ALTERED BRAIN SENSITIVITY TO ETHANOL IN MICE AFTER MPTP TREATMENT

Previous studies demonstrated the role of the dopaminergic receptors i n brain sensitivity to ethanol. The present study was designed to asse ss the relative contribution of the nigrostriatal component to this br ain sensitivity. Adult male C57BL mice were given 1-Methyl-4-Phenyl-1, 2,3,6-Tetrahydropyridine (MPTP) injections (30 mg/kg daily for 2 conse cutive days). The treatment decreased the striatal dopamine level by 3 5% from the control level, and the number (B-max) of dopaminergic rece ptors was increased by 67%. Ethanol-induced sleep time was reduced in the MPTP-treated mice, as compared to controls, and this gap progressi vely widened during the 3 weeks of testing to 29%. Brain ethanol level s upon awakening increased by 22%. The results suggest that the nigros triatal dopaminergic pathways play a major role in determining brain s ensitivity to ethanol which may represent an important component in th e addictive process.