Cycling of cations between T-tubular and surface membranes in a
model of guinea-pig ventricular cardiomyocyte

J 2005

Cycling of cations between T-tubular and surface membranes in a model of guinea-pig ventricular cardiomyocyte

CHRISTÉ, Georges; Jiří ŠIMURDA; Clive ORCHARD and Michal PÁSEK

Basic information

Original name

Cycling of cations between T-tubular and surface membranes in a model of guinea-pig ventricular cardiomyocyte

Name in Czech

Cirkulace iontů mezi tubulární a periferní membránou v modelu srdeční komorové buňky morčete

Authors

CHRISTÉ, Georges (250 France); Jiří ŠIMURDA (203 Czech Republic); Clive ORCHARD (826 United Kingdom of Great Britain and Northern Ireland) and Michal PÁSEK (203 Czech Republic, guarantor)

Edition

Journal of Molecular and Cellular Cardiology, Elsevier Ltd. 2005, 0022-2828

Other information

Language

English

Type of outcome

Article in a journal

Field of Study

30105 Physiology

Country of publisher

United Kingdom of Great Britain and Northern Ireland

Confidentiality degree

is not subject to a state or trade secret

Impact factor

Impact factor: 3.872

RIV identification code

RIV/00216224:14110/05:00014822

Organization unit

Faculty of Medicine

UT WoS

000230435000034

Keywords in English

cardiac cell; tubular system; ion cycling; quantitative modelling

Abstract

ORIG CZ

In the original language

The contribution of surface and t-tubular membranes to cation homeostasis was evaluated in a model of the guinea-pig ventricular myocyte with a single-compartment representation of the transverse-axial tubular system (TATS) matching detailed ultrastructural data (1), with 53% of the cell membrane in the TATS, and ionic diffusion data (2). The TATS fraction of ion transfer mechanisms was set to 0.53 (uniform distribution) except for INa and ICaL (0.64), IK1 (0.8), Na/Ca exchange (0.7) and Ca-pump (0.2). At steady-state during 4 Hz stimulation in current-clamp, 67% of Ca2+ influx occurred across the TATS membrane, while 53% of Ca2+ extrusion occurred across the surface membrane. Thus the TATS membrane mediates net Ca2+ influx, while the surface membrane mediates net Ca2+ efflux. Transient partial depletion of Ca2+ within the TATS lumen during the action potential was compensated by diffusion from the bulk external solution. Thus within a single beat there was net intracellular Ca2+ flux from the TATS membrane to the surface membrane, and Ca2+ diffusion from the bulk extracellular solution into the TATS completed the cycle to produce steady-state conditions. Similar cycling was computed for Na+, whereas K+ cycled from the surface sarcolemma to the TATS membrane. Thus it appears that the differential localization of ion transfer mechanisms and the depletion of Ca2+ and Na+ (and accumulation of K+) in the TATS lumen result in specialised roles for each membrane, with TATS causing most of the excitation-induced changes of intracellular cation concentrations and the surface membrane being predominantly responsible for their restoration during diastole.

In Czech

Práce prezentuje výsledky kvantitativního vyšetření role periferní a tubulární membrány v udržení intracelulární iontové rovnovahy u modelu srdeční komorové buňky morčete.

Links

MSM0021622402, plan (intention)

Name: Časná diagnostika a léčba kardiovaskulárních chorob

Investor: Ministry of Education, Youth and Sports of the CR, Early diagnostics and treatment of cardiovascular diseases

Cite

CHRISTÉ, Georges; Jiří ŠIMURDA; Clive ORCHARD and Michal PÁSEK. Cycling of cations between T-tubular and surface membranes in a model of guinea-pig ventricular cardiomyocyte. Journal of Molecular and Cellular Cardiology. Elsevier Ltd., 2005, vol. 39, No 1, p. 174-175. ISSN 0022-2828.

@article{622377,
   author = {Christé, Georges and Šimurda, Jiří and Orchard, Clive and Pásek, Michal},
   article_number = {1},
   keywords = {cardiac cell; tubular system; ion cycling; quantitative modelling},
   language = {eng},
   issn = {0022-2828},
   journal = {Journal of Molecular and Cellular Cardiology},
   title = {Cycling of cations between T-tubular and surface membranes in a model of guinea-pig ventricular cardiomyocyte},
   volume = {39},
   year = {2005}
}

TY  - JOUR
ID  - 622377
AU  - Christé, Georges - Šimurda, Jiří - Orchard, Clive - Pásek, Michal
PY  - 2005
TI  - Cycling of cations between T-tubular and surface membranes in a model of guinea-pig ventricular cardiomyocyte
JF  - Journal of Molecular and Cellular Cardiology
VL  - 39
IS  - 1
SP  - 174-175
EP  - 174-175
PB  - Elsevier Ltd.
SN  - 00222828
KW  - cardiac cell
KW  - tubular system
KW  - ion cycling
KW  - quantitative modelling
N2  - The contribution of surface and t-tubular membranes to cation homeostasis was evaluated in a model of the guinea-pig ventricular myocyte with a single-compartment representation of the transverse-axial tubular system (TATS) matching detailed ultrastructural data (1), with 53% of the cell membrane in the TATS, and ionic diffusion data (2). The TATS fraction of ion transfer mechanisms was set to 0.53 (uniform distribution) except for INa and ICaL (0.64), IK1 (0.8), Na/Ca exchange (0.7) and Ca-pump (0.2). At steady-state during 4 Hz stimulation in current-clamp, 67% of Ca2+ influx occurred across the TATS membrane, while 53% of Ca2+ extrusion occurred across the surface membrane. Thus the TATS membrane mediates net Ca2+ influx, while the surface membrane mediates net Ca2+ efflux. Transient partial depletion of Ca2+ within the TATS lumen during the action potential was compensated by diffusion from the bulk external solution. Thus within a single beat there was net intracellular Ca2+ flux from the TATS membrane to the surface membrane, and Ca2+ diffusion from the bulk extracellular solution into the TATS completed the cycle to produce steady-state conditions. Similar cycling was computed for Na+, whereas K+ cycled from the surface sarcolemma to the TATS membrane. Thus it appears that the differential localization of ion transfer mechanisms and the depletion of Ca2+ and Na+ (and accumulation of K+) in the TATS lumen result in specialised roles for each membrane, with TATS causing most of the excitation-induced changes of intracellular cation concentrations and the surface membrane being predominantly responsible for their restoration during diastole.
ER  -

CHRISTÉ, Georges; Jiří ŠIMURDA; Clive ORCHARD and Michal PÁSEK. Cycling of cations between T-tubular and surface membranes in a model of guinea-pig ventricular cardiomyocyte. \textit{Journal of Molecular and Cellular Cardiology}. Elsevier Ltd., 2005, vol.~39, No~1, p.~174-175. ISSN~0022-2828.

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