Electrophysiology of Smooth Muscle

Publisher Website
Google Scholar
Abstract
Smooth muscles occur in a wide range of properties; at one end are the nerve-controlled, nonspontaneous, multiunit muscles and at the other are the stretch-sensitive, spontaneous, unitary muscles in which there is a marked degree of electrical interaction between cells. Resting potentials of smooth muscle are smaller and more labile than those of striated muscle. Spikes may not show an overshoot; they may be unaffected by replacement of as much as 90% of the sodium in the medium. Potassium lost during activity has been demonstrated. Many excitatory agents[long dash]stretch, acetyl-choline[long dash]act by depolarizing the membrane into the zone of firing; estrogens increase uterine resting potential into the zone of activity. Other agents[long dash]adrenaline, sympathetic stimulation nerve impulses on intestine, progesterone on uterus [long dash]can reduce activity by hyper-polarizing the membranes beyond the zone of firing. Acetylcholine and adrenaline may have either excitatory or inhibitory effects, according to the muscle. Control of smooth muscle activity by nerves, stretch, temperature, and hormones is largely by modulation of resting potentials.

This publication has 127 references indexed in Scilit: