Macroscopic currents in WT TRPV1 activated by 4 µM capsaicin or 5 µM LPA. (A) Representative currents at −60 and +60 mV. The gray lines correspond to the leak current, the black lines are the response to capsaicin, and the red lines are the response to LPA. The dashed line indicates zero current. (B) Paired data for eight independent experiments at −60 and at 60 mV. Each color represents one membrane patch. (C) The bar graph corresponds to the normalized currents of data in (B). Data obtained in the presence of LPA 5 µM are normalized to the current elicited by 4 µM capsaicin, where values for currents elicited by the latter agonist were set to 1 (gray bars). The increase elicited by LPA was 1.36 ± 0.1–fold larger at −60 mV (*, P 0.01, n = 8) and 1.36 ± 0.056–fold larger at +60 mV (*, P 0.01, n = 8), as compared with capsaicin. Recordings were performed in the inside-out configuration of the patch clamp, the holding potential was 0 mV, and 60 and −60 mV square pulses lasted 100 ms. Leak currents were obtained first; then capsaicin was applied to obtain the currents elicited by this agonist; then capsaicin was washed; and finally, currents in the presence of LPA were obtained. Agonists were applied using a rapid solution changer, as described in the Materials and methods section. Group data are reported as the average ± SEM.