I696X mutants display an altered response to capsaicin and voltage. (A and B) Normalized g-V curves obtained 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 I696X mutants obtained from the G-V curves at the vanilloid concentrations used. (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 (Tables 1 and 2). g-V curves were normalized with respect to the true g_max of the channel obtained in the presence of 100 µM capsaicin (Table 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.