Role of hydrogen sulfide within the dorsal motor nucleus of the vagus in the control of gastric function in rats.

Abstract

Hydrogen sulfide (H2 S) is a gaseous messenger and serves as an important neuromodulator in the central nervous system. This study aimed to clarify the role of H2 S within the dorsal motor nucleus of the vagus (DMV) in the control of gastric function in rats. Cystathionine β-synthetase (CBS) is an important generator of endogenous H2 S in the brain. We investigated the distribution of CBS in the DMV using immunohistochemical method, and the effects of H2 S on gastric motility and on gastric acid secretion. CBS-immunoreactive (IR) neurons were detected in the rostral, intermediate and caudal DMV, with the highest number of CBS-IR neurons in the caudal DMV, and the lowest in the intermediate DMV. We also found that microinjection of the exogenous H2 S donor NaHS (0.04 and 0.08 mol/L; 0.1 μL; n = 6; p < 0.05) into the DMV significantly inhibited gastric motility with a dose-dependent trend, and promoted gastric acid secretion in Wistar rats. Microinjection of the same volume of physiological saline (PS; 0.1 μL, n = 6, p > 0.05) at the same location did not noticeably change gastric motility and acid secretion. The data from these experiments suggest that the CBS that produces H2 S is present in the DMV, and microinjection of NaHS into the DMV inhibited gastric motility and enhanced gastric acid secretion in rats.