Ethanol modulates allosteric interaction between Ca²⁺ binding and voltage sensor activation in cbv1+β1 channels. (A and B) Averaged G/G_max-V curves obtained over a wide range of Ca²⁺_i, in the absence (A) and presence (B) of 50 mM ethanol. These plots were fitted with Eq. 1. For curves in panel A, L₀, z_L, V_h(J), z_J, D, K_d, and C were fixed to 1.25 × 10⁻⁷, 0.41, 80, 0.6, 30.1, 19, and 27.2, respectively, whereas E was allowed to vary. For curves in panel B, L₀, z_L, V_h(J), z_J, D, and K_d were fixed to 1.3 × 10⁻⁷, 0.42, 80.83, 0.59, 29.3, and 11.3, respectively (Figs. 11 and 12), whereas E was allowed to vary. Best-fit parameters (±95% confidence interval) are shown in the corresponding plots. Data demonstrate that ethanol decreases allosteric parameter E. n = 4–8; each patch was excised from a different cell. Data are expressed as mean ± SEM.