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Titolo:
GABA-mediated synchronization in the human neocortex: Elevations in extracellular potassium and presynaptic mechanisms
Autore:
Louvel, J; Papatheodoropoulos, C; Siniscalchi, A; Kurcewicz, I; Pumain, R; Devaux, B; Turak, B; Esposito, V; Villemeure, JG; Avoli, M;
Indirizzi:
McGill Univ, Montreal Neurol Inst, Montreal, PQ H3A 2B4, Canada McGill Univ Montreal PQ Canada H3A 2B4 Inst, Montreal, PQ H3A 2B4, Canada McGill Univ, Dept Neurol & Neurosurg, Montreal, PQ H3A 2B4, Canada McGill Univ Montreal PQ Canada H3A 2B4 surg, Montreal, PQ H3A 2B4, Canada McGill Univ, Dept Physiol, Montreal, PQ H3A 2B4, Canada McGill Univ Montreal PQ Canada H3A 2B4 siol, Montreal, PQ H3A 2B4, Canada Ctr Rech P Broca, INSERM, U109, F-75014 Paris, France Ctr Rech P Broca Paris France F-75014 NSERM, U109, F-75014 Paris, France Hop St Anne, F-75014 Paris, France Hop St Anne Paris France F-75014Hop St Anne, F-75014 Paris, France Univ Patras, Dept Physiol, Patras, Greece Univ Patras Patras GreeceUniv Patras, Dept Physiol, Patras, Greece IRCCS Neuromed, I-86077 Pozzilli, Isernia, Italy IRCCS Neuromed Pozzilli Isernia Italy I-86077 77 Pozzilli, Isernia, Italy Univ Strasbourg 1, F-67000 Strasbourg, France Univ Strasbourg 1 Strasbourg France F-67000 , F-67000 Strasbourg, France INSERM, U398, F-67000 Strasbourg, France INSERM Strasbourg France F-67000 NSERM, U398, F-67000 Strasbourg, France
Titolo Testata:
NEUROSCIENCE
fascicolo: 4, volume: 105, anno: 2001,
pagine: 803 - 813
SICI:
0306-4522(2001)105:4<803:GSITHN>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
METABOTROPIC GLUTAMATE RECEPTORS; RAT HIPPOCAMPUS; PYRAMIDAL CELLS; SYNAPTIC INHIBITION; IONIC MECHANISMS; IN-VITRO; 4-AMINOPYRIDINE; NEURONS; FREQUENCY; DEPOLARIZATION;
Keywords:
GABA; human cortex; [K+](0); opioid receptors; synchronization;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Avoli, M 3801 Univ St, Montreal, PQ H3A 2B4, Canada 3801 Univ St MontrealPQ Canada H3A 2B4 real, PQ H3A 2B4, Canada
Citazione:
J. Louvel et al., "GABA-mediated synchronization in the human neocortex: Elevations in extracellular potassium and presynaptic mechanisms", NEUROSCIENC, 105(4), 2001, pp. 803-813

Abstract

Field potential and extracellular [K+] ([K+](o)) recordings were made in the human neocortex in an in vitro slice preparation to study the synchronous activity that occurs in the presence of 4-aminopyridine (50 muM) and ionotropic excitatory amino acid receptor antagonists. Under these experimentalconditions, negative or negative-positive field potentials accompanied by rises in [K+](o) (up to 4.1 mM from a baseline of 3.25 mM) occurred spontaneously at intervals of 3-27 s. Both field potentials and [K+], elevations were largest at approximately 1000 mum from the pia. Similar events were induced by neocortical electrical stimuli. Application of medium containing low [Ca2+]/high [Mg2+] (n = 3 slices) antagonism of the GABAA receptor (n = 7) or mu -opioid receptor activation (n = 4) abolished these events. Hence, they represented network, GABA-mediated potentials mainly reflecting the activation of type A receptors following GABA release from interneurons. The GABAB receptor agonist baclofen (10-100 muM, n = 11) reduced and abolished the GABA-mediated potentials (ID50 = 18 muM). Baclofen effects were antagonized by the GABA(B) receptor antagonist CGP 35348 (0.1-1 mM, n = 6; ID50 = 0.19 mM). CGP 38345 application to control medium increased the amplitude of the GABA-mediated potentials and the concomitant [K+](o) rises without modifying their rate of occurrence. The GABA-mediated potentials were not influenced by the broad-spectrum metabotropic glutamate agonist (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (100 muM, n = 10), but decreased inrate with the group I receptor agonist (S)-3,5-dihydroxyphenylglycine (10-100 muM, n = 9). Our data indicate that human neocortical networks challenged with 4-aminopyridine generate glutamatergic-independent, GABA-mediated potentials that are modulated by mu -opioid and GABAB receptors presumably located on interneuron terminals. These events are associated with [K+](o) elevations that may contribute to interneuron synchronization in the absence of ionotropic excitatory synaptic transmission. (C) 2001 IBRO. Published by Elsevier Science Ltd. All rights reserved.

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Documento generato il 23/01/20 alle ore 03:29:55