Potassium gating currents from squid axon. (a) Time constants (τ) of ionic and gating currents during (ON) and after the pulses (OFF) of the indicated voltages. (b) Normalized Q–V (Q_rel) and G–V (f_o) curves. Inset shows a representative potassium gating current showing a rising phase after the partially blocked sodium gating currents. Adapted from White and Bezanilla (1985).