Fig. 1.
Effects of pretreatment with the D2R antagonist L-741,626 or the D3R antagonist PG01037 on basal locomotor activity, acute cocaine-induced locomotor activity, and cocaine-induced sensitization in mice. a Total number of ambulations in the 30-min period following i.p. administration of L-741,626. b Effects of pretreatment with L-741,626 on locomotor activity in the 60-min period following i.p. administration of cocaine. c Effects of L-741,626 on cocaine-induced sensitization. Mice received one of the following four combinations of L-741,626 and cocaine daily for 5 days: vehicle + saline; vehicle + 15.0 mg/kg cocaine; 10.0 mg/kg L-741,626 + saline; 10.0 mg/kg L-741,626 + 15.0 mg/kg cocaine. Shown are the total number of ambulations in the 60-min period following administration of saline or 15.0 mg/kg cocaine, which was administered 30 min after pretreatment with either 10.0 mg/kg L-741,626 or its vehicle. d Total number of ambulations in the 30-min period following i.p. administration of PG01037. e Effects of pretreatment with PG01037 on locomotor activity in the 60-min period following i.p. administration of cocaine. f Effects of PG01037 on cocaine-induced sensitization. Mice received one of the following four combinations of PG01037 and cocaine daily for 5 days: vehicle + saline; vehicle + 5.0 mg/kg cocaine; 10.0 mg/kg PG01037 + saline; 10.0 mg/kg PG01037 + 5.0 mg/kg cocaine. Shown are the total number of ambulations in the 60-min period following administration of saline or 5.0 mg/kg cocaine, which was administered 30 min after pretreatment with either 10.0 mg/kg PG01037 or its vehicle. For panels (a), (b), (d), and (e), all mice (n = 15) received all treatments. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001, significant difference by Dunnett’s test as compared to vehicle dose of pretreatment drug at the same dose of cocaine. For panels (c) and (f), mice (n = 6–8 per group) received the same drug combination once per day for 5 consecutive days. ***p < 0.001, ****p < 0.0001, significant difference by Dunnett’s test compared to day 1 within the same drug combination group. For all panels, each data point represents mean ± SEM ambulations