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Simulation of developmental changes in action potentials with ventricular cell models.

Itoh H, Naito Y, Tomita M - Syst Synth Biol (2007)

Bottom Line: The simulated action potential of the early embryonic ventricular cell model exhibited spontaneous activity, which ceased in the simulated action potential of the late embryonic and neonatal ventricular cell models.The simulations with our models were able to reproduce action potentials that were consistent with the reported characteristics of the cells in vitro.The action potential of rodent ventricular cells at different developmental stages can be reproduced with common sets of mathematical equations by multiplying conductance or conversion factors for ionic currents, pumps, exchangers, and SR Ca(2+) kinetics by relative activities.

View Article: PubMed Central - PubMed

Affiliation: Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa, 252-8520, Japan, ducky@sfc.keio.ac.jp.

ABSTRACT
During cardiomyocyte development, early embryonic ventricular cells show spontaneous activity that disappears at a later stage. Dramatic changes in action potential are mediated by developmental changes in individual ionic currents. Hence, reconstruction of the individual ionic currents into an integrated mathematical model would lead to a better understanding of cardiomyocyte development. To simulate the action potential of the rodent ventricular cell at three representative developmental stages, quantitative changes in the ionic currents, pumps, exchangers, and sarcoplasmic reticulum (SR) Ca(2+) kinetics were represented as relative activities, which were multiplied by conductance or conversion factors for individual ionic systems. The simulated action potential of the early embryonic ventricular cell model exhibited spontaneous activity, which ceased in the simulated action potential of the late embryonic and neonatal ventricular cell models. The simulations with our models were able to reproduce action potentials that were consistent with the reported characteristics of the cells in vitro. The action potential of rodent ventricular cells at different developmental stages can be reproduced with common sets of mathematical equations by multiplying conductance or conversion factors for ionic currents, pumps, exchangers, and SR Ca(2+) kinetics by relative activities.

No MeSH data available.


Related in: MedlinePlus

Simulated action potential and ionic currents at early embryonic stage with two different electrophysiological models. Simulated action potential can be divided into three phases: diastolic slow depolarization (DSD) phase, depolarization phase (DP), and repolarization phase (RP). (A) Simulated action potential, IKr current, and ICaL current in the Kyoto model. (B) Simulated action potential, IKr current, and ICaL current in the Luo–Rudy model. Sum of IKr and ICaL shows that the increase in outward (positive) current is slower in the Kyoto model than in the Luo–Rudy model
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Fig3: Simulated action potential and ionic currents at early embryonic stage with two different electrophysiological models. Simulated action potential can be divided into three phases: diastolic slow depolarization (DSD) phase, depolarization phase (DP), and repolarization phase (RP). (A) Simulated action potential, IKr current, and ICaL current in the Kyoto model. (B) Simulated action potential, IKr current, and ICaL current in the Luo–Rudy model. Sum of IKr and ICaL shows that the increase in outward (positive) current is slower in the Kyoto model than in the Luo–Rudy model

Mentions: A spontaneous action potential was observed in both the Kyoto (Fig. 3A) and Luo–Rudy models (Fig. 3B). The MDP was more negative in the Luo–Rudy model (−71.16 mV) than in the Kyoto model (−62.86 mV). Repolarization of the spontaneous action potential started from the overshoot at 13.74 mV in the Luo–Rudy model. Both the depolarization phase (DP) and the repolarization phase (RP) were faster in the Luo–Rudy model, resulting in a shorter BCL (414 ms); differences in simulated action potential were determined by differences in ionic currents.Fig. 3


Simulation of developmental changes in action potentials with ventricular cell models.

Itoh H, Naito Y, Tomita M - Syst Synth Biol (2007)

Simulated action potential and ionic currents at early embryonic stage with two different electrophysiological models. Simulated action potential can be divided into three phases: diastolic slow depolarization (DSD) phase, depolarization phase (DP), and repolarization phase (RP). (A) Simulated action potential, IKr current, and ICaL current in the Kyoto model. (B) Simulated action potential, IKr current, and ICaL current in the Luo–Rudy model. Sum of IKr and ICaL shows that the increase in outward (positive) current is slower in the Kyoto model than in the Luo–Rudy model
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2533146&req=5

Fig3: Simulated action potential and ionic currents at early embryonic stage with two different electrophysiological models. Simulated action potential can be divided into three phases: diastolic slow depolarization (DSD) phase, depolarization phase (DP), and repolarization phase (RP). (A) Simulated action potential, IKr current, and ICaL current in the Kyoto model. (B) Simulated action potential, IKr current, and ICaL current in the Luo–Rudy model. Sum of IKr and ICaL shows that the increase in outward (positive) current is slower in the Kyoto model than in the Luo–Rudy model
Mentions: A spontaneous action potential was observed in both the Kyoto (Fig. 3A) and Luo–Rudy models (Fig. 3B). The MDP was more negative in the Luo–Rudy model (−71.16 mV) than in the Kyoto model (−62.86 mV). Repolarization of the spontaneous action potential started from the overshoot at 13.74 mV in the Luo–Rudy model. Both the depolarization phase (DP) and the repolarization phase (RP) were faster in the Luo–Rudy model, resulting in a shorter BCL (414 ms); differences in simulated action potential were determined by differences in ionic currents.Fig. 3

Bottom Line: The simulated action potential of the early embryonic ventricular cell model exhibited spontaneous activity, which ceased in the simulated action potential of the late embryonic and neonatal ventricular cell models.The simulations with our models were able to reproduce action potentials that were consistent with the reported characteristics of the cells in vitro.The action potential of rodent ventricular cells at different developmental stages can be reproduced with common sets of mathematical equations by multiplying conductance or conversion factors for ionic currents, pumps, exchangers, and SR Ca(2+) kinetics by relative activities.

View Article: PubMed Central - PubMed

Affiliation: Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa, 252-8520, Japan, ducky@sfc.keio.ac.jp.

ABSTRACT
During cardiomyocyte development, early embryonic ventricular cells show spontaneous activity that disappears at a later stage. Dramatic changes in action potential are mediated by developmental changes in individual ionic currents. Hence, reconstruction of the individual ionic currents into an integrated mathematical model would lead to a better understanding of cardiomyocyte development. To simulate the action potential of the rodent ventricular cell at three representative developmental stages, quantitative changes in the ionic currents, pumps, exchangers, and sarcoplasmic reticulum (SR) Ca(2+) kinetics were represented as relative activities, which were multiplied by conductance or conversion factors for individual ionic systems. The simulated action potential of the early embryonic ventricular cell model exhibited spontaneous activity, which ceased in the simulated action potential of the late embryonic and neonatal ventricular cell models. The simulations with our models were able to reproduce action potentials that were consistent with the reported characteristics of the cells in vitro. The action potential of rodent ventricular cells at different developmental stages can be reproduced with common sets of mathematical equations by multiplying conductance or conversion factors for ionic currents, pumps, exchangers, and SR Ca(2+) kinetics by relative activities.

No MeSH data available.


Related in: MedlinePlus