Biological Membranes - A. N. Ogurtsov 2012

Electrogenesis of Biomembranes
Secondary Transport via Cotransporters
Cardiomyocyte Na+/Ca2+ Exchangers

In cardiomyocytes (Heart Muscle Cells (myocardium)), Cell/33.html">Plasma Membrane 3-Na+/1-Ca2+ exchangers (even more so than Ca2+-ATPases) maintain a low concentration of Ca2+ ions in the Cytosol. This transport process can be written as

Class="center">

Since this transporter couples the movement of three sodium ions with the translocation of one calcium ion, the equilibrium concentrations of calcium in the cytosol ([Ca2+] ≈ 2×10-7 M) and extracellularly ([Ca2+] ≈ 2×10-3 M) differ by a factor of 10,000. As in other muscle cells, an increase in cytosolic calcium concentration triggers cardiomyocyte contraction, while a decrease in cytosolic calcium leads to muscle relaxation.



Last update: 13/08/2026

Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.

What was processed:

  • elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
  • editorial organization of content;
  • standardization of terminology in accordance with academic sources;
  • verification of factual statements against the original source text.

All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.