Sustained laryngeal transient receptor potential vanilloid 1 activation inhibits mechanically-induced swallowing in anesthetized rats.

Sustained laryngeal transient receptor potential vanilloid 1 activation inhibits mechanically-induced swallowing in anesthetized rats. Am J Physiol Gastrointest Liver Physiol. 2020 Aug 05;: Authors: Yoshihara M, Tsujimura T, Suzuki T, Nagoya K, Shiraishi N, Magara J, Terunuma M, Inoue M Abstract A major component of gastric acid is hydrochloric acid (HCl), which can activate transient receptor potential vanilloid 1 (TRPV1). In the present study, we investigated how sustained laryngeal TRPV1 activation affects the frequency of the swallowing reflex. Experiments were carried out on 85 male Sprague-Dawley rats. The effects of short and sustained application of chemicals (3 µl of 0.1 N HCl or capsaicin) on the frequency of swallowing and of time-dependent changes in the occurrence of swallowing evoked by supralaryngeal nerve stimulation were determined. To evaluate vascular permeability of the larynx, Evans blue dye was intravenously injected after 5 or 60 min of sustained TRPV1 activation. SB366791 (a TRPV1 inhibitor) and Cap/QX-314 (a TRPV1-expressed neuronal inhibitor) significantly inhibited HCl/capsaicin-induced swallowing, but air flow-induced swallowing was not affected. Although the number of air flow-induced swallows induced by capsaicin stimulation was not affected within 5 min, but significantly reduced by 60-min capsaicin or HCl application. The swallowing threshold associated with supralaryngeal nerve stimulation did not si...
Source: American Journal of Physiology. Gastrointestinal and Liver Physiology - Category: Physiology Authors: Tags: Am J Physiol Gastrointest Liver Physiol Source Type: research