Fig. 5.
Single-channel patch data of the gain-of-function IKs-S209F mutant. (A) Single-channel sweeps for 4 s to +60 mV show opening of a single channel throughout almost the entire 4-s pulse, usually opening after a short latency. Note that in sweep 1 the channel remains closed. The solid line indicates zero current. (B) Ensemble average current for 67 current recordings shows rapid activation of IKs and sustained current on repolarization to −40 mV. (C) Histogram of idealized event amplitudes. Note that because of high Po, events are dominated by the fully open level at +60 mV (I = 0.43 ± 0.03 pA). (D) Po during 100 sweeps of train shows the high opening frequency of the channel. (E) Ensemble-averaged Po from 100 successive sweeps during 4-s depolarizing pulses to 60 mV.