Brain locations controlling the behavioral effects of chronic amphetamine intoxication

Abstract

Rats were administered d-amphetamine repeatedly for 4days. After day 1 of treatment, the amphetamine-induced increases in ambulation, rearing, and stereotyped activity were augmented. However, after 4 dats treatment, the rearing and ambulatory responses became attenuated while the stereotyped activities remained augmented. Microinjection studies revealed that both the augmentation and attenuation of nonstereotyped ambulation were generated from the nucleus accumbens. The augmentation of stereotyped behaviors was generated from the caudate nucleus. Chronically treated animals who were administered 0.7 but not 1.0 mg/kg apomorphine showed augmented behavioral response. Chronic amphetamine treatment significantly decreased (³H) spiroperidol binding in both the nucleus accumbens and caudate nucleus. However, no effect on the DA-stimulated adenyl cyclase activity was observed in either brain region. It is concluded that repeated d-amphetamine administration selectively augments and attenuates d-amphetamine-induced behaviours and that these selective effects are mediated by different dopamine systems.