Effects of Enzyme Inhibitors on the Contractility and Membrane Potentials of the Rat Atrium

Abstract

Enzyme inhibitors alter the rate of ion movement across the membrane of the rat atrial cell during the repolarization phase. There is simultaneously no constant change in the resting potential while the action potential amplitude is usually depressed to a moderate degree. The relationship between these membrane changes and the altered contractility is investigated. It is concluded that metabolic depression reduces the contractility by two mechanisms: one is a membrane effect, the result of the shortening of the action potential duration, and the other is an effect more directly on the contractile processes.