FIGURE 7.

Na-channel inactivation in cerebellar nuclear cells induced by quasiphysiological voltage steps. (A) Voltage protocol and representative traces for a cerebellar nuclear cell, mimicking depolarizations occurring during spontaneous firing at 20 Hz, a 250-ms period of inhibition, and a rebound burst of three action potentials at 100 Hz. (B) Peak transient Na currents normalized to the amplitude of the first current, plotted time locked to the traces in A (N = 5). For the rebound burst, symbols designate the voltage of the preceding hyperpolarization. (C, left) Voltage protocol and representative traces for rebound burst (B, boxed area) at high gain. (C, right) Rebound currents from B plotted versus recovery voltage (N = 5). The data set for each rebound current was fit with a straight line (rebound current 1, 2%/mV; rebound current 2, 0.5%/mV; rebound current 3, 0.3%/mV).