Voltage-dependent inactivation of maxi-anion channel currents recorded in macro-patches excised from mammary C127 cells. a Steady-state ramp I–V records from a macro-patch containing five active channels. b Inactivating current traces recorded in response to step pulses from 0 to ±50 mV in 10-mV increments in a macro-patch containing 20 active channels. c Voltage dependence of steady-state open-channel probability. Filled circles represent the ratio of steady-state macro-patch current to instantaneous macro-patch current (from b). The Boltzmann fit (dashed line) yields a half-maximal open-channel probability at V1/2 = +13.9 and −36.9 mV for positive and negative potentials, respectively. The solid line is the ensemble-averaged current of 11 consecutive ramp-pulse records similar to those shown in (a). Modified from Sabirov et al.