Heat production associated with neuromuscular transmission in the toad nerve-muscle preparation.

The time course of the heat produced by the toad sartorius muscle in response to nerve stimulation was determined by using a new type of heat-sensor with a high time resolution. The records obtained showed the existence of a brief burst of large heat production prior to the onset of the muscle heat associated with contraction. This initial heat-burst was shown to be produced at the motor endplates. The implications of these findings are discussed.