Potentiation of proton-gated currents by prokineticin 2 in rat dorsal root ganglia neurons. Three types of proton-induced currents were recorded in DRG neurons. Example traces of a (A) slow-inactivating current, (B) fast-inactivating current and (C) sustained current. All three types of proton-induced currents could be inhibited by 20 μM amiloride, a broad-spectrum ASIC channel blocker. Pre-application of PK2 increased the peak phases of all three types of proton-induced currents. Proton-induced currents were evoked by extracellular application of a pH 5.5 solution for 5 s in the presence of the TRPV1 inhibitor capsazepine (10 μm). The pretreatment time for PK2 (1 nM) was 60 s. ASIC: acid-sensing ion channels; DRG: dorsal ganglia root; PK2: prokineticin 2; TRPV1: transient receptor potential vanilloid receptor-1.