Involvement of capsaicin-sensitive nerves in the initiation of swallowing evoked by carbonated water in anesthetized rats
Involvement of capsaicin-sensitive nerves in the initiation of swallowing evoked by carbonated water in anesthetized rats
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辣椒素敏感神经参与麻醉大鼠碳酸水诱发的吞咽启动
DOI：
10.1152/ajpgi.00233.2020
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Makoto Inoue
中科院分区：
文献类型：
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作者：
Kojun Tsuji;Takanori Tsujimura;Shogo Sakai;Taku Suzuki;Midori Yoshihara;Kouta Nagoya;Jin Magara;Yoshihide Sato;Makoto Inoue
辣椒素有力地唤起吞咽反射，是一种已知的治疗剂，用于改善吞咽困难和预防吸入性肺炎。然而，辣椒素敏感神经在各种自然刺激引起的吞咽启动中的作用仍不清楚。为了探讨这一问题，我们在QX-314和辣椒素（QX/Cap）共同应用后阻断喉辣椒素敏感神经，研究麻醉大鼠机械和化学刺激对吞咽的影响。用辣椒素、碳酸水（CW）、蒸馏水（DW）和用von Frey细丝局部施加于喉部的点状机械刺激来诱发燕子。通过记录舌骨上肌和甲状舌骨肌的肌电图激活来记录燕子。在QX/Cap治疗后5分钟，辣椒素开始吞咽被强烈抑制，并以时间依赖性的方式恢复。与治疗前和治疗后30分钟相比，QX/Cap治疗后5分钟cw诱发的燕子明显减少。相比之下，QX/Cap处理对dw和机械唤起的燕子没有影响。此外，横断喉上神经几乎可以消除cw诱发的燕子，局部应用酸敏感离子通道3 （ASIC3）抑制剂APETx2可以显著减少燕子的反应，但非选择性瞬时受体电位通道抑制剂钌红或ASIC1抑制剂mambalgin-1对它们没有影响。综上所述，我们推测辣椒素敏感神经在cw诱发的燕子的启动中起重要作用。QX-314和辣椒素的联合应用减少了喉用辣椒素和碳酸水引起的吞咽起始。碳酸水诱发的燕子也可以通过切断喉上神经来消除，酸感离子通道-3抑制剂可以抑制。辣椒素敏感神经参与了碳酸水诱发燕子的启动。
Capsaicin powerfully evokes the swallowing reflex and is a known therapeutic agent for improving dysphagia and preventing aspiration pneumonia. However, the role of capsaicin-sensitive nerves in the initiation of swallowing evoked by various natural stimuli remains unclear. To explore this question, we blocked laryngeal capsaicin-sensitive nerves following the coapplication of QX-314 and capsaicin (QX/Cap), and investigated the effects on swallowing evoked by mechanical and chemical stimulation in anesthetized rats. Swallows were evoked by capsaicin, carbonated water (CW), distilled water (DW), and punctate mechanical stimulation using von Frey filaments applied topically to the larynx. Swallows were documented by recording electromyographic activation of the suprahyoid and thyrohyoid muscles. The initiation of swallowing by capsaicin was strongly suppressed at 5 min following QX/Cap treatment and returned in a time-dependent manner. CW-evoked swallows at 5 min following QX/Cap treatment were significantly diminished compared with before and 30 min after treatment. In contrast, DW-evoked and mechanically evoked swallows were unchanged by QX/Cap treatment. Furthermore, CW-evoked swallows were virtually abolished by transection of the superior laryngeal nerves and significantly decreased by the topical application of acid-sensing ion channel-3 (ASIC3) inhibitor APETx2, but they were not affected by the nonselective transient receptor potential channel inhibitor ruthenium red or the ASIC1 inhibitor mambalgin-1. Taken together, we speculate that capsaicin-sensitive nerves play an important role in the initiation of CW-evoked swallows.NEW & NOTEWORTHYThe 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.