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
Joint Authors
Christé, G.
Šimurda, Jiří
Pásek, Michal
Source
Issue
Vol. 2017, Issue 2017 (31 Dec. 2017), pp.1-9, 9 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2017-02-22
Country of Publication
Egypt
No. of Pages
9
Main Subjects
Abstract EN
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 5 Hz, 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.
American Psychological Association (APA)
Pásek, Michal& Šimurda, Jiří& Christé, G.. 2017. 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. BioMed Research International،Vol. 2017, no. 2017, pp.1-9.
https://search.emarefa.net/detail/BIM-1138058
Modern Language Association (MLA)
Pásek, Michal…[et al.]. 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. BioMed Research International No. 2017 (2017), pp.1-9.
https://search.emarefa.net/detail/BIM-1138058
American Medical Association (AMA)
Pásek, Michal& Šimurda, Jiří& Christé, G.. 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. BioMed Research International. 2017. Vol. 2017, no. 2017, pp.1-9.
https://search.emarefa.net/detail/BIM-1138058
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-1138058