The effect of varying doses of d-amphetamine on activity levels of prepubertal mice.

The effect of varying doses of d-amphetamine on the activity level of C57BL/6J mice (known for their high activity level), DBA/1J, C3H/HeJ, and C3D2F1 mice was investigated (all mice were 25 to 30 days old). Activity was measured by the use of an activity cage with a revolving drum. After determination of baseline activity level, the animals were assigned to the following set of i.p. injections: (1) normal saline, (2) d-amphetamine 0.2 mg/kg, (3) d-amphetamine 0.5 mg/kg, (4) d-amphetamine 5 mg/kg. The mean activity level of the C57BL/6J mice was significantly higher than that of the other strains. The mean activity level after 5 mg/kg was significantly lower than after other dosages in all strains. All strains responded similarly to d-amphetamine as is apparent from the parallel profiles for the dose-response curves. The response of the developing mice to d-amphetamine is at variance with the known response of mature mice.