Figure 10.

Camphor activates a TRPV1-like current in DRG neurons. A, Currents evoked by voltage ramps (400 ms; from –100 to +100 mV) are shown in basal conditions (dashed line), in the presence of 3 mm (red line) and 10 mm (blue line) camphor, and during application of 1 μm capsaicin (solid black line). The holding potential between ramps was –60 mV. B, Increasing concentrations of camphor (applied during bars) elicited increasing amounts of current in a DRG neuron. The currentat +80 mV(triangles) and –80 mV (squares) during the ramps are shown. The positions of the ramp currents plotted in A are indicated by the green symbols; the dotted line indicates zero current level. C, Currents in the presence of 10 mm camphor recorded from a camphor-unresponsive neuron (green line) and from the same camphor-responsive neuron shown in A for comparison. The entire voltage protocol is shown, including the 40 ms at –100 and +100 mV flanking the ramp. The black dashed line shows the basal current recorded in the camphor-unresponsive neuron, which happened to have similar amplitude to the camphor-responsive cell.