On the changes of the time course of the end-plate current during repetitive stimulation.

In a previous study it was observed that prolonged repetitive stimulation (10.s-1) markedly lengthened the time course of the end-plate current. In order to investigate whether this effect could be due to a more dispersed release of the mediator or to a decreased clearance of the mediator from the synaptic cleft, the rise time of the end-plate current and of the miniature end-plate current were analyzed. The results show that presynaptic factors may be involved.