THE INTERACTION OF CHOLINE ESTERS, VAGAL-STIMULATION AND H-2-RECEPTOR BLOCKADE ON ACID-SECRETION INVITRO

Abstract

Choline esters, bethanechol and carbachol, and electrical field stimulation increased acid secretion in the mouse, isolated, lumen-perfused, stomach. Electrical field stimulation was apparently mediated by vagal nerve ending because treatment with either tetrodotoxin or atropine abolished the response. Using a 2 + 2 assay design, experiments with bethanechol showed that the H2-receptor antagonists metiamide and cimetidine (1 mM) were devoid of antimuscarinic activity. However, the effects of carbachol, which unlike bethanechol stimulates both muscarinic and nicotinic receptors, were significantly antagonised by metiamide (1 mM) at a concentration which was not anticholinergic. We conclude th..