Properties of the inward ionic currents and their regulating agents in smooth muscle cells.

Abstract

After Hamil et al. (1981) introduced the patch clamp procedure for the investigation of ionic channels, studies on the biophysical features of smooth muscle membranes have progressed remarkably. From results with the patch and voltage clamp procedures, more than two voltage-dependent Ca channels, and several Ca-dependent and Ca-independent K channels have been classified from their physiological and pharmacological properties. With the whole cell patch clamp technique, a Na current was also isolated from vascular smooth muscles. In this article, we want to review recent advances in biophysical investigation of the ionic current of smooth muscle membranes. We will focus on the inward currents, following through the voltage-dependent and receptor-operated Ca permeable channels and voltage-dependent Na channel in relation to some drug actions.