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Tonic GABA-ergic modulation of striatal dopamine release studied by in vivo microdialysis in the freely moving rat.
- Source :
-
European journal of pharmacology [Eur J Pharmacol] 1995 Sep 15; Vol. 284 (1-2), pp. 83-91. - Publication Year :
- 1995
-
Abstract
- GABAA and GABAB receptor agonists and antagonists were administered locally in the striatum of intact and kainic acid lesioned rats. (+/-)-Baclofen, a GABAB receptor agonist, significantly decreased the level of extracellular dopamine in the striatum of intact rats. (+/-)-Phaclofen, a GABAB receptor antagonist, increased the level of extracellular dopamine in the striatum of intact rats and to a lesser extent in the striatum after kainic acid lesion. Pregnanolone (5 beta-pregnan-3 alpha-ol-20-one), a positive allosteric modulator of the GABAA receptor, significantly decreased the level of extracellular dopamine in intact rats. (-)-Bicuculline, a GABAB receptor antagonist, increased the level of extracellular dopamine in the striatum of intact rats, but failed to increase the level of extracellular dopamine after kainic acid lesion. The release of extracellular dopamine, due to infusion of phaclofen or bicuculline, was totally suppressed by tetrodotoxin. These results support a direct influence of GABA on the dopaminergic terminals via presynaptic GABAB receptors, while the effects via the GABAA receptor seem to be postsynaptic and mediated by striatal interneurons or the striatonigral feedback loop.
- Subjects :
- 3,4-Dihydroxyphenylacetic Acid metabolism
Animals
Dopamine physiology
Excitatory Amino Acid Agonists toxicity
Extracellular Space drug effects
Extracellular Space metabolism
Feedback drug effects
GABA-A Receptor Agonists
GABA-A Receptor Antagonists
GABA-B Receptor Agonists
GABA-B Receptor Antagonists
Homovanillic Acid metabolism
Interneurons drug effects
Kainic Acid toxicity
Male
Microdialysis
Neostriatum drug effects
Presynaptic Terminals drug effects
Rats
Rats, Wistar
Substantia Nigra drug effects
Substantia Nigra metabolism
Dopamine metabolism
Neostriatum metabolism
Neostriatum physiology
gamma-Aminobutyric Acid physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0014-2999
- Volume :
- 284
- Issue :
- 1-2
- Database :
- MEDLINE
- Journal :
- European journal of pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 8549640
- Full Text :
- https://doi.org/10.1016/0014-2999(95)00369-v