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Titolo:
A NOVEL SLOW HYPERPOLARIZATION-ACTIVATED POTASSIUM CURRENT (I-K(SHA))FROM A MOUSE HIPPOCAMPAL CELL-LINE
Autore:
WISCHMEYER E; KARSCHIN A;
Indirizzi:
MAX PLANCK INST BIOPHYS CHEM,FASSBERG 11 D-37070 GOTTINGEN GERMANY MAX PLANCK INST BIOPHYS CHEM D-37070 GOTTINGEN GERMANY
Titolo Testata:
Journal of physiology
fascicolo: 3, volume: 504, anno: 1997,
pagine: 591 - 602
SICI:
0022-3751(1997)504:3<591:ANSHPC>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
BULLFROG SYMPATHETIC NEURONS; RECTIFYING K+ CHANNELS; VOLTAGE-CLAMP ANALYSIS; ATRIAL NODE CELLS; ANOMALOUS RECTIFICATION; GANGLION NEURONS; XENOPUS-OOCYTES; PATCH-CLAMP; CURRENT IF; MODULATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
39
Recensione:
Indirizzi per estratti:
Citazione:
E. Wischmeyer e A. Karschin, "A NOVEL SLOW HYPERPOLARIZATION-ACTIVATED POTASSIUM CURRENT (I-K(SHA))FROM A MOUSE HIPPOCAMPAL CELL-LINE", Journal of physiology, 504(3), 1997, pp. 591-602

Abstract

1. A slow hyperpolarization-activated inwardly rectifying K+ current (I-K(SHA)) with novel characteristics was identified from the mouse embryonic hippocampus x neuroblastoma cell line HN9.10e. 2. The non-inactivating current activated negative to a membrane potential of -80 mV with slow and complex activation kinetics (tau(act) approximate to 1-7s) and a characteristic delay of 1-10 s (-80 to -140 mV) that was linearly dependent on the membrane potential. 3. Tail currents and instantaneous open channel currents determined through fast voltage ramps reversed at the K+ equilibrium potential (E-K) indicating that primarilyK+, but not Na+, permeated the channels. 4. I-K(SHA) was unaffected by altering the intracellular Ca2+ concentration between similar to 0 and 10 mu M, but was susceptible to block by 5 mM extracellular Ca2+, Ba2+ (K-i = 0.42 mM), and Cs+ (K-i = 2.77 mM) 5. In cells stably transformed with M2 muscarinic receptors, I-K(SHA) was rapidly, but reversibly, suppressed by application of micromolar concentrations of muscarine. 6. At the single channel level II(SHA) channel openings were observed with the characteristic delay upon membrane hyperpolarization. Analysis of unitary currents revealed an inwardly rectifying I-V profile and a channel slope conductance of 7 pS. Channel activity persisted in the inside-out configuration for many minutes. 7. It is concluded thatI-K(SHA) in HN9.10e cells represents a novel K+ current, which is activated upon membrane hyperpolarization. It is functionally different from both classic inwardly rectifying I-Kir currents and other cationichyperpolarization-activated I-H currents that have been previously described in neuronal or glial cells.

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Documento generato il 22/09/20 alle ore 10:56:25