Dopamine D2 receptors play a role in the (-)-apomorphine-like discriminative stimulus effects of (+)-PD 128907.
The discriminative stimulus effects of the dopamine D3 receptor-preferring agonist, S(+)-(4aR,10bR)-3,4,4a,10b-tetrahydro-4-propyl -2H, 5H-[1]benzopyrano-[4,3-b]-1,4-oxazin-9-ol ((+)-PD 128907), were examined in rats trained to discriminate (-)-apomorphine (0.16 m/kg) from saline in a two-lever, fixed ratio 10 drug-discrimination paradigm. Both (-)-apomorphine and (+)-PD 128907 produced dose-related (-)-apomorphine-lever selection, with full substitution observed at 0.16 mg/kg, i.p. (ca. 0.5 mumol/kg). Drug-appropriate responding produced by either (-)-apomorphine or (+)-PD 128907 was antagonized by the putative dopamine D3 receptor antagonists, (1S,2R)-cis-5-methoxy-1-methyl-2-(n-propylamino)tetralin) ((+)-AJ76) and cis-(+)-5-methoxy-1-methyl-2-(di-n-propylamino)tetralin ((+)-UH 232), as well as by the dopamine D2 receptor antagonist haloperidol. Because haloperidol was approximately 30-150-times more potent than (+)-AJ76 or (+)-UH-232 in blocking the effects of either receptor agonist, the results indicate that dopamine D2 receptors play a role in the discriminative stimulus effects of (+)-PD 128907.
Kleven
M S
MS
Centre de Recherche Pierre Fabre, Castres, France.
Koek
W
W
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001578:Benzopyrans / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects; D004192:Discrimination, Psychological / Q000187:drug effects*; D018491:Dopamine Agonists / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D010078:Oxazines / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000187:drug effects*
D001578:Benzopyrans; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D010078:Oxazines; D017448:Receptors, Dopamine D2; C062458:3,4,4a,10b-tetrahydro-4-propyl-2H,5H-(1)benzopyrano(4,3-b)-1,4-oxazin-9-ol; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; C045971:UH 232; D006220:Haloperidol; D001058:Apomorphine