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001-es BibID:	BIBFORM030250
035-os BibID:	WOS:000182475600002
Első szerző:	Fülöp László (kardiológus)
Cím:	Differences in electrophysiological and contractile properties of mammalian cardiac tissues bathed in bicarbonate - and HEPES-buffered solutions / L. Fülöp, G. Szigeti, J. Magyar, N. Szentandrássy, T. Ivanics, Z. Miklós, L. Ligeti, A. Kovács, G. Szénási, L. Csernoch, P. P. Nánási, T. Bányász
Dátum:	2003
ISSN:	0001-6772
Megjegyzések:	Aim: The aim of this study was to compare the action potential configuration, contractility, intracellular Ca2+ and H+ concentrations in mammalian cardiac tissues bathed with Krebs and Tyrode solutions at 37 degreesC. Results: In Langendorff-perfused guinea-pig hearts, loaded with the fluorescent Ca2+ -indicator Fura-2, or H+ -sensitive dye carboxy-SNARF, shifts from Krebs to Tyrode solution caused intra-cellular acidification, increased diastolic pressure and [Ca2+ ](i) , decreased systolic pressure and [Ca2+ ](i) , leading to a reduction in the amplitude of [Ca2+ ](i) transients and pulse pressure. Contractility was also depressed in canine ventricular trabeculae when transferred from Krebs to Tyrode solution. Shifts from Krebs to Tyrode solution increased the duration of action potentials in multicellular cardiac preparations excised from canine and rabbit hearts but not in isolated cardiomyocytes. All these changes in action potential morphology, contractility, [Ca2+ ](i) and [H+ ](i) were readily reversible by addition of 26 mmol L-1 bicarbonate to Tyrode solution. Effects of dofetilide and CsCl, both blockers of the delayed rectifier K current, on action potential duration were compared in Krebs and Tyrode solutions. Dofetilide lengthened rabbit ventricular action potentials in a significantly greater extent in Tyrode than in Krebs solution. Exposure of canine Purkinje fibres to CsCl evoked early after depolarizations within 40 min in all preparations incubated with Tyrode solution, but not in those bathed with Krebs solution. Conclusion: It is concluded that the marked differences in action potential morphology, [Ca2+ ](i) , [H+ ](i) and contractility observed between preparations bathed with Krebs and Tyrode solutions are more likely attributable to differences in the intracellular buffering capacities of the two media.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	Acta Physiologica Scandinavica. - 178 : 1 (2003), p. 11-18. -
További szerzők:	Szigeti Gyula (1969-) (élettanász, elektrofiziológus) Magyar János (1961-) (élettanász) Szentandrássy Norbert (1976-) (élettanász) Ivanics Tamás Miklós Zsuzsanna Ligeti László Kovács A. Szénási Gábor Csernoch László (1961-) (élettanász) Nánási Péter Pál (1956-) (élettanász) Bányász Tamás (1960-) (élettanász)
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM030248
035-os BibID:	WOS:000187850300006
Első szerző:	Fülöp László (kardiológus)
Cím:	Reopening of L-type calcium channels in human ventricular myocytes during applied epicardial action potentials / L. Fülöp, T. Bányász, J. Magyar, N. Szentandrássy, A. Varró, P. P. Nánási
Dátum:	2004
ISSN:	0001-6772
Megjegyzések:	Aims: Present study was performed to compare the dynamics of human L-type calcium current (I-Ca,I-L) flowing during rectangular voltage pulses, voltage ramps, and action potentials (APs) recorded from epicardiac and endocardiac canine ventricular cells. Methods: I-Ca,I-L was recorded in single myocytes isolated from undiseased human hearts using the whole cell voltage clamp technique. Results: The decay of I-Ca,I-L was monotonic when using rectangular pulses or endocardial APs as voltage commands, whereas the current became double-peaked (displaying a second rise and fall) during epicardial (EPI) APs or voltage ramps used to mimic EPI APs. These I-Ca,I-L profiles were associated with single-hooked and double-hooked phase-plane trajectories, respectively. No sustained current was observed during the AP commands. Kinetics of deactivation and recovery from inactivation of human I-Ca,I-L were determined using twin-pulse voltage protocols and voltage ramps, and the results were similar to those obtained previously in canine cells under identical experimental conditions. Conclusions: I-Ca,I-L can inactivate partially before and deactivate during the phase-1 repolarization of the epicardiac AP, and reopening of these channels seems to be associated with formation of the dome.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	Acta Physiologica Scandinavica. - 180 : 1 (2004), p. 39-47. -
További szerzők:	Bányász Tamás (1960-) (élettanász) Magyar János (1961-) (élettanász) Szentandrássy Norbert (1976-) (élettanász) Varró András (1954-) (farmakológus, klinikai farmakológus) Nánási Péter Pál (1956-) (élettanász)
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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