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Titolo:
SUSTAINED OUTWARD RECTIFICATION OF OXYTOCINERGIC NEURONS IN THE RAT SUPRAOPTIC NUCLEUS - IONIC DEPENDENCE AND PHARMACOLOGY
Autore:
STERN JE; ARMSTRONG WE;
Indirizzi:
UNIV TENNESSEE,COLL MED,DEPT ANAT & NEUROBIOL,855 MONROE AVE MEMPHIS TN 38163
Titolo Testata:
Journal of physiology
fascicolo: 2, volume: 500, anno: 1997,
pagine: 497 - 508
SICI:
0022-3751(1997)500:2<497:SOROON>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
MAGNOCELLULAR NEUROENDOCRINE CELLS; VASOPRESSIN-SECRETING NEURONS; NEUROSECRETORY NEURONS; ELECTROPHYSIOLOGICAL CHARACTERISTICS; POTASSIUM CURRENT; ACTION-POTENTIALS; CALCIUM CURRENTS; SENSORY NEURONS; K+ CURRENT; INVITRO;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
40
Recensione:
Indirizzi per estratti:
Citazione:
J.E. Stern e W.E. Armstrong, "SUSTAINED OUTWARD RECTIFICATION OF OXYTOCINERGIC NEURONS IN THE RAT SUPRAOPTIC NUCLEUS - IONIC DEPENDENCE AND PHARMACOLOGY", Journal of physiology, 500(2), 1997, pp. 497-508

Abstract

1. Intracellular recordings were obtained in vitro from oxytocin and vasopressin neurones from dioestrous and lactating female rats. Oxytocin neurones were characterized under current clamp by the expression of a depolarization-activated, sustained outward rectification (SOR) and a rebound depolarization (RD). 2. An increment in extracellular K+ shifted the expression of the SOR and RD towards a more depolarized membrane potential, indicating that the mechanisms underlying these events are dependent on extracellular potassium. 3. The SOR and RD were blocked by external tetraethylammonium (10 mM) and Ba2+ (0.1-05 mM). Cs+ (2 mM) blocked the hyperpolarization-activated inward rectification without affecting the expression of the SOR and RD. 4. The SOR was not affected by 4-aminopyridine (6 mM). However, the rebound amplitude was significantly enhanced, indicating that the activation of a transient outward current interacts with the expression of the rebound. 5. Iberiotoxin (100 nM) and apamin (50 nM), toxins known to block some calcium-dependent potassium conductances, did not affect the expression of the SOR and RD. 6. The SOR and RD were significantly reduced by Cd2+ (0.5 mM) but not by Ni2+ (0.25 mM). 7. Muscarine (10 mu M) did not affectthe SOR or the RD. 8. These results indicate that the SOR and RD depend upon a depolarization-activated, sustained outward potassium current, which might be calcium dependent. A current with these characteristics has never been described before in the magnocellular system. Voltage-clamp experiments are needed to completely characterize this potassium conductance selectively expressed by oxytocin neurones.

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Documento generato il 09/07/20 alle ore 17:10:59