[Dopaminergic sensitivity after ethanol pretreatment and its relation to alcohol preference]

The interactions between ethanol and the central dopaminergic synaptic transmission also refer to the ethanol drinking behaviour. In mice the alteration of the locomotoric activity induced by apomorphine is influenced by ethanol pretreatment for 28 days in a different way referring to drinking behaviour. Ethanol preferent animals do not differ significantly from the ethanol untreated animals in respect to the apomorphine induced locomotion. The nonpreferent animals show, by comparison, a decrease of the sedative effect of low apomorphine doses (0.25 mg/kg; i.p.) and an increase of the stimulating effect of higher doses (1.0 mg/kg; i.p.). These behavioural alterations may be understood as an expression of dopaminergic presynaptic subsensitivity and of a postsynaptic supersensitivity in ethanol pretreated nonpreferent animals.