Kv7 currents in human ASMCs. A: time course of endogenous Kv7 current recorded in a human ASMC at −20 mV holding voltage before and during treatment with retigabine (10 μM) followed by XE991 (10 μM) (C = 16 pF, representative of 3 similar experiments). Vertical gray lines indicate a 10-min break to record I-V relationships from −4 mV holding voltage in the presence of retigabine. B: average I-V relationships of Kv7 currents measured in control (●, n = 5) in the presence of 10 μM retigabine (○, n = 3) and in the presence of XE991 (10 μM, ▲, n = 3). C: averaged fractional conductance plot calculated from retigabine sensitive portion of sustained Kv7 currents (currents measured in the presence of retigabine minus control currents) fitted to a Boltzmann distribution (V0.5 = −45.1 ± 1.7 mV, n = 3). Currents measured before retigabine treatment were subtracted from currents measured in the presence of retigabine at the same voltages.