Figure 2.

Paradoxical effect of cocaine, amphetamine, nomifensine, and bupropion on motor activity of DAT-CI mutants. Horizontal motor activity induced in WT and DAT-CI mice by intraperitoneal administration of 40 mg/kg cocaine (WT, n = 8; DAT-CI, n = 7) (a, b), 5 mg/kg amphetamine (n = 8 per genotype) (c, d), 15 mg/kg nomifensine (n = 8 per genotype) (e, f), or 30 mg/kg bupropion (n = 8 per genotype) (g, h), after 1 h of cage habituation. Cocaine, amphetamine, and nomifensine shared the same vehicle group (n = 16 per genotype), whereas bupropion-treated mice were compared with a different vehicle group (WT, n = 4; DAT-CI, n = 8). Locomotion is expressed as number of sector crossings, measured every 10 min over a 1 h test, and presented as time course (a, c, e, g) or total activity (b, d, f, h). All values are expressed as mean ± SEM. **p < 0.01, ***p < 0.0001 versus vehicle group within genotype (one-way ANOVA). Genotypes and treatments are as indicated.