A quantitative model of the cardiac ventricular cell incorporating the transverse-axial tubular system
Language English Country Slovakia Media print
Document type Evaluation Study, Journal Article, Research Support, Non-U.S. Gov't
PubMed
14986886
Knihovny.cz E-resources
- MeSH
- Action Potentials physiology MeSH
- Cell Membrane physiology MeSH
- Electric Stimulation MeSH
- Myocytes, Cardiac physiology ultrastructure MeSH
- Humans MeSH
- Models, Cardiovascular * MeSH
- Computer Simulation MeSH
- Sarcoplasmic Reticulum physiology MeSH
- Ventricular Function * MeSH
- Heart Ventricles ultrastructure MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Evaluation Study MeSH
- Research Support, Non-U.S. Gov't MeSH
The role of the transverse-axial tubular system (TATS) in electrical activity of cardiac cells has not been investigated quantitatively. In this study a mathematical model including the TATS and differential distribution of ionic transfer mechanisms in peripheral and tubular membranes was described. A model of ventricular cardiac cell described by Jafri et al. (1998) was adopted and slightly modified to describe ionic currents and Ca2+ handling. Changes of concentrations in the lumen of the TATS were computed from the total of transmembrane ionic fluxes and ionic exchanges with the pericellular medium. Long-term stability of the model was attained at rest and under regular stimulation. Depletion of Ca2+ by 12.8% and accumulation of K+ by 4.7% occurred in the TATS-lumen at physiological conditions and at a stimulation frequency of 1 Hz. The changes were transient and subsided on repolarization within 800 ms (Ca2+) and 300 ms (K+). Nevertheless, the course of action potentials remained virtually unaltered. Simulations of voltage clamp experiments demonstrated that variations in tubular ionic concentrations were detectable as modulation of the recorded membrane currents.
