Inhibition of Histamine-Stimulated Gastric Acid Secretion by Hydrogen Sulfide in Male Rats

Abstract

Recently, hydrogen sulfide (H_2S) introduces as the third gaseous transmitter that has many physiologic and pharmacologic roles in the body. The aim of the present study was to investigate the effect of exogenously given H_2S on histamine-induced gastric acid secretion in rats. Thirtytwo male Wistar rats (150-200 g) were randomly assigned into 4 groups (8 per group). Animals were deprived of food but not water 24 h before the experiment and were randomly assigned into two control groups, distention-, and histamine-stimulated groups, and two NaHS-treated groups. To evaluate the effect of H_2S on histamine-induced gastric acid secretion, one group of animals were received an I.V. bolus of NaHS (a H_2S donor) at 80 μg/kg. To investigate the possible involved mechanism of the antisecretory effect of NaHS, mRNA expression of histidine decarboxylase (HDC) were evaluated by reverse-transcriptase PCR. The gastric acid output in response to histamine decreased by NaHS treatment (P＜0.01). Also the results showed that the level of gene expression of HDC was higher in NaHS-treated group than in control rats. The findings showed that the inhibitory effect of H_2S on gastric acid secretion was not related to a decrease in histamine release. It seems that up-regulation of HDC mRNA expression is secondary to inhibition of gastric acid secretion by NaHS.