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Titolo:
Properties and role of I-h in the pacing of subthreshold oscillations in entorhinal cortex layer II neurons
Autore:
Dickson, CT; Magistretti, J; Shalinsky, MH; Fransen, E; Hasselmo, ME; Alonso, A;
Indirizzi:
Montreal Neurol Inst, Dept Neurol & Neurosurg, Montreal, PQ H3A 2B4, Canada Montreal Neurol Inst Montreal PQ Canada H3A 2B4 treal, PQ H3A 2B4, Canada Ist Nazl Neurol C Besta, Dept Expt Neurophysiol, I-20133 Milan, Italy Ist Nazl Neurol C Besta Milan Italy I-20133 hysiol, I-20133 Milan, Italy Royal Inst Technol, Dept Numer Anal & Comp Sci, S-10044 Stockholm, Sweden Royal Inst Technol Stockholm Sweden S-10044 i, S-10044 Stockholm, Sweden Boston Univ, Dept Psychol, Boston, MA 02215 USA Boston Univ Boston MA USA02215 Univ, Dept Psychol, Boston, MA 02215 USA McGill Univ, Dept Neurol & Neurosurg, Montreal, PQ H3A 2B4, Canada McGill Univ Montreal PQ Canada H3A 2B4 surg, Montreal, PQ H3A 2B4, Canada
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 5, volume: 83, anno: 2000,
pagine: 2562 - 2579
SICI:
0022-3077(200005)83:5<2562:PAROII>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
HYPERPOLARIZATION-ACTIVATED CURRENT; LONG-TERM POTENTIATION; HIPPOCAMPAL THETA-RHYTHM; VOLTAGE-CLAMP ANALYSIS; SINO-ATRIAL NODE; ANOMALOUS RECTIFICATION; CATION CURRENT; INWARD CURRENT; NEOCORTICAL NEURONS; SINOATRIAL NODE;
Tipo documento:
Review
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
106
Recensione:
Indirizzi per estratti:
Indirizzo: Alonso, A McGill Univ, Dept Neurol & Neurosurg, 3801 Univ St, Montreal, PQH3A 2B4, Canada McGill Univ 3801 Univ St Montreal PQ Canada H3A 2B4 2B4, Canada
Citazione:
C.T. Dickson et al., "Properties and role of I-h in the pacing of subthreshold oscillations in entorhinal cortex layer II neurons", J NEUROPHYS, 83(5), 2000, pp. 2562-2579

Abstract

Various subsets of brain neurons express a hyperpolarization-activated inward current (I-h) that has been shown to be instrumental in pacing oscillatory activity at both a single-cell and a network level. A characteristic feature of the stellate cells (SCs) of entorhinal cortex (EC) layer II, thoseneurons giving rise to the main component of the perforant path input to the hippocampal formation, is their ability to generate persistent, Na+-dependent rhythmic subthreshold membrane potential oscillations, which are thought to be instrumental in implementing theta rhythmicity in the entorhinal-hippocampal network. The SCs also display a robust time-dependent inward rectification in the hyperpolarizing direction that may contribute to the generation of these oscillations. We performed whole cell recordings of SCs inin vitro slices to investigate the specific biophysical and pharmacological properties of the current underlying this inward rectification and to clarify its potential role in the genesis of the subthreshold oscillations. Involtage-clamp conditions, hyperpolarizing voltage steps evoked a slow, noninactivating inward current, which also deactivated slowly on depolarization. This current was identified as I-h because it was resistant to extracellular Ba2+, sensitive to Cs+, completely and selectively abolished by ZD7288, and carried by both Na+ and K+ ions. I-h in the SCs had an activation threshold and reversal potential at approximately -45 and -20 mV, respectively. Its half-activation voltage was -77 mV. Importantly, bath perfusion with ZD7288, but not Ba2+ gradually and completely abolished the subthreshold oscillations, thus directly implicating I-h in their generation. Using experimentally derived biophysical parameters for I-h and the low-threshold persistent Na+ current (I-NaP) present in the SCs, a simplified model of these neurons was constructed and their subthreshold electroresponsiveness simulated. This indicated that the interplay between I-NaP and I-h can sustain persistent subthreshold oscillations in SCs. I-NaP and I-h operate in a "push-pull" fashion where the delay in the activation/deactivation of I-h gives rise to the oscillatory process.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 07/04/20 alle ore 22:53:53