NK-1R activation enhances Ca_v2.2/Ca_Vβ2a currents. HEK-M1 cells were transiently transfected with Ca_V2.2, α₂δ-1, β2a, and NK-1R. (A) Individual traces taken before and 2 min after application of 5 nM SP. (left) 0.1 mM BAPTA was present in the internal solution. (right) 20 mM BAPTA in the internal solution. (B) Comparison of the mean percent enhancement for cells dialyzed with 0.1 or 20 mM BAPTA (n = 4–9); *, P < 0.05 compared with inhibition in the presence of 0.1 mM BAPTA. (C) Individual traces taken before and 2 min after application of SP. P1 and P2 represent current measured before and after a prepulse, respectively. (D) Summary of the percent enhancement by SP at 0 mV before and after a prepulse (n = 9); *, P < 0.05 compared with P1 and P2 control currents before SP application. (E) Averaged current–voltage relationships measured before (closed circles) and after (open circles) application of SP. (F) Summary of TTP before and after application of SP (n = 6); *, P < 0.05 compared with control. Error bars represent SEM. Bars, 10 ms and 200 pA.