Endogenous serotonin stimulates striatal dopamine release in conscious rats.
Serotonin (5-HT) and dopamine (DA) are established neurotransmitters in the brain. This study examined whether, in conscious, free-moving rats, increased concentrations of endogenous 5-HT in extracellular fluid of the corpus striatum affect local release of endogenous DA. Administration of the 5-HT reuptake blocker alaproclate via a microdialysis probe increased striatal dialysate levels of DA and its metabolites dihydroxyphenylacetic acid and homovanillic acid as well as levels of 5-HT and the 5-HT metabolite 5-hydroxyindoleacetic acid. Whereas DA reuptake blockade with GBR-12909 did not prevent these effects of alaproclate, serotonergic ablation by i.c.v. administration of 5,7-dihydroxytryptamine markedly decreased basal levels of 5-HT and 5-hydroxyindoleacetic acid and abolished the effects of alaproclate on dialysate levels of DA, 5-HT and their metabolites. The results are consistent with a stimulatory action of endogenous 5-HT on striatal DA release in conscious animals.
Yadid
G
G
Clinical Neuroscience Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland.
Pacak
K
K
Kopin
I J
IJ
Goldstein
D S
DS
D015116:5,7-Dihydroxytryptamine / Q000494:pharmacology; D000409:Alanine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D010477:Perfusion; D010879:Piperazines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000502:physiology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology
D015116:5,7-Dihydroxytryptamine; D000409:Alanine; D004298:Dopamine; D018765:Dopamine Uptake Inhibitors; D010879:Piperazines; D011810:Quinoxalines; D012701:Serotonin; D017366:Serotonin Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors; C052561:CGS 12066B; C043425:vanoxerine; C025293:alaproclate