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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.


Simulated action potential and ionic currents of SA node cells. Simulated action potential and changes in IKr current, ICaL current, and sum of IKr and ICaL accompanying the spontaneous action potential are indicated. BCL of the action potential was 382 ms, which was shorter than that of early embryonic ventricular cells (492 ms). The MDP was approximately the same in the SA node cells (−62.17 mV) and early embryonic ventricular cells (−62.86 mV). The overshoot was 16.14 mV in the SA node cells: this value was more positive than that in the early embryonic ventricular cells (3.13 mV)
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Fig5: Simulated action potential and ionic currents of SA node cells. Simulated action potential and changes in IKr current, ICaL current, and sum of IKr and ICaL accompanying the spontaneous action potential are indicated. BCL of the action potential was 382 ms, which was shorter than that of early embryonic ventricular cells (492 ms). The MDP was approximately the same in the SA node cells (−62.17 mV) and early embryonic ventricular cells (−62.86 mV). The overshoot was 16.14 mV in the SA node cells: this value was more positive than that in the early embryonic ventricular cells (3.13 mV)

Mentions: The spontaneous action potential is one of the important features of electrical activity in early embryonic ventricular cells. It is well known that fully differentiated SA node cells show spontaneous action potential. Figure 5 shows the action potential of the SA node cells, as simulated by using common sets of mathematical equations; the SA node cells had a longer RP phase than early embryonic ventricular cells. The amplitude parameters of the current components in early embryonic ventricular cells were similar to those in SA node cells, but one prominent difference is that the early embryonic ventricular cells had more ICaT and INaCa than did the SA node cells.Fig. 5


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 of SA node cells. Simulated action potential and changes in IKr current, ICaL current, and sum of IKr and ICaL accompanying the spontaneous action potential are indicated. BCL of the action potential was 382 ms, which was shorter than that of early embryonic ventricular cells (492 ms). The MDP was approximately the same in the SA node cells (−62.17 mV) and early embryonic ventricular cells (−62.86 mV). The overshoot was 16.14 mV in the SA node cells: this value was more positive than that in the early embryonic ventricular cells (3.13 mV)
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Related In: Results  -  Collection

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Fig5: Simulated action potential and ionic currents of SA node cells. Simulated action potential and changes in IKr current, ICaL current, and sum of IKr and ICaL accompanying the spontaneous action potential are indicated. BCL of the action potential was 382 ms, which was shorter than that of early embryonic ventricular cells (492 ms). The MDP was approximately the same in the SA node cells (−62.17 mV) and early embryonic ventricular cells (−62.86 mV). The overshoot was 16.14 mV in the SA node cells: this value was more positive than that in the early embryonic ventricular cells (3.13 mV)
Mentions: The spontaneous action potential is one of the important features of electrical activity in early embryonic ventricular cells. It is well known that fully differentiated SA node cells show spontaneous action potential. Figure 5 shows the action potential of the SA node cells, as simulated by using common sets of mathematical equations; the SA node cells had a longer RP phase than early embryonic ventricular cells. The amplitude parameters of the current components in early embryonic ventricular cells were similar to those in SA node cells, but one prominent difference is that the early embryonic ventricular cells had more ICaT and INaCa than did the SA node cells.Fig. 5

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.