VR1 forms functional channels in Xenopus oocytes. (A) Current family activated by a saturating capsaicin concentration (4 μM) in an outside-out patch obtained from stepping the voltage from a holding potential of 0 mV to between -100 and +100 mV. For scale bar see (C). (B) Current-voltage relation for currents activated by 4 μM capsaicin. Data were normalized to the value of the current at -100 mV. (C) Current family activated by a sub-saturating capsaicin concentration (0.5 μM). (D) Current-voltage relation for currents activated by 0.5 μM capsaicin (red) with data from currents obtained with 4 μM capsaicin shown also (blue). Data were normalized to the value of the current at -100 mV. (E) Dose-response relation for activation by capsaicin plotted on a double-log scale. The smooth curves are fits with the Hill equation with K½ = 440 nM, Imax = 567 pA, and n = 2.2. Filled circles represent actual data values. All data in this figure are from the same patch.