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Titolo:
UNITARY CONDUCTANCE OF NA-CELLS( CHANNEL ISOFORMS IN CARDIAC AND NB2ANEUROBLASTOMA)
Autore:
BAUMGARTEN CM; DUDLEY SC; ROGART RB; FOZZARD HA;
Indirizzi:
VIRGINIA COMMONWEALTH UNIV,MED COLL VIRGINIA,DEPT PHYSIOL RICHMOND VA23298 UNIV CHICAGO,DEPT MED CARDIOL CHICAGO IL 60637 UNIV CHICAGO,DEPT PHARMACOL & PHYSIOL SCI CHICAGO IL 60637
Titolo Testata:
American journal of physiology. Cell physiology
fascicolo: 6, volume: 38, anno: 1995,
pagine: 1356 - 1363
SICI:
0363-6143(1995)38:6<1356:UCONCI>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
SINGLE SODIUM-CHANNELS; NEURO-BLASTOMA CELLS; RAT SKELETAL-MUSCLE; FUNCTIONAL EXPRESSION; VENTRICULAR MYOCYTES; PURKINJE-CELLS; BINDING-SITE; OPEN STATES; TETRODOTOXIN; SAXITOXIN;
Keywords:
SODIUM CURRENT; PATCH CLAMP; KINETICS; MYOCARDIUM; NEURONS; NB2A; RABBIT; MOUSE; NACH6; RH1;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
42
Recensione:
Indirizzi per estratti:
Citazione:
C.M. Baumgarten et al., "UNITARY CONDUCTANCE OF NA-CELLS( CHANNEL ISOFORMS IN CARDIAC AND NB2ANEUROBLASTOMA)", American journal of physiology. Cell physiology, 38(6), 1995, pp. 1356-1363

Abstract

Unitary conductances of native Na+ channel isoforms (YNa) have been determined under a variety of conditions, making comparisons of gamma(Na) difficult. To allow direct comparison, we measured gamma(Na) in cell-attached patches on NB2a neuroblastoma cells and rabbit ventricular myocytes under identical conditions [pipette solution (in mM): 280 Naand 2 Ca2+, pH 7.4; 10 degrees C]. gamma(Na) of NB2a channels, 22.9 +/- 0.9 pS, was 21% greater than that of cardiac channels, 18.9 +/- 0.9pS. In contrast, respective extrapolated reversal potentials, +62.4 +/- 4.6 and +57.9 +/- 5.1 mV, were not significantly different. Severalkinetic differences between the channel types were also noted. Negative to -20 mV, mean open time (MOT) of the NB2a isoform was significantly less than that of cardiac channels, and, near threshold, latency tochannel opening decayed more rapidly in NB2a. On the basis of analysis of MOT between -60 and 0 mV, the rate constants at 0 mV for the open-to-closed (O --> C) and open-to-inactivated (O --> I) transitions were 0.42 +/- 0.11 and 0.41 +/- 0.11 ms(-1) in NB2a and 0.10 +/- 0.06 and1.19 +/- 0.07 ms(-1) in myocytes. The slope factors were -38.9 +/- 8.7 and +10.1 +/- 6.1 mV in NB2a and -21.3 +/- 7.1 and +23.7 +/- 4.9 mV in myocytes. Transition rate constants were significantly different inNB2a and cardiac cells, but voltage dependence was not.

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Documento generato il 23/09/20 alle ore 13:40:47