Mutations that reduce CaM binding to the TRPV1-ARD or TRPV1-CT caused different defects in TRPV1 current desensitization in HEK293 cells. (A) Representative traces of capsaicin-evoked whole cell currents in response to repeated capsaicin applications in the presence of extracellular Ca²⁺. Cells were repeatedly stimulated with 1 µM capsaicin for 1 min followed by 1-min washouts. The +80 mV (red) and −80 mV (black) currents extracted from 1,500-ms voltage ramps are shown. (B) Mean current amplitudes for successive capsaicin applications were normalized to the maximal current amplitudes of the first capsaicin application. *, P < 0.01 versus TRPV1 wild type using two-tailed unpaired t tests. (C) Mean current density of the maximal response to the first capsaicin application normalized to the cell capacitance. The values in B and C were calculated from current amplitudes at −80 mV (negative scale) and +80 mV (positive scale) measured in experiments as in A. Bars represent mean ± SEM (n = 6, 8, 8, and 8 for wild type, W787A, K155A, and W787A/K155A, respectively).