Contribution of IKs to ventricular repolarization in canine myocytes

Balázs Horváth, J. Magyar, N. Szentandrássy, Péter Birinyi, P. Nánási, Tamás Bányász

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

The role of the slow delayed rectifier K+ current (I Ks) in cardiac repolarization seems to be largely influenced by the experimental conditions including the species and tissue studied. The aim of this study was to determine the contribution of IKs to repolarization in canine ventricular myocytes by measuring the frequency dependent action potential lengthening effect of 10 μM chromanol 293B using sharp microelectrodes. Pretreatment with isoproterenol (2 nM), E-4031 (1 μM), and injection of inward current pulses were applied to modify action potential configuration. Chromanol alone caused moderate but statistically significant lengthening of action potentials at cycle lengths longer than 500 ms. The lengthening effect of chromanol, which was strongly enhanced in the presence of either isoproterenol or E-4031, was proportional to the amplitude of plateau, whereas poor correlation was found with action potential duration. Similar results were obtained when action potential configuration was modified by injection of depolarizing current pulses. Computer simulations revealed that activation of IKs is a sharp function of the plateau amplitude within the physiological range, while elongation of repolarization may enhance I Ks only when it is excessive. It was concluded that the effect of IKs on ventricular repolarization critically depends on the level of action potential plateau; however, other factors, like action potential duration, cycle length, or suppression of other K+ currents can also influence its contribution.

Original languageEnglish
Pages (from-to)698-706
Number of pages9
JournalPflugers Archiv European Journal of Physiology
Volume452
Issue number6
DOIs
Publication statusPublished - Sep 2006

Fingerprint

Isoproterenol
Muscle Cells
Action Potentials
Canidae
Microelectrodes
Elongation
Chemical activation
Tissue
Computer simulation
Injections
2,2,5,7,8-pentamethyl-1-hydroxychroman
E 4031
Computer Simulation
6-cyano-4-(N-ethylsulfonyl-N-methylamino)-3-hydroxy-2,2-dimethylchromane

Keywords

  • Action potential duration
  • Cardiac repolarization
  • Chromanol 293B
  • Computer simulation
  • Delayed rectifier K current
  • E-4031
  • I blockers
  • Isoproterenol

ASJC Scopus subject areas

  • Physiology

Cite this

Contribution of IKs to ventricular repolarization in canine myocytes. / Horváth, Balázs; Magyar, J.; Szentandrássy, N.; Birinyi, Péter; Nánási, P.; Bányász, Tamás.

In: Pflugers Archiv European Journal of Physiology, Vol. 452, No. 6, 09.2006, p. 698-706.

Research output: Contribution to journalArticle

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