Figure 6.

Effect of HLE (30 mg/kg, p.o.), (a), and morphine (3 mg/kg, i.p.), (b), challenge on mice chronically treated with saline, HLE (60 mg/ kg, p.o.), morphine (6 mg/kg, i.p.), or combination of HLE (60 mg/kg, p.o.) and morphine (6 mg/kg, i.p.) for 8 days on the total nociceptive score of both phases of the formalin-induced licking test in mice. Each column represents mean ± SEM (n=5). ^†P<0.05 and ^††P<0.01 compared to respective vehicle-treated controls; ^*P< 0.05 compared to HLE 30 mg/kg and ^‡P<0.05 compared to morphine 3 mg/kg (one-way ANOVA followed by the Newman–Keuls post hoc test)