%0 Journal Article %1 Mats_2003_105 %A Matsuoka, Satoshi %A Sarai, Nobuaki %A Kuratomi, Shinobu %A Ono, Kyoichi %A Noma, Akinori %D 2003 %J Jpn. J. Physiol. %K ATPase Action Algorithms; Animals; Biological; Calcium Calcium-Binding Calcium; Cardiac; Cell Channel; Channels; Computer Cytosol; Electric Exchanger; Guinea Heart Ion Ions; Kinetics; Membrane Models, Myocytes, Patch-Clamp Pigs; Potassium; Potentials; Proteins; Receptor Release Reticulum; Ryanodine Sarcolemma; Sarcomeres; Sarcoplasmic Simulation; Size; Sodium-Calcium Sodium-Potassium-Exchanging Sodium; Stimulation; Techniques; Transport; Ventricles; %N 2 %P 105--123 %T Role of individual ionic current systems in ventricular cells hypothesized by a model study. %V 53 %X Individual ion channels or exchangers are described with a common set of equations for both the sinoatrial node pacemaker and ventricular cells. New experimental data are included, such as the new kinetics of the inward rectifier K$^+$ channel, delayed rectifier K$^+$ channel, and sustained inward current. The gating model of Shirokov et al. (J Gen Physiol 102: 1005-1030, 1993) is used for both the fast Na$^+$ and L-type Ca$^2+$ channels. When combined with a contraction model (Negroni and Lascano: J Mol Cell Cardiol 28: 915-929, 1996), the experimental staircase phenomenon of contraction is reconstructed. The modulation of the action potential by varying the external Ca$^2+$ and K$^+$ concentrations is well simulated. The conductance of I(CaL) dominates membrane conductance during the action potential so that an artificial increase of I(to), I(Kr), I(Ks), or I(KATP) magnifies I(CaL) amplitude. Repolarizing current is provided sequentially by I(Ks), I(Kr), and I(K1). Depression of ATP production results in the shortening of action potential through the activation of I(KATP). The ratio of Ca$^2+$ released from SR over Ca$^2+$ entering via I(CaL) (Ca$^2+$ gain = approximately 15) in excitation-contraction coupling well agrees with the experimental data. The model serves as a predictive tool in generating testable hypotheses.

@article{Mats_2003_105, abstract = {Individual ion channels or exchangers are described with a common set of equations for both the sinoatrial node pacemaker and ventricular cells. New experimental data are included, such as the new kinetics of the inward rectifier {K}$^{+}$ channel, delayed rectifier {K}$^{+}$ channel, and sustained inward current. The gating model of Shirokov et al. (J Gen Physiol 102: 1005-1030, 1993) is used for both the fast {N}a$^{+}$ and L-type {C}a$^{2+}$ channels. When combined with a contraction model (Negroni and Lascano: J Mol Cell Cardiol 28: 915-929, 1996), the experimental staircase phenomenon of contraction is reconstructed. The modulation of the action potential by varying the external {C}a$^{2+}$ and {K}$^{+}$ concentrations is well simulated. The conductance of I(CaL) dominates membrane conductance during the action potential so that an artificial increase of I(to), I(Kr), I(Ks), or I(KATP) magnifies I(CaL) amplitude. Repolarizing current is provided sequentially by I(Ks), I(Kr), and I(K1). Depression of ATP production results in the shortening of action potential through the activation of I(KATP). The ratio of {C}a$^{2+}$ released from SR over {C}a$^{2+}$ entering via I(CaL) ({C}a$^{2+}$ gain = approximately 15) in excitation-contraction coupling well agrees with the experimental data. The model serves as a predictive tool in generating testable hypotheses.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Matsuoka, Satoshi and Sarai, Nobuaki and Kuratomi, Shinobu and Ono, Kyoichi and Noma, Akinori}, biburl = {https://www.bibsonomy.org/bibtex/20d49df8a40c82bb554c570155c7f8af2/hake}, description = {The whole bibliography file I use.}, institution = {Department of Physiology and Biophysics, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.}, interhash = {3ec021029a748b9f02b49d1f59ede847}, intrahash = {0d49df8a40c82bb554c570155c7f8af2}, journal = {Jpn. J. Physiol.}, keywords = {ATPase Action Algorithms; Animals; Biological; Calcium Calcium-Binding Calcium; Cardiac; Cell Channel; Channels; Computer Cytosol; Electric Exchanger; Guinea Heart Ion Ions; Kinetics; Membrane Models, Myocytes, Patch-Clamp Pigs; Potassium; Potentials; Proteins; Receptor Release Reticulum; Ryanodine Sarcolemma; Sarcomeres; Sarcoplasmic Simulation; Size; Sodium-Calcium Sodium-Potassium-Exchanging Sodium; Stimulation; Techniques; Transport; Ventricles;}, month = Apr, number = 2, pages = {105--123}, pmid = {12877767}, timestamp = {2009-06-03T11:21:22.000+0200}, title = {Role of individual ionic current systems in ventricular cells hypothesized by a model study.}, volume = 53, year = 2003 }