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Titolo:
Function of NMDA receptors and persistent sodium channels in a feedback pathway of the electrosensory system
Autore:
Berman, N; Dunn, RJ; Maler, L;
Indirizzi:
Univ Ottawa, Dept Cellular & Mol Med, Ottawa, ON K1H 8M5, Canada Univ Ottawa Ottawa ON Canada K1H 8M5 Mol Med, Ottawa, ON K1H 8M5, Canada Montreal Gen Hosp, Res Inst, Neurosci Res Ctr, Montreal, PQ H3G 1A4, Canada Montreal Gen Hosp Montreal PQ Canada H3G 1A4 Montreal, PQ H3G 1A4, Canada
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 4, volume: 86, anno: 2001,
pagine: 1612 - 1621
SICI:
0022-3077(200110)86:4<1612:FONRAP>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
LATERAL-LINE LOBE; WEAKLY ELECTRIC FISH; NEOCORTICAL PYRAMIDAL NEURONS; APTERONOTUS-LEPTORHYNCHUS; COINCIDENCE DETECTION; SENSORY SEARCHLIGHT; HIPPOCAMPAL-NEURONS; GYMNOTIFORM FISH; BARREL CORTEX; MESSENGER-RNA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
49
Recensione:
Indirizzi per estratti:
Indirizzo: Maler, L Univ Ottawa, Dept Cellular & Mol Med, Ottawa, ON K1H 8M5, Canada Univ Ottawa Ottawa ON Canada K1H 8M5 Ottawa, ON K1H 8M5, Canada
Citazione:
N. Berman et al., "Function of NMDA receptors and persistent sodium channels in a feedback pathway of the electrosensory system", J NEUROPHYS, 86(4), 2001, pp. 1612-1621

Abstract

Voltage-dependent amplification of ionotropic glutamatergic excitatory postsynaptic potentials (EPSPs) can, in many vertebrate neurons, be due eitherto the intrinsic voltage dependence of N-methyl-D-aspartate (NMDA) receptors, or voltage-dependent persistent sodium channels expressed on postsynaptic dendrites or somata. In the electrosensory lateral line lobe (ELL) of the gymnotiform fish Apteronotus leptorhynchus, glutamatergic inputs onto pyramidal cell apical dendrites provide a system where both amplification mechanisms are possible. We have now examined the roles for both NMDA receptorsand sodium channels in the control of EPSP amplitude at these synapses. Anantibody specific for the A. leptorhynchus NR1 subunit reacted strongly with ELL pyramidal cells and were particularly abundant in the spines of pyramidal cell apical dendrites. We have also shown that NMDA receptors contributed strongly to the late phase of EPSPs; evoked by stimulation of the feedback fibers terminating on the apical dendritic spines; further, these EPSPs were voltage dependent. Blockade of NMDA receptors did not, however, eliminate the voltage dependence of these EPSPs. Blockade of somatic sodium channels by local somatic ejection of tetrodotoxin (TTX), or inclusion of QX314 (an intracellular sodium channel blocker) in the recording pipette, reduced the evoked EPSPs and completely eliminated their voltage dependence. We therefore conclude that, in the subthreshold range, persistent sodium currents are the main contributor to voltage-dependent boosting of EPSPs, even when they have a large NMDA receptor component.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/07/20 alle ore 00:09:11