title: Hyperactivity induced by stimulation of separate dopamine D-1 and D-2 receptors in rats with bilateral 6-OHDA lesions.
abstract: The effects of DA agonists and antagonists with different dopamine (DA) D-1 and D-2 receptor selectivity have been studied in rats with bilateral 6-OHDA lesions. The D-1 agonist SK & F 38393, the D-2 agonist pergolide and the mixed agonist apomorphine all induced marked hyperactivity in lesioned rats in doses which were without stimulant effect in sham-operated animals. The hyperactivity induced by SK & F 38393 was blocked by the DA D-1 antagonist SCH 23390, but unaffected by the D-2 antagonists spiroperidol or clebopride. Pergolide-induced hyperactivity showed the reverse selectivity. The mixed D-1/D-2 antagonists, cis(Z)-flupentixol and cis(Z)-clopenthixol, however blocked the effect of both agonists. Apomorphine-induced hyperactivity was neither blocked by selective D-1 nor D-2 antagonists, but was dose-dependently inhibited by cis(Z)-flupentixol and cis(Z)-clopenthixol. Potent blockade was also obtained by combined treatment with SCH 23390 and spiroperidol, indicating the need of blocking both D-1 and D-2 receptors simultaneously. The results indicate that D-1 and D-2 receptor function can be independently manipulated in denervated rats and they confirm similar results obtained in rats with unilateral 6-OHDA lesions using circling behaviour.
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001549:Benzamides / Q000494:pharmacology; D001552:Benzazepines / Q000494:pharmacology*; D003006:Clopenthixol / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004873:Ergolines / Q000494:pharmacology*; D005475:Flupenthixol / Q000494:pharmacology; D006892:Hydroxydopamines / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects / Q000502:physiology; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D016627:Oxidopamine; D010479:Pergolide; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000378:metabolism*; D013134:Spiperone / Q000494:pharmacology
chemical_list: D001549:Benzamides; D001552:Benzazepines; D004873:Ergolines; D006892:Hydroxydopamines; D011954:Receptors, Dopamine; D010479:Pergolide; D013134:Spiperone; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D016627:Oxidopamine; D003006:Clopenthixol; D005475:Flupenthixol; C014417:clebopride; D001058:Apomorphine; D004298:Dopamine