Involvement of MAPK kinases and PKC in the mechanical hyperalgesia induced by formalin in gastrocnemius muscle. Mice were treated with the protein kinase inhibitors (A) p38 (SB203580 11 µg per site, i.m.), (B) JNK (SP60015 7 µg per site, i.m.) or (C) PKC (GF109203X 0.4 µg per site, i.m.) 5 min before the i.m. injection of formalin. The mechanical hyperalgesia was evaluated from 1 h after formalin injection. B, baseline measurement (before formalin injection). Data represent the mean ± SEM (n= 5). The symbols denote a significant difference: *P < 0.05 compared to the naive group and #P < 0.05 compared to the formalin i.m. group. Statistical analyses were performed using one-way anova (repeated measures) followed by Bonferroni's test.