(A) hKv7.2/7.3 current evoked by staircase depolarizations before and after application of 100 nM CBD. (B) Collected results (mean ± SEM) for current at –50 mV after application of 100 nM (n = 20) or 300 nM CBD (n = 14) for 4–6 min, normalized to current before CBD application, using the protocol in (A). ‘No CBD’ values (n = 11) are for 6 min dummy applications of solution containing only vehicle (DMSO). (C) Voltage-dependent activation of hKv7.2/7.3 channels measured in a cell before and after application of 300 nM CBD. Relative conductance at each voltage was measured from the initial tail current at a step to –50 mV following 1 s depolarizations to voltages between –100 mV and +20 mV from a holding potential of –80 mV. Solid lines: fits to data points of fourth power Boltzmann function, [1/ (1 + exp(-(V – Vhn)/k))]4, where V is test pulse voltage, Vhn is voltage of half-maximal activation for single ‘n’ particle, and k is slope factor for activation of n particles. Control: Vhn = –54.4 mV, k = 12.8 mV (midpoint of function = –33.1); 300 nM CBD: Vhn = –67.9 mV, k = 11.8 mV (midpoint of function –48.3 mV). (D) Concentration-dependent shift of activation midpoint by CBD. Measurements of the midpoint were made before and 10 min after exposure to CBD at various concentrations. mean ± SEM, n = 9 for 30 nM CBD, n = 21 for 100 nM CBD, n = 17 for 300 nM CBD, n = 12 for 500 nM CBD, n = 7 for 1 µM CBD, n = 16 for 3 µM CBD, n = 19 for 10 µM CBD, n = 10 for 20 µM CBD. Value for 0 CBD represents the measurement of a small shift that occurred with dummy applications of DMSO-containing control solution for 10 min (n = 11). Solid line: fit to the Hill equation, ΔVh = −2.5 mV − 17.5 mV/(1 + (EC50/[CBD])^nH), where EC50 = 214 nM and the Hill coefficient nH = 1.3.