The effect of membrane polarization on the time course of the end-plate current in frog sartorius muscle.

1. Intracellular recordings of the end-plate current at different membrane potentials were made, using a voltage-clamp technique.2. When the membrane potential is varied between about +40 and -120 mV, the half-decline time of the end-plate current increases from about 0.6 msec to about 1.6 msec.3. It is suggested that the stability of receptor-mediator complex is affected by the membrane potential.