Gastric cytoprotection by pirenzepine: role of endogenous catecholamines.

Acute gastric ulcerations were produced in fasted rats by pylorus ligation or by administration of polymyxin B or absolute ethanol. In pylorus-ligated rats pirenzepine 25 mg/kg per os decreased by about 50% the ulceration score, without affecting gastric acid and pepsin output. A similar percentage inhibition of ulceration score with no change of gastric acidity was obtained with pirenzepine 5 mg/kg per os in the case of gastric lesions provoked by polymyxin B. Ethanol-induced gastric lesions were also markedly reduced by pirenzepine, with 50% inhibition occurring with the dose of 25 mg/kg. The release of catecholamines from rat isolated gastric tissue during stimulation of sympathetic periarterial nerves was significantly reduced by pirenzepine 1 X 10(-6) g/ml. The present results indicate that pirenzepine significantly reduced gastric lesions induced by various stimulants; the protective effect of pirenzepine did not appear to be related to increased sympathetic tone.