PMID: 3746687May 1, 1986Paper

The arrhythmogenic current ITI in the absence of electrogenic sodium-calcium exchange in sheep cardiac Purkinje fibres

The Journal of Physiology
M B Cannell, W J Lederer

Abstract

Sheep cardiac Purkinje fibres were voltage clamped with a two-microelectrode technique. Under conditions that are known to elevate intracellular calcium (0 mM-external potassium), membrane currents were examined. In the above conditions, a brief depolarizing pulse leads to an oscillatory inward current (ITI) which peaks at about 300 ms after the repolarization. An after-contraction is also observed, the peak of which occurs about 80 ms after the peak of ITI. This result is in accord with the results of Kass, Lederer, Tsien & Weingart (1978a). We replaced external sodium with an isotonic CaCl2 solution to remove the sodium-calcium exchange mechanism as a possible current carrier for ITI. In the steady state under these conditions an oscillatory membrane current and after-contraction are seen following repolarization. This current was identified as ITI on the basis of its temporal relation to both the repolarization step and the after-contraction. In isotonic CaCl2, ITI has a reversal potential of -37 mV. Because of this fact ITI cannot be explained by an electrogenic sodium-calcium exchange mechanism alone. The reversal potential suggests that ITI arises from a channel which is permeable to both potassium and calcium. Fluctuatio...Continue Reading

Citations

Apr 1, 1991·Pflügers Archiv : European journal of physiology·K BenndorfH Hirche
Dec 1, 1988·Cardiovascular Drugs and Therapy·L H Opie, W A Coetzee
Jan 5, 2000·The Journal of Physiology·Y Wu, M E Anderson
Feb 1, 1991·Archives Internationales De Physiologie, De Biochimie Et De Biophysique·E Wettwer, U Ravens
Jul 4, 2012·Biochemical Pharmacology·Hugues AbrielJean-Sébastien Rougier
Jun 18, 2004·Annals of the New York Academy of Sciences·Thomas R Shannon, Donald M Bers
Apr 27, 2005·Heart Rhythm : the Official Journal of the Heart Rhythm Society·Penelope A BoydenHenk E D J Ter Keurs
Jul 26, 2005·Pharmacology & Therapeutics·Penelope A Boyden, Henk ter Keurs
Oct 1, 1991·British Journal of Pharmacology·D WilhelmT Peters
Sep 1, 1995·Pflügers Archiv : European journal of physiology·K R SipidoE Carmeliet
Sep 1, 1987·Pflügers Archiv : European journal of physiology·P LippL Pott
May 1, 1991·Circulation Research·M C DanielsH E ter Keurs
Apr 1, 1991·Circulation Research·W SpinelliB F Hoffman
Feb 1, 1991·Circulation Research·A C Zygmunt, W R Gibbons
Feb 1, 1988·Circulation Research·J A HillH C Strauss
Apr 1, 1996·Circulation Research·M A Laflamme, P L Becker
Jun 20, 1998·Circulation Research·L Priebe, D J Beuckelmann
Apr 13, 2007·Physiological Reviews·Henk E D J Ter Keurs, Penelope A Boyden
Oct 17, 2008·Physiological Reviews·Heping Cheng, W J Lederer
Jul 3, 1999·Physiological Reviews·M P Blaustein, W J Lederer
Jun 1, 1990·The American Journal of Physiology·C H Orchard, J C Kentish

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