Effects of atropine and pirenzepine on healing of gastric ulcer induced by mucosal excision in rats.

We studied the effects of atropine and pirenzepine on acid secretion induced by electrical vagal stimulation (EVS) and on healing of gastric ulcers after mucosal excision in rats. Both atropine (50, 125, and 250 micrograms/kg/hr) and pirenzepine (2.5, 5.0, and 12.5 mg/kg/hr), administered intraperitoneally, inhibited vagally stimulated acid secretion in a dose-dependent manner. Pirenzepine given at a rate of 0.25 mg/kg/hr had no effect on the acid secretory response to EVS. Either atropine (125 micrograms/kg/hr) or pirenzepine (2.5 mg/kg/hr) given for one week caused an inhibition of approximately 80% in acid secretory response to EVS. The antisecretory dosage of pirenzepine caused a significant reduction in the surface area of the ulcer by the seventh postoperative day, whereas neither the antisecretory dosage of atropine nor the nonantisecretory dosage of pirenzepine significantly affected the size of the ulcer. We conclude that an antisecretory dosage of pirenzepine accelerates the healing of gastric ulcers produced in rats.