Effects of pirenzepine and atropine on amylase response to various secretagogues from the rat pancreatic acini

Abstract

CCK-8, bombesin, secretin and urecholine added in various concentrations to the incubation medium of the dispersed pancreatic acini, obtained from rats, resulted in a dose-dependent stimulation of amylase secretion, the half-maximal response being achieved at 3 X 10(-12), 10(-10), 10(-7) and 10(-5) M, respectively. Pirenzepine (selective muscarinic M1 receptor blocker) or atropine failed to affect the amylase responses to all these secretagogues except that to urecholine, which was reduced by both antimuscarinic agents. The inhibition of urecholine-induced half-maximal amylase secretion by both anticholinergics was concentration-dependent, and the inhibitory potency of pirenzepine was about 1,000 times lower than that of atropine.