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001-es BibID:BIBFORM001024
Első szerző:Lengyel Csaba (Szeged)
Cím:Diabetes mellitus attenuates the repolarization reserve in mammalian heart / Lengyel Cs., Virág L., Bíró T., Jost N., Magyar J., Biliczki P., Kocsis E., Skoumal R., Nánási P.P., Tóth M., Kecskeméti V., Papp Gy. J., Varró A.
ISSN:0008-6363 (Print)
Megjegyzések:In diabetes mellitus several cardiac electrophysiological parameters are known to be affected. In rodent experimental diabetes models changes in these parameters were reported, but no such data are available in other mammalian species including the dog. The present study was designed to analyse the effects of experimental type 1 diabetes on ventricular repolarization and its underlying transmembrane ionic currents and channel proteins in canine hearts. METHODS AND RESULTS: Diabetes was induced by a single injection of alloxan, a subgroup of dogs received insulin substitution. After the development of diabetes (8 weeks) electrophysiological studies were performed using conventional microelectrodes, whole cell voltage clamp, and ECG. Expression of ion channel proteins was evaluated by Western blotting. The QTc interval and the ventricular action potential duration in diabetic dogs were moderately prolonged. This was accompanied by significant reduction in the density of the transient outward K+ current (I(to)) and the slow delayed rectifier K+ current (I(Ks)), to 54.6% and 69.3% of control, respectively. No differences were observed in the density of the inward rectifier K+ current (I(K1)), rapid delayed rectifier K+ current (I(Kr)), and L-type Ca2+ current (I(Ca)). Western blot analysis revealed a reduced expression of Kv4.3 and MinK (to 25+/-21% and 48+/-15% of control, respectively) in diabetic dogs, while other channel proteins were unchanged (HERG, MiRP1, alpha(1c)) or increased (Kv1.4, KChIP2, KvLQT1). Insulin substitution fully prevented the diabetes-induced changes in I(Ks), KvLQT1 and MinK, however, the changes in I(to), Kv4.3, and Kv1.4 were only partially diminished by insulin. CONCLUSION: It is concluded that type 1 diabetes mellitus, although only moderately, lengthens ventricular repolarization, attenuates the repolarization reserve by decreasing I(to) and I(Ks) currents, and thereby may markedly enhance the risk of sudden cardiac death.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Cardiovascular Research 73 : 3 (2007), p. 512-520. -
További szerzők:Virág László (élettanász Szeged) Bíró Tamás (1968-) (élettanász) Jost Norbert Magyar János (1961-) (élettanász) Biliczki Péter Kocsis E. Skoumal, R. Nánási Péter Pál (1956-) (élettanász) Tóth M. Kecskeméti Valéria Papp Gy. Julius (Szeged) Varró András (1954-) (farmakológus, klinikai farmakológus)
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001-es BibID:BIBFORM030240
Első szerző:Nagy, Zsolt A.
Cím:Selective inhibition of sodium-calcium exchanger by SEA-0400 decreases early and delayed after depolarization in canine heart / Zsolt A. Nagy, László Virág, András Tóth, Péter Biliczki, Károly Acsai, Tamás Bányász, Péter Nánási, Julius Gy. Papp, András Varro
Megjegyzések:The sodium-calcium exchanger (NCX) was considered to play an important role in arrhythmogenesis under certain conditions such as heart failure or calcium overload. In the present study, the effect of SEA-0400, a selective inhibitor of the NCX, was investigated on early and delayed afterdepolarizations in canine ventricular papillary muscles and Purkinje fibres by applying conventional microelectrode techniques at 37degreesC. The amplitude of both early and delayed afterdepolarizations was markedly decreased by 1 mum SEA-0400 from 26.6 +/- 2.5 to 14.8 +/- 1.8 mV (n = 9, P < 0.05) and from 12.5 &PLUSMN; 1.7 to 5.9 &PLUSMN; 1.4 mV (n = 3, P < 0.05), respectively. In enzymatically isolated canine ventricular myocytes, SEA-0400 did not change significantly the L-type calcium current and the intracellular calcium transient, studied using the whole-cell configuration of the patch-clamp technique and Fura-2 ratiometric fluorometry. It is concluded that, through the reduction of calcium overload, specific inhibition of the NCX current by SEA-0400 may abolish triggered arrhythmias.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
egyetemen (Magyarországon) készült közlemény
Megjelenés:British Journal of Pharmacology. - 143 : 7 (2004), p. 827-831. -
További szerzők:Virág László (élettanász Szeged) Tóth András (farmakológus) Biliczki Péter Acsai Károly Bányász Tamás (1960-) (élettanász) Nánási Péter Pál (1956-) (élettanász) Papp Gy. Julius (Szeged) Varró András (1954-) (farmakológus, klinikai farmakológus)
Internet cím:DOI
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