Voltage sensitivity of inhibitory postsynaptic currents in Aplysia buccal ganglia
Inhibitory postsynaptic currents (IPSCs) which were recorded in voltage-clamped neurones in buccal ganglia of Aplysia were blocked by D-tubocurarine and lengthened by prostigmine. Their amplitude varied with membrane potential and the mean null potential was --58 mV. The conductance change producing the IPSCs was in the range 1-5 x 10 -7 ~2-1. The decay of IPSCs was exponential, with a mean time constant of decay (z) of 12 msec at a membrane potential of --40 mV (20 °C). z varied exponentially with membrane potential, increasing e-fold for a hyperpolarization of 155 mV. It was concluded that the voltage sensitivity of the decay of synaptic conductance is not related to the ion-selectivity of the ionophore.