FUNCTIONAL CORRELATES OF HEROIN SENSITIZATION IN THE RAT-BRAIN

The aim of the study was to measure the changes in cerebral energy met abolism and c-Sos mRNA expression following challenge with heroin in d rug-naive rats and in animals previously sensitized to the drug. Acute heroin administration to drug naive-rats produced a generalized metab olic depression. In contract, challenge with heroin in drug-sensitized rats produced selective metabolic increases in structures belonging t o the basal ganglia. These changes were accompanied by increased c-fos mRNA expression in the caudate-putamen nucleus. These results demonst rate that the process of sensitization to heroin is coupled to functio nal changes that are confined to the subcortical motor circuits of the basal ganglia. (C) 1997 Elsevier Science B.V.