Figure 5.

Dopamine D₂R-mediated functions in DAT-CI mutants. a, Firing of DA neurons (outward current; in picoamperes) measured by sharp microelectrode recordings in response to bath application of 1 μm quinpirole in WT and DAT-CI mice (n = 9 per genotype). The top panel shows representative trace recordings. b, Horizontal motor activity in WT and DAT-CI mice in response to intraperitoneal administration of 0.5 mg/kg quinpirole (n = 5 per genotype) or vehicle (n = 8 per genotype), in a novel cage. Locomotion is expressed as total number of sector crossings over a 30 min test. c, P-Ser40-TH protein levels determined by Western blotting in the striatum of WT and DAT-CI mice, after intraperitoneal injection of 0.1 mg/kg haloperidol or vehicle (n = 6 per genotype and treatment). The top panels show representative blots comparing the different treatments. d, Horizontal motor activity in WT and DAT-CI mice in response to intraperitoneal administration of 0.1 mg/kg haloperidol (n = 5 per genotype) or vehicle (n = 8 per genotype), over a 60 min test, in a novel cage. All values are expressed as mean ± SEM. a, ***p < 0.0001 versus WT (Student's t test); b–d, *p < 0.05, **p < 0.01, ***p < 0.0001 versus vehicle group within genotype (one-way ANOVA). Genotypes and treatments are as indicated.