| D-dopa and L-dopa similarly elevate brain dopamine and produce turning behavior in rats. | |
| | |
MedLine Citation:
|
PMID: 3129126 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
In the intact rat, intragastric administration of D-dihydroxyphenylalanine (D-DOPA) together with carbidopa (alpha-methyldopa hydrazine, a peripheral dopadecarboxylase inhibitor) increased striatal dopamine concentration to the same extent as a similar treatment with L-DOPA plus carbidopa. In rats with unilateral 6-hydroxydopamine-induced lesions of their substantia nigra, both stereoisomers of DOPA produced significant increases in dopamine and its metabolites in the intact striata. Although dopamine concentrations in the lesioned striata did not change, a significant increase in dopamine metabolites was observed, indicating some extraneuronal formation of dopamine. These results suggest that D-DOPA can be converted to dopamine in the normal striatum as well as in the striatum devoid of dopamine nerve terminals. D- and L-DOPA produced turning behavior in unilaterally lesioned rats with a similar efficacy. The onset of turning after D-DOPA was delayed compared with L-DOPA. Turning behavior elicited by these amino acids was attributed to stimulation of supersensitive dopamine receptors in the lesioned striata by the extraneuronally formed dopamine. Preliminary results suggest that D-DOPA is converted to dopamine via transamination and/or D-amino acid oxidation to 3,4-dihydroxyphenylpyruvic acid which upon further transamination gives rise to L-DOPA and hence dopamine. The relatively fast and slow onset of stimulation of dopamine receptors L-DOPA and D-DOPA respectively suggests that the use of the racemic mixture of DOPA combined with a peripheral dopadecarboxylase inhibitor may prove useful in the treatment of parkinsonism. |
| | |
Authors:
|
F Karoum; W J Freed; L W Chuang; E Cannon-Spoor; R J Wyatt; E Costa |
Related Documents
:
|
2421656 - Dementias, psychological tests, and neurotransmitters. 6514016 - Influence of serosal hydrostatic pressure on net water and electrolyte transport across... 9660106 - Cerebrospinal fluid levels of non-neurotransmitter amino acids in patients with alzheim... 1239956 - Folate transport in the central nervous system. 3757726 - Bile acid accumulation by rabbit esophageal mucosa. 1768836 - Evidence for the possible involvement of protein kinase c in the activation of non-spec... |
Publication Detail:
|
Type: Comparative Study; Journal Article |
Journal Detail:
|
Title: Brain research Volume: 440 ISSN: 0006-8993 ISO Abbreviation: Brain Res. Publication Date: 1988 Feb |
Date Detail:
|
Created Date: 1988-05-27 Completed Date: 1988-05-27 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 0045503 Medline TA: Brain Res Country: NETHERLANDS |
Other Details:
|
Languages: eng Pagination: 190-4 Citation Subset: IM |
Affiliation:
|
Neuropsychiatry Branch, National Institute of Mental Health, Saint Elizabeths Hospital, Washington, DC 20032. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
3,4-Dihydroxyphenylacetic Acid
/
metabolism Animals Brain / drug effects, metabolism* Carbidopa / pharmacology Cerebral Ventricles / drug effects, physiology Dihydroxyphenylalanine / pharmacology* Dopamine / metabolism* Homovanillic Acid / metabolism Levodopa / pharmacology* Male Rats Rats, Inbred Strains Stereotyped Behavior / drug effects* Structure-Activity Relationship |
| Chemical | |
Reg. No./Substance:
|
0/Levodopa; 102-32-9/3,4-Dihydroxyphenylacetic Acid; 306-08-1/Homovanillic Acid; 38821-49-7/Carbidopa; 63-84-3/Dihydroxyphenylalanine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Aging blocks the thermoregulatory action of thyrotropin-releasing hormone in anaesthetized rats.
Next Document: Localization and induction of c-fos protein-like immunoreactive material in the nuclei of adult mamm...