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001-es BibID:	bibEBI00019167
Első szerző:	Deli Tamás (szülész-nőgyógyász, endokrinológus szakorvos)
Cím:	Contribution from P2X and P2Y purinoreceptors to ATP-evoked changes in intracellular calcium concentration on cultured myotubes / Tamás Deli, Henrietta Szappanos, Gyula Péter Szigeti, Julianna Cseri, László Kovács, László Csernoch
Dátum:	2007
ISSN:	0031-6768
Megjegyzések:	Although the alteration of purinoreceptor pattern on skeletal muscle is known to accompany physiological muscle differentiation and the pathogenesis of muscle dystrophy, the exact identity of and the relative contribution from the individual receptor subtypes to the purinergic signal have been controversial. To identify these subtypes in cultured myotubes of 5-10 nuclei, changes in intracellular calcium concentration and surface membrane ionic currents were detected and calcium fluxes calculated after the application of the subtype-specific agonists 2'3'-O-(benzoyl-4-benzoyl)-ATP (BzATP), 2-methyltio-ADP and UTP. The effectiveness of these agonists together with positive immunocytochemical staining revealed the presence of P2X(4), P2X(5), P2X(7), P2Y(1) and P2Y(4) receptors. siRNA-reduced protein expression of P2X(5), P2X(7) and P2Y(1) receptors was accompanied by reduction in the ATP-evoked calcium transients. Furthermore, anti-P2X(7) siRNA caused a significant drop in the early peak and delayed steady component of the calculated calcium flux. The use of its antagonist, oxidized ATP, similarly to transfection with anti-P2X(7) siRNA caused significant reduction in the agonist-elicited ionic currents I (ATP) and I (BzATP), with a greater drop in the latter. Our results demonstrate that the activation of ionotropic P2X(4), P2X(5) and P2X(7) and metabotropic P2Y(1) and P2Y(4) purinoreceptors participates in forming the calcium transients of multinucleated myotubes.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Pflügers Archiv. - 453 : 4 (2007), p. 519-529. -
További szerzők:	Szappanos Henrietta (1976-) (biológus, élettanász) Szigeti Gyula (1969-) (élettanász, elektrofiziológus) Cseri Julianna (1949-2022) (laboratóriumi diagnosztika szakorvos) Kovács László (1939-) (élettanász) Csernoch László (1961-) (élettanász)
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001-es BibID:	BIBFORM004139
Első szerző:	Szappanos Henrietta (biológus, élettanász)
Cím:	Determination of depolarisation- and agonist-evoked calcium fluxes on skeletal muscle cells in primary culture / Szappanos H., Cseri J., Deli T., Kovacs L., Csernoch L.
Dátum:	2004
Megjegyzések:	Changes in intracellular calcium concentration ([Ca2+]i) evoked by prolonged depolarisation (120 mM KCl) or by the application of 15 mM caffeine were measured on skeletal muscle cells in primary culture. The extrusion rate (PVmax) of calcium from the myoplasm was determined, which in turn enabled the calculation of the calcium flux (Fl) underlying the measured calcium transients. PVmax was found to increase during differentiation, from 107±10 nM/s at the early myotube stage to 596±36 ?M/s in secondary myotubes. This was paralleled by a decrease in resting [Ca2+]i from 99±4 to 51±2 ?M. The depolarisation-evoked Fl rose to peak and then ceased despite the continuous presence of KCl. In contrast, the caffeine-induced Fl showed a peak and a clear steady-level with a peak-to-steady ratio of 5.6±1.2. Removal of external calcium suppressed the depolarisation-induced flux by 88±5% indicating that both an influx and a release from the SR underlie the K+-evoked calcium transients. Subsequent applications of caffeine resulted in essentially identical fluxes indicating an efficient refilling of the internal stores. Moreover, if a depolarisation-induced calcium transient preceded the second caffeine-evoked release, the latter was significantly larger than the first suggesting that much of the calcium that entered was stored in the SR rather than extruded.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Biochemical and Biophysical Methods. - 59 : 1 (2004), p. 89-101. -
További szerzők:	Cseri Julianna (1949-2022) (laboratóriumi diagnosztika szakorvos) Deli Tamás (1979-) (szülész-nőgyógyász, endokrinológus szakorvos) Kovács László (1939-) (élettanász) Csernoch László (1961-) (élettanász)
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001-es BibID:	BIBFORM001402
Első szerző:	Szigeti Gyula (élettanász, elektrofiziológus)
Cím:	Differentiation-dependent alterations in the extracellular ATP-evoked calcium fluxes of cultured skeletal muscle cells from mice / Gyula Péter Szigeti, Henrietta Szappanos, Tamás Deli, Julianna Cseri, László Kovács, László Csernoch
Dátum:	2007
ISSN:	0031-6768
Megjegyzések:	Although extracellular adenosine triphosphate (ATP) has been generally accepted as the regulator of cellular differentiation, the relative contribution of the various purinoreceptor subtypes to purinergic signalling at distinct stages of skeletal muscle differentiation is still poorly understood. Here we measured extracellular ATP-evoked changes in intracellular calcium concentration and surface membrane ionic currents (I (ATP)), calculated the calcium flux (FL) entering the myoplasmic space and compared these parameters at different stages of differentiation on cultured mouse myotubes. The ATP-evoked FL displayed an early peak and then declined to a steady level. With differentiation, the early peak became separated from the maintained component and was absent on mature myotubes. Repeated ATP applications caused desensitization of the response in both immature and differentiated myotubes, owing mainly to the reduction of the early peak of FL in the former and to a decline of both components in the latter group of cells. Depolarization of the cell or removal of external calcium suppressed the early peak. I (ATP) showed no inactivation, and its voltage dependence displayed strong inward rectification. The concentration dependence of I (ATP) can be fitted using a Hill equation, yielding an EC(50) of 56 microM. Results are consistent with the parallel activation of both P2X and P2Y receptors.
Tárgyszavak:	Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Pflügers Archiv. - 453 : 4 (2007), p. 509-518. -
További szerzők:	Deli Tamás (1979-) (szülész-nőgyógyász, endokrinológus szakorvos) Cseri Julianna (1949-2022) (laboratóriumi diagnosztika szakorvos) Kovács László (1939-) (élettanász) Csernoch László (1961-) (élettanász) Szappanos Henrietta (1976-) (biológus, élettanász)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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