Gastric cytoprotection by pirenzepine. Role of endogenous prostaglandins.

This study compared the effects of pirenzepine, a novel selective antimuscarinic agent, and PGE2 applied topically on the gastric mucosa or parenterally on gastric secretion and formation of ASA and ethanol-induced gastric ulcerations in rats. Pirenzepine given topically in nonantisecretory dose prevented the formation of gastric ulcerations induced by ASA + 0.15 M HCl and absolute ethanol. These cytoprotective effects were comparable to those observed after PGE2 administered intragastrically or subcutaneously. Pirenzepine did not affect ulcer formation by ASA combined with 0.30 M HCl, whereas PGE2 was fully effective under these conditions. The cytoprotective action of pirenzepine was not accompanied by any change in the mucosal generation of PGs, indicating that endogenous PGs do not contribute to the cytoprotective property of this agent.