Figure 9.

Gating current fluctuations in the full model. (A) Plots of the mean current and variance assessed from 10,000 simulated microscopic gating currents obtained in response to a depolarizing step to 0 mV (initial position of the voltage sensor −1.67 nm). Each simulated microscopic current was filtered with an eight-pole Bessel filter with a cutoff frequency of 8 kHz. (B) Plot of variance versus mean current made with the data shown in (A). The solid line represents the fit of the data from the decaying part of the gating current with Eq. 13, with qapp = 2.0 e₀. (C) Total energy profile experienced by the voltage sensor during its movement, at an applied potential of 0 mV. Notice that this energy profile, differently from those arbitrarily chosen in the simplified model, is self-consistently assessed with the Poisson equation, considering the effect of all the charges present in the system. (D) Plot of the mean current and variance assessed from 10,000 simulated microscopic gating currents obtained in response to a depolarizing step to −40 mV (initial position of the voltage sensor −1.67 nm). (E) Apparent charge obtained at various applied potentials. (F) Plot of variance versus mean current made from data obtained with a repolarization to −140 mV (from an initial position of the voltage sensor of +1.56 nm). The solid line represents the fit of the data from the decaying part of the gating current with Eq. 13, with qapp = 1.35 e₀. To see this figure in color, go online.