Prostaglandin mediated gastric acid secretion inhibitory effect as a possible mechanism for the antiulcer effect of angiotensin converting enzyme inhibitor (captopril) in pylorus ligated rats

Objective: To study the gastric secretory changes induced by antiulcer property of captopril and the role of prostaglandins in them. Methods: The effect of single dose of captopril and famotidine on different gastric parameters like ulcer index, pH, total acidity, mucopolysaccharide content and surface tension of gastric juice was studied by pyloric ligation alone and after pretreatment with ibuprofen. Results: Captopril and famotidine caused significant reduction in ulcer index and gastric acid secretion (p<0.01) when compared to saline control group. Both of them did not show any effect on mucus content and surface tension of gastric juice. Concurrent administration of ibuprofen reduced the anti-ulcer effect of captopril significantly (P<0.01) and nullified the acid secretion inhibitory effect of captopril. However, the anti-ulcer and acid secretion inhibitory effects of famotidine were not altered by pretreatment with ibuprofen. Conclusion: Captopril may act through prostaglandins to inhibit gastric acid secretion and this effect of captopril on acid secretion may be the mechanism involved in its anti-ulcer effect.