A quantitative model of the cardiac ventricular cell incorporating the transverse-axial tubular system

0212512 - UT-L 20030229 RIV SK eng J - Journal Article
Pásek, Michal - Christé, G. - Šimurda, J.
A quantitative model of the cardiac ventricular cell incorporating the transverse-axial tubular system.
General Physiology and Biophysics. Roč. 22, č. 3 (2003), s. 355-368. ISSN 0231-5882. E-ISSN 1338-4325
R&D Projects: GA ČR GP204/02/D129
Institutional research plan: CEZ:AV0Z2076919
Keywords : cardiac cell * tubular system * quantitative modelling
Subject RIV: BO - Biophysics
Impact factor: 0.794, year: 2003

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.
Permanent Link: http://hdl.handle.net/11104/0108060