Assessment of dopamine autoreceptor agonist properties of apomorphine, (+)-3-PPP and (-)-3-PPP by recording of yawning behaviour in rats.
Yawning behaviour in rats was studied by direct observation. Apomorphine dose dependently induced yawning: 0.05 mg/kg was most effective, 0.2 mg/kg induced locomotor and sniffing behaviour but less yawning. Sulpinide (2 and 10 mg/kg) dose dependently blocked the apomorphine (0.05 mg/kg)-induced yawning. (+)-3-PPP (1-10 mg/kg) induced yawning in a manner similar to that of apomorphine but (-)-3-PPP (1-10 mg/kg) did so only weakly. Yawning induced by (+)-3-PPP was blocked by sulpiride 10 mg/kg. It is concluded that (+)-3-PPP but not (-)-3-PPP is at least as effective as apomorphine to induce yawning in rats, indicating that (+)-3-PPP, but not (-)-3-PPP, is a pure agonist on dopamine autoreceptors.
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects*; D004294:Domperidone / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000502:physiology*; D013237:Stereoisomerism; D013469:Sulpiride / Q000494:pharmacology
D010880:Piperidines; D011954:Receptors, Dopamine; D004294:Domperidone; D013469:Sulpiride; C026539:preclamol; D001058:Apomorphine