Synthesis of H2S in the Gastrointestinal Tract

Abstract

Hydrogen sulfide (H2S) is the third gaseous signal molecule with interest which is endogenously generated in gastrointestinal tract. H2S play important physiological and pathophysiological roles in regulation of gastrointestinal functions, for example, gastrointestinal motility, secretion and nociception. In the present review we have mainly reviewed the recent findings about the study of H2S in regulation of gastrointestinal motility and its mechanism. The effect of H2S on gastrointestinal smooth muscle shows difference in different concentration of H2S and different regions. In gastric smooth muscle, H2S exhibits dual effects, that is, excitatory (low concentration) and inhibitory (high concentration) effects via suppressing voltage- dependent potassium channels and activating ATP-sensitive potassium channels (KATP), respectively, in guinea-pig and mouse. In intestinal smooth muscle, NaHS induced a biphasic effect, that is, a transient excitatory effect followed a long-lasting inhibitory effect in rat. The excitatory effect is mediated by TRPV1 and NK1 receptors and the inhibitory effect is mediated by KATP. In colonic smooth muscle, H2S induces inhibitory effect mediated by both KATP and SKCa channels in human, rat and mouse. This review gives a synopsis of the H2S function in regulation of gastrointestinal motility and its mechanism.