Antagonism of apomorphine-induced yawning by SCH 23390: evidence against the autoreceptor hypothesis.
The ability of apomorphine to induce yawning (YWG) in normal and reserpinized rats and its interaction with SCH 23390, a potent and specific D-1 receptor antagonist, was studied. Apomorphine was more potent in inducing YWG in reserpine-pretreated as compared to control rats. SCH 23390, in low doses (0.05 mg/kg SC), was able to significantly reduce the YWG evoked by apomorphine both in control and in reserpine-pretreated rats. The results indicate that D-1 receptors contribute to YWG elicited by apomorphine and contradict the idea that this effect is mediated by DA autoreceptors.
D000818:Animals; D001058:Apomorphine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D001552:Benzazepines / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects / Q000502:physiology; D012018:Reflex / Q000187:drug effects / Q000502:physiology
D001552:Benzazepines; D011954:Receptors, Dopamine; D001058:Apomorphine