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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2002-2-1
pubmed:abstractText
The activity of dopamine neurons in the ventral tegmental area is modulated by excitatory (glutamatergic) and inhibitory (GABAergic) afferents. GABA, released by intrinsic neurons and by projection neurons originating in the nucleus accumbens and other regions, inhibits dopamine neurons via activation of GABA(A) and GABA(B) receptor subtypes. Using in vivo microdialysis in freely moving rats, we investigated the role of ventral tegmental area GABA(B) receptors in modulating levels of dopamine and glutamate within the ventral tegmental area, both in naive rats and in rats treated repeatedly with saline or amphetamine (5 mg/kg i.p., for 5 days). In naive rats, administration of a potent and selective GABA(B) receptor antagonist (CGP 55845A) into the ventral tegmental area elicited a concentration-dependent increase in dopamine levels, but did not alter glutamate levels. In rats tested 3 days after discontinuing repeated amphetamine administration, 50 microM CGP 55845A increased dopamine levels to a greater extent than in saline controls. This difference was no longer present in rats tested 10-14 days after discontinuing repeated amphetamine injections. CGP 55845A (50 microM) had no effect on glutamate levels in the ventral tegmental area of saline-treated rats. However, it produced a robust increase in glutamate levels in rats tested 3 days, but not 10-14 days, after discontinuing repeated amphetamine injections. These results suggest that somatodendritic dopamine release is normally under strong tonic inhibitory control by GABA(B) receptors. Repeated amphetamine administration enhances GABA(B) receptor transmission in the ventral tegmental area during the early withdrawal period, increasing inhibitory tone on both dopamine and glutamate levels. This is the first demonstration, in an intact animal, that drugs of abuse alter GABA(B) receptor transmission in the ventral tegmental area.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:volume
109
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
585-95
pubmed:dateRevised
2009-11-3
pubmed:meshHeading
pubmed-meshheading:11823068-Amphetamine, pubmed-meshheading:11823068-Amphetamine-Related Disorders, pubmed-meshheading:11823068-Animals, pubmed-meshheading:11823068-Dopamine, pubmed-meshheading:11823068-Dose-Response Relationship, Drug, pubmed-meshheading:11823068-Drug Administration Schedule, pubmed-meshheading:11823068-Drug Interactions, pubmed-meshheading:11823068-Extracellular Space, pubmed-meshheading:11823068-GABA Antagonists, pubmed-meshheading:11823068-Glutamic Acid, pubmed-meshheading:11823068-Male, pubmed-meshheading:11823068-Neural Inhibition, pubmed-meshheading:11823068-Neurons, pubmed-meshheading:11823068-Phosphinic Acids, pubmed-meshheading:11823068-Propanolamines, pubmed-meshheading:11823068-Rats, pubmed-meshheading:11823068-Rats, Sprague-Dawley, pubmed-meshheading:11823068-Receptors, GABA-B, pubmed-meshheading:11823068-Reward, pubmed-meshheading:11823068-Synaptic Transmission, pubmed-meshheading:11823068-Ventral Tegmental Area
pubmed:year
2002
pubmed:articleTitle
In vivo modulation of ventral tegmental area dopamine and glutamate efflux by local GABA(B) receptors is altered after repeated amphetamine treatment.
pubmed:affiliation
Department of Neuroscience, FUHS/The Chicago Medical School, North Chicago, IL 60064-3095, USA.
pubmed:publicationType
Journal Article