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Titolo:
Laminar differences in recurrent excitatory transmission in the rat entorhinal cortex in vitro
Autore:
Dhillon, A; Jones, RSG;
Indirizzi:
Univ Oxford, Dept Pharmacol, Oxford OX1 3QT, England Univ Oxford Oxford England OX1 3QT pt Pharmacol, Oxford OX1 3QT, England Univ Bristol, Sch Med Sci, Dept Physiol, Bristol BS8 1TD, Avon, England Univ Bristol Bristol Avon England BS8 1TD Bristol BS8 1TD, Avon, England
Titolo Testata:
NEUROSCIENCE
fascicolo: 3, volume: 99, anno: 2000,
pagine: 413 - 422
SICI:
0306-4522(2000)99:3<413:LDIRET>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
TEMPORAL-LOBE EPILEPSY; PREFERENTIAL NEURONAL LOSS; AMINO-ACID RECEPTORS; LAYER-II NEURONS; PYRAMIDAL NEURONS; HIPPOCAMPAL SLICE; IN-VITRO; SYNAPTIC TRANSMISSION; CORTICAL-CELLS; INTRACELLULAR-RECORDINGS;
Keywords:
entorhinal cortex; recurrent excitatory synapses; epilepsy;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
71
Recensione:
Indirizzi per estratti:
Indirizzo: Jones, RSG Univ Oxford, Dept Pharmacol, Mansfield Rd, Oxford OX1 3QT, England Univ Oxford Mansfield Rd Oxford England OX1 3QT 1 3QT, England
Citazione:
A. Dhillon e R.S.G. Jones, "Laminar differences in recurrent excitatory transmission in the rat entorhinal cortex in vitro", NEUROSCIENC, 99(3), 2000, pp. 413-422

Abstract

Paired intracellular recordings were used to investigate recurrent excitatory transmission in layers II, III and V of the rat entorhinal cortex in vitro. There was a relatively high probability of Ending a recurrent connection between pairs of pyramidal neurons in both layer V (around 12%) and layer III (around 9%). In complete contrast, we have failed to find any recurrent synaptic connections between principal neurons in layer II, and this maybe an important factor in the relative resistance of this layer in generating synchronized epileptiform activity. In general, recurrent excitatory postsynaptic potentials in layers III and V of the entorhinal cortex had similar properties to those recorded in other cortical areas, although the probabilities of connection are among the highest reported. Recurrent excitatory postsynaptic potentials recorded in layer V were smaller with faster risetimes than those recorded in layer III. In both layers, the recurrent potentials were mediated by glutamate primarily acting at alpha-amino-3-hydroxy-5-methyl-3-isoxazole receptors, although there appeared to be a slow component mediated by N-methyl-D-aspartate receptors. In layer III, recurrent transmission failed on about 30% of presynaptic action potentials evoked at 0.2 Hz. This failure rate increased markedly with increasing (2, 3 Hz) frequency of activation. In layer V the failure rate at low frequency was less (19%), and although it increased at higher frequencies this effect was less pronounced than in layer III. Finally, in layer III, there was evidence fora relatively high probability of electrical coupling between pyramidal neurons. We have previously suggested that layers IV/V of the entorhinal cortex readily generate synchronized epileptiform discharges, whereas layer II is relatively resistant to seizure generation. The present demonstration that recurrent excitatory connections are widespread in layer V but not layer II could support this proposal. The relatively high degree of recurrent connections and electrical coupling between layer III cells may he a factor in it'ssusceptibility to neurodegeneration during chronic epileptic conditions. (C) 2000 IBRO. Published by Elsevier Science Ltd. All rights reserved.

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Documento generato il 09/08/20 alle ore 23:37:19