scholarly journals Simulation of the Effects of Extracellular Calcium Changes Leads to a Novel Computational Model of Human Ventricular Action Potential With a Revised Calcium Handling

2020 ◽  
Vol 11 ◽  
Author(s):  
Chiara Bartolucci ◽  
Elisa Passini ◽  
Jari Hyttinen ◽  
Michelangelo Paci ◽  
Stefano Severi
Keyword(s):  
Action Potential ◽  
Computational Model ◽  
Extracellular Calcium ◽  
Calcium Handling ◽  
Ventricular Action Potential

scholarly journals A Novel Computational Model of the Human Ventricular Action Potential and Ca transient

2009 ◽  
Vol 96 (3) ◽  
pp. 664a-665a ◽  
Author(s):  
Eleonora Grandi ◽  
Francesco S. Pasqualini ◽  
Jose L. Puglisi ◽  
Donald M. Bers
Keyword(s):  
Action Potential ◽  
Computational Model ◽  
Ventricular Action Potential

Action potential propagation through embryonic dorsal root ganglion cells in culture. II. Decrease of conduction reliability during repetitive stimulation

1994 ◽  
Vol 72 (2) ◽  
pp. 634-643 ◽  
Author(s):  
C. Luscher ◽  
J. Streit ◽  
P. Lipp ◽  
H. R. Luscher
Keyword(s):  
Dorsal Root Ganglion ◽  
Action Potential ◽  
Intracellular Calcium ◽  
Dorsal Root ◽  
Channel Blocker ◽  
Extracellular Calcium ◽  
Repetitive Stimulation ◽  
Calcium Currents ◽  
Double Pulse ◽  
Extracellular Potassium

1. The reliability of the propagation of action potentials (AP) through dorsal root ganglion (DRG) cells in embryonic slice cultures was investigated during repetitive stimulation at 1–20 Hz. Membrane potentials of DRG cells were recorded intracellularly while the axons were stimulated by an extracellular electrode. 2. In analogy to the double-pulse experiments reported previously, either one or two types of propagation failures were recorded during repetitive stimulation, depending on the cell morphology. In contrast to the double-pulse experiments, the failures appeared at longer interpulse intervals and usually only after several tens of stimuli with reliable propagation. 3. In the period with reliable propagation before the failures, a decrease in the conduction velocity and in the amplitude of the afterhyperpolarization (AHP), an increase in the total membrane conductance, and the disappearance of the action potential “shoulder” were observed. 4. The reliability of conduction during repetitive stimulation was improved by lowering the extracellular calcium concentration or by replacing the extracellular calcium by strontium. The reliability of conduction decreased by the application of cadmium, a calcium channel blocker, 4-amino pyridine, a fast potassium channel blocker, or apamin or muscarine, the blockers of calcium-dependent potassium channels. The reliability of conduction was not effected by blocking the sodium potassium pump with ouabain or by replacing extracellular sodium with lithium. 5. In the period with reliable propagation cadmium, apamin, and muscarine reduced the amplitude of the AHP. The shoulder of the action potential was more pronounced and not sensitive to repetitive stimulation when extracellular calcium was replaced by strontium. It disappeared when cadmium was applied. 6. In DRG somata changes of the intracellular Ca2+ concentration were monitored by measuring the fluorescence of the Ca2+ indicator Fluo-3 with a laser-scanning confocal microscope. During repetitive stimulation, an accumulation of intracellular calcium occurred that recovered very slowly (tens of seconds) after the AP trains. 7. Computer model simulations performed in analogy to the experimental protocols produced conduction failures during repetitive stimulation only when the calcium currents during the APs were reduced. 8. From these findings it is concluded that conduction failures during repetitive stimulation are dependent on an accumulation of intracellular calcium leading to an inactivation of calcium currents, combined with small contributions of an accumulation of extracellular potassium and a summation of slow potassium conductances.

scholarly journals Effects of Serum Calcium Changes on the Cardiac Action Potential and the ECG in a Computational Model

2018 ◽  
Vol 4 (1) ◽  
pp. 251-254 ◽  
Author(s):  
María Hernández Mesa ◽  
Nicolas Pilia ◽  
Olaf Dössel ◽  
Stefano Severi ◽  
Axel Loewe
Keyword(s):  
Action Potential ◽  
Computational Model ◽  
Cell Model ◽  
Cellular Level ◽  
Calcium Dependent ◽  
Cardiac Action ◽  
Dependent Inactivation ◽  
End Stage ◽  
Extracellular Sodium ◽  
Ventricular Cell Model

AbstractPatients suffering from end stage of chronic kidney disease (CKD) often undergo haemodialysis to normalize the electrolyte concentrations. Moreover, cardiovascular disease (CVD) is the main cause of death in CKD patients. To study the connection between CKD and CVD, we investigated the effects of an electrolyte variation on cardiac signals (action potential and ECG) using a computational model. In a first step, simulations with the Himeno et al. ventricular cell model were performed on cellular level with different extracellular sodium ([Na+]o), calcium ([Ca2+]o) and potassium ([K+]o) concentrations as occurs in CKD patients. [Ca2+]o and [K+]o changes caused variations in different features describing the morphology of the AP. Changes due to a [Na+]o variation were not as prominent. Simulations with [Ca2+]o variations were also carried out on ventricular ECG level and a 12-lead ECG was computed. Thus, a multiscale simulator from ion channel to ECG reproducing the calcium-dependent inactivation of ICaL was achieved. The results on cellular and ventricular level agree with results from literature. Moreover, we suggest novel features representing electrolyte changes that have not been described in literature. These results could be helpful for further studies aiming at the estimation of ionic concentrations based on ECG recordings.

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