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001-es BibID:	BIBFORM032923
035-os BibID:	PMID:16086157
Első szerző:	Birinyi Péter (élettanász)
Cím:	Effects of SEA0400 and KB-R7943 on Na+/Ca2+ exchange current and L-type Ca2+ current in canine ventricular cardiomyocytes / Péter Birinyi, Károly Acsai, Tamás Bányász, András Tóth, Balázs Horváth, László Virág, Norbert Szentandrássy, János Magyar, András Varró, Ferenc Fülöp, Péter P. Nánási
Dátum:	2005
ISSN:	0028-1298
Megjegyzések:	SEA0400 and KB-R7943 are compounds synthesised to block transsarcolemmal Na+/Ca2+ exchange current (INa/Ca); however, they Have also been shown to inhibit L-type Ca2+ current (ICa). The potential value of these compounds depends critically on their relative selectivity for INa/Ca over ICa. In the present work, therefore, the concentration-dependent effects of SEA0400 and KB-R7943 on INa/Ca and ICa were studied and compared in canine ventricular cardiomyocytes using the whole-cell configuration of the patch clamp technique. SEA0400 and KB-R7943 decreased INa/Ca in a concentration-dependent manner, having EC50 values of 111?43 nM and 3.35?0.82 mgrM, when suppressing inward currents, while the respective EC50 values were estimated at 108?18 nM and 4.74?0.69 mgrM in the case of outward current block. SEA0400 and KB-R7943 also blocked ICa, having comparable EC50 values (3.6 mgrM and 3.2 mgrM, respectively). At higher concentrations (10 mgrM) both drugs accelerated inactivation of ICa, retarded recovery from inactivation and shifted the voltage dependence of inactivation towards more negative voltages. The voltage dependence of activation was slightly modified by SEA0400, but not by KB-R7943. Based on the relatively good selectivity of submicromolar concentrations of SEA0400?but not KB-R7943?for INa/Ca over ICa, SEA0400 appears to be a suitable tool to study the role of INa/Ca in Ca2+ handling in canine cardiac cells. At concentrations higher than 1 mgrM, however, ICa is progressively suppressed by the compound.
Tárgyszavak:	Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban SEA0400 KB-R7943 Na+/Ca2+ exchanger Ca2+ current Cardiac cells Dog Voltage clamp egyetemen (Magyarországon) készült közlemény
Megjelenés:	Naunyn-Schmiedebergs Archives Of Pharmacology. - 372 : 1 (2005), p. 63-70. -
További szerzők:	Acsai Károly Bányász Tamás (1960-) (élettanász) Tóth András Horváth Balázs (1981-) (élettanász) Virág László (élettanász Szeged) Szentandrássy Norbert (1976-) (élettanász) Magyar János (1961-) (élettanász) Varró András (1954-) (farmakológus, klinikai farmakológus) Fülöp Ferenc (Szeged) Nánási Péter Pál (1956-) (élettanász)
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001-es BibID:	BIBFORM004074
Első szerző:	Birinyi Péter (élettanász)
Cím:	The Na+/Ca2+ exchange blocker SEA0400 fails to enhance cytosolic Ca2+ transient and contractility in canine ventricular cardiomyocytes / Birinyi P., Tóth A., Jóna I., Acsai K., Almássy J., Nagy N., Prorok J., Gherasim I., Papp Z., Hertelendi Z., Szentandrássy N., Bányász T., Fülöp F., Papp J. G., Varró A., Nánási P. P., Magyar J.
Dátum:	2008
Megjegyzések:	Aims This study was designed to evaluate the effects of the Na+/Ca2+ exchange (NCX) inhibitor SEA0400 on Ca2+ handling in isolated canine ventricular myocytes. Methods and results Intracellular Ca2+ ([Ca2+](i)) transients, induced by either field stimulation or caffeine flush, were monitored using Ca2+ indicator dyes. [Ca2+](i)-dependent modulation of the inhibitory effect of SEA0400 on NCX was characterized by the changes in Ni2+-sensitive current in voltage-clamped myocytes. Sarcoplasmic reticulum (SR) Ca2+ release and uptake were studied in SIR membrane vesicles. Gating properties of single-ryanodine receptors were analysed in lipid bilayers. Ca2+ sensitivity of the contractile machinery was evaluated in chemically skinned myocytes. In myocytes paced at 1 Hz, neither diastolic [Ca2+](i) nor the amplitude of [Ca2+](i) transients was significantly altered by SEA0400 up to the concentration of 1 mu M, which was shown to inhibit the exchange current. The blocking effect of SEA0400 on NCX decreased with increasing [Ca2+](i), and it was more pronounced in reverse than in forward mode operation at every [Ca2+](i) examined. The rate of decay of the caffeine-induced [Ca2+](i) transients was decreased significantly by 1 mu M SEA0400; however, this effect was only a fraction of that observed with 10 mM NiCl2. Neither SR Ca2+ release and uptake nor cell shortening and Ca2+ sensitivity of the contractile proteins were influenced by SEA0400. Conclusion The lack of any major SEA0400-induced shift in Ca2+ transients or contractility of myocytes can well be explained by its limited inhibitory effect on NCX (further attenuated by elevated [Ca2+](i) levels) and a concomitant reduction in Ca2+ influx due to the predominantly reverse mode blockade of NCX and suppression of L-type Ca2+ current.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Cardiovascular Research. - 78 : 3 (2008), p. 476-484. -
További szerzők:	Tóth András (farmakológus) Jóna István (1948-) (élettanász, fizikus) Acsai Károly Almássy János (1981-) (élettanász, biológus, angol-magyar szakfordító) Nagy Norbert (1977-) (kísérletes farmakológus) Prorok János Gherasim, Iuliana Papp Zoltán (1965-) (kardiológus, élettanász) Hertelendi Zita (1978-) (orvos) Szentandrássy Norbert (1976-) (élettanász) Bányász Tamás (1960-) (élettanász) Fülöp Ferenc Papp Gy. Julius (Szeged) Varró András (1954-) (farmakológus, klinikai farmakológus) Nánási Péter Pál (1956-) (élettanász) Magyar János (1961-) (élettanász)
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001-es BibID:	BIBFORM009061
Első szerző:	Jost Norbert
Cím:	Contribution of I Kr and I K1 to ventricular repolarization in canine and human myocytes : is there any influence of action potential duration? / Jost, N., Acsai, K., Horvath, B., Banyasz, T., Baczko, I., Bitay, M., Bogats, G., Nanasi, P. P.
Dátum:	2009
ISSN:	0300-8428 (Print)
Megjegyzések:	The aim of the present work was to study the profile of the rapid delayed rectifier potassium current (I (Kr)) and the inward rectifier potassium current (I (K1)) during ventricular repolarization as a function of action potential duration and rate of repolarization. METHODS: Whole cell configuration of the patch clamp technique was used to monitor I (Kr) and I (K1) during the action potential plateau and terminal repolarization. Action potentials recorded at various cycle lengths (0.4-5 s) and repolarizing voltage ramps having various slopes (0.5-3 V/s) were used as command signals. I (Kr) and I (K1) were identified as difference currents dissected by E-4031 and BaCl(2), respectively. RESULTS: Neither peak amplitudes nor mean values of I (Kr) and I (K1) recorded during the plateau of canine action potentials were influenced by action potential duration. The membrane potential where I (Kr) and I (K1) peaked during the terminal repolarization was also independent of action potential duration. Similar results were obtained in undiseased human ventricular myocytes, and also in canine cells when I (Kr) and I (K1) were evoked using repolarizing voltage ramps of various slopes. Action potential voltage clamp experiments revealed that the peak values of I (Kr), I (K1), and net outward current during the terminal repolarization were independent of the pacing cycle length within the range of 0.4 and 5 s. CONCLUSIONS: The results indicate that action potential configuration fails to influence the amplitude of I (Kr) and I (K1) during the ventricular action potential in dogs and humans, suggesting that rate-dependent changes in action potential duration are not likely related to rate-dependent alterations in I (Kr) or I (K1) kinetics in these species.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban Action Potentials Animals Barium Compounds Chlorides Dogs Electrophysiology Humans KATP Channels Kinetics Muscle Cells Patch-Clamp Techniques Potassium Channels, Inwardly Rectifying Reference Values Ventricular Function
Megjelenés:	Basic Research in Cardiology. - 104 : 1 (2009), p. 33-41. -
További szerzők:	Acsai Károly Horváth Balázs (1981-) (élettanász) Bányász Tamás (1960-) (élettanász) Baczkó István Bitay Miklós Bogáts Gábor Nánási Péter Pál (1956-) (élettanász)
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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
Dátum:	2004
ISSN:	0007-1188
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)
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