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Numerical Analysis of Ca2+ Signaling in Rat Ventricular Myocytes with Realistic Transverse-Axial Tubular Geometry and Inhibited Sarcoplasmic Reticulum.
- Source :
- PLoS Computational Biology; Oct2010, Vol. 6 Issue 10, p1-16, 16p, 1 Color Photograph, 1 Diagram, 4 Charts, 6 Graphs
- Publication Year :
- 2010
-
Abstract
- The t-tubule's of mammalian ventricular myocytes are invaginations of the cell membrane that occur at each Z-line. These invaginations branch within the cell to form a complex network that allows rapid propagation of the electrical signal, and hence synchronous rise of intracellular calcium (Ca<superscript>2+</superscript>). To investigate how the t-tubulemicroanatomy and the distribution of membrane Ca<superscript>2+</superscript> flux affect cardiac excitation-contraction coupling we developed a 3-D continuum model of Ca<superscript>2+</superscript> signaling, buffering and diffusion in rat ventricular myocytes. The transverse-axial t-tubule geometry was derived from light microscopy structural data. To solve the nonlinear reaction-diffusion system we extended SMOL software tool (http://mccammon.ucsd.edu/smol/). The analysis suggests that the quantitative understanding of the Ca<superscript>2+</superscript> signaling requires more accurate knowledge of the t-tubule ultra-structure and Ca2+ flux distribution along the sarcolemma. The results reveal the important role for mobile and stationary Ca<superscript>2+</superscript> buffers, including the Ca<superscript>2+</superscript> indicator dye. In agreement with experiment, in the presence of fluorescence dye and inhibited sarcoplasmic reticulum, the lack of detectible differences in the depolarization-evoked Ca<superscript>2+</superscript> transients was found when the Ca<superscript>2+</superscript> flux was heterogeneously distributed along the sarcolemma. In the absence of fluorescence dye, strongly non-uniform Ca<superscript>2+</superscript> signals are predicted. Even at modest elevation of Ca<superscript>2+</superscript>, reached during Ca<superscript>2+</superscript> influx, large and steep Ca<superscript>2+</superscript> gradients are found in the narrow sub-sarcolemmal space. The model predicts that the branched t-tubule structure and changes in the normal Ca<superscript>2+</superscript> flux density along the cell membrane support initiation and propagation of Ca<superscript>2+</superscript> waves in rat myocytes. [ABSTRACT FROM AUTHOR]
- Subjects :
- CALCIUM in the body
MUSCLE cells
SARCOLEMMA
NUMERICAL analysis
LABORATORY mice
Subjects
Details
- Language :
- English
- ISSN :
- 1553734X
- Volume :
- 6
- Issue :
- 10
- Database :
- Complementary Index
- Journal :
- PLoS Computational Biology
- Publication Type :
- Academic Journal
- Accession number :
- 55250925
- Full Text :
- https://doi.org/10.1371/journal.pcbi.1000972