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001-es BibID:	BIBFORM049392
Első szerző:	Csernoch László (élettanász)
Cím:	The Low Affinity Calcium Buffer TPEN Alters Calcium Release From the Sarcoplasmic Reticulum (SR) of Mammalian Skeletal Muscle / Laszlo Csernoch, Cecilia Simut, János Almássy, Carole Jung, Ernst Niggli, István Jona
Dátum:	2005
ISSN:	0006-3495
Megjegyzések:	Recent experiments suggested that chelating calcium within the SR using phosphate in the intracellular solution of skinned mammalian skeletal muscle fibers leads to the increase in the frequency of elementary calcium release events (ECRE) as observed under laser scanning confocal microscopy (Csernoch et al. 2003. Biophys. J. 84, 386a). To understand if this phenomenon was solely due to the buffering of intra SR calcium we incubated our saponin skinned, Fluo-4 loaded fibers with the low affinity membrane permeant buffer N,N,N',N'-tetrakis (2-pyridylmethyl)ethylene diamine (TPEN) and measured ECRE in the line-scan mode using a confocal scanner. In the concentration of 0.2 mM TPEN suppressed, rather than increased the frequency of ECRE sometimes to the point that no events were detectable. To determine whether this effect was due to chelating calcium or to a direct inhibition of ryanodine receptors (RyR1) by TPEN, the effects of the drug were studied on isolated RyR1-s incorporated into planar lipid bilayers. TPEN increased channel activity (open probability) at negative (cis compared to trans) holding potentials in a concentration and calcium dependent manner. In contrast, at positive holding potentials an inhibition was observed. Channel inhibition exhibited a voltage dependence resulting in a full inhibition at and above 40 mV. On the other hand, no potential dependence was observed when negative holding potentials were applied. In addition, the activity of the calcium pump was also inhibited by TPEN with a Kd of 639?44 ?M and a Hill coefficient of 0.87 ? 0.06. It is concluded that chelation alone of intra SR calcium will not increase ECRE frequency.This work was supported by OTKA T034894, T037727 and ETT 250/2003.
Tárgyszavak:	Természettudományok Biológiai tudományok idézhető absztrakt calcium release
Megjelenés:	Biophysical Journal. - 88 : Supplement 2 (2005), p. 636a. -
További szerzők:	Simut, Cecilia Almássy János (1981-) (élettanász, biológus, angol-magyar szakfordító) Jung, Carole Niggli, Ernst Jóna István (1948-) (élettanász, fizikus)
Pályázati támogatás:	T037727 OTKA
Internet cím:	Szerző által megadott URL Intézményi repozitóriumban (DEA) tárolt változat
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001-es BibID:	BIBFORM001041
Első szerző:	Jung, Carole
Cím:	Ca2+ release from the sarcoplasmic reticulum activated by the low affinity Ca2+ chelator TPEN in ventricular myocytes / Jung C., Zima A.V., Szentesi P., Jóna I., Blatter L.A., Niggli E.
Dátum:	2007
ISSN:	0143-4160 (Print)
Megjegyzések:	The Ca2+ content of the sarcoplasmic reticulum (SR) of cardiac myocytes is thought to play a role in the regulation and termination of SR Ca2+ release through the ryanodine receptors (RyRs). Experimentally altering the amount of Ca2+ within the SR with the membrane-permeant low affinity Ca2+ chelator TPEN could improve our understanding of the mechanism(s) by which SR Ca2+ content and SR Ca2+ depletion can influence Ca2+ release sensitivity and termination. We applied laser-scanning confocal microscopy to examine SR Ca2+ release in freshly isolated ventricular myocytes loaded with fluo-3, while simultaneously recording membrane currents using the whole-cell patch-clamp technique. Following application of TPEN, local spontaneous Ca2+ releases increased in frequency and developed into cell-wide Ca2+ waves. SR Ca2+ load after TPEN application was found to be reduced to about 60% of control. Isolated cardiac RyRs reconstituted into lipid bilayers exhibited a two-fold increase of their open probability. At the low concentration used (20-40microTPEN did not significantly inhibit the SR-Ca2+-ATPase in SR vesicles. These results indicate that TPEN, traditionally used as a low affinity Ca2+ chelator in intracellular Ca2+ stores, may also act directly on the RyRs inducing an increase in their open probability. This in turn results in an increased Ca2+ leak from the SR leading to its Ca2+ depletion. Lowering of SR Ca2+ content may be a mechanism underlying the recently reported cardioprotective and antiarrhythmic features of TPEN.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Cell Calcium. - 41 : 2 (2007), p. 187-194. -
További szerzők:	Zima, A.V. Blatter, L.A. Niggli, Ernst Szentesi Péter (1967-) (élettanász) Jóna István (1948-) (élettanász, fizikus)
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001-es BibID:	BIBFORM011459
Első szerző:	Sztretye Mónika (élettanász, elektrofiziológus)
Cím:	Altered sarcoplasmic reticulum calcium transport in the presence of the heavy metal chelator TPEN / Sztretye M., Almássy J., Deli T., Szentesi P., Jung C., Dienes B., Simut C. A., Niggli E., Jona I., Csernoch L.
Dátum:	2009
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Cell Calcium. - 46 : 5-6 (2009), p. 347-355. -
További szerzők:	Almássy János (1981-) (élettanász, biológus, angol-magyar szakfordító) Deli Tamás (1979-) (szülész-nőgyógyász, endokrinológus szakorvos) Szentesi Péter (1967-) (élettanász) Jung, Carole Dienes Beatrix (1972-) (élettanász, molekuláris biológus) Simut, Cecilia Niggli, Ernst Jóna István (1948-) (élettanász, fizikus) Csernoch László (1961-) (élettanász)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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