Inactivating BK currents are absent in CCs from kcnmb2^−/− mice. (A) The indicated voltage protocol was used to elicit currents in a dissociated mouse CC to establish the presence of BK_i currents. In the middle, 120 nM paxilline removed all current activated at 80 mV that was dependent on the loading step to 10 mV. Washout of paxilline reversed the inhibition. (B) Selected traces from A before (black) and in the presence of 120 nM paxilline (red; obscured in top example by control trace) show currents evoked by direct step to 80 mV (top) and then currents at 80 mV after a Ca²⁺ loading step to 10 mV. (C) The identical protocol was used on a dissociated CC from a β2 KO mouse, showing the strong paxilline sensitivity and reversibility of the noninactivating BK current. (D) Traces highlight the robust noninactivating paxilline-sensitive BK current in a CC from a β2 KO mouse. (E) Traces show currents from a CC from a slo1/BK KO mouse, without and with 1 µM paxilline. (F) Traces from the slo1/BK KO example in E, showing the absence of paxilline effect on currents elicited either by a direct step to 80 mV (top; red trace in paxilline is obscured by control trace) or after a Ca²⁺ loading step (bottom).