Cholesterol depletion inhibits Kv7 channel function in mesenteric arteries. (A i) Representative recording of a Kv7.4 current from a Xenopus oocyte before (black) and after (red) application of 1 mM M-βCD. (A ii) Mean data showing the effect of M-βCD on the Kv7.4 current in Xenopus oocytes at 40 mV (n = 5). **, P < 0.01 according to a paired t test. (B) Representative isometric tension recordings of rat mesenteric artery segments preconstricted with methoxamine (•) before sequentially increasing concentrations of Kv7.2–Kv7.5–specific activator NS15370 were applied in (from left to right) control, M-βCD–treated, cholesterol-saturated M-βCD–treated, and M-βCD + ciliobrevin D–treated arteries. (C) Mean concentration-effect curves and EC₅₀ values for the Kv7.2–Kv7.5–specific activator NS15370 in isometric tension recordings from either segments of mesenteric artery treated with 5 mM M-βCD (blue, n = 8), 5 mM M-βCD supplemented with cholesterol (green, n = 5), 10 µM ciliobrevin D (red, n = 10), or 5 mM M-βCD + 10 µM ciliobrevin D (orange, n = 6) or from control vessels (black, n = 14) when methoxamine was used to preconstrict the artery segments. M-βCD significantly attenuates the relaxation for NS15370, while cholesterol-saturated M-βCD had no effect compared with control vessels. Ciliobrevin D was unable to enhance relaxation in M-βCD–treated vessels. (D) Mean concentration-effect curves and EC₅₀ values for the Kv7.2–Kv7.5–specific activator NS15370 in isometric tension recordings from segments of mesenteric artery treated with 3 µM Filipin III. 3 µM Filipin III significantly attenuates relaxation for NS15370. Statistical comparisons on the mean EC₅₀ values were performed with a one-way ANOVA followed by a Tukey multiple comparisons test. *, P < 0.05; **, P < 0.001; ***, P < 0.0001. Error bars show mean values and SEM.