Ganglionic stimulant action of muscarine

¹ Department of Pharmacology, Geigy Research Laboratories, Ardsley, New York

Ganglionic stimulant action of muscarine has been demonstrated on the inferior mesenteric ganglion of the cat. The stimulant effect of muscarine on this ganglion is slow in onset and highly sensitive to atropine, thus differing from "nicotinic" ganglion stimulants such as 1,1-dimethyl-4-phenylpiperazinium iodide. The racemic form of muscarine is less potent than the natural l(+) muscarine and the d(–) form is inactive. Three stereoisomers of muscarine, inactive on the postganglionic parasympathetic receptor sites, were also found to be inactive on the ganglion. The existence of ganglionic receptors functionally similar to postganglionic parasympathetic receptors is proposed.