Functional correlates of repeated administration of cocaine and apomorphine in the rat

The [14C]2-deoxyglucose method was applied to measure the effects of repeated (8 consecutive days) administration of apomorphine (0.5 mg/kg/day s.c.) or cocaine (15 mg/kg/day i.p.) on cerebral glucose utilization in freely moving rats. Altered rates of glucose utilization were measured in extrapyramidal motor areas, such as the globus pallidus, entopeduncular nucleus, subthalamic nucleus, substantia nigra and lateral habenula of both cocaine- and apomorphine-treated rats. Furthermore, cocaine-treated animals displayed increased glucose metabolism in the mesolimbic dopaminergic projections, such as nucleus accumbens and olfactory tubercle, and in the hippocampus. These results suggest that altered functional activity within the dopaminergic mesolimbic system may play a role in the process of sensitization to psychomotor stimulant drugs.