Monoamine release in the rat striatum is induced by delta-guanidinovaleric acid and inhibited by GABA agonists.
delta-Guanidinovaleric acid (GVA) is an endogenous convulsant and is thought to be a specific gamma-aminobutyric acid (GABA) antagonist. In this study, we examined the effects of GVA and GABA agonists, GABA, muscimol and baclofen, on the release of dopamine (DA) and serotonin (5-HT) in the rat striatum using a brain dialysis technique. GVA produced a significant increase in the amount of DA and 5-HT released compared with controls. Both GABA (10mM) and muscimol (10mM) inhibited the GVA-induced release of DA and 5-HT. Muscimol was a more potent inhibitor of 5-HT release than DA release. Baclofen (10mM) inhibited only the GVA-induced DA release. These results suggest that the activation of GABA receptors inhibits the release of DA and 5-HT in the striatum, and that the dopaminergic system regulates GABA-B receptors and the serotonergic system mainly regulates GABA-A receptors.
Kabuto
H
H
Department of Neurochemistry, Okayama University Medical School, Japan.
Yokoi
I
I
Iwaya
K
K
Mori
A
A
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism*; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004357:Drug Synergism; D004563:Electrochemistry; D018755:GABA Agonists / Q000494:pharmacology*; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D014631:Valerates / Q000037:antagonists & inhibitors* / Q000494:pharmacology*
D018755:GABA Agonists; D014631:Valerates; D009118:Muscimol; D012701:Serotonin; C053509:delta-guanidinovaleric acid; D001418:Baclofen; D004298:Dopamine