Effects of Withdrawal from Chronic Amphetamine Administration on Activity Levels of Albino Rats

18 albino rats were administered either saline or various dosages of d-amphetamine sulfate in activity wheel cages over a 13-wk. period. Food consumption was decreased under the 2.0, 4.0 and 8.0 mg/kg dosages, while water consumption was reduced only under the highest dose. Motor activity was elevated under 1.0 mg/kg and was depressed under 8.0 mg/kg, while no reliable effects were noted under the middle range of doses. Withdrawal from 1.0 and 2.0 mg/kg of amphetamine led to significant elevations in baseline activity. These changes in activity could not be readily explained in terms of a simple conditioning process. It was suggested that amphetamine may produce long lasting changes in the central nervous system which are reflected in elevated activity when the drug is withdrawn.