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@article{1387883,
author = {Pásek, Michal and Šimurda, Jiří and Christé, G.},
article_location = {New York},
article_number = {6343821},
doi = {http://dx.doi.org/10.1155/2017/6343821},
keywords = {SODIUM-CALCIUM EXCHANGE; NA+-CA2+ EXCHANGE; CARDIAC MYOCYTES; FAILING HEARTS; NA/CA EXCHANGE; PROTEIN; CELLS; LOCALIZATION; MECHANISM; RELEASE},
language = {eng},
issn = {2314-6133},
journal = {Biomed Research International},
title = {Different Densities of Na-Ca Exchange Current in T-Tubular and Surface Membranes and Their Impact on Cellular Activity in a Model of Rat Ventricular Cardiomyocyte},
volume = {2017},
year = {2017}
}
TY - JOUR
ID - 1387883
AU - Pásek, Michal - Šimurda, Jiří - Christé, G.
PY - 2017
TI - Different Densities of Na-Ca Exchange Current in T-Tubular and Surface Membranes and Their Impact on Cellular Activity in a Model of Rat Ventricular Cardiomyocyte
JF - Biomed Research International
VL - 2017
IS - 6343821
SP - 1-9
EP - 1-9
PB - Hindawi Publishing Corporation
SN - 23146133
KW - SODIUM-CALCIUM EXCHANGE
KW - NA+-CA2+ EXCHANGE
KW - CARDIAC MYOCYTES
KW - FAILING HEARTS
KW - NA/CA EXCHANGE
KW - PROTEIN
KW - CELLS
KW - LOCALIZATION
KW - MECHANISM
KW - RELEASE
N2 - The ratio of densities of Na-Ca exchanger current (I-NaCa) in the t-tubular and surface membranes (I-NaCa-ratio) computed from the values of I-NaCa and membrane capacitances (C-m) measured in adult rat ventricular cardiomyocytes before and after detubulation ranges between 1.7 and 25 (potentially even 40). Variations of action potential waveform and of calcium turnover within this span of the I-NaCa-ratio were simulated employing previously developed model of rat ventricular cell incorporating separate description of ion transport systems in the t-tubular and surface membranes. The increase of I-NaCa-ratio from 1.7 to 25 caused a prolongation of APD (duration of action potential at 90% repolarisation) by 12, 9, and 6% and an increase of peak intracellular Ca2+ transient by 45, 19, and 6% at 0.1, 1, and 5Hz, respectively. The prolonged APD resulted from the increase of I-NaCa due to the exposure of a larger fraction of Na-Ca exchangers to higher Ca2+ transients under the t-tubular membrane. The accompanying rise of Ca2+ transient was a consequence of a higher Ca2+ load in sarcoplasmic reticulum induced by the increased Ca2+ cycling between the surface and t-tubular membranes. However, the reason for large differences in the I-NaCa-ratio assessed from measurements in adult rat cardiomyocytes remains to be explained.
ER -
PÁSEK, Michal, Jiří ŠIMURDA and G. CHRISTÉ. Different Densities of Na-Ca Exchange Current in T-Tubular and Surface Membranes and Their Impact on Cellular Activity in a Model of Rat Ventricular Cardiomyocyte. \textit{Biomed Research International}. New York: Hindawi Publishing Corporation, 2017, vol.~2017, No~6343821, p.~1-9. ISSN~2314-6133. Available from: https://dx.doi.org/10.1155/2017/6343821.
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