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001-es BibID:	BIBFORM016885
Első szerző:	Virág László (élettanász Szeged)
Cím:	Analysis of the contribution of Ito to repolarization in canine ventricular myocardium / Virág L., Jost N., Papp R., Koncz I., Kristóf A., Kohajda Z., Harmati G., Carbonell-Pascual B., Ferrero J. M. Jr., Papp J. Gy., Nánási P. P., Varró A.
Dátum:	2011
ISSN:	0007-1188
Megjegyzések:	Contribution of the transient outward potassium current (Ito) to ventricular repolarization is controversial depending on the experimental conditions, the region of myocardium or the species studied. The aim of the present study was, therefore, to characterize Ito and estimate its contribution to repolarization reserve in canine ventricular myocardium. Experimental approach: Ion currents were recorded using conventional whole cell voltage clamp and action potential voltage clamp techniques in isolated canine ventricular cells. Action potentials were recorded from canine ventricular preparations using microelectrodes. Key results: Contribution of Ito to repolarization was studied using 100 ?M chromanol 293B in full IKs blockade by 0.5 ?M HMR 1556. This high concentration of chromanol 293B effectively suppressed Ito without affecting other repolarizing K(+) currents (IK1, IKr, Ip). Action potential clamp experiments revealed a slowly inactivating and a "late" chromanol-sensitive current component flowing during the action potential plateau. Action potentials were significantly lengthened by chromanol 293B in the presence of HMR 1556. This lengthening effect of Ito inhibition showed reverse rate-dependent properties. It was extremely augmented after additional attenuation of repolarization reserve by 0.1 ?M dofetilide resulting in the occurrence of early afterdepolarizations (EADs). The results have been confirmed by computer simulation. Conclusions and Implications: The results indicate that Ito is involved in governing repolarization in canine ventricular myocardium and, it contributes significantly to the repolarization reserve. Therefore, blockade of Ito may enhance proarrhythmic risk.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban transient outward current action potential duration repolarization reserve cardiac ventricular muscle arrhythmia
Megjelenés:	British Journal Of Pharmacology. - 164 : 1 (2011), p. 93-105. -
További szerzők:	Jost Norbert Papp R. Koncz István (Szeged) Kristóf A. (Szeged) Kohajda Zsófia Harmati Gábor (1983-) (élettanász) Carbonell-Pascual, B. Ferrero, J. M. Jr Papp Gy. Julius (Szeged) Nánási Péter Pál (1956-) (élettanász) Varró András (1954-) (farmakológus, klinikai farmakológus)
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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