Publication detail

A model of the guinea-pig ventricular cardiac myocyte incorporating a transverse-axial tubular system

PÁSEK, M. ŠIMURDA, J. ORCHARD, C. CHRISTÉ, G.

Original Title

A model of the guinea-pig ventricular cardiac myocyte incorporating a transverse-axial tubular system

Type

journal article - other

Language

English

Original 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 SR Ca2+ load. Thus, the TATS plays a potentially important role in modulating the function of guinea-pig ventricular myocyte in physiological conditions.

Keywords

ion accumulation, ion depletion; extracellular space; TATS; restricted diffusion; quantitative model

Authors

PÁSEK, M.; ŠIMURDA, J.; ORCHARD, C.; CHRISTÉ, G.

RIV year

2008

Released

30. 11. 2007

Publisher

ISSN 0079-6107

Location

Great Britain

ISBN

0079-6107

Periodical

PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY

Year of study

2007 (96)

Number

1-3

State

United Kingdom of Great Britain and Northern Ireland

Pages from

258

Pages to

280

Pages count

23

BibTex

@article{BUT45341,
  author="Michal {Pásek} and Jiří {Šimurda}",
  title="A model of the guinea-pig ventricular cardiac myocyte incorporating a transverse-axial tubular system",
  journal="PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY",
  year="2007",
  volume="2007 (96)",
  number="1-3",
  pages="258--280",
  issn="0079-6107"
}