Muscarinic receptors of the pancreas: a correlation between displacement of (3 H)-quinuclidinyl benzilate binding and amylase secretion.

(3H)-quinuclidinyl benzilate [(3H)-QNB], A potent muscarinic antagonist, was used as a tool to reveal the presence of muscarinic receptors in rat pancreas. Binding assays were performed on a 49,000 g pellet. Known muscarinic antagonists and agonists were used for competition assays on (3N)-QNB binding and studies on amylase secretion in vitro. A correlation was established between the binding assays and the studies on amylase release which suggests that the binding sites and those involved in the cholinergic control of pancreatic enzyme secretion are similar.