Effects of haloperidol or SCH-23390 on ethanol-induced conditioned taste aversion.

Dopaminergic systems are thought to play an important role in the motivational effects of ethanol. The present experiments examined the effects of haloperidol (a D2 antagonist) and SCH-23390 (a D1 antagonist) on the acquisition of ethanol-induced conditioned taste aversion. In four separate experiments, adult male Swiss-Webster mice were acclimated to a 2-h/day water restriction regimen. Subsequently they received four conditioning trials consisting of 1-h access to either 0.2 M NaCl (experiments 1-3) or 0.15 % w/v saccharin (experiment 4). After flavor access on trials 1-3, subjects received either haloperidol (0.1, 0.15, or 0.3 mg/kg), SCH-23390 (0.05 mg/kg), or saline followed 30 min later by 0, 2, or 4 g/kg ethanol. Ethanol-flavor pairings reduced subsequent flavor intakes, indicating the development of conditioned taste aversion. Neither haloperidol of SCH-23390 reduced flavor intakes in the absence of ethanol. However, both haloperidol and SCH-23390 reduced ethanol-conditioned aversion depending on ethanol dose and conditioned flavor. These results are consistent with the notion that dopaminergic processes are important for the development of ethanol-induced conditioned taste aversion, and the notion that dopaminergic receptor systems influence both positive and negative motivational effects of ethanol.