Mutation of W697 alters the response to capsaicin and voltage. (A and B) Normalized g-V relationships for selected W697X mutants in the presence of 1 µM (A) and 100 µM (B) capsaicin. Solid smooth lines depict the best fit to a Boltzmann distribution to obtain the V_0.5 and z_g values. (C) V_0.5 values of the different W697X mutants obtained from the g-V curves. (D) ΔG_o values obtained as the sum of the voltage dependent components at 0 mV (ΔG_o(V)) and independent (ΔG_o(I)) components considering a simple two-state model between a closed and open state. g-V curves were normalized with respect to the true g_max of the channel obtained in the presence of 100 µM capsaicin (Tables 1 and 2). Data are given as mean ± SEM (error bars), with n (number of cells) ≥ 5. *, P < 0.05 as compared with wild type, using the nonparametric Wilcoxon test.