Single cells and rapid inward sodium current

Abstract

This chapter presents a brief review of measurements of rapid inward sodium current in single cardiac cells. It is shown that the simplified morphology of the individual cells, with a lack of restricted extracellular space, has been exploited to provide improved spatial and temporal voltage control, resulting in the first recordings of both the activation and inactivation phases of rapid inward sodium current. It is to be expected that future research will produce much interesting data on this component of membrane current, which will have direct relevance to many processes concerned with cardiac function at the cellular level.