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Titolo:
PHYSIOLOGICAL AND THEORETICAL-ANALYSIS OF K+ CURRENTS CONTROLLING DISCHARGE IN NEONATAL RAT MESENCEPHALIC TRIGEMINAL NEURONS
Autore:
DELNEGRO CA; CHANDLER SH;
Indirizzi:
UNIV CALIF LOS ANGELES,DEPT PHYSIOL SCI,2851 SLICHTER HALL LOS ANGELES CA 90095 UNIV CALIF LOS ANGELES,DEPT PHYSIOL SCI LOS ANGELES CA 90095
Titolo Testata:
Journal of neurophysiology
fascicolo: 2, volume: 77, anno: 1997,
pagine: 537 - 553
SICI:
0022-3077(1997)77:2<537:PATOKC>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
ROOT GANGLION NEURONS; SPINAL-CORD INJURY; TRANSIENT OUTWARD CURRENT; MUSCLE SPINDLE AFFERENTS; PATCH-CLAMP RECORDINGS; POTASSIUM CURRENTS; SENSORY NEURONS; SYMPATHETIC NEURONS; SLICE PREPARATION; SOMATIC MEMBRANE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
50
Recensione:
Indirizzi per estratti:
Citazione:
C.A. Delnegro e S.H. Chandler, "PHYSIOLOGICAL AND THEORETICAL-ANALYSIS OF K+ CURRENTS CONTROLLING DISCHARGE IN NEONATAL RAT MESENCEPHALIC TRIGEMINAL NEURONS", Journal of neurophysiology, 77(2), 1997, pp. 537-553

Abstract

Whole cell voltage- and current-clamp recordings were obtained from mesencephalic trigeminal sensory (Mes 5) neurons identified visually inthin brain stem slices of neonatal rats with the use of infrared video microscopy. These cells exhibited accommodation in spike discharge responses to depolarizing current injection protocols whose duration differed as a function of holding potential (-50 vs. -65 mV). Several spikes were elicited before the membrane response accommodated from -50 mV, whereas from -65 mV only single action potentials were evoked. In response to similar protocols, application of the K+ channel blocker 4-aminopyridine (4-AP) (50 mu M to 2 mM) caused sustained repetitive spiking whereas tetraethylammonium (TEA) (10-30 mM) did not cause repetitive spiking. In voltage clamp, 4-AP application (100 mu M) revealed asustained outward current (I-4-AP) that was active between -60 and -30 mV. I-4-AP was responsible for suppressing sustained repetitive spiking behavior, producing accommodation under normal circumstances. TEA application in voltage clamp revealed a sustained outward current evoked positive to -40 mV. Two transient outward currents (TOCs) were identified by prepulse protocols typically used to characterize A-type currents: a 4-AP-insensitive fast TOC, and a slow TOC (I-TOC-S) sensitiveto 4-AP(>500 mu M). A Ca2+-dependent outward current that activated positive to -30 mV was also characterized. A mathematical model of a Mes 5 neuron was assembled from our voltage-clamp records to simulate the dynamic interaction of outward currents during membrane excitation. We conclude that in Mes 5 neurons, the 4-AP-sensitive currents I-TOC-Sand I-4-AP determine the duration of spike trains. In particular, thenoninactivating I-4-AP determines whether cells exhibit sustained repetitive discharge or accommodate in response to depolarizing current. Neurotransmitter modulation of this current or modulation of the resting membrane potential could modify the output properties of Mes 5 neurons, and therefore the properties of these currents must be incorporated into our current understanding of how these cells contribute to shaping oral-motor pattern generation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 05/12/20 alle ore 01:59:01