Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Physiological Society  

The initiation of swallowing evoked by laryngeal capsaicin and carbonated water application was diminished by the coapplication of QX-314 and capsaicin. Carbonated water-evoked swallows were also abolished by transection of the superior laryngeal nerves and were inhibited by the acid-sensing ion channel-3 inhibitor. Capsaicin-sensitive nerves are involved in the initiation of carbonated-water-evoked swallows.

DOI： 10.1152/ajpgi.00233.2020

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Authorship：Lead author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Physiological Society  

Although a transient receptor potential vanilloid 1 (TRPV1) inhibitor or TRPV1-expressed neuronal inhibitor significantly inhibited HCl/capsaicin-evoked swallowing, air flow-induced swallowing was not affected. The number of air flow-induced swallows was significantly reduced within 60 min of TRPV1 activation. Evans blue dye concentration in the larynx increased 60 min after capsaicin application. TPRV1 activation not only desensitizes TRPV1 but also inactivates mechanoreceptors caused by increases in vascular permeability and edema.

DOI： 10.1152/ajpgi.00082.2020

PubMed

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Language：Japanese   Publisher：(一社)歯科基礎医学会  

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Language：Japanese   Publisher：(一社)歯科基礎医学会  

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Language：Japanese   Publisher：日本顎口腔機能学会  

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Language：Japanese   Publisher：(一社)歯科基礎医学会  

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Language：Japanese   Publisher：(一社)歯科基礎医学会  

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Language：Japanese   Publisher：(一社)日本摂食嚥下リハビリテーション学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Key points: Afferents carried by the superior laryngeal nerve play a primary role in the initiation of laryngeal mechanically evoked swallows in anaesthetized rats. Amiloride and its analogues inhibit swallowing evoked by mechanical stimulation, but not swallowing evoked by chemical and electrical stimulation. The epithelial sodium channel is probably involved in the initiation of laryngeal mechanically evoked swallows. Abstract: The swallowing reflex plays a critical role in airway protection. Because impaired laryngeal mechanosensation is associated with food bolus aspiration, it is important to know how the laryngeal sensory system regulates swallowing initiation. This study was performed to clarify the neuronal mechanism of mechanically evoked swallows. Urethane-anaesthetized Sprague–Dawley male rats were used. A swallow was identified by activation of the suprahyoid and thyrohyoid muscles on electromyography. The swallowing threshold was measured by von Frey filament and electrical stimulation of the larynx. The number of swallows induced by upper airway distension and capsaicin application (0.03 nmol, 3 μl) to the vocal folds was counted. The effects of topical application (0.3–30 nmol, 3 μl) of the epithelial sodium channel (ENaC) blocker amiloride and its analogues (benzamil and dimethylamiloride), acid-sensing ion channel (ASIC) inhibitors (mambalgine-1 and diminazene) and gadolinium to the laryngeal mucosa on swallowing initiation were evaluated. A nerve transection study indicated that afferents carried by the superior laryngeal nerve play a primary role in the initiation of laryngeal mechanically evoked swallows. The mechanical threshold of swallowing was increased in a dose-dependent manner by amiloride and its analogues and gadolinium, but not by ASIC inhibitors. The number of swallows by upper airway distension was significantly decreased by benzamil application. However, the initiation of swallows evoked by capsaicin and electrical stimulation was not affected by benzamil application. We speculate that the ENaC is involved in the initiation of laryngeal mechanically evoked swallows.

DOI： 10.1113/jp277895

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Other Link： https://onlinelibrary.wiley.com/doi/full-xml/10.1113/JP277895

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.brainres.2018.05.002

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Language：Japanese   Publisher：(一社)歯科基礎医学会  

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Physiological Society  

Swallowing pressure generation is important to ensure safe transport of an ingested bolus without aspiration or leaving residue in the pharynx. To clarify the mechanism, we measured swallowing pressure at the oropharynx (OP), upper esophageal sphincter (UES), and cervical esophagus (CE) using a specially designed manometric catheter in anesthetized rats. A swallow, evoked by punctate mechanical stimulation to the larynx, was identified by recording activation of the suprahyoid and thyrohyoid muscles using electromyography (EMG). Areas under the curve of the swallowing pressure at the OP, UES, and CE from two trials indicated high intrasubject reproducibility. Effects of transecting the hypoglossal nerve (12N) and recurrent laryngeal nerve (RLN) on swallowing were investigated. Following bilateral hypoglossal nerve transection (Bi-12Nx), OP pressure was significantly decreased, and time intervals between peaks of thyrohyoid EMG bursts and OP pressure were significantly shorter. Decreased OP pressure and shortened times between peaks of thyrohyoid EMG bursts and OP pressure following Bi-12Nx were significantly increased and longer, respectively, after covering the hard and soft palates with acrylic material. UES pressure was significantly decreased after bilateral RLN transection compared with that before transection. These results suggest that the 12N and RLN play crucial roles in OP and UES pressure during swallowing, respectively. We speculate that covering the palates with a palatal augmentation prosthesis may reverse the reduced swallowing pressure in patients with 12N or tongue damage by the changes of the sensory information and of the contact between the tongue and a palates.

NEW & NOTEWORTHY Hypoglossal nerve transection reduced swallowing pressure at the oropharynx. Covering the hard and soft palates with acrylic material may reverse the reduced swallowing function caused by hypoglossal nerve damage. Recurrent laryngeal nerve transection reduced upper esophageal sphincter negative pressure during swallowing.

DOI： 10.1152/japplphysiol.00944.2017

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Language：Japanese   Publisher：日本顎口腔機能学会  

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Other Link： https://search.jamas.or.jp/index.php?module=Default&action=Link&pub_year=2017&ichushi_jid=J02994&link_issn=&doc_id=20180411290011&doc_link_id=%2Fex2gakuk%2F2017%2F002401%2F011%2F0040-0041%26dl%3D0&url=http%3A%2F%2Fwww.medicalonline.jp%2Fjamas.php%3FGoodsID%3D%2Fex2gakuk%2F2017%2F002401%2F011%2F0040-0041%26dl%3D0&type=MedicalOnline&icon=https%3A%2F%2Fjk04.jamas.or.jp%2Ficon%2F00004_2.gif

Language：Japanese   Publisher：(一社)歯科基礎医学会  

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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Authorship：Lead author   Language：Japanese  

低酸素脳症発症後に嚥下障害を認めた一例を報告する。症例は69歳女性。2015年11月より右気胸にて当院呼吸器感染症内科に入院した。入院6日目に院内で緊張性気胸を再発し、心肺停止に伴う低酸素脳症を発症した。発症58日目に意識レベルの改善を認め、嚥下機能評価のため当科初診となった。指示理解不良で意識レベルはJCS I-3であり、口腔衛生状態は不良で、残存歯は少ないが義歯使用により咬合支持が得られる状態であった。発声・腹式呼吸は不可だった。顎舌顔面の感覚あるものの、舌運動は不良で、呼吸状態不良につき頬ふくらまし・吸引は不可だった。頸部運動は不良で、反復唾液嚥下テストは0回だった。介入3日目(発症60日目)、嚥下内視鏡検査を実施した。安静時より咽頭に分泌物の貯留あり。とろみ摂取時には、喉頭侵入および咽頭残留があったものの誤嚥は認められなかった。先行期から嚥下咽頭期にわたる機能的嚥下障害と診断し、口腔ケア・間接訓練から介入を開始した。呼吸状態安定時のみ少量の直接訓練を実施した。介入57日目(発症114日目)には、義歯調整を行った後に、嚥下造影検査を実施した。液体・ゆるめのとろみにて声門上まで喉頭侵入し、固形物は喉頭蓋谷及び舌背に残留を認めた。ティースプーン一杯量を摂取した際に、患者は咽頭残留を自覚できた。食事による訓練が可能と判断し、全粥・半固形食とろみ付きの食事を開始した。並行して舌運動訓練を実施し、最終的に全粥・半固形食を3食摂取可能となった。(著者抄録)

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