Figure 8.

Time-dependent slowly activating currents through outside-out patches. A, Current as a function of time in response to voltage clamp pulses from a holding potential of −80 mV to V_m values between −180 and 90 mV at 30-mV increments in 1 mm KCl. B and C, Current-voltage curves for initial (▪) and final currents (▴) for four patches in 1 mm KCl (B) and five patches in 10 mm KCl (C). Currents were normalized to the final current at 90 mV for each patch. D, Current voltage curves obtained from nonstationary noise analysis on smooth time-dependent currents obtained from outside-out patches in 10 mm KCl (▴, n = 4 patches) or 1 mm KCl (▪, n = 3 patches). The conductances estimated from linear regressions were 2.5 and 0.5 pS, respectively. The fitted line for 1 mm KCl extrapolates to a reversal potential of −40 mV. The voltage intercept for the 10 mm KCl line is −1.5 mV. Bath solution: 1 or 10 mm KCl, 1 mm CaCl₂, and 5 mm MES; pipette solution was type I. Data were filtered at 1 kHz and sampled at 2 or 4 kHz.