Figure 8.

Effect of XAE (300 mg kg^-1), XA (100 mg kg^-1) and morphine (MOR; 3 mg kg^-1) challenge on mice chronically treated with vehicle, XAE (600 mg kg^-1), XA (200 mg kg^-1) or morphine (6 mg kg^{- 1}) for 8 days on the total nociceptive score in Phase 1 (a) and Phase 2 (b) of formalin-induced pain in mice. Each column represent the mean ± S.E.M. (n = 8); ^*P 0.05, ^***P < 0.01, ^***P < 0.001 compared to vehicle-treated control group (ctrl) (one-way ANOVA followed by Newman-Keuls post hoc test)