FIG. 4.

Spontaneous and antagonist-precipitated withdrawal behaviors of mice on day 5 after four daily injections of cannabinoid agonists. Male C57BL/6 mice were injected with 50 mg/kg THC (n=8), 30 mg/kg JWH-073 (n=8), 1 mg/kg AM-2201 (n=9), or vehicle (n=6) on days 1–4 (Fig. 3), then on day 5 were injected with 10 mg/kg of the CB₁-selective antagonist, SR141716A. Behaviors were observed and each event noted. Data shown are the mean±SEM number of events observed for each treatment group during the 10 min before (spontaneous withdrawal) and 10–30 min after (antagonist-precipitated withdrawal) injection of 10 mg/kg SR141716A. Data were analyzed by two-way ANOVA followed by Tukey's multiple comparisons test. ****p<0.0001 versus vehicle; ⁺⁺p<0.01, ⁺⁺⁺⁺p<0.0001 versus THC; ^$$$$p<0.0001 versus JWH-073.