Abstract |
Dopamine (DA) elevations in rat striatum produced by combined administration of L-dopa and carbidopa were abolished when L-dopa was injected with NSD-1015, an inhibitor of central dopa-decarboxylase. In all rats with unilateral 6-OH-DA nigral lesions, L-dopa-induced contraversive circling occurred after carbidopa, but was totally abolished (in 60%) or markedly suppressed after pretreatment with NSD-1015. Administration of the DA metabolites DOPAC and HVA systemically and of 3-methoxytyramine intrastriatally evoked no circling in animals with 6-OH-DA lesions. In rats with unilateral nigrotomies, the direction of L-dopa-induced circling was reversed and became ipsiversive after DA receptors were reduced by the addition of kainic acid lesions in ipsilateral striata. Findings provide evidence that circling in rats--and by analogy, efficacy in parkinsonians--requires the decarboxylation of exogenous L-dopa and interaction of the formed DA with DA receptors in striatum.
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Authors | E Melamed, F Hefti, V Bitton, M Globus |
Journal | Neurology
(Neurology)
Vol. 34
Issue 12
Pg. 1566-70
(Dec 1984)
ISSN: 0028-3878 [Print] United States |
PMID | 6504328
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.)
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Chemical References |
- Dopamine Antagonists
- Hydrazines
- Receptors, Dopamine
- Levodopa
- 3-hydroxybenzylhydrazine
- Dopa Decarboxylase
- Dopamine
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Topics |
- Animals
- Behavior, Animal
(drug effects)
- Corpus Striatum
(drug effects, metabolism)
- Dopa Decarboxylase
(pharmacology)
- Dopamine
(metabolism)
- Dopamine Antagonists
- Hydrazines
(metabolism, pharmacology)
- Levodopa
(metabolism, pharmacology)
- Male
- Parkinson Disease
(drug therapy, metabolism)
- Rats
- Rats, Inbred Strains
- Receptors, Dopamine
(metabolism)
- Substantia Nigra
(drug effects, metabolism)
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