AIMS: Present study was performed to compare the dynamics of human L-type calcium current (ICa,L) flowing during rectangular voltage pulses, voltage ramps, and action potentials (APs) recorded from epicardiac and endocardiac canine ventricular cells. METHODS: ICa,L was recorded in single myocytes isolated from undiseased human hearts using the whole cell voltage clamp technique. RESULTS: The decay of ICa,L was monotonic when using rectangular pulses or endocardial APs as voltage commands, whereas the current became double-peaked (displaying a second rise and fall) during epicardial (EPI) APs or voltage ramps used to mimic EPI APs. These ICa,L profiles were associated with single-hooked and double-hooked phase-plane trajectories, respectively. No sustained current was observed during the AP commands. Kinetics of deactivation and recovery from inactivation of human ICa,L were determined using twin-pulse voltage protocols and voltage ramps, and the results were similar to those obtained previously in canine cells under identical experimental conditions. CONCLUSIONS: ICa,L can inactivate partially before and deactivate during the phase-1 repolarization of the epicardiac AP, and reopening of these channels seems to be associated with formation of the dome.
AIMS: Present study was performed to compare the dynamics of human L-type calcium current (ICa,L) flowing during rectangular voltage pulses, voltage ramps, and action potentials (APs) recorded from epicardiac and endocardiac canine ventricular cells. METHODS:ICa,L was recorded in single myocytes isolated from undiseased human hearts using the whole cell voltage clamp technique. RESULTS: The decay of ICa,L was monotonic when using rectangular pulses or endocardial APs as voltage commands, whereas the current became double-peaked (displaying a second rise and fall) during epicardial (EPI) APs or voltage ramps used to mimic EPI APs. These ICa,L profiles were associated with single-hooked and double-hooked phase-plane trajectories, respectively. No sustained current was observed during the AP commands. Kinetics of deactivation and recovery from inactivation of humanICa,L were determined using twin-pulse voltage protocols and voltage ramps, and the results were similar to those obtained previously in canine cells under identical experimental conditions. CONCLUSIONS:ICa,L can inactivate partially before and deactivate during the phase-1 repolarization of the epicardiac AP, and reopening of these channels seems to be associated with formation of the dome.
Authors: Géza Berecki; Jan G Zegers; Arie O Verkerk; Zahurul A Bhuiyan; Berend de Jonge; Marieke W Veldkamp; Ronald Wilders; Antoni C G van Ginneken Journal: Biophys J Date: 2004-10-08 Impact factor: 4.033
Authors: Bence Hegyi; Balázs Horváth; Krisztina Váczi; Mónika Gönczi; Kornél Kistamás; Ferenc Ruzsnavszky; Roland Veress; Leighton T Izu; Ye Chen-Izu; Tamás Bányász; János Magyar; László Csernoch; Péter P Nánási; Norbert Szentandrássy Journal: J Mol Cell Cardiol Date: 2017-06-29 Impact factor: 5.000
Authors: Krisztina Váczi; Bence Hegyi; Ferenc Ruzsnavszky; Kornél Kistamás; Balázs Horváth; Tamás Bányász; Péter P Nánási; Norbert Szentandrássy; János Magyar Journal: Naunyn Schmiedebergs Arch Pharmacol Date: 2014-10-26 Impact factor: 3.000