Gastric cytoprotection by pirenzepine is not mediated by catecholamines.

The effects of pirenzepine (in a dose of 25.0 mg X kg-1) and atropine (2.5 mg X kg-1) were studied on the development of gastric ulceration produced by pylorus ligation, polymyxin B and absolute ethanol, as well as on the gastric secretory responses and plasma level of noradrenaline. It was found that: (1) pirenzepine significantly decreased the development of ulcer formation produced by pylorus ligation, polymyxin B and absolute ethanol without any antisecretory response; (2) atropine inhibited gastric acid secretion, but no effect was obtained on ulcus produced by pylorus ligation, polymyxin B and absolute ethanol; (3) the plasma level of noradrenaline could be decreased by atropine and pirenzepine, although the difference did not reach statistical significance. It has been concluded that catecholamines are not involved in the gastric cytoprotective mechanism of pirenzepine.