An electrophysiological study of the innervation of the smooth muscle of the colon

Abstract

1. Micro‐electrodes were used to examine transmission from intrinsic and extrinsic nerves to single cells of the longitudinal and circular muscle coats of colons from guinea‐pigs and rabbits. 2. When intrinsic nerves were stimulated, inhibitory junction potentials (IJPs) were observed in over 90% of the cells of the longitudinal coat and nearly all of the cells of the circular coat. The characteristics of IJPs in the guinea‐pig and rabbit were similar. Facilitation of two or three successive IJP's was sometimes observed. The IJPs were unaffected by guanethedine but were blocked by procaine. IJPs could not be elicited by stimulation of either the pelvic parasympathetic or periarterial sympath..