Continuous cocaine induces persisting alterations in dopamine overflow in caudate following perfusion with a D1 agonist.
The present study examined whether exposure to 5 days of continuous cocaine in rats would produce any persisting alterations of the decrease in striatal dopamine (DA) overflow produced by local infusion of a D1 receptor agonist. Using a microdialysis probe in striatum, changes in DA, DA metabolites, and GABA were assessed 14 to 21 days following a 5-day continuous cocaine treatment. There were no differences in baseline levels of DA and it's metabolites. SKF 38393 (10(-6) infusion into the striatum decreased striatal DA levels in the controls and this effect was attenuated in cocaine-pretreated rats. This result, together with other observations, supports the hypothesis of a persistently altered D1-mediated negative feedback produced by previous exposure to continuous cocaine.
Keys
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Department of Psychology, UCLA.
Ellison
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D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D004343:Drug Implants; D005246:Feedback / Q000502:physiology; D005260:Female; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D017551:Microdialysis; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000819:agonists*; D013788:Thalamus / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D004343:Drug Implants; D017447:Receptors, Dopamine D1; D006897:Hydroxyindoleacetic Acid; D005680:gamma-Aminobutyric Acid; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D003042:Cocaine; D004298:Dopamine