The voltage dependence of the decay of the excitatory postsynaptic current and the effect of concanavalin A at the crayfish neuromuscular junction.

In voltage clamped crayfish muscle fibers the time constant tau of decay of the EPSC was measured at different clamp potentials E. At 6 degrees C, the average potential dependence of tau is described by tau = 2.3 ms.eE/328 mV. tau was shorter in fast fibers than in slow ones. Concanavalin A supressed the potential dependence by tau, resulting in an increase in tau compared with the control, especially at high negative potentials.