Inhibition of gastric acid secretion by Ya-hom in isolated mouse whole stomach

Abstract

Background: Ya-hom, the traditional Thai formula for abdominal discomfort treatment has, been reported to inhibit gastric acid secretion in gastric fistula rats. However, the mechanism underlying its action remains unclear. Objective: To investigate the gastric acid inhibitory action of Ya-hom and its mechanism of action by using an isolated mouse whole stomach model. Methods: The gastric acid secretion of isolated mouse whole stomach was stimulated by histamine (5.0 μM) or bethanechol (10 or 100 μM) after adding the inhibitors (atropine 1 μM, ranitidine 10 μM, indomethacin 0.1 μM or L-NAME 300 μM) and/or Ya-hom to the serosal solution. The effluent perfusate was collected continuously in 10-minute fractions for 120 minutes after stimulation. Results: Re-dissolved lyophilized Ya-hom extract at doses of 2.5, 5.0, 10.0, and 20.0 mg/mL inhibited histaminestimulated gastric acid secretion in a dose-dependent manner. Inhibition of Ya-hom (10 mg/mL) was also observed in the presence of atropine (1 μM), which was used to eliminate effects of endogenous acetylcholine. Ya-hom inhibited bethanechol-stimulated gastric acid secretion in the presence and absence of ranitidine. While the inhibitory action of Ya-hom on histamine-stimulated gastric secretion was not affected by indomethacin, it was attenuated by concomitant treatment with the nitric oxide synthase inhibitor (L-NAME). Conclusion: Ya-hom did not stimulate gastric acid secretion in the isolated mouse whole stomach. Ya-hom significantly inhibited gastric acid secretion after this was stimulated via histamine or bethanechol. Nitric oxide stimulation plays an important role in the inhibitory action of Ya-hom.