RESUMO
To determine the role of dopamine and 5-hydroxytryptamine [5-HT; serotonin] in the reinforcing effects of alcohol and apomorphine. Experimental study. Department of Biochemistry, University of Karachi from September to November 2004. The study was conducted on 24 male albino Wistar rats. Reinforcing effects were monitored in a conditioned place preference [CPP] paradigm using a light-dark activity box. Slicing and punching method was used to collect dorsal and ventral striatum. Neurochemical estimations were done by HPLC-EC. Withdrawal from repeated administration of ethanol [1g/kg/day] as well as apomorphine [1 mg/kg/day] elicited reinforcement that could be monitored in a CPP paradigm. CNS depressant effects of ethanol were not altered on repeated administration but CNS stimulatory effects of apomorphine increased. Reinforcing effects of ethanol but not apomorphine were associated with a decrease in dopamine metabolism in the ventral striatum. A decrease in the activity of dopaminergic neurons following withdrawal from repeated administration is involved in the compulsive use of abused drugs