Effect of SA (0.5, 1 and 2 mg/kg i.p.) repeated treatment on mechanical withdrawal threshold of the ipsi- (A, C) and contralateral (B, D) hind paw 3 and 7 days after formalin injection in mouse. SA (2 mg/kg i.p.) was also administered in combination with nor-BNI (20 mg/kg i.p.), AM251 (1 mg/kg i.p.) or AM630 (1 mg/kg i.p.) (C, D). Data were expressed as mean ± SEM of mechanical withdrawal thresholds in grams. # indicate significant differences vs veh/saline-treated mice, * indicate significant differences vs vehicle treatment in formalin injected mice and ° indicate significant differences vs SA/formalin injected mice. P values <0.05 were considered statistically significant (one-way ANOVA followed by Student-Newman Keuls).