The amplitude and the time course of the end‐plate current at various pH levels in the frog sartorius muscle.

Abstract

1. The amplitude and the time course of the end-plate current are dependent on the pH of the bathing solution. 2. When pH is changed from 5.4 to 9.4 the amplitude of the end-plate current is increased and its decay is speeded up. 3. The change in the amplitude seems to be a result of a variation of quantal content. 4. The change in the time course of the end-plate current is explained by assuming that the rate constants which determine the dissociation of the receptor-mediator complex are affected by a change in pH. 5. This speculation is supported by the finding that the effect of membrane potential on amplitude and time course of the end-plate current are dependent on pH of the bathing solution.