Figure 1
DAT-Cre KI mice have sex-dependent changes in baseline and amphetamine-induced locomotor activity. (A) Mice were divided according to their genotype and sex. The color-coding scheme illustrated here applies to all other figures in this study. (B) Mice were placed in an open field for 20 min, given a saline injection, and returned to the arena for 40 min. The next day animals went through a similar procedure, except they received injections of d-amphetamine (2 mg/kg). (C) Total distance travelled (5-min bins) for male WT and KI mice. KI mice displayed a hyperlocomotor phenotype. Note that saline injection creates only a minimal disruption in behavior. (D) Same as (C), but for females. Note that female KIs were also hyperactive. (E) Difference in distance travelled between the last and first 20 min of the experiment. There was no significant difference between groups. (F) Locomotor activity of male mice before and after d-amphetamine injections. Male KIs showed a blunted response to the drug. (G) Same as E, but for females. While WT females show increases in open field locomotion after the amphetamine injections, KI females decreased their activity. (H) Same as (E), but for the amphetamine experiment. Note that most groups showed an average increase in locomotion, except for the female KIs, which showed a consistent reduction in activity. Asterisks atop specific data points indicate multiple comparison tests results between groups. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.
