Effects of chronic d-amphetamine sulfate administration during development in rats

Abstract

The present investigation was concerned with the effects of long-term administration of d-amphetamine in the daily drinking water of rats on weight and three behavioral tasks. No tolerance to the drug was found for weight measures, nor in the behavioral measures of lever pressing for illumination change or gross activity. Drug animals were significantly lighter than non-drug animals, pressed more for illumination change, and were more active. No difference was found between performance of drug and non-drug animals in an avoidance conditioning task. It may be that tolerance to the drug does not appear when measured by situations not employing strong motivational conditions (e.g. pressing for illumination change and activity), but where such conditions are employed (e.g. shock), tolerance as reflected in the lack of difference between drug and non-drug groups does appear.