Dataset Information

Pasek2006_VentricularCardioMyocytes

ABSTRACT: This a model from the article: The functional role of cardiac T-tubules explored in a model of rat ventricular myocytes. Pásek M, Simurda J, Christé G. Philos Transact A Math Phys Eng Sci. 2006 May 15;364(1842):1187-206. 16608703 , Abstract: The morphology of the cardiac transverse-axial tubular system (TATS) has been known for decades, but its function has received little attention. To explore the possible role of this system in the physiological modulation of electrical and contractile activity, we have developed a mathematical model of rat ventricular cardiomyocytes in which the TATS is described as a single compartment. The geometrical characteristics of the TATS, the biophysical characteristics of ion transporters and their distribution between surface and tubular membranes were based on available experimental data. Biophysically realistic values of mean access resistance to the tubular lumen and time constants for ion exchange with the bulk extracellular solution were included. The fraction of membrane in the TATS was set to 56%. The action potentials initiated in current-clamp mode are accompanied by transient K+ accumulation and transient Ca2+ depletion in the TATS lumen. The amplitude of these changes relative to external ion concentrations was studied at steady-state stimulation frequencies of 1-5 Hz. Ca2+ depletion increased from 7 to 13.1% with stimulation frequency, while K+ accumulation decreased from 4.1 to 2.7%. These ionic changes (particularly Ca2+ depletion) implicated significant decrease of intracellular Ca2+ load at frequencies natural for rat heart. This model was taken from the CellML repository and automatically converted to SBML. The original model was: Pásek M, Simurda J, Christé G. (2006) - version03 The original CellML model was created by: Lloyd, Catherine, May c.lloyd@aukland.ac.nz The University of Auckland The Bioengineering Institute This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information. In summary, you are entitled to use this encoded model in absolutely any manner you deem suitable, verbatim, or with modification, alone or embedded it in a larger context, redistribute it, commercially or not, in a restricted way or not.. To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.

SUBMITTER: Vijayalakshmi Chelliah

PROVIDER: MODEL0406553884 | BioModels | 2005-01-01

REPOSITORIES: BioModels

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The functional role of cardiac T-tubules explored in a model of rat ventricular myocytes.

Pásek Michal M Simurda Jiri J Christé Georges G

Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 20060501 1842

The morphology of the cardiac transverse-axial tubular system (TATS) has been known for decades, but its function has received little attention. To explore the possible role of this system in the physiological modulation of electrical and contractile activity, we have developed a mathematical model of rat ventricular cardiomyocytes in which the TATS is described as a single compartment. The geometrical characteristics of the TATS, the biophysical characteristics of ion transporters and their dis ...[more]

PMID: 16608703

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Project description:This a model from the article: A model of the guinea-pig ventricular cardiac myocyte incorporating a transverse-axial tubular system. Pásek M, Simurda J, Orchard CH, Christé G. Prog Biophys Mol Biol. 2008 Jan-Apr;96(1-3):258-80. 17888503 , Abstract: A model of the guinea-pig cardiac ventricular myocyte has been developed that includes a representation of the transverse-axial tubular system (TATS), including heterogeneous distribution of ion flux pathways between the surface and tubular membranes. The model reproduces frequency-dependent changes of action potential shape and intracellular ion concentrations and can replicate experimental data showing ion diffusion between the tubular lumen and external solution in guinea-pig myocytes. The model is stable at rest and during activity and returns to rested state after perturbation. Theoretical analysis and model simulations show that, due to tight electrical coupling, tubular and surface membranes behave as a homogeneous whole during voltage and current clamp (maximum difference 0.9 mV at peak tubular INa of -38 nA). However, during action potentials, restricted diffusion and ionic currents in TATS cause depletion of tubular Ca2+ and accumulation of tubular K+ (up to -19.8% and +3.4%, respectively, of bulk extracellular values, at 6 Hz). These changes, in turn, decrease ion fluxes across the TATS membrane and decrease sarcoplasmic reticulum (SR) Ca2+ load. Thus, the TATS plays a potentially important role in modulating the function of guinea-pig ventricular myocyte in physiological conditions. This model was taken from the CellML repository and automatically converted to SBML. The original model was: Pásek M, Simurda J, Orchard CH, Christé G. (2008) - version03 The original CellML model was created by: Lloyd, Catherine, May c.lloyd@aukland.ac.nz The University of Auckland The Bioengineering Institute This model originates from BioModels Database: A Database of Annotated Published Models (http://www.ebi.ac.uk/biomodels/). It is copyright (c) 2005-2011 The BioModels.net Team. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information. In summary, you are entitled to use this encoded model in absolutely any manner you deem suitable, verbatim, or with modification, alone or embedded it in a larger context, redistribute it, commercially or not, in a restricted way or not.. To cite BioModels Database, please use: Li C, Donizelli M, Rodriguez N, Dharuri H, Endler L, Chelliah V, Li L, He E, Henry A, Stefan MI, Snoep JL, Hucka M, Le Novère N, Laibe C (2010) BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. BMC Syst Biol., 4:92.

Project description:Background: High-altitude hypoxia significantly impacts cardiovascular function, but the effects of adipose/metabolic factors on cardiovascular regulation remain unclear. Thus, a deeper understanding of adipose/metabolic factors’ role in cardiovascular function changes is needed. Methods: We assessed lung ventilation function, cardiovascular function, electrocardiogram, plasma CK-MB, sPecam-1, and 11 plasma adipose/metabolic factors in expeditioners at Antarctic Kunlun Station (4087m). To investigate adipose/metabolic factors’ effects and mechanisms on cardiac function, we constructed a rat model exposed to simulated hypobaric hypoxia (5000 m) with the same oxygen concentration as Kunlun Station. Echocardiography, ELISA, histology, and gene and protein expression studies were employed to examine cardiac function changes, pathological alterations, and leptin’s role in cardiac pathology under acute and chronic hypoxic exposure. Results: The Antarctic ice plateau environment significantly altered lung ventilation function, weakened cardiac pumping and contractile function, increased systematic vascular resistance (SVR), induced adaptive changes in cardiac conduction, significantly increased plasma CK-MB and Pecam-1, and significantly reduced plasma leptin, resistin, insulin, and lipocalin-2 levels. Decreased leptin was significantly correlated to cardiopulmonary function. Rats chronically exposed to simulated hypobaric hypoxia at 5000m exhibited pulmonary arterial hypertension (PAH), right ventricular hypertrophy (RVH), impaired left ventricular systolic and diastolic function, and significant deteriorated left ventricular global longitudinal strain (GLS), lateral and radial strains of the myocardium, with increased plasma CK-MB and sPecam-1 in hypoxic rats. Protein levels of leptin/ob-Rb, JAK2/STAT3, PI3K/AKT/GSK3β, and ERK/JNK were decreased in biventricular myocardial tissues of chronic hypoxia-exposed rats, accompanied by increased myocytes hypertrophy, fibrosis, lipid deposition, cell apoptosis, and mitochondrial dysfunction, and decreased metabolic gene levels. Left ventricular transcriptome analysis revealed that decreased myocardial leptin in hypoxic rats regulated cardiac pathology via down-regulated genes related to circadian rhythm, sodium/potassium ion transport, and cell skeleton. Conclusion: Our findings suggest that leptin is a crucial metabolic factor in regulating cardiac pathological changes and cardiac contractile and diastolic function under high altitudes. These regulatory pathways may involve leptin's classical signaling pathways and genes related to circadian rhythm, sodium/potassium ion transport, and cell skeleton in the heart.

Dataset Information

Pasek2006_VentricularCardioMyocytes

Publications

The functional role of cardiac T-tubules explored in a model of rat ventricular myocytes.

Similar Datasets

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