Fig. 3

The effect of naloxone (NAL) on anxiolytic-like behaviours induced by mitragynine (MG) and morphine (MOR) in rats. The animals received a pre-test injection of saline (1 ml/kg) or NAL (2 mg/kg) 15 min before MG (40 mg/kg) or MOR (6 mg/kg) treatments. Control (5 ml/kg) and NAL groups received saline (1 ml/kg) 15 min before treatments. The anxolytic-like behaviour indices include changes in %OAE (a), %OAT (b) and the total arm entries (c). Each bar represents mean ± SEM. ***p < 0.001 when compared to control group; ⁺⁺⁺ p < 0.001 when compared to MG group; ^## p < 0.01 and ^### p < 0.001 when compared to MOR group