Heterogeneity of transverse-axial tubule system in mouse atria: Remodeling in atrial-specific Na+ -Ca2+ exchanger knockout mice

Journal of Molecular and Cellular Cardiology
Xin YueJoshua I Goldhaber

Abstract

Transverse-axial tubules (TATs) are commonly assumed to be sparse or absent in atrial myocytes from small animals. Atrial myocytes from rats, cats and rabbits lack TATs, which results in a characteristic "V"-shaped Ca release pattern in confocal line-scan recordings due to the delayed rise of Ca in the center of the cell. To examine TAT expression in isolated mouse atrial myocytes, we loaded them with the membrane dye Di-4-ANEPPS to label TATs. We found that >80% of atrial myocytes had identifiable TATs. Atria from male mice had a higher TAT density than female mice, and TAT density correlated with cell width. Using the fluorescent Ca indicator Fluo-4-AM and confocal imaging, we found that wild type (WT) mouse atrial myocytes generate near-synchronous Ca transients, in contrast to the "V"-shaped pattern typically reported in other small animals such as rat. In atrial-specific Na-Ca exchanger (NCX) knockout (KO) mice, which develop sinus node dysfunction and atrial hypertrophy with dilation, we found a substantial loss of atrial TATs in isolated atrial myocytes. There was a greater loss of transverse tubules compared to axial tubules, resulting in a dominance of axial tubules. Consistent with the overall loss of TATs, NCX KO atr...Continue Reading

References

Oct 25, 2016·Heart Rhythm : the Official Journal of the Heart Rhythm Society·Rishi AroraJ Andrew Wasserstrom

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Citations

Jan 18, 2020·American Journal of Physiology. Heart and Circulatory Physiology·Tesfaye Negash AsfawVladimir E Bondarenko
Feb 28, 2020·Biochemical Society Transactions·Aleksandra JudinaPeter T Wright
Jul 17, 2019·Cold Spring Harbor Perspectives in Biology·Guillaume GilbertH Llewelyn Roderick
May 13, 2018·Journal of Cardiovascular Development and Disease·Navneet K BhogalJulia Gorelik
Aug 1, 2020·Frontiers in Physiology·Peter T WrightSteven B Marston

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