Rate of induction of the slowing of Kv1.2 charge return and the voltage dependence of return of stabilized voltage sensors. (A) Representative gating current demonstrating the slowing in the kinetics of IgOFF currents at a repolarizing voltage of −100 mV as the duration of depolarization to 0 mV was extended in 0.5-ms increments (n = 4). (B) Isolated traces from A after depolarization of 0.5, 1.5, 3.5, 9.5, and 14.5 ms. (C) Plot of the Qoff/Qon as a function of pulse duration. Qoff was calculated by integrating the first 11 ms of IgOFF. (D) Representative gating currents obtained using the two-pulse protocol shown. Return of charge was observed after a 50-ms depolarizing pulse to 10 mV by a series of hyperpolarizing pulses in 10-mV increments from −40 to −190 mV. Linear membrane leak was subtracted online using a −P/8 leak subtraction protocol from a subtraction holding potential of −140 mV (n = 6). (E) The first 11 ms of IgOFF were integrated, and the values were plotted against voltage and compared with the Qon-V relationship from Fig. 1 D. Error bars represent SEM.
