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001-es BibID:	BIBFORM030251
035-os BibID:	WOS:000182446700007
Első szerző:	Bányász Tamás (élettanász)
Cím:	Endocardial versus epicardial differences in L-type calcium current in canine ventricular myocytes studied by action potential voltage clamp / Tamás Bányász, László Fülöp, János Magyar, Norbert Szentandrássy, András Varró, Péter P. Nánási
Dátum:	2003
ISSN:	0008-6363
Megjegyzések:	Objectives: The aim of the present study was to assess and compare the dynamics of L-type Ca2+ current (I-Ca.L) during physiologic action potential (AP) in canine ventricular cardiomyocytes of epicardial (EPI) and endocardial (ENDO) origin. Methods: I-Ca.L was recorded on cells derived from the two regions of the heart using both AP voltage clamp and conventional whole cell voltage clamp techniques. Results: AP voltage clamp experiments revealed that the decay of I-Ca.L is monotonic during endocardial AP, whereas the current is double-peaked (displaying a second rise) during epicardial AP. The amplitude of the first peak was significantly greater in ENDO (-4.6+/-0.8 pA/pF) than in EPI cells (-2.8+/-0.3 pA/pF). Application of epicardial APs as command pulses to endocardial cells yielded double-peaked I-Ca.L profiles, and increased the net charge entry carried by I-Ca.L during the AP from 0.187+/-0.059 to 0.262+/-0.056 pC/pF (n=5, P<0.05). No differences were observed in current densities and inactivation kinetics of I-Ca.L between EPI and ENDO cells when studied under conventional voltage clamp conditions. Nisoldipine shortened action potentials and eliminated the dome of the epicardial AP. Conclusion: I-Ca.L was shown to partially inactivate before and deactivate during phase-1 repolarization and reopening of these channels is responsible for the formation of the dome in canine EPI cells. The transmural differences in the profile of I-Ca.L could be well explained with differences in AP configuration. (C) 2003 European Society of Cardiology. Published by Elsevier Science B.V. All rights reserved.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	Cardiovascular Research. - 58 : 1 (2003), p. 66-75. -
További szerzők:	Fülöp László (1976-) (kardiológus) 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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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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001-es BibID:	BIBFORM030259
035-os BibID:	WOS:000175824200020
Első szerző:	Magyar János (élettanász)
Cím:	Effects of thymol on calcium and potassium currents in canine and human ventricular cardiomyocytes / János Magyar, Norbert Szentandrássy, Tamás Bányász, László Fülöp, András Varró, Péter P. Nánási
Dátum:	2002
ISSN:	0007-1188
Megjegyzések:	1 Concentration-dependent effects of thymol (1 - 1000 pm) was Studied on action potential configuration and ionic currents in isolated canine ventricular cardiomyocytes using conventional microelectrode and patch clamp techniques. 2 Low concentration of thymol (10 muM) removed the notch of the action potential, whereas high concentrations (100 pm or higher) caused an additional shortening of action potential duration accompanied by progressive depression of plateau and reduction of V-max. 3 In the canine cells L-type Ca current (I-Ca) was decreased by thymol in a concentration-dependent manner (EC50: 158 +/- 7 muM, Hill coeff.: 2.96+/-0.43). In addition. thymol (50 - 250 muM) accelerated the inactivation of I-Ca, increased the time constant of recovery from inactivation, shifted the steady-state inactivation curve of I-Ca leftwards, but voltage dependence of activation remained unaltered. Qualitatively similar results were obtained with thymol in ventricular myocytes isolated from healthy human hearts. 4 Thymol displayed concentration-dependent suppressive effects on potassium currents: the transient outward current, I-10 (EC50: 60.6 +/- 11.4 muM, Hill coeff.: 1.03 +/- 0.11), the rapid component of the delayed rectifier, I-Kr (EC50: 63.4 +/- 6.1 muM, Hill coeff.: 1.29 +/- 0.15), and the slow component of the delayed rectifiers I-Ks (EC50: 202+/-11 muM, Hill coeff.: 0.72+/-0.14), however, K channel kinetics were not much altered by thymol. These effects on Ca and K Currents developed rapidly (within 0.5 min) and were readily reversible. 5 In conclusion, thymol suppressed cardiac ionic channels in a concentration-dependent manner, however, both drug-sensitivities as well as the mechanism of action seems to be different when blocking calcium and potassium channels.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	British Journal of Pharmacology. - 136 : 2 (2002), p. 330-338. -
További szerzők:	Szentandrássy Norbert (1976-) (élettanász) Bányász Tamás (1960-) (élettanász) Fülöp László (1976-) (kardiológus) Varró András (1954-) (farmakológus, klinikai farmakológus) Nánási Péter Pál (1956-) (élettanász)
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM030245
035-os BibID:	WOS:000220687400004
Első szerző:	Magyar János (élettanász)
Cím:	Effects of terpenoid phenol derivatives on calcium current in canine and human ventricular cardiomyocytes / János Magyar, Norbert Szentandrassy, Tamás Banyasz, László Fülöp, András Varro, Péter P. Nanasi
Dátum:	2004
ISSN:	0014-2999
Megjegyzések:	Concentration-dependent (10-1000 muM) effects of terpenoid phenol derivatives were studied on L-type Ca2+ current in isolated canine and human ventricular cardiomyocytes using the whole-cell configuration of patch clamp technique. Carvacrol, thymol and eugenol suppressed peak Ca2+ current at +5 mV, having EC50 values and Hill coefficients of 98 +/- 11, 158 +/- 7 and 187 +/- 15 muM and 1.42 +/- 0.05, 2.96 +/- 0.43 and 1.6 +/- 0.1, respectively, in canine myocytes. Zingerone displayed a weak effect (estimated EC50: 2 +/- 0.37 mM, Hill coefficient: 0.73 +/- 0.07), while vanillin and guaiacol failed to substantially modify Ca2+ current up to the concentration of I mM. In addition to tonic block, thymol and carvacrol, but not eugenol, evoked marked rate-dependent block at 2 Hz. Carvacrol and eugenol accelerated inactivation of Ca2+ current and caused leftward shift in the voltage dependence of steady-state inactivation without altering activation kinetics. Carvacrol, but not eugenol, increased the time constant of recovery from inactivation. These effects of carvacrol and eugenol developed rapidly and were largely reversible. In myocytes isolated from undiseased human hearts, the effect of carvacrol was similar to that observed in canine cells. It is concluded that suppression of cardiac Ca2+ currents by phenol derivatives is influenced by the substituent in the benzene ring, and the blocking effect of these drugs may involve interactions with the inactivation machinery of the channel. (C) 2004 Elsevier B.V. All rights reserved.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban egyetemen (Magyarországon) készült közlemény
Megjelenés:	European Journal of Pharmacology. - 487 : 1-3 (2004), p. 29-36. -
További szerzők:	Szentandrássy Norbert (1976-) (élettanász) Bányász Tamás (1960-) (élettanász) Fülöp László (1976-) (kardiológus) Varró András (1954-) (farmakológus, klinikai farmakológus) Nánási Péter Pál (1956-) (élettanász)
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
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