYGEN TRANSPORT TO TISSUE XXXVII876   19 - 26   2016年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Time-resolved near-infrared spectroscopy (TRS-NIRS) allows absolute quantitation of deoxygenated haemoglobin and myoglobin concentration ([HHb]) in skeletal muscle. We recently showed that the spatial distribution of peak [HHb] within the quadriceps during moderate-intensity cycling is reduced with progressive hypoxia and this is associated with impaired aerobic energy provision. We therefore aimed to determine whether reduced spatial distribution of skeletal muscle [HHb] was associated with impaired aerobic energy transfer during exhaustive ramp-incremental exercise in hypoxia. Seven healthy men performed ramp-incremental cycle exercise (20 W/min) to exhaustion at 3 fractional inspired O-2 concentrations (FIO2): 0.21, 0.16, 0.12. Pulmonary O-2 uptake ((V) over dot O-2) was measured using a flow meter and gas analyser system. Lactate threshold (LT) was estimated non-invasively. Absolute muscle deoxygenation was quantified by multichannel TRS-NIRS from the rectus femoris and vastus lateralis (proximal and distal regions). (V) over dotO(2peak) and LT were progressively reduced (p< 0.05) with hypoxia. There was a significant effect (p< 0.05) of FIO2 on [HHb] at baseline, LT, and peak. However the spatial variance of [HHb] was not different between FIO2 conditions. Peak total Hb ([Hb(tot)]) was significantly reduced between FIO2 conditions (p< 0.001). There was no association between reductions in the spatial distribution of skeletal muscle [HHb] and indices of aerobic energy transfer during ramp-incremental exercise in hypoxia. While regional [HHb] quantified by TRS-NIRS at exhaustion was greater in hypoxia, the spatial distribution of [HHb] was unaffected. Interestingly, peak [Hb(tot)] was reduced at the tolerable limit in hypoxia implying a vasodilatory reserve may exist in conditions with reduced FIO2.

    DOI: 10.1007/978-1-4939-3023-4_2

    Web of Science

    researchmap

  • Modulation of muscle metaboreceptor activation upon sweating and cutaneous vascular responses to rising core temperature in humans 査読

    Tatsuro Amano, Masashi Ichinose, Yoshimitsu Inoue, Takeshi Nishiyasu, Shunsaku Koga, Narihiko Kondo

    AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY308 ( 12 ) R990 - R997   2015年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    The present study investigated the role of muscle metaboreceptor activation on human thermoregulation by measuring core temperature thresholds and slopes for sweating and cutaneous vascular responses during passive heating associated with central and peripheral mechanisms. Six male and eight female subjects inserted their lower legs into hot water (43 degrees C) while wearing a water perfusion suit on the upper body (34 degrees C). One minute after immersion, an isometric handgrip exercise-40% of maximum voluntary contraction-was conducted for 1.5 min in both control and experimental conditions, while postexercise occlusion was performed in the experimental condition only for 9 min. The postexercise forearm occlusion during passive heating consistently stimulated muscle metaboreceptors, as implicated by significantly elevated mean arterial blood pressure throughout the experimental period (P < 0.05). Stimulation of the forearm muscle metaboreceptors increased sweating and cutaneous vascular responses during passive heating, and was associated with significant reductions in esophageal temperature threshold of sweating and cutaneous vasodilation (Delta threshold, sweating: 0.33 +/- 0.05 and 0.16 +/- 0.04 degrees C, cutaneous vascular conductance: 0.38 +/- 0.08 and 0.16 +/- 0.05 degrees C for control and experimental groups, respectively, P < 0.05). The slopes of these responses were not different between the conditions. These results suggest that muscle metaboreceptor activation in the forearm accelerates sweating and cutaneous vasodilation during passive heating associated with a reduction in core temperature thresholds and may be related to central mechanisms controlling heat loss responses.

    DOI: 10.1152/ajpregu.00005.2015

    Web of Science

    researchmap

  • Influence of exercise training with thigh compression on heat-loss responses 査読

    T. Amano, Y. Inoue, S. Koga, T. Nishiyasu, N. Kondo

    SCANDINAVIAN JOURNAL OF MEDICINE & SCIENCE IN SPORTS25   173 - 182   2015年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-BLACKWELL  

    We investigated the effect of thigh compression, which accelerates activation of central command and muscle metabo- and mechanoreceptors, on the adaptation of sweating and cutaneous vascular responses during exercise heat acclimation. Nine non-heat-acclimated male subjects were acclimated to heat (32 degrees C and 50% RH) while cycling [50% of maximum oxygen uptake ( , acetylcholine-induced forearm sweating rate (iontophoresis), and mean sweating and cutaneous vascular responses on the forehead, chest, and forearm (SRmean and CVCmean) during passive heating were evaluated before and after training. Training significantly increased while did not affect acetylcholine-induced sweating rates in either group. Training significantly decreased T-b thresholds for SRmean and CVCmean during passive heating without the alternations of sensitivities in both groups. Although SRmean during passive heating at a given T-b was not improved in either group, CVCmean was significantly (P<0.05) attenuated after exercise training only in experimental group. Our results indicate that thigh cuff compression during exercise heat acclimation does not influence adaptation of the sweating response but attenuate cutaneous vasodilation.

    DOI: 10.1111/sms.12365

    Web of Science

    researchmap

  • Changes in whole tissue heme concentration dissociates muscle deoxygenation from muscle oxygen extraction during passive head-up tilt 査読

    Alessandra Adami, Shunsaku Koga, Narihiko Kondo, Daniel T. Cannon, John M. Kowalchuk, Tatsuro Amano, Harry B. Rossiter

    JOURNAL OF APPLIED PHYSIOLOGY118 ( 9 ) 1091 - 1099   2015年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    Skeletal muscle deoxygenated hemoglobin and myoglobin concentration ([HHb]), assessed by near-infrared spectroscopy (NIRS), is commonly used as a surrogate of regional O-2 extraction (reflecting the O-2 delivery-to-consumption ratio, (Q) over dot/(V) over dot O-2). However, [HHb] change (Delta[HHb]) is also influenced by capillary-venous heme concentration, and/or small blood vessel volume (reflected in total heme; [THb]). We tested the hypotheses that Delta[HHb] is associated with O-2 extraction, and insensitive to [THb], over a wide range of (Q) over dot/(V) over dot O-2 elicited by passive head-up tilt (HUT; 10-min, 15 degrees increments, between -10 degrees and 75 degrees). Steady-state common femoral artery blood flow (FBF) was measured by echo-Doppler, and time-resolved NIRS measured [HHb] and [THb] of vastus lateralis (VL) and gastrocnemius (GS) in 13 men. EMG confirmed muscles were inactive. During HUT in VL [HHb] increased linearly (57 +/- 10 to 101 +/- 16 mu M; P < 0.05 above 15 degrees) and was associated (r(2) similar to 0.80) with the reduction in FBF (618 +/- 75 ml/min at 0 degrees to 268 +/- 52 ml/min at 75 degrees; P < 0.05 above 30 degrees) and the increase in [THb] (228 +/- 30 vs. 252 +/- 32 mu M; P < 0.05 above 15 degrees). GS response was qualitatively similar to VL. However, there was wide variation within and among individuals, such that the overall limits of agreement between Delta[HHb] and Delta FBF ranged from -35 to + 19% across both muscles. Neither knowledge of tissue O-2 saturation nor vascular compliance could appropriately account for the Delta[HHb]- FBF dissociation. Thus, under passive tilt, [HHb] is influenced by (Q) over dot/(V) over dot O-2, as well as microvascular hematocrit and/or tissue blood vessel volume, complicating its use as a noninvasive surrogate for muscle microvascular O-2 extraction.

    DOI: 10.1152/japplphysiol.00918.2014

    Web of Science

    researchmap

  • Muscle O-2 extraction reserve during intense cycling is site-specific 査読

    Matthew D. Spencer, Tatsuro Amano, Narihiko Kondo, John M. Kowalchuk, Shunsaku Koga

    JOURNAL OF APPLIED PHYSIOLOGY117 ( 10 ) 1199 - 1206   2014年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    The present study compared peak muscle deoxygenation ([HHb](peak)) responses at three quadriceps sites during occlusion (OCC), ramp incremental (RI), severe-(SVR) and moderate-intensity (MOD) exercise. Seven healthy men (25 +/- 4 yr) each completed a stationary cycling RI (20 W/min) test to determine [HHb](peak) [at distal and proximal vastus lateralis (VLD and VLP) and rectus femoris (RF)], peak (V) over dotO(2) ((V) over dotO(2peak)), gas exchange threshold (GET), and peak work rate (WRpeak). Subjects also completed MOD (WR = 80% GET) and SVR exercise (WR corresponding to 120% (V) over dotO(2peak)) with absolute [HHb] (quantified by multichannel, time-resolved near-infrared spectroscopy) and pulmonary VO2 ((V) over dotO(2p)) monitored continuously. Additionally, [HHb] and total hemoglobin ([Hb](tot)) were monitored at rest and during subsequent OCC (250 mmHg). Site-specific adipose tissue thickness was assessed (B-mode ultrasound), and its relationship with resting [Hb](tot) was used to correct absolute [HHb]. For VLD and RF, [HHb](peak) was higher (P < 0.05) during OCC (VLD = 111 +/- 38, RF = 114 +/- 26 mu M) than RI (VLD 64 +/- 14, RF = 85 +/- 20) and SVR (VLD = 63 +/- 13, RF = 81 +/- 18). [HHb](peak) was similar (P > 0.05) across these conditions at the VLP (OCC = 67 +/- 17, RI = 69 +/- 17, SVR = 63 +/- 17 mu M). [HHb] peaked and then decreased prior to exercise cessation during SVR at all three muscle sites. [HHb](peak) during MOD was consistently lower than other conditions at all sites. A "[HHb] reserve" exists during intense cycling at the VLD and RF, likely implying either sufficient blood flow to meet oxidative demands or insufficient diffusion time for complete equilibration. In VLP this [HHb] reserve was absent, suggesting that a critical PO2 may be challenged during intense cycling.

    DOI: 10.1152/japplphysiol.00060.2014

    Web of Science

    researchmap

  • Sweating response to passive stretch of the calf muscle during activation of forearm muscle metaboreceptors in heated humans 査読

    Tatsuro Amano, Masashi Ichinose, Takeshi Nishiyasu, Yoshimitsu Inoue, Shunsaku Koga, Mikio Miwa, Narihiko Kondo

    AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY306 ( 10 ) R728 - R734   2014年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    Activation of muscle metaboreceptors and mechanoreceptors has been shown to independently influence the sweating response, while their integrative control effects remain unclear. We examined the sweating response when the two muscle receptors are concurrently activated in different limbs, as well as the blood pressure response. In total, 27 young males performed passive calf muscle stretches (muscle mechanoreceptor activation) for 30 s in a semisupine position with and without postisometric handgrip exercise muscle ischemia (PEMI, muscle metaboreceptor activation) at exercise intensities of 35 and 50% of maximum voluntary contraction (MVC) under hot conditions (ambient temperature, 35 degrees C, relative humidity, 50%). Passive calf muscle stretching alone increased the mean sweating rate significantly on the forehead, chest, and thigh (SRmean) and mean arterial blood pressure (MAP), but not the heart rate (HR), from prestretching levels by 0.04 +/- 0.01 mg center dot cm(2)center dot min(-1), 4.0 +/- 1.3 mmHg (P < 0.05), and -1.0 +/- 0.5 beats/min (P > 0.05), respectively. The SRmean and MAP during PEMI were significantly higher than those at rest. The passive calf muscle stretch during PEMI increased MAP significantly by 3.4 +/- 1.0 and 2.0 +/- 0.7 mmHg for 35 and 50% of MVC, respectively (P < 0.05), but not that of SRmean or HR at either exercise intensity. These results suggest that sweating and blood pressure responses to concurrent activation of the two muscle receptors in different limbs differ and that the influence of calf muscle mechanoreceptor activation alone on the sweating response disappears during forearm muscle metaboreceptor activation.

    DOI: 10.1152/ajpregu.00515.2013

    Web of Science

    researchmap

  • Slowed oxygen uptake kinetics in hypoxia correlate with the transient peak and reduced spatial distribution of absolute skeletal muscle deoxygenation 査読

    T. Scott Bowen, Harry B. Rossiter, Alan P. Benson, Tatsuro Amano, Narihiko Kondo, John M. Kowalchuk, Shunsaku Koga

    EXPERIMENTAL PHYSIOLOGY98 ( 11 ) 1585 - 1596   2013年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    It remains unclear whether an overshoot in skeletal muscle deoxygenation (HHb; reflecting a microvascular kinetic mismatch of O-2 delivery to consumption) contributes to the slowed adjustment of oxidative energy provision at the onset of exercise. We progressively reduced the fractional inspired O-2 concentration (F-I,(O2)) to investigate the relationship between slowed pulmonary O-2 uptake ((V) over dot(O2)) kinetics and the dynamics and spatial distribution of absolute [HHb]. Seven healthy men performed 8 min cycling transitions during normoxia (F-I,(O2) = 0.21), moderate hypoxia (F-I,(O2) = 0.16) and severe hypoxia (F-I,(O2) = 0.12). (V) over dot(O2) uptake was measured using a flowmeter and gas analyser system. Absolute [HHb] was quantified by multichannel, time-resolved near-infrared spectroscopy from the rectus femoris and vastus lateralis (proximal and distal regions), and corrected for adipose tissue thickness. The phase II. (V) over dot(O2) time constant was slowed (P < 0.05) as F-I,(O2) decreased (normoxia, 17 +/- 3 s; moderate hypoxia, 22 +/- 4 s; and severe hypoxia, 29 +/- 9 s). The [HHb] overshoot was unaffected by hypoxia, but the transient peak [HHb] increased with the reduction in F-I,(O2) (P < 0.05). Slowed. (V) over dot(O2) kinetics in hypoxia were positively correlated with increased peak [HHb] in the transient (r(2) = 0.45; P < 0.05), but poorly related to the [HHb] overshoot. A reduction of spatial heterogeneity in peak [HHb] was inversely correlated with slowed. (V) over dot(O2) kinetics (r(2) = 0.49; P < 0.05). These data suggest that aerobic energy provision at the onset of exercise may be limited by the following factors: (i) the absolute ratio (i. e. peak [HHb]) rather than the kinetic ratio (i. e. [HHb] overshoot) of microvascular O-2 delivery to consumption; and (ii) a reduced spatial distribution in the ratio of microvascular O-2 delivery to consumption across the muscle.

    DOI: 10.1113/expphysiol.2013.073270

    Web of Science

    researchmap

  • Characteristics of sweating responses and peripheral sweat gland function during passive heating in sprinters 査読

    Tatsuro Amano, Shunsaku Koga, Yoshimitsu Inoue, Takeshi Nishiyasu, Narihiko Kondo

    EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY113 ( 8 ) 2067 - 2075   2013年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    The purpose of this study was to compare sweating function in sprinters who have trained for several years with untrained subjects and trained endurance runners. Two separate experiments were conducted. Nine sprinters, eight untrained men, and nine distance runners ( 50.9 +/- A 1.4, 38.2 +/- A 1.8, and 59.1 +/- A 1.2 mL/kg/min, respectively; P < 0.05) were passively heated for 50 min (Experiment 1), and ten sprinters, 11 untrained men and nine distance runners (similar levels compared with Experiment 1 in each group) had their sweat gland capacity assessed based on acetylcholine-induced sweating rate (SR) (Experiment 2). The slope of the mean non-glabrous SR plotted against change in mean body temperature during passive heating did not differ significantly between sprinters and untrained men (1.21 +/- A 0.10 and 0.97 +/- A 0.12 mg cm(-2)/min/A degrees C, respectively); in contrast, compared with untrained men, distance runners exhibited a significantly greater slope (1.42 +/- A 0.11 mg cm(-2)/min/A degrees C, P < 0.05). The mean body temperature threshold for SR was not significantly different among the groups. Acetylcholine-induced SR did not differ significantly between sprinters and untrained men, whereas distance runners showed a significantly higher induced SR compared with untrained men. The sweating function was not improved in sprinters who have trained 2-3 h/day, 5 days/week, for at least 3 years compared with untrained men, although the was markedly greater in sprinters. Thus, there is a case that daily training was not sufficient to improve sweating function in sprinters relative to those in distance runners.

    DOI: 10.1007/s00421-013-2641-8

    Web of Science

    researchmap

  • The relationship between muscle deoxygenation and activation in different muscles of the quadriceps during cycle ramp exercise 査読

    Lisa M. K. Chin, John M. Kowalchuk, Thomas J. Barstow, Narihiko Kondo, Tatsuro Amano, Tomoyuki Shiojiri, Shunsaku Koga

    JOURNAL OF APPLIED PHYSIOLOGY111 ( 5 ) 1259 - 1265   2011年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    Chin LM, Kowalchuk JM, Barstow TJ, Kondo N, Amano T, Shiojiri T, Koga S. The relationship between muscle deoxygenation and activation in different muscles of the quadriceps during cycle ramp exercise. J Appl Physiol 111: 1259-1265, 2011. First published July 28, 2011; doi:10.1152/japplphysiol.01216.2010.-The relationship between muscle deoxygenation and activation was examined in three different muscles of the quadriceps during cycling ramp exercise. Seven young male adults (24 +/- 3 yr; mean +/- SD) pedaled at 60 rpm to exhaustion, with a work rate (WR) increase of 20 W/min. Pulmonary oxygen uptake was measured breath-by-breath, while muscle deoxygenation (HHb) and activity were measured by time-resolved near-infrared spectroscopy (NIRS) and surface electromyography (EMG), respectively, at the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM). Muscle deoxygenation was corrected for adipose tissue thickness and normalized to the amplitude of the HHb response, while EMG signals were integrated (iEMG) and normalized to the maximum iEMG determined from maximal voluntary contractions. Muscle deoxygenation and activation were then plotted as a percentage of maximal work rate (%WR(max)). The HHb response for all three muscle groups was fitted by a sigmoid function, which was determined as the best fitting model. The c/d parameter for the sigmoid fit (representing the %WR(max) at 50% of the total amplitude of the HHb response) was similar between VL (47 +/- 12% WR(max)) and VM (43 +/- 11% WR(max)), yet greater (P < 0.05) for RF (65 +/- 13% WR(max)), demonstrating a "right shift" of the HHb response compared with VL and VM. The iEMG also showed that muscle activation of the RF muscle was lower (P < 0.05) compared with VL and VM throughout the majority of the ramp exercise, which may explain the different HHb response in RF. Therefore, these data suggest that the sigmoid function can be used to model the HHb response in different muscles of the quadriceps; however, simultaneous measures of muscle activation are also needed for the HHb response to be properly interpreted during cycle ramp exercise.

    DOI: 10.1152/japplphysiol.01216.2010

    Web of Science

    researchmap

  • Changes in eccrine sweating on the glabrous skin of the palm and finger during isometric exercise. 査読 国際誌

    T Amano, Y Kato, C A Machado-Moreira, N A Taylor, Y Inoue, T Nishiyasu, N Kondo

    Acta physiologica (Oxford, England)202 ( 4 ) 649 - 55   2011年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    AIM: The goals of this study were to investigate changes in the sweating and cutaneous vascular responses on the palm and the volar aspect of the index finger during sustained static exercise of increasing intensity and to determine whether the former can be attributed to altered sweat gland activity. METHODS: Five male and five female subjects performed maximal voluntary handgrip contractions (MVC: right hand) for 60 s at 20, 35 and 50% MVC (ambient temperature 25 °C, relative humidity 50%). RESULTS: The sweat rate and the number of activated sweat glands on the non-exercised hand showed intensity-dependent increases (P < 0.05). At 35 and 50% MVC, finger sweat secretion was significantly higher than on the palm, which was primarily associated with the number of activated sweat glands (P < 0.05). In addition, there was a marked simultaneous decrease in the cutaneous vascular conductance for the finger at 35 and 50% MVC (P < 0.05), but not for the palm. CONCLUSION: Our results suggest that a difference exists between intensity-dependent increases of sudomotor responses within more than one glabrous skin site. Specifically, markedly greater sweating occurs on the volar finger than on the palmar surface during sustained static exercise. These differences in sweat rate mainly resulted from changes in the number of activated sweat glands. In addition, intra-segment variations in cutaneous blood flow on the glabrous hand are shown.

    DOI: 10.1111/j.1748-1716.2011.02299.x

    PubMed

    researchmap

  • Sweating responses and the muscle metaboreflex under mildly hyperthermic conditions in sprinters and distance runners 査読

    Tatsuro Amano, Masashi Ichinose, Shunsaku Koga, Yoshimitsu Inoue, Takeshi Nishiyasu, Narihiko Kondo

    JOURNAL OF APPLIED PHYSIOLOGY111 ( 2 ) 524 - 529   2011年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER PHYSIOLOGICAL SOC  

    Amano T, Ichinose M, Koga S, Inoue Y, Nishiyasu T, Kondo N. Sweating responses and the muscle metaboreflex under mildly hyperthermic conditions in sprinters and distance runners. J Appl Physiol 111: 524-529, 2011. First published June 9, 2011; doi:10.1152/japplphysiol.00212.2011.-To investigate the effects of different training methods on nonthermal sweating during activation of the muscle metaboreflex, we compared sweating responses during postexercise muscle occlusion in endurance runners, sprinters, and untrained men under mild hyperthermia (ambient temperature, 35 C; relative humidity, 50%). Ten endurance runners, nine sprinters, and ten untrained men (maximal oxygen uptakes: 57.5 +/- 1.5, 49.3 +/- 1.5, and 36.6 +/- 1.6 ml.kg(-1).min(-1), respectively; P < 0.05) performed an isometric handgrip exercise at 40% maximal voluntary contraction for 2 min, and then a pressure of 280 mmHg was applied to the forearm to occlude blood circulation for 2 min. The Delta change in mean arterial blood pressure between the resting level and the occlusion was significantly higher in sprinters than in untrained men (32.2 +/- 4.4 vs. 17.3 +/- 2.6 mmHg, respectively; P < 0.05); however, no difference was observed between distance runners and untrained men. The Delta mean sweating rate (averaged value of the forehead, chest, forearm, and thigh) during the occlusion was significantly higher in distance runners than in sprinters and untrained men (0.38 +/- 0.07, 0.19 +/- 0.03, and 0.11 +/- 0.04 mg.cm(-2).min(-1), respectively; P < 0.05) and did not differ between sprinters and untrained men. Our results suggest that the specificity of training modalities influences the sweating response during activation of the muscle metaboreflex. In addition, these results imply that a greater activation of the muscle metaboreflex does not cause a greater sweating response in sprinters.

    DOI: 10.1152/japplphysiol.00212.2011

    Web of Science

    researchmap

▶ 全件表示

書籍等出版物

  • 人間科学の百科事典

    天野 達郎, 近藤 徳彦( 担当: 分担執筆 ,  範囲: 3章 カラダの機能 体温調節,発汗)

    2015年 

     詳細を見る

  • ニュー運動生理学Ⅱ

    天野 達郎, 近藤 徳彦( 担当: 分担執筆 ,  範囲: Section 12,運動と体温,熱放散)

    真興交易  2015年 

     詳細を見る

MISC

  • 【筋肉・エクササイズとミネラル代謝】エクササイズ時の発汗と汗電解質の調節

    天野 達郎, 藤井 直人, Gerrett Nicola, 西保 岳, 近藤 徳彦

    腎と骨代謝32 ( 3 ) 233 - 239   2019年7月

     詳細を見る

    記述言語:日本語   出版者・発行元:(株)日本メディカルセンター  

    <文献概要>運動時における発汗と汗電解質の調節に関して最近の研究をもとに概説した.運動時の発汗は体温などの温熱性要因と温度に依存しないセントラルコマンドや活動筋からの求心性入力などの非温熱性要因により統合的に調節されている.発汗調節の経路は視床下部からの遠心性交感神経信号が主となるが,それ以外にも末梢でさまざまな要因に影響される.汗の前駆物質には血漿と同じレベルの塩分が含まれるが,汗腺の導管部で多くの塩分が再吸収される.皮膚コンダクタンス-発汗量の関係から間接的にこの再吸収能が評価できると考えられ,汗腺での再吸収能が暑熱順化,身体部位差,性差などに修飾されることがこの手法により明らかとなった.このように運動時には発汗量と汗電解質はさまざまな要因により調節されている.

    researchmap

  • 運動トレーニングに伴う発汗機能の改善機序 アドレナリン機構の役割

    天野 達郎

    若手研究者のための健康科学研究助成成果報告書 ( 34 ) 56 - 60   2019年4月

     詳細を見る

    記述言語:日本語   出版者・発行元:(公財)明治安田厚生事業団  

    運動選手の発汗機能を支える非温熱性の発汗にβアドレナリン受容体が関与しているのかどうかについて検討した。陸上競技部に所属する中距離・長距離選手10名を被験者とした。異なる日程で2回の実験に参加し、1日は静的掌握(IH)運動を、1日は両側の静的膝伸展(KE)運動を実施した。さらに、運動開始前に水循環スーツを着用させて安静状態での発汗が認められた後、βアドレナリン受容体の非選択的阻害薬であるプロプラノロールを投与した。IH運動時および運動後阻血(PEMI)時の発汗量は運動前と比較して有意に増大したが、薬剤処置の主効果や相互作用は認められなかった。IH運動およびKE運動時の心拍数は安静時よりも有意に増加したが、PEMIには安静レベルまで低下した。平均血圧はいずれの運動でも増加し、PEMI時には安静時よりも高い値で推移した。

    researchmap

  • 暑熱環境における身体能力のリミットコントロール

    天野達郎, Zachary Schlader, Toby Mundel, Nicola Gerrett, 近藤徳彦

    体育の科学68 ( 8 ) 561 - 565   2018年8月

     詳細を見る

    担当区分:筆頭著者   記述言語:日本語  

    researchmap

  • 【暑さと熱中症対策-スポーツの安全とパフォーマンスのために-】対策に必要な基礎知識 運動時の体温調節

    天野 達郎, Gerrett Nicola, 近藤 徳彦

    臨床スポーツ医学35 ( 7 ) 660 - 663   2018年7月

     詳細を見る

    記述言語:日本語   出版者・発行元:(株)文光堂  

    researchmap

  • 自覚的に"汗っかき"な人の実際の発汗機能と熱中症リスクに関する研究

    天野 達郎

    デサントスポーツ科学39   241 - 248   2018年5月

     詳細を見る

    記述言語:日本語   出版者・発行元:(公財)石本記念デサントスポーツ科学振興財団  

    本研究では、自覚的に汗っかきな人とそうではない人の安静温熱負荷時の発汗反応およびそれに対する一酸化窒素合成酵素の寄与を比較した。自覚的汗っかき群8名と自覚的非汗っかき群7名が安静温熱負荷を舌下温が1.0℃上昇するまで行った。前腕部には2本のマイクロダイアリシス用ファイバーを留置し、1本には乳酸リンゲル液を(Control)、もう1本にはL-NAME(非選択的一酸化窒素合成酵素阻害薬)を循環させて、その皮膚上の発汗量を計測した。安静温熱負荷時の発汗量は両群ともL-NAME部位でControl部位よりも有意に低下したが、いずれの部位においても両群間の発汗量に差は認められなかった。また、加温40分間における舌下温の上昇程度にも両群間に差は認められなかった。これらの結果は、自覚的に汗っかきな人の発汗反応およびそれに対する一酸化窒素合成酵素の寄与程度は自覚的に汗っかきではない人と差がないことを示している。また、自覚的に汗っかきかどうかは、安静温熱負荷時の舌下温の上昇程度から推察される熱中症リスク指標にも影響しないようである。本研究より主観的な汗っかきの分類方法や加温の方法に関する課題を抽出することができた。(著者抄録)

    researchmap

  • 運動時におけるヒトの発汗調節特性

    近藤 徳彦, 天野 達郎, Gerrett Nicola

    発汗学24 ( 1 ) 2 - 5   2017年4月

     詳細を見る

    記述言語:日本語   出版者・発行元:日本発汗学会  

    researchmap

  • 高強度のウォームアップ運動が活動筋の酸素動態に及ぼす影響

    古賀 俊策, 近藤 徳彦, 福岡 義之, 天野 達郎, 奥島 大

    デサントスポーツ科学37   154 - 160   2016年6月

     詳細を見る

    記述言語:日本語   出版者・発行元:(公財)石本記念デサントスポーツ科学振興財団  

    高強度のウォームアップ(W-up)運動を用いると,W-up運動後の主運動における活動筋の酸素消費量(VO2)の増加が速くなり,酸素不足が減少する.本研究では,表層筋に加えて深層筋も含めた活動筋の酸素動態を計測し,高強度のW-up運動が活動筋の酸素動態に及ぼす影響を明らかにした.時間分解・近赤外分光装置を用いて,活動筋における脱酸素化ヘモグロビン+ミオグロビン(HHb)を計測した.大腿直筋深層部のHHbは第1運動と第2運動の開始後の約5分目において定常状態を示し,VO2とQの増加速度のマッチングが生じたことが示唆された.さらに,第1運動と第2運動において大腿直筋深層部におけるHHbの時定数と平均応答時間は表層部に比べて有意に遅かった.HHbはVO2/Qを反映するので,表層筋に比べて遅筋線維が多く含まれ,運動中の筋温がより高い深層筋では,酸素供給が十分になって活動筋全体のVO2とQのバランスが改善され,酸素不足が減少したと推測される.(著者抄録)

    researchmap

  • ヒトの体温調節特性を生かしたスポーツウエアの開発

    天野 達郎, 島名 孝次, 堀川 直幹, Gerrett Nicola, 近藤 徳彦

    臨床スポーツ医学33 ( 3 ) 313 - 315   2016年3月

     詳細を見る

    記述言語:日本語   出版者・発行元:(株)文光堂  

    researchmap

  • 【エネルギー代謝と体温】エネルギー代謝と運動時の体温調節

    近藤 徳彦, Kenny Glen, 天野 達郎, 藤井 直人, 西保 岳

    体育の科学61 ( 8 ) 589 - 594   2011年8月

     詳細を見る

    記述言語:日本語   出版者・発行元:(株)杏林書院  

    researchmap

▶ 全件表示

受賞

  • 学長賞(若手教員研究奨励賞)

    2018年11月   新潟大学  

    天野達郎

     詳細を見る

  • 若手研究者賞(口頭発表)

    2012年9月   第26回運動と体温の研究会   筋からの複合的な求心性入力が発汗反応に及ぼす影響

    天野達郎

     詳細を見る

  • 若手研究者賞(口頭発表)

    2011年7月   International Conference on Environmental Ergonomics  

    Tatsuro Amano

     詳細を見る

共同研究・競争的資金等の研究

  • 学校における子どもの体温調節能力の発達過程の解明と熱中症予防の教育介入研究

    研究課題/領域番号:20K20515  2020年07月 - 2024年03月

    日本学術振興会  科学研究費助成事業 挑戦的研究(開拓)  挑戦的研究(開拓)

    天野 達郎

      詳細を見る

    配分額:26000000円 ( 直接経費:20000000円 、 間接経費:6000000円 )

    researchmap

  • 化学的・物理的促進法を用いた経皮的薬剤投与に基づく新たな発汗研究手法の開発

    研究課題/領域番号:19K22831  2019年06月 - 2022年03月

    日本学術振興会  科学研究費助成事業 挑戦的研究(萌芽)  挑戦的研究(萌芽)

    井上 芳光, 天野 達郎, 近藤 徳彦

      詳細を見る

    配分額:6370000円 ( 直接経費:4900000円 、 間接経費:1470000円 )

    researchmap

  • 運動に伴う汗腺機能の適応メカニズム解明と熱中症予防への応用

    研究課題/領域番号:18H03146  2018年04月 - 2021年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    天野 達郎, 藤井 直人, 井上 芳光, 近藤 徳彦

      詳細を見る

    配分額:17680000円 ( 直接経費:13600000円 、 間接経費:4080000円 )

    カルシトニン遺伝子関連ペプチド(CGRP)に対する発汗反応(発汗増幅作用)を運動選手と非運動選手で比較した.陸上部に所属する長距離選手10名および非運動選手8名を対象に,マイクロダイアリシス法を用いて①メタコリン(コントロール),②メタコリン+CGRP,③メタコリン+CGRP+テオフィリンをメタコリン濃度を4濃度に分けて投与した時の発汗量を測定した.その結果,両群ともメタコリンの濃度依存性に発汗量が増加したものの,CGRPやテオフィリン投与はその反応に影響しなかった.これらは一部の先行研究と一致しない結果であるため,その理由について考察したところ,本研究で使用したマイクロダイアリシスファイバーの膜がCGRPに合っていない可能性が考えられた.次年度以降にその点を改善して研究を進める予定である.
    また,2年目の研究に関連して,運動時の発汗反応にαアドレナリン受容体が関与するのかどうかも検討した.長距離選手12名を対象に,漸増負荷運動時に①フェントラミン(α1,α2受容体阻害薬)あるいは②テラゾシン(α1受容体阻害薬)をイオントフォレーシス法で投与した時の発汗反応をコントロール部位(生理食塩水処置)と比較した.その結果,フェントラミン部位では最大運動時の発汗量が増大したものの,テラゾシンは運動時の発汗に影響しなかった.これらの結果から,おそらく末梢神経にあるα2受容体はアドレナリン性の発汗に対して抑制的に関与しており(例:ノルアドレナリンの再取り込み),汗腺側にあるα1受容体は運動時の発汗に寄与していない可能性が考えられた.この知見を基に2年目の研究を進める予定である.

    researchmap

  • スポーツ栄養食品の機能性評価研究 国際共著

    2018年04月 - 2021年03月

    株式会社ブルボン  共同研究 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:産学連携による資金

    配分額:3680000円 ( 直接経費:3200000円 、 間接経費:480000円 )

    researchmap

  • 暑熱環境下における身体活動時の熱中症を予防する簡便な方策の検討

    2020年07月 - 2021年03月

    公益財団法人内田エネルギー科学振興財団 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:500000円 ( 直接経費:500000円 )

    researchmap

  • 精神性発汗メカニズムを解明するための新たな経皮ドラッグデリバリー装置の開発

    2020年07月 - 2021年03月

    一般財団法人永井エヌエス知覚科学振興財団 

    天野達郎

      詳細を見る

    資金種別:競争的資金

    配分額:850000円 ( 直接経費:850000円 )

    researchmap

  • 精神性発汗メカニズムを解明するための新たな経皮ドラッグデリバリー装置の開発

    2020年05月 - 2021年03月

    公益財団法人ユニオンツール育英奨学会 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:1000000円 ( 直接経費:1000000円 )

    researchmap

  • ヒト熱放散反応におけるTRPチャネルの役割解明 -熱中症予防法確立を目指して-

    研究課題/領域番号:20H04065  2020年04月 - 2023年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    藤井 直人, 天野 達郎, 近藤 徳彦, 西保 岳

      詳細を見る

    配分額:17680000円 ( 直接経費:13600000円 、 間接経費:4080000円 )

    researchmap

  • 環境温度の違いがヒトのαおよびβアドレナリン性発汗に及ぼす影響

    2019年07月 - 2020年03月

    筑波大学ARIHHP公募型共同利用共同研究 

    天野達郎

      詳細を見る

    担当区分:研究代表者 

    配分額:100000円 ( 直接経費:100000円 )

    researchmap

  • 暑熱環境下における簡便で効果的な新しい熱中症対策:学校現場への応用へ向けて

    2019年07月 - 2020年03月

    公益財団法人内田エネルギー科学振興財団 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:500000円 ( 直接経費:500000円 )

    researchmap

  • 教育学・工学分野における身体運動科学のグローカリゼーションを促進する学士教育戦略の試み

    2019年04月 - 2020年03月

    新潟大学  平成31年度新潟大学学長教育助成制度 

      詳細を見る

    担当区分:研究代表者 

    配分額:500000円 ( 直接経費:500000円 )

    researchmap

  • 温熱・寒冷環境下における中枢神経活動と運動制御

    2018年07月 - 2019年03月

    新潟医療福祉大学SHAINプロジェクト 2018年度共同研究・共同利用 

    天野達郎

      詳細を見る

    担当区分:研究代表者 

    配分額:250000円 ( 直接経費:250000円 )

    researchmap

  • 精神性発汗のメカニズム解明:心理・知覚研究の発展を目指して

    2018年07月 - 2019年03月

    一般財団法人永井エヌ・エス知覚科学振興財団 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:850000円 ( 直接経費:850000円 )

    researchmap

  • 分野横断的アプローチによる熱中症症状の解明とそれに基づく予防法の開発

    2018年04月 - 2019年03月

    新潟大学  平成30年度新潟大学U-goグラント 

      詳細を見る

    担当区分:研究代表者 

    配分額:1000000円 ( 直接経費:1000000円 )

    researchmap

  • 乳ペプチドの体温調節・疲労軽減作用に関する研究

    2017年11月 - 2020年03月

    森永乳業株式会社  共同研究 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:産学連携による資金

    配分額:6831000円 ( 直接経費:6210000円 、 間接経費:621000円 )

    researchmap

  • 運動トレーニングに伴う発汗機能の改善機序-アドレナリン機構の役割-

    2017年11月 - 2019年03月

    公益財団法人明治安田厚生事業団 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:500000円 ( 直接経費:500000円 )

    researchmap

  • 運動と遺伝子が高温下での運動パフォーマンスに関係する汗イオン濃度調節に及ぼす影響

    研究課題/領域番号:17H02153  2017年04月 - 2021年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    近藤 徳彦, 天野 達郎, 井上 芳光, 西保 岳

      詳細を見る

    配分額:16900000円 ( 直接経費:13000000円 、 間接経費:3900000円 )

    運動が汗イオン濃度の調節に及ぼす影響を検討するため,運動時の汗イオン濃度の調節と安静温熱負荷時(安静時)のそれを比較することで,運動がどのようにこの調節に影響するのか検討した.
    <BR>
    被験者は健康な学生12名であった.実験条件として,環境温25-27°C,相対湿度50%の環境試験室内で,以下に示す二つの実験を実施した.いずれの場合も全身の皮膚温と局所皮膚温(発汗や汗イオン濃度を測定している部位)を水循環スーツで一定にし,運動時と安静時,運動強度間で汗イオン濃度の調節を比較した.また,皮膚温が汗イオン濃度の調節にどのような影響を及ぼすのかについても,局所の皮膚温を変化させてながら検討し,運動時と安静時によって皮膚温が異なった場合の影響程度を推測した.1)下肢温浴(42°Cの湯に下肢を浸す)を40分間負荷し,その際,体表面の皮膚温を一定にするため水循環スーツを用いた.2)最大酸素摂取量の30%と60%の運動負荷を,それぞれ別の日に実施した.いずれの実験でも,心拍数,血圧,体温,皮膚温,前腕部の発汗量・皮膚電気コンダクタンス,アルドステロン濃度など測定した.その結果,最大酸素摂取量の60%の運動時汗イオン最大再吸収能は安静温熱負荷時のそれより有意に高かった(0.63 ± 0.28 mg/cm2/min vs. 0.44 ± 0.3 mg/cm2/min, P<0.05).また,居所皮膚温の影響を検討した実験で3℃程度の局所皮膚温の差は汗イオンの最大再吸収能に大きな影響を及ぼさないが,その差が6℃程度になると生理的に影響することが示された.この結果をもとに検討すると,運動時と安静時によるこの能力の差には局所皮膚温は大きく影響しておらず,運動時に分泌されるホルモンなどが汗イオン濃度調節機構に影響することを及ぼすことが明らかとなった.

    researchmap

  • 運動による汗腺機能の適応機序の解明:カルシトニン遺伝子関連ペプチドの役割

    2017年04月 - 2018年03月

    ヤマハ発動機スポーツ振興財団 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:1200000円 ( 直接経費:1200000円 )

    researchmap

  • 自覚的に汗っかきな人の実際の発汗機能と熱中症リスクに関する研究

    2017年04月 - 2017年11月

    石本記念デサントスポーツ科学振興財団 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:500000円 ( 直接経費:500000円 )

    researchmap

  • 運動トレーニングによる高齢者の発汗機能改善特性とその性差

    研究課題/領域番号:16H04851  2016年04月 - 2020年03月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    井上 芳光, 上田 博之, 天野 達郎, 近藤 徳彦

      詳細を見る

    配分額:19240000円 ( 直接経費:14800000円 、 間接経費:4440000円 )

    本研究では,以下の2実験を実施した.実験(1)では,女性の高齢マラソンランナーと一般高齢者と若年陸上長距離ランナーに対し,アセチルコリン誘発性発汗テストを実施した.女性高齢ランナーは一般高齢女性より,発汗量(SR;前腕:178%,大腿:200%)・活動汗腺数(ASG)・単一汗腺あたりの汗出力(SGO;前腕:140%,大腿:162%)が有意に高かった.しかし,女性高齢ランナーのSR,SGOは,前腕・大腿とも女性若年ランナーより有意に低かった.また,女性高齢ランナーのSRは男性高齢マラソンランナー(昨年度データ)と前腕・大腿とも同等だったが,女性高齢ランナーは男性高齢ランナーより,有意に高いASGと有意に低いSGOを示した.その結果,女性高齢ランナーの汗腺機能は女性若年ランナーよりは劣るものの,マラソントレーニングで亢進し,その亢進の程度は男女ほぼ同程度であることが窺われた.ただし,女性高齢ランナーは男性高齢ランナーより低いSGOを高いASGで補償する特徴が見出された.実験(2)では女性高齢マラソンランナーの身体8部位における温覚・冷覚閾値の熱流束差を一般若年女性と男性高齢マラソンランナー(昨年度データ)と比較検討した.その結果,温覚・冷覚閾値からみた女性高齢ランナーの皮膚温度感受性は,一般若年女性とほぼ同等で,男性高齢ランナーより鋭敏であることが見出された.この結果と先行研究結果(皮膚の温度感受性は若年者では女が男より鋭敏で,その後加齢に伴い男女とも低下し,その性差は80歳代で小さくなる)を考え合わせると,身体部位差はあるものの,1)女性のマラソントレーニングは,加齢に伴う皮膚温度感受性の低下を予防する有効な手段であること,2)60歳代のマラソンランナーでも皮膚温度感受性には性差が存在すること,が推察された.

    researchmap

  • 運動トレーニングに伴う発汗機能の改善メカニズムの解明:神経伝達物質に着目して

    研究課題/領域番号:16K16521  2016年04月 - 2018年03月

    日本学術振興会  科学研究費助成事業 若手研究(B)  若手研究(B)

    天野 達郎

      詳細を見る

    配分額:3900000円 ( 直接経費:3000000円 、 間接経費:900000円 )

    運動トレーニングによる発汗機能の改善メカニズムを明らかにするため,汗腺周囲の神経伝達物質に対する反応性が運動トレーニングで改善されるのかどうかを検討した.これまではアセチルコリンという神経伝達物質が発汗機能の改善に主に関与すると考えられてきたが,本研究の結果より,アドレナリンに関するメカニズムや一酸化窒素などの役割が新たに明らかになった.これらの結果は従来考えられているより複雑なメカニズムによって発汗機能は改善されることを示しており,まだ不明な点については今後も研究を継続する必要がある.

    researchmap

  • 運動後の血液量変化が発汗機能に及ぼす影響 :牛乳を用いた熱中症予防のエビデンス

    2016年04月 - 2017年03月

    一般社団法人Jミルク 

    天野達郎

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:1500000円 ( 直接経費:1500000円 )

    researchmap

  • 高温下における長時間の間欠運動時の体温調節特性

    研究課題/領域番号:26882026  2014年08月 - 2016年03月

    日本学術振興会  科学研究費助成事業 研究活動スタート支援  研究活動スタート支援

    天野 達郎

      詳細を見る

    配分額:2730000円 ( 直接経費:2100000円 、 間接経費:630000円 )

    間欠運動時の体温調節特性を検討するため,10名の健康な男子大学生が室温25℃,相対湿度50%の環境下で50%VO2maxの継続運動を30分間および同じ運動強度の間欠運動(30s運動+30s休息および180s運動+180s休息)を60分間実施した.運動・休息時間に関わらず間欠運動時の食道温は継続運動のそれと同様であった.一方,発汗および皮膚血管拡張は間欠運動時に低い値を示した.間欠運動時の熱放散反応に影響する体温以外の要因のうち,筋代謝受容器活動は筋機械受容器活動よりも大きな熱放散反応を示すことや,この活動が体温上昇時の熱放散反応を促進することも明らかになった.

    researchmap

  • 運動に関わる複合的な要因を用いたトレーニングが体温調節機能の改善に及ぼす影響

    研究課題/領域番号:12J04185  2012年 - 2013年

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    天野 達郎

      詳細を見る

    配分額:2000000円 ( 直接経費:2000000円 )

    本年度は①大腿部圧迫を用いた運動トレーニングが発汗および皮膚血流反応の改善に及ぼす影響および②間欠運動が鶏放散反応の改善に及ぼす影響の可能性について検討した. ①に関連して, 過去3年間授業以外の運動経験がない健康な若年男性10名が環境温32℃および相対温度50%環境下で大腿部を圧迫(60mmHg)した自転車運動トレーニング(最大酸素摂取量の50%強度, 30分間×2セット)を7日間実施した. その前後で温熱性熱放散反応(43℃の湯に膝から下を浸水する下肢温浴)および非温熱性熱放散反応(静的掌握運動・運動後阻血および下肢ストレッチ)を測定し, 運動トレーニング後の改善程度を昨年度実施したコントロール群の結果(圧迫をしないで上述のトレーニングを行う)と比較した. 大腿部圧迫を用いた運動トレーニングはトレーニング時の有意に背部発汗量を増大させて同皮膚血流量を有意に低下させた・運動トレーニングによる最大酸素摂取量および汗腺機能の改善程度は両群間で差はなかった. 大腿部圧迫群における安静加温時の発汗反応は運動トレーニングで大きく改善されていたわけではないものの, コントロール群で認められた平均体温0.1℃ごとの上昇に対する発汗反応の低下は大腿部圧迫群では認められなかつた. 一方, 大腿部圧迫群のみ安静加温時の平均体温0.1℃ごとの上昇に対する皮膚血流反応が運動トレーニング後に低下していた. 非温熱性要因による熱放散反応と関連して, 各群の運動トレーニングは静的掌握運動および運動後阻血時の発汗および皮膚血流反応に大きく影響しなかった. 以上より, 本研究における大腿部圧迫を用いた運動トレーニングは発汗反応の改善程度を大きくするものではなく, 皮膚血流反応に対してはその改善を減弱させる可能性が示唆された.
    また, 上述した②に関連して, 被験者8名が90%VO2max強度で30秒間, 20W強度で1分30秒間の間欠運動を繰り返す運動を行ったところ, 同じ仕事量の継続運動で想定されるよりも大きな食道温上昇と発汗反応が認められた. そのため, 下肢圧迫を用いた運動トレーニングよりも大きな熱放散反応改善効果が間欠運動を用いたトレーニングでは期待されることが明らかになった.

    researchmap

▶ 全件表示

 

担当経験のある授業科目

  • 運動生理学演習

    2020年
    -
    現在
    機関名:新潟大学

  • 課題研究Ⅱ

    2020年
    -
    現在
    機関名:新潟大学

  • 体育科教育法

    2020年
    -
    現在
    機関名:新潟大学

  • 課題研究Ⅰ

    2020年
    -
    現在
    機関名:新潟大学

  • 健康スポーツ科学講義b

    2018年
    -
    現在
    機関名:新潟大学

  • 健康スポーツ科学講義a

    2018年
    -
    現在
    機関名:新潟大学

  • 運動生理学特論

    2018年
    -
    現在
    機関名:新潟大学

  • 健康スポーツ科学実習 Ib

    2018年
    -
    現在
    機関名:新潟大学

  • 健康スポーツ科学実習 Ia

    2018年
    -
    現在
    機関名:新潟大学

  • ヘルスプロモーション研究演習II

    2017年
    -
    現在
    機関名:新潟大学

  • スタディ・スキルズP

    2017年
    -
    現在
    機関名:新潟大学

  • 陸上競技

    2017年
    -
    現在
    機関名:新潟大学

  • 卒業研究

    2017年
    -
    現在
    機関名:新潟大学

  • 生理学・運動生理学

    2016年
    -
    現在
    機関名:新潟大学

  • 生理学・運動生理学演習I

    2016年
    -
    現在
    機関名:新潟大学

  • スポーツ生理学II

    2016年
    -
    現在
    機関名:新潟大学

  • 小学校体育

    2016年
    -
    現在
    機関名:新潟大学

  • 生理学・運動生理学演習II

    2016年
    -
    現在
    機関名:新潟大学

  • スポーツ生理学I

    2016年
    -
    現在
    機関名:新潟大学

  • スポーツ科学研究演習II

    2016年
    -
    2019年
    機関名:新潟大学

  • 運動処方論

    2016年
    -
    2018年
    機関名:新潟大学

  • 保健体育科教育学演習II

    2016年
    -
    2018年
    機関名:新潟大学

  • 保健体育科教育学演習I

    2016年
    -
    2018年
    機関名:新潟大学

  • 健康スポーツ科学実習 I

    2016年
    -
    2017年
    機関名:新潟大学

  • 健康スポーツ科学講義

    2016年
    機関名:新潟大学

▶ 全件表示