Pulmonary, gastrointestinal and urogenital pharmacologyRole of KATP channels and TRPV1 receptors in hydrogen sulfide-enhanced gastric emptying of liquid in awake mice

Hydrogen sulphide (H2S) has shown to relax gastrointestinal muscle. Here in, we evaluated the effects of H2S donors on gastric emptying and in pyloric sphincter muscle relaxation, and whether these effects involved KATP channels or TRPV1 receptors. Mice were treated with l-cysteine (alone or with propargylglycine-an inhibitor of H2S synthesis), NaHS, Lawesson's reagent (H2S donors) or saline. After 30 min, mice were gavaged with a liquid meal containing a nonabsorbable marker and then killed at 10, 20 or 30 min intervals to assess marker recovery from the stomach and intestine. This experiment was repeated in mice pre-treated with KATP channel (glibenclamide) or TRPV1 receptor (capsazepine) antagonists. In addition, pyloric sphincter muscles were mounted in an organ bath, incubated with saline, glibenclamide or capsazepine, and NaHS dose-responses were determined. H2S donors and l-cysteine enhanced gastric emptying in a dose-dependent manner; propargylglycine reversed the effect of l-cysteine. Both glibenclamide and capsazepine abolished l-cysteine and H2S donors' augmentation of gastric emptying. Dose-dependent inductions of pyloric sphincter relaxation by NaHS were abolished by glibenclamide or capsazepine. These data suggest that H2S donors-induced acceleration of gastric emptying and relaxation of pyloric sphincter muscle by KATP channel and TRPV1 receptor activations.