Current clamp and voltage clamp study of the inhibitory action of DNP on membrane electrical properties of frog auricular heart muscle.

Current clamp studies showed that after 10 minutes under DNP 10(-4) M the membrane potential does not change significantly while an important shortening of the action potential duration and a diminished amplitude are observed. Voltage clamp studies have been performed on the slow inward and delayed outward currents. DNP 10(-4) M induced a marked decrease of the slow inward current related to the reduction in both conductance and driving force, and a decrease in the amplitude of the delayed current. The decrease of the slow inward current seems to be mainly responsible for the suppression of the plateau of the action potential during metabolic inhibition.