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Titolo:
Excitation of nigral dopamine neurons by the GABA(A) receptor agonist muscimol is mediated via release of glutamate
Autore:
Erhardt, S; Engberg, G;
Indirizzi:
Karolinska Inst, Dept Physiol & Pharmacol, SE-17177 Stockholm, Sweden Karolinska Inst Stockholm Sweden SE-17177 ol, SE-17177 Stockholm, Sweden
Titolo Testata:
LIFE SCIENCES
fascicolo: 15, volume: 67, anno: 2000,
pagine: 1901 - 1911
SICI:
0024-3205(20000901)67:15<1901:EONDNB>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
FOREBRAIN-BUNDLE STIMULATION; METHYL-D-ASPARTATE; SUBSTANTIA-NIGRA; FIRING PATTERN; KYNURENIC ACID; MONKEY MIDBRAIN; FRONTAL-CORTEX; RAT; ANTEROGRADE; ACTIVATION;
Keywords:
substantia nigra; muscimol; glutamate; kynurenic acid; dopamine; MK 801;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Erhardt, S Karolinska Inst, Dept Physiol & Pharmacol, SE-17177 Stockholm, Sweden Karolinska Inst Stockholm Sweden SE-17177 7 Stockholm, Sweden
Citazione:
S. Erhardt e G. Engberg, "Excitation of nigral dopamine neurons by the GABA(A) receptor agonist muscimol is mediated via release of glutamate", LIFE SCI, 67(15), 2000, pp. 1901-1911

Abstract

Previous electrophysiological studies have shown that the GABA(A)receptor agonist muscimol is able to markedly increase the firing rate of rat nigraldopamine (DA) neurons. This action of the drug is paradoxical since local microiontophoretic application of the drug is associated with a clearcut inhibition of this neurons. In the present electrophysiological study, an attempt was made to analyze the mechanism of this action of the drug. Administration of muscimol (0.25-4.0 mg/kg, i.v.) was associated with a dose-dependent increase in firing rate as well as an increased bursting activity of the nigral DA neurons. Both these effects of muscimol were clearly antagonised by intravenous administration of the NMDA receptor antagonist MK 801(1 mg/kg) or by intracerebroventricular administration of the broadspectrum excitatory amino acid receptor antagonist kynurenic acid. Furthermore, pretreatment with PNU 156561A (40 mg/kg, i.v., 5-8h), a compound that raised endogenous kynurenic acid levels about 9 times, also clearly antagonised the actions of muscimol. Indeed, this treatment reversed the excitatory action of muscimol into an inhibitory effect on the nigral DA neurons. Here, we reportthat the excitatory action of muscimol is mediated indirectly by release of glutamate. (C) 2000 Elsevier Science Inc. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/04/20 alle ore 23:07:41