Abstract
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.
MeSH terms
-
Adrenergic alpha-Agonists / pharmacology
-
Adrenergic alpha-Antagonists / pharmacology
-
Animals
-
Apomorphine / pharmacology
-
Female
-
Hydroxydopamines / toxicity*
-
Motor Activity / drug effects*
-
Naphthalenes / pharmacology*
-
Oxidopamine
-
Piperidines / pharmacology*
-
Rats
-
Rats, Inbred Strains
-
Receptors, Dopamine / drug effects*
-
Substantia Nigra / drug effects*
-
Substantia Nigra / physiopathology
-
Tetrahydronaphthalenes / pharmacology*
-
Yohimbine / pharmacology
Substances
-
Adrenergic alpha-Agonists
-
Adrenergic alpha-Antagonists
-
Hydroxydopamines
-
Naphthalenes
-
Piperidines
-
Receptors, Dopamine
-
Tetrahydronaphthalenes
-
Yohimbine
-
2-(N,N-dimethylamino)-6,7-dihydroxytetralin
-
Oxidopamine
-
preclamol
-
Apomorphine