FIGURE 6.
NMU-induced IA increase involves activation of ERK. A–C, NMU induced increased phosphorylation of ERK (p-ERK, A) in DRG neurons, whereas the protein expression levels of p-JNK (B) or p-38 (C) were not affected. β-Actin showed equal loading. D and E, NMU-induced p-ERK increase was abolished by NMUR1 knockdown and pretreatment of the cells with PD98059 or H89. Exposure of DRG neurons to NMU still increased p-ERK expression in cells transfected with control siRNA. All experiments were performed in triplicate with similar results. Inset, numbers 1–4 represents control siRNA, NMUR1 siRNA, H89, and PD98059, respectively. F, representative current traces (upper) and summary data (lower) showed the effects of 1 μm NMU on IA in the presence of U0126 (n = 9) or PD98059 (n = 7). **, p < 0.01 versus control; ***, p < 0.01 versus control.