Lack of effect of dopamine receptor blockade on expression of ethanol-induced conditioned place preference in mice

Abstract Rationale. Self-administration studies have suggested that dopamine (DA) is important for the reinforcing effects of ethanol. However, ethanol place conditioning studies have less consistently demonstrated a role for DA in conditioned place preference. Objectives. The purpose of the present study was to determine whether blockade of D₁, D₂ or D₃ DA receptors would impact the expression of the conditioned place preference induced by ethanol in DBA/2J mice. Methods. Mice underwent an unbiased place conditioning procedure with 2 g/kg ethanol. Prior to the preference test, mice were injected i.p. with SCH23390 (0, 0.015 or 0.03 mg/kg), raclopride (0, 0.3 or 0.6 mg/kg) or U99194A (0, 10 or 20 mg/kg). Results. Ethanol produced a significant conditioned place preference that was not affected by any of the dopamine antagonists tested. Each of the antagonists decreased locomotor activity, though U99194A was minimally effective. Conclusions. These findings suggest that the conditioned reinforcing effects of ethanol in DBA/2J mice as assessed by place conditioning are mediated by non-dopaminergic mechanisms. Electronic Publication