The ethanol response of wt β2–containing BK channels is similar to the ethanol response of cbv1+β1 channels. (A and B) Single-channel recordings of cbv1+wt β2 channels from I/O patches at 0.3 (A) and 100 µM Ca²⁺_i (B); V_m = −40 mV. Records were obtained before (top traces), during (middle traces), and immediately after (bottom traces) patch exposure to 50 mM ethanol. Arrows indicate the baseline (all channels in nonpermeant states). (C) Averaged NPo ratios in the presence and absence of ethanol from cbv1+wt β2 at 0.3, 3, 10, 30, and 100 µM Ca²⁺_i. Data demonstrate that the activation to inhibition crossover for ethanol effect on cbv1+wt β2 channels occurs at ≈3 µM Ca²⁺_i, which is similar to that found in cbv1+β1 channels. n = 5–7; each patch was excised from a different cell. *, different from control (P < 0.05); **, different from control (P < 0.01). Data are expressed as mean ± SEM.