Effect of inhibitors of choline acetylation on acetylcholine output and motility in response to anticholinesterases and to distension of the lumen of isolated guinea-pig ileum.

Some pharmacological effects of acyl-aryl compounds, which inhibit the enzymatic acetylation of choline, have been studied on the isolated guinea-pig ileum. Diphenylylbutylacetic acid (M.G. 1763) greatly reduced the output of acetylcholine from intestine. The intestinal contractions produced by anticholinesterase drugs were inhibited, while the response to acetylcholine itself was little affected. The contraction of longitudinal muscle elicited by raising intra-luminal pressure was also decreased, while the emptying phase of the peristaltic reflex was scarcely affected. There was a correlation between inhibitory activity and chemical structure.