Effect of NMP-4 administered by i.t. (A and B) or i.pl. (C and D) (co-administered with formalin) routes on the first (A, C) and second (B, D) phases of formalin-induced pain. Each bar represents the mean responses from 4-7 animals and the error bars indicate the S.E.M. Control values (indicated by "C") are from animals injected with 5% of DMSO and the asterisks denote the significance relative to the control group. *P < 0.05, **P < 0.01, ***P < 0.001. (one-way ANOVA followed by Dunnett' test).