scholarly journals Tropomyosin Fluctuations Over a Multi-Well Energy Landscape: A Brownian Ratchet Model of Cardiac Muscle Contraction

2017 ◽  
Vol 112 (3) ◽  
pp. 259a-260a ◽  
Author(s):  
Yasser Aboelkassem ◽  
Natalia Trayanova
2014 ◽  
Vol 106 (2) ◽  
pp. 32a
Author(s):  
Ivanka Sevrieva ◽  
Andrea Knowles ◽  
Yin-Biao Sun

1991 ◽  
Vol 260 (3) ◽  
pp. H989-H997 ◽  
Author(s):  
C. S. Moravec ◽  
M. Bond

We have used electron-probe microanalysis (EPMA) to address the question of Ca2+ release by junctional sarcoplasmic reticulum (JSR) as well as Ca2+ regulation by mitochondria (MT) during cardiac muscle contraction. Hamster papillary muscles were rapidly frozen during relaxation or at the peak rate of tension rise (+dT/dt). Total Ca2+ content was measured by EPMA in the JSR, within a MT, over the A band, and in the whole cell, in nine cells per animal (five animals per group). JSR Ca2+ content was found to be significantly lower in muscles frozen at the peak of contraction [7.3 +/- 1.3 (mean +/- SE) mmol Ca2+/kg dry wt] than in those frozen during relaxation (12.5 +/- 1.9 mmol Ca2+/kg dry wt; P less than 0.01), suggesting that Ca2+ is released from this storage site during cardiac muscle contraction. In contrast, MT Ca2+ content did not change significantly during contraction (0.4 +/- 0.1 mmol/kg dry wt) compared with relaxation (0.1 +/- 0.2 mmol/kg dry wt). A third group of muscles was frozen during relaxation after pretreatment with 10(-7) M ryanodine. Ca2+ content of the JSR was significantly decreased (P less than 0.01) in this group of muscles, (6.4 +/- 1.8 mmol/kg dry wt) compared with those frozen during relaxation in the absence of the drug. This suggests that the intracellular storage site with a decreased Ca2+ content in muscles frozen at the peak of contraction is the ryanodine-releasable store. These results provide the first direct measurement of the Ca2+ content of both JSR and MT during a normal cardiac muscle contraction and demonstrate that Ca2+ is released from the JSR during muscle contraction.


CALCOLO ◽  
1983 ◽  
Vol 20 (2) ◽  
pp. 129-141 ◽  
Author(s):  
J. Douglas ◽  
F. A. Milner

2016 ◽  
Vol 7 ◽  
Author(s):  
Lorenzo R. Sewanan ◽  
Jeffrey R. Moore ◽  
William Lehman ◽  
Stuart G. Campbell

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