Figure 3. Stimulation of protein kinase A phosphorylation by the adenylyl cyclase activator forskolin. (A) Current traces evoked by depolarization from −80 mV to 0 mV before and after extracellular application of 10 µM forskolin (FSK) for NaV1.8 from rat, hNaV1.8, and hNaV1.8−Δe11 in ND7/23 cells. (B) Current-voltage relationships for the channels in (A) before and after FSK application normalized to the peak inward current and averaged for 6–8 cells ± s.e.m. (C) Time course of peak current changes upon FSK stimulation normalized to control level for NaV1.8 from rat, hNaV1.8, and hNaV1.8−Δe11. Application of FSK starts at t = 0 s. Data points are mean values for 7–11 cells each ± s.e.m.