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1.

001-es BibID:BIBFORM020028
Első szerző:Gönczi Mónika (élettanász)
Cím:Investigation of the role of TASK-2 channels in rat pulmonary arteries; pharmacological and functional studies following RNA interference procedures / Mónika Gönczi, Norbert Szentandrássy, Ian T. Johnson, Anthony M. Heagerty, Arthur H. Weston
Dátum:2006
ISSN:0007-1188
Megjegyzések:1 In the present study, we investigated the ability of RNA interference technology to suppress TASK-2 potassium channel expression in human embryonic kidney (HEK293) cells stably transfected with TASK-2 cDNA and in rat isolated intact pulmonary arteries. 2 Lipofectamine-induced transfection of a specific siRNA sequence targeted against TASK-2 resulted in a dose- and time-dependent decrease in TASK-2 channel protein expression. In siRNA-transfected cells the TASK-2 peak currents were significantly smaller than in control cells at every investigated pH, while the pH sensitivity was not altered. Using scrambled siRNA as a negative control, there were no significant changes in TASK-2 protein expression or current compared to mock-transfected cells. 3 In TASK-2 siRNA-transfected small pulmonary arteries, but not in scrambled siRNA-treated vessels, myocyte resting membrane potential at pH 7.4 was significantly less negative and the hyperpolarisations in response to increasing pH from 6.4 to 8.4 were significantly smaller compared with control. 4 The application of levcromakalim ( 10 mu M), NS1619 ( 33 mu M) and a potassium channel inhibitor cocktail ( 5 mM 4-aminopyridine, 10 mM tetraethylammonium chloride, 30 mu M Ba2+ and 10 mu M glibenclamide) had similar effects in control and in siRNA-transfected vessels. The TASK-1 (anandamide-sensitive) contribution to resting membrane potential was comparable in each group. Clofilium ( 100 mu M) generated significantly smaller responses in transfected artery segments. 5 These results suggest that RNA interference techniques are effective at inhibiting TASK-2 channel expression in cultured cells and in intact vessels and that TASK-2 channels have a functional role in setting the membrane potential of pulmonary artery myocytes.
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:British Journal of Pharmacology. - 147 : 5 (2006), p. 496-505. -
További szerzők:Szentandrássy Norbert (1976-) (élettanász) Johnson, Ian T. Heagerty, Anthony M. Weston, Arthur H.
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2.

001-es BibID:BIBFORM013054
Első szerző:Harmati Gábor (élettanász)
Cím:Effects of β-adrenoceptor stimulation on delayed rectifier K(+) currents in canine ventricular cardiomyocytes / Harmati G., Bányász T., Bárándi L., Szentandrássy N., Horváth B., Szabó G., Szentmiklósi J., Szénási G., Nánási P., Magyar J.
Dátum:2011
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
isoproterenol
beta adrenerg
canine
cardiomyocyte
ionic current
Megjelenés:British Journal of Pharmacology. - 162 : 4 (2011), p. 890-896. -
További szerzők:Bányász Tamás (1960-) (élettanász) Bárándi László (1984-) (élettanász) Szentandrássy Norbert (1976-) (élettanász) Horváth Balázs (1981-) (élettanász) Szabó G. (orvos) Szentmiklósi József András (1948-) (farmakológus, klinikai laboratóriumi szakorvos) Szénási Gábor Nánási Péter Pál (1956-) (élettanász) Magyar János (1961-) (élettanász)
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3.

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)
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4.

001-es BibID:BIBFORM037321
Első szerző:Szentandrássy Norbert (élettanász)
Cím:Effects of rosiglitazone on the configuration of action potentials and ion currents in canine ventricular cells / Szentandrássy N., Harmati G., Bárándi L., Simkó J., Horváth B., Magyar J., Bányász T., Lőrincz I., Szebeni A., Kecskeméti V., Nánási P.P.
Dátum:2011
ISSN:0007-1188
Megjegyzések:BACKGROUND AND PURPOSEIn spite of its widespread clinical application, there is little information on the cellular cardiac effects of the antidiabetic drug rosiglitazone in larger experimental animals. In the present study therefore concentration-dependent effects of rosiglitazone on action potential morphology and the underlying ion currents were studied in dog hearts.EXPERIMENTAL APPROACHStandard microelectrode techniques, conventional whole cell patch clamp and action potential voltage clamp techniques were applied in enzymatically dispersed ventricular cells from dog hearts.KEY RESULTSAt concentrations ?10 mM rosiglitazone decreased the amplitude of phase-1 repolarization, reduced the maximum velocity of depolarization and caused depression of the plateau potential. These effects developed rapidly and were readily reversible upon washout. Rosiglitazone suppressed several transmembrane ion currents, oncentration-dependently, under conventional voltageclamp conditions and altered their kinetic properties. The EC50 value for this inhibition was 25.2 ? 2.7 mM for the transient outward K+ current (Ito), 72.3 ? 9.3 mM for the rapid delayed rectifier K+ current (IKr) and 82.5 ? 9.4 mM for the L-type Ca2+ current (ICa) with Hill coefficients close to unity. The inward rectifier K+ current (IK1) was not affected by rosiglitazone up to concentrations of 100 mM. Suppression of Ito, IKr, and ICa was confirmed also under action potential voltage clamp conditions.CONCLUSIONS AND IMPLICATIONSAlterations in the densities and kinetic properties of ion currents may carry serious pro-arrhythmic risk in case of overdose with rosiglitazone, especially in patients having multiple cardiovascular risk factors, like elderly diabetic patients.
Tárgyszavak:Orvostudományok Egészségtudományok idegen nyelvű folyóiratközlemény külföldi lapban
antidiabetic agents
rosiglitazone
dog cardiomyocytes
action potential
ion currents
Megjelenés:British Journal Of Pharmacology 163 : 3 (2011), p. 499-509. -
További szerzők:Harmati Gábor (1983-) (élettanász) Bárándi László (1984-) (élettanász) Simkó József (1974-) (belgyógyász, kardiológus) Horváth Balázs (1981-) (élettanász) Magyar János (1961-) (élettanász) Bányász Tamás (1960-) (élettanász) Lőrincz István (1950-) (belgyógyász, kardiológus) Szebeni Andrea Kecskeméti Valéria Nánási Péter Pál (1956-) (élettanász)
Pályázati támogatás:TÁMOP-4.2.1/B-09/1/KONV-2010-0007
TÁMOP
A feszültségfüggő K-csatornák szerepe excitábilis sejtekben
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5.

001-es BibID:BIBFORM037346
Első szerző:Szentandrássy Norbert (élettanász)
Cím:Role of action potential configuration and the contribution of Ca2+ and K+ currents to isoprenaline-induced changes in canine ventricular cells / N. Szentandrássy, V. Farkas, L. Bárándi, B. Hegyi, F. Ruzsnavszky, B. Horváth, T. Bányász, J. Magyar, I. Márton, P. P. Nánási
Dátum:2012
ISSN:0007-1188
Megjegyzések:BACKGROUND AND PURPOSE: Although isoprenaline (ISO) is known to activate several ion currents in mammalian myocardium, little is known about the role of action potential morphology in the ISO-induced changes in ion currents. Therefore, the effects of ISO on action potential configuration, L-type Ca2+ current (ICa), slow delayed rectifier K+ current (IKs) and fast delayed rectifier K+ current (IKr)were studied and compared in a frequency-dependent manner using canine isolated ventricular myocytes from varioustransmural locations.EXPERIMENTAL APPROACHAction potentials were recorded with conventional sharp microelectrodes; ion currents were measured using conventional and action potential voltage clamp techniques.KEY RESULTSIn myocytes displaying a spike-and-dome action potential configuration (epicardial and midmyocardial cells), ISO caused reversible shortening of action potentials accompanied by elevation of the plateau. ISO-induced action potential shortening was absent in endocardial cells and in myocytes pretreated with 4-aminopyridine. Application of the IKr blocker E-4031 failed to modify the ISO effect, while action potentials were lengthened by ISO in the presence of the IKs blocker HMR-1556. Bothaction potential shortening and elevation of the plateau were prevented by pretreatment with the ICa blocker nisoldipine.Action potential voltage clamp experiments revealed a prominent slowly inactivating ICa followed by a rise in IKs, both currents increased with increasing the cycle length.CONCLUSIONS AND IMPLICATIONSThe effect of ISO in canine ventricular cells depends critically on action potential configuration, and the ISO-induced activation of IKs ? but not IKr ? may be responsible for the observed shortening of action potentials
Tárgyszavak:Orvostudományok Elméleti orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
heart
action potential
calcium current
potassium current
Megjelenés:British Journal of Pharmacology. - 167 : 3 (2012), p. 599-611. -
További szerzők:Farkas Viktória Bárándi László (1984-) (élettanász) Hegyi Bence (1987-) (élettanász) Ruzsnavszky Ferenc (1984-) (élettanász) Horváth Balázs (1981-) (élettanász) Bányász Tamás (1960-) (élettanász) Magyar János (1961-) (élettanász) Márton Ildikó (1954-) (fogszakorvos) Nánási Péter Pál (1956-) (élettanász)
Pályázati támogatás:TÁMOP-4.2.1/B-09/1/KONV-2010-0007
TÁMOP
A feszültségfüggő K-csatornák szerepe excitábilis sejtekben
Internet cím:DOI
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