Effect of Retigabine on the activity of the heteromeric K_V7.2/K_V7.3 channel. (A) K⁺ currents recorded in the absence or presence of 1–5-µM Retigabine using the same protocol shown in Fig. 1. (B) Average normalized K⁺ current amplitude measured at the beginning of the deactivating currents (I_TAIL; arrows in A). Normalized I_TAIL versus test pulse potential (I_TAIL–V_PULSE) plots incrementally shift toward negative potentials as the concentration of Retigabine (RTG) was increased. Individual I_TAIL–V_PULSE plots were fitted to a double Boltzmann distribution, and the weighted average half-maximum potential (weighted V_1/2) was plotted as a function of the concentration of Retigabine (inset). Although the weighted V_1/2 values were not statistically different, this parameter changed to more negative potentials as a function of the concentration of Retigabine in all our recordings. Error bars represent standard deviation. n = 5–8.