Apomorphine effects on behavioral response to ethanol in mice selectively bred for differential sensitivity to ethanol.
Two lines of mice selectively bred for differences in response to a hypnotic dose of ethanol were administered apomorphine alone or in combination with ethanol. When administered by itself, apomorphine produced similar dose-dependent depression of locomotor activity and increases in stereotypy in the two lines. Doses of apomorphine (0.5 microM/kg and 2 microM/kg) thought to bind only presynaptic dopamine receptors blocked the slight locomotor activation to 1.5 g/kg ethanol in the ethanol-sensitive Long-Sleep (LS) mice; in the ethanol-insensitive Short-Sleep (SS) mice which show marked activation to all subhypnotic doses of ethanol, these doses of apomorphine only attenuated the activation. A higher apomorphine dose (8 microM/kg) antagonized the locomotor depressant effects of 2.0 and 2.5 g/kg of ethanol in LS mice but did not alter the shape of the SS ethanol dose response curve for locomotor activity. Apomorphine (2 and 8 microM/kg) potentiated ethanol-induced loss of the righting reflex in LS mice in a dose dependent fashion, but did not alter this soporific effect of ethanol in SS mice. These findings extend the data base suggesting a role for dopamine both in the mechanism(s) differentiating the LS and SS mice and the stimulant and intoxicating properties of ethanol.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects*; D011187:Posture; D013239:Stereotyped Behavior / Q000187:drug effects*
D000431:Ethanol; D001058:Apomorphine