An attempt at an analysis of the factors determining the time course of the end-plate current. II. Temperature.

1. An attempt was made to analyse further the factors which might determine the time course of the falling phase of the end-plate current.2. The end-plate current was measured by ;clamping' the membrane potential during neuromuscular transmission. The falling phase of the end-plate current had an exponential and a non-exponential portion.3. The exponential portion of the falling phase of the end-plate current was found to be strongly affected by changes in the membrane potential and by relatively small changes in temperature.4. It is suggested that the two rate constants which determine the dissociation of the receptor-mediator complex are affected by both temperature and the membrane potential. Under certain experimental conditions these two rate constants alone seem to determine the time course of the exponential portion of the falling phase of the end-plate current.