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Titolo:
Presynaptic kynurenate-sensitive receptors inhibit glutamate release
Autore:
Carpenedo, R; Pittaluga, A; Cozzi, A; Attucci, S; Galli, A; Raiteri, M; Moroni, F;
Indirizzi:
Univ Florence, Dept Preclin & Clin Pharmacol, I-50139 Florence, Italy UnivFlorence Florence Italy I-50139 Pharmacol, I-50139 Florence, Italy Dept Expt Med, I-16148 Genoa, Italy Dept Expt Med Genoa Italy I-16148Dept Expt Med, I-16148 Genoa, Italy
Titolo Testata:
EUROPEAN JOURNAL OF NEUROSCIENCE
fascicolo: 11, volume: 13, anno: 2001,
pagine: 2141 - 2147
SICI:
0953-816X(200106)13:11<2141:PKRIGR>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHARMACOLOGICAL CHARACTERIZATION; KAINATE RECEPTORS; RAT STRIATUM; IN-VIVO; ACID; BRAIN; ANTAGONIST; ACETYLCHOLINE; MODULATION; CORTEX;
Keywords:
AMPA; basal ganglia; kainate; nicotinic ACh receptors; mGlu receptors; microdialysis; NMDA; tryptophan and kynurenine metabolism;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
52
Recensione:
Indirizzi per estratti:
Indirizzo: Moroni, F Univ Florence, Dept Preclin & Clin Pharmacol, Viale Pieraccini 6, I-50139 Florence, Italy Univ Florence Viale Pieraccini 6 Florence Italy I-50139 , Italy
Citazione:
R. Carpenedo et al., "Presynaptic kynurenate-sensitive receptors inhibit glutamate release", EUR J NEURO, 13(11), 2001, pp. 2141-2147

Abstract

Kynurenic acid is a tryptophan metabolite provided with antagonist activity on ionotropic glutamate and alpha7 nicotinic acetylcholine receptors. We noticed that in rats with a dialysis probe placed in the head of their caudate nuclei, local administration of kynurenic acid (30-100 nM) significantly reduced glutamate output. Qualitatively and quantitatively similar effects were observed after systemic administration of kynurenine hydroxylase inhibitors, a procedure able to increase brain kynurenate concentrations. Interestingly, in microdialysis studies, methyllycaconitine (0.3-10 nM), a selective alpha7 nicotinic receptor antagonist. also reduced glutamate output. in isolated superfused striatal synaptosomes, kynurenic acid (100 nM), but not methyllycaconitine, inhibited the depolarization (KCl 12.5 mM)-induced release of transmitter or previously taken-up [H-3]-D-aspartate. This inhibition was not modified by glycine, N-methyl-D-aspartate or subtype-selective kainate receptor agents, while CNQX or DNQX (10 muM), two AMPA and kainate receptor antagonists, reduced kynurenic acid effects. Low concentrations of kynurenic acid, however, did not modify [H-3]-kainate (high and low affinity) or [H-3]-AMPA binding to rat brain membranes. Finally, because metabotropic glutamate (mGlu) receptors modulate transmitter release in striatal preparations, we evaluated, with negative results, kynurenic acid (1-100 nM) effects in cells transfected with mGlu(1), mGlu(2), mGlu(4) or mGlu(5) receptors. In conclusion, our data show that kynurenate-induced inhibition ofglutamate release is not mediated by glutamate receptors. Nicotinic acetylcholine receptors, however, may contribute to the inhibitory effects of kynurenate found in microdialysis studies, but not in those found in isolated synaptosomes.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/04/20 alle ore 06:03:14