Beta-adrenergic mechanisms and ulcer formation in pylorus-ligated rats

The importance of beta-adrenergic receptor activity for ulcer formation was studied. In rats fasted for 48 hours, ulcers in the rumen were produced constantly after 17 hours of pyloric ligation. d,1,Propranolol in doses of 1 to 30 mg/kg given 4 times during 12 hours caused a dose-dependent inhibition of ulcer formation. The ulcero-protective potency of d,1,propranolol was about 20 times that of d,propranolol. No explanation of the ulcero-protective effect was observed when the gastric acid secretion was studied after 17 hours. Serum gastrin concentration after 17 hours of ligation was in all animals less than 5 pmol per liter, i.e. below one-third of the normal fasting value. For all pharmacological effects apart from beta-adrenergic blockage, d,1, and d,propranolol do not differ, while the results presented here suggest that intact beta-adrenergic receptor activity is important for the development of gastric ulcers in the pylorus-ligated rat. The mechanism behind the ulcero-protective effect of beta-adrenergic blockage remains to be solved.