Fig. 1.

PGE₂ and forskolin treatment enhance the amplitude of the whole-cell current elicited by capsaicin.A, Voltage-clamp recording (holding potential −60 mV) obtained from a representative neuron in which PGE₂treatment increased the amplitude of the current elicited by a 2 sec focal application of capsaicin. B, Sensitizing effects of 100 nm and 1 μm forskolin treatment (top and bottom traces, respectively) on capsaicin responses in two other neurons. The times indicate when these recordings were obtained after the onset of prostaglandin or forskolin treatment. The extent and time courses of sensitization induced by different concentrations of forskolin are summarized inC. The amplitude of the capsaicin response after forskolin treatment was normalized to the average of the two control responses and represented as the fold increase relative to the control value. The bar beginning at 3 min represents the change to forskolin-containing Ringer’s solution. D, Effects of dideoxyforskolin on the capsaicin response. Thehatched and open bars indicate the applications of dideoxyforskolin and PGE₂, respectively. Asterisks indicate significant differences at p < 0.05 compared with control.