Fig. 5.
Expression of amphetamine sensitization after a shorter period of abstinence. a Repeated exposure of mice (n=8 per genotype) to amphetamine (1 mg/kg) for three consecutive days induced locomotor stimulation and sensitization in D1+/+ mice, but not in D1−/− mice. **P< 0.005–0.0001 compared to saline-pretreated controls; #P<0.006 compared to day 1. b Amphetamine challenge after 11 days of abstinence had no effect in mice pretreated with saline but induced locomotor sensitization in mice pretreated with amphetamine from both genotypes. **P<0.004; *P<0.01 compared to their own responses to saline treatment, although it was less pronounced in D1−/− mice than D1+/+ mice. #P<0.006–0.0003 compared to saline-pretreated mice challenged with amphetamine. Values are means + SEM