Sucrose self-administration predicts only initial phase of ethanol-reinforced behaviour in Wistar rats.

AIMS To characterize the relationship between the sucrose- and ethanol-reinforced behaviour in Wistar rats. METHODS Subjects (n = 31) were trained to lever press for 8% (v/v) ethanol in an operant procedure where increasing concentrations of ethanol were introduced in the presence of 8% (w/v) sucrose. The sucrose concentration was subsequently decreased from 8 to 0%. Subjects were allowed to stabilize their intake of 8% ethanol over the next 20 days. RESULTS Self-administration of 8% sucrose (ml/kg) significantly correlated with ethanol consumption (g/kg) on days 1-5 of the 8% ethanol self-administration period. This relationship completely disappeared during the subsequent weeks of ethanol self-administration (days 6-20). CONCLUSIONS The results of the present study, combined with our previous findings, may indicate that self-administration of sucrose predicts only the initial phase of ethanol-taking behaviour in Wistar rats.