Figure 1.

Effect of the systemic administration of vehicle, amphetamine (10 mg/kg i.p.), cocaine (20 mg/kg i.p.), JWH-018 (0.3 mg/kg i.p.), and AKB48 (1 mg/kg i.p.) on the total distance traveled (A), on the immobility time (B), and on the total time spent in the peripheral and central area (C,D) of the mouse. Interaction of JWH-018 and AKB48 with the selective CB₁ receptor antagonist AM 251 [6 mg/kg, i.p.; (E)], the D₁ receptor antagonist SCH23390 [0.1 mg/kg i.p.; (E)], and the D₂ receptor antagonist haloperidol [HAL; 0.05 mg/kg i.p.; (E)]. AM 251, and SCH23390 + HAL were administered 20 min before synthetic cannabinoids injection. Data are expressed as meters (total distance traveled) and as seconds (immobility time; time in the peripheral and central zone). Data represent the mean ± SEM of eight determinations for each treatment. Statistical analysis was performed by two-way ANOVA followed by Bonferroni’s test for multiple comparisons (A–D) or by one-way ANOVA followed by Tukey’s test (E). *p < 0.05, **p < 0.01, ***p < 0.001 versus vehicle; ^§§p < 0.01 versus JWH-018; ⁺⁺p < 0.01 versus AKB48.