Effect of naloxone and morphine on dopamine agonist-induced stereotypy in rats and guinea pigs.
Naloxone (0.80 mg/kg) and morphine (7.5 mg/kg) were given to rats or guinea pigs with increasing doses of amphetamine (0.5-6.0 mg/kg) to determine their respective effects on amphetamine-induced stereotypy. In contrast to the inhibiting and potentiating effect of these agents on apomorphine-induced stereotyped behavior, naloxone enhanced and morphine markedly attenuated amphetamine-induced stereotypy. Since other investigators have reported that drugs inhibiting release of dopamine block amphetamine-induced stereotypy and enhance apomorphine-induced stereotypy, whilst compounds stimulating the release of dopamine potentiate amphetamine-induced stereotypy and inhibit apomorphine-elicited stereotyped behavior, it is likely that naloxone stimulates and morphine inhibits the release of DA following their acute administration.
D000661:Amphetamine / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D006168:Guinea Pigs; D006801:Humans; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D013239:Stereotyped Behavior / Q000187:drug effects*
D011954:Receptors, Dopamine; D009270:Naloxone; D009020:Morphine; D000661:Amphetamine; D001058:Apomorphine