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001-es BibID:BIBFORM037320
Első szerző:Simkó József (belgyógyász, kardiológus)
Cím:Effects of ropinirole on action potential characteristics and the underlying ion currents in canine ventricular myocytes / Simkó József, Szentandrássy Norbert, Harmati Gábor, Bárándi László, Horváth Balázs, Magyar János, Bányász Tamás, Lőrincz István, Nánási Péter P.
Dátum:2010
ISSN:0028-1298
Megjegyzések:In spite of its widespread clinical application, there is little information on the cellular cardiac effects of the dopamine receptor agonist ropinirole. In the present study, therefore, the concentration-dependent effects of ropinirole on action potential morphology and the underlying ion currents were studied in enzymatically dispersed canine ventricular cardiomyocytes using standard microelectrode, conventional whole-cell patch clamp, and action potential voltage clamp techniques. At concentrations > or = 1 microM, ropinirole increased action potential duration (APD(90)) and suppressed the rapid delayed rectifier K(+) current (I (Kr)) with an IC(50) value of 2.7 +/- 0.25 microM and Hill coefficient of 0.92 +/- 0.09. The block increased with increasing depolarizations to more positive voltages, but paradoxically, the activation of I (Kr) was accelerated by 3 muM ropinirole (time constant decreased from 34 +/- 4 to 14 +/- 1 ms). No significant changes in the fast and slow deactivation time constants were observed with ropinirole. At higher concentrations, ropinirole decreased the amplitude of early repolarization (at concentrations > or = 10 microM), reduced the maximum rate of depolarization and caused depression of the plateau (at concentrations > or = 30 microM), and shortened APD measured at 50% repolarization (at 300 microM) indicating a concentration-dependent inhibition of I (to), I (Na), and I (Ca). Suppression of I (Kr), I (to), and I (Ca) has been confirmed under conventional patch clamp and action potential voltage clamp conditions. I (Ks) and I (K1) were not influenced significantly by ropinirole at concentrations less than 300 microM. All these effects of ropinirole were fully reversible upon washout. The results indicate that ropinirole treatment may carry proarrhythmic risk for patients with inherited or acquired long QT syndrome due to inhibition of I (Kr)-especially in cases of accidental overdose or intoxication.
Tárgyszavak:Orvostudományok Egészségtudományok idegen nyelvű folyóiratközlemény külföldi lapban
dopamine receptor agonists
ropinirole
dog cardiomyocytes
action potential duration
ion currents
HERG channel
Megjelenés:Naunyn-Schmiedebergs Archives Of Pharmacology. - 382 : 3 (2010), p. 213-220. -
További szerzők:Szentandrássy Norbert (1976-) (élettanász) Harmati Gábor (1983-) (élettanász) Bárándi László (1984-) (élettanász) Horváth Balázs (1981-) (élettanász) Magyar János (1961-) (élettanász) Bányász Tamás (1960-) (élettanász) Lőrincz István (1950-) (belgyógyász, kardiológus) Nánási Péter Pál (1956-) (élettanász)
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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
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