Fig. 7.

Collected results for measurements of sodium channel availability during action potential firing at 23°C. A: maximum availability in between spikes (filled circles) and minimum availability after spikes (filled triangles) during repetitive action potential firing at different frequencies. B: kinetics of recovery of sodium channel availability from minimum to maximum during the ISI, expressed as the time constant for a single exponential fit to the recovery. C: sodium entry ratio during the action potential as a function of firing rate.