Different actions of TL-99 and 3-PPP in producing contraversive turning in the 6-OHDA-lesioned rat.
The putatively selective dopamine autoreceptor agonists TL-99 and 3-PPP were compared with apomorphine for the production of contraversive turning in the 6-hydroxydopamine-lesioned rat. Although less potent than apomorphine, 3-PPP produced dose-related contralateral turning. The contralateral turning produced by TL-99 plateaued at the 3 mg/kg i.p. dose level. Yohimbine significantly enhanced the TL-99-induced turning, whereas it failed to modify the 3-PPP turning. The results suggest that the alpha 2-adrenergic properties of TL-99 at doses of greater than 3.0 mg/kg masked its dopaminergic effects. Hence, 3-PPP is clearly the more selective agent for DA receptors.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D005260:Female; D006892:Hydroxydopamines / Q000633:toxicity*; D009043:Motor Activity / Q000187:drug effects*; D009281:Naphthalenes / Q000494:pharmacology*; D016627:Oxidopamine; D010880:Piperidines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D013378:Substantia Nigra / Q000187:drug effects* / Q000503:physiopathology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology*; D015016:Yohimbine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D006892:Hydroxydopamines; D009281:Naphthalenes; D010880:Piperidines; D011954:Receptors, Dopamine; D013764:Tetrahydronaphthalenes; D015016:Yohimbine; C016893:2-(N,N-dimethylamino)-6,7-dihydroxytetralin; D016627:Oxidopamine; C026539:preclamol; D001058:Apomorphine