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001-es BibID:	BIBFORM030260
035-os BibID:	(Scopus)0346266098 (WoS)000187507900005
Első szerző:	Fülöp László (kardiológus)
Cím:	The role of transmembrane chloride current in afterdepolarisations in canine ventricular cardiomyocytes / L. Fülöp, E. Fiák, N. Szentandrássy, J. Magyar, P. P. Nánási, T. Bányász
Dátum:	2003
ISSN:	0231-5882
Megjegyzések:	The physiological role of chloride currents (I-Cl) in cardiac cells is poorly understood. The aim of the present study was to reveal the role of I-Cl in the genesis of early and delayed afterdepolarisations (EADs and DADs, respectively). First we identified I-Cl under action potential voltage clamp conditions as the anthracene-9-carboxylic acid (ANTRA) (0.5 mmol/l)-sensitive current. The ANTRA-sensitive current was large and outwardly directed at the beginning, while it was moderate and inwardly directed at the end of the action potential. Application of ANTRA under current clamp conditions decreased the depth of the incisura, shifted the plateau upwards and lengthened the duration of action potentials. The effect of ANTRA was studied in three models of afterdepolarisations: the ouabain-induced DAD model, the caesium-induced EAD model, and in the presence of subthreshold concentration of isoproterenol. Preincubation of the cells with 0.5 mmol/l ANTRA failed to induce afterdepolarisations. Ouabain (200 nmol/l) alone caused DADs in 62.5 % of the cells within 15 min. When ouabain was applied in the presence of ANTRA, 60 % of the myocytes transiently displayed EADs before the development of DADs, and all cells developed DADs within 7 min. Isoproterenol (5 nmol/l) alone failed to induce afterdepolarisations. However, 75 % of the cells produced DADs within 6 min when superfused with isoproterenol in the presence of ANTRA. Incubation of the myocytes with 3.6 mmol/l CsCl caused EADs in 71.4 % of the cells within 30 min. Application of CsCl in the presence of ANTRA resulted in immediate depolarisation of the membrane from -79.6 +/- 0.4 to -54.2 +/- 3.5 mV. Summarizing our results we conclude that the ANTRA-sensitive current is an important mechanism of defence against afterdepolarisations. Suppression of I-Cl may thus increase the incidence and accelerate the rate of development of both EADs and DADs.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	General Physiology and Biophysics. - 22 : 3 (2003), p. 341-353. -
További szerzők:	Fiák Edit Szentandrássy Norbert (1976-) (élettanász) Magyar János (1961-) (élettanász) Nánási Péter Pál (1956-) (élettanász) Bányász Tamás (1960-) (élettanász)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
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