%0 Journal Article %1 Louc_2006_519 %A Louch, William E %A M�rk, Halvor K %A Sexton, Joseph %A Str�mme, Taevje A %A Laake, Petter %A Sjaastad, Ivar %A Sejersted, Ole M %D 2006 %J J. Physiol. %K imported %N Pt 2 %P 519--533 %R 10.1113/jphysiol.2006.107227 %T T-tubule disorganization and reduced synchrony of Ca$^2+$ release in murine cardiomyocytes following myocardial infarction. %U http://dx.doi.org/10.1113/jphysiol.2006.107227 %V 574 %X In cardiac myocytes, initiation of excitation-contraction coupling is highly localized near the T-tubule network. Myocytes with a dense T-tubule network exhibit rapid and homogeneous sarcoplasmic reticulum (SR) Ca$^2+$ release throughout the cell. We examined whether progressive changes in T-tubule organization and Ca$^2+$ release synchrony occur in a murine model of congestive heart failure (CHF). Myocardial infarction (MI) was induced by ligation of the left coronary artery, and CHF was diagnosed by echocardiography (left atrial diameter >2.0 mm). CHF mice were killed at 1 or 3 weeks following MI (1-week CHF, 3-week CHF) and cardiomyocytes were isolated from viable regions of the septum, excluding the MI border zone. Septal myocytes from SHAM-operated mice served as controls. T-tubules were visualized by confocal microscopy in cells stained with di-8-ANEPPS. SHAM cells exhibited a regular striated T-tubule pattern. However, 1-week CHF cells showed slightly disorganized T-tubule structure, and more profound disorganization occurred in 3-week CHF with irregular gaps between adjacent T-tubules. Line-scan images of Ca$^2+$ transients (fluo-4 AM, 1 Hz) showed that regions of delayed Ca$^2+$ release occurred at these gaps. Three-week CHF cells exhibited an increased number of delayed release regions, and increased overall dyssynchrony of Ca$^2+$ release. A common pattern of Ca$^2+$ release in 3-week CHF was maintained between consecutive transients, and was not altered by forskolin application. Thus, progressive T-tubule disorganization during CHF promotes dyssynchrony of SR Ca$^2+$ release which may contribute to the slowing of SR Ca$^2+$ release in this condition.

@article{Louc_2006_519, abstract = {In cardiac myocytes, initiation of excitation-contraction coupling is highly localized near the T-tubule network. Myocytes with a dense T-tubule network exhibit rapid and homogeneous sarcoplasmic reticulum (SR) {C}a$^{2+}$ release throughout the cell. We examined whether progressive changes in T-tubule organization and {C}a$^{2+}$ release synchrony occur in a murine model of congestive heart failure (CHF). Myocardial infarction (MI) was induced by ligation of the left coronary artery, and CHF was diagnosed by echocardiography (left atrial diameter >2.0 mm). CHF mice were killed at 1 or 3 weeks following MI (1-week CHF, 3-week CHF) and cardiomyocytes were isolated from viable regions of the septum, excluding the MI border zone. Septal myocytes from SHAM-operated mice served as controls. T-tubules were visualized by confocal microscopy in cells stained with di-8-ANEPPS. SHAM cells exhibited a regular striated T-tubule pattern. However, 1-week CHF cells showed slightly disorganized T-tubule structure, and more profound disorganization occurred in 3-week CHF with irregular gaps between adjacent T-tubules. Line-scan images of {C}a$^{2+}$ transients (fluo-4 AM, 1 Hz) showed that regions of delayed {C}a$^{2+}$ release occurred at these gaps. Three-week CHF cells exhibited an increased number of delayed release regions, and increased overall dyssynchrony of {C}a$^{2+}$ release. A common pattern of {C}a$^{2+}$ release in 3-week CHF was maintained between consecutive transients, and was not altered by forskolin application. Thus, progressive T-tubule disorganization during CHF promotes dyssynchrony of SR {C}a$^{2+}$ release which may contribute to the slowing of SR {C}a$^{2+}$ release in this condition.}, added-at = {2009-06-03T11:20:58.000+0200}, author = {Louch, William E and M�rk, Halvor K and Sexton, Joseph and Str�mme, Taevje A and Laake, Petter and Sjaastad, Ivar and Sejersted, Ole M}, biburl = {https://www.bibsonomy.org/bibtex/20f860cad5d92c6f0a45b49a7e1ea0279/hake}, description = {The whole bibliography file I use.}, doi = {10.1113/jphysiol.2006.107227}, file = {Louc_2006_519.pdf:Louc_2006_519.pdf:PDF}, interhash = {e05cf59053c2c6639997de50c8bb1159}, intrahash = {0f860cad5d92c6f0a45b49a7e1ea0279}, journal = {J. Physiol.}, keywords = {imported}, month = Jul, number = {Pt 2}, pages = {519--533}, pii = {jphysiol.2006.107227}, pmid = {16709642}, timestamp = {2009-06-03T11:21:21.000+0200}, title = {T-tubule disorganization and reduced synchrony of {C}a$^{2+}$ release in murine cardiomyocytes following myocardial infarction.}, url = {http://dx.doi.org/10.1113/jphysiol.2006.107227}, volume = 574, year = 2006 }