Regulation of cardiac muscle contraction: how paramount are the sarcomeres?

2007 ◽  
Vol 293 (3) ◽  
pp. R961-R962
Author(s):  
Kerry S. McDonald
Keyword(s):  
Muscle Contraction ◽  
Cardiac Muscle ◽  
Cardiac Muscle Contraction

scholarly journals Molecular Mechanism for the Regulation of Cardiac Muscle Contraction by Troponin

2014 ◽  
Vol 106 (2) ◽  
pp. 32a
Author(s):  
Ivanka Sevrieva ◽  
Andrea Knowles ◽  
Yin-Biao Sun
Keyword(s):  
Muscle Contraction ◽  
Cardiac Muscle ◽  
Molecular Mechanism ◽  
Cardiac Muscle Contraction

Calcium is released from the junctional sarcoplasmic reticulum during cardiac muscle contraction

1991 ◽  
Vol 260 (3) ◽  
pp. H989-H997 ◽  
Author(s):  
C. S. Moravec ◽  
M. Bond
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Muscle Contraction ◽  
Cardiac Muscle ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Storage Site ◽  
Papillary Muscles ◽  
Cardiac Muscle Contraction ◽  
Intracellular Storage ◽  
Junctional Sarcoplasmic Reticulum

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.

Numerical methods for a model of cardiac muscle contraction

CALCOLO ◽  
1983 ◽  
Vol 20 (2) ◽  
pp. 129-141 ◽  
Author(s):  
J. Douglas ◽  
F. A. Milner
Keyword(s):  
Numerical Methods ◽  
Muscle Contraction ◽  
Cardiac Muscle ◽  
Cardiac Muscle Contraction

scholarly journals Predicting Effects of Tropomyosin Mutations on Cardiac Muscle Contraction through Myofilament Modeling

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

Invited Review: Pathophysiology of cardiac muscle contraction and relaxation as a result of alterations in thin filament regulation

2001 ◽  
Vol 90 (3) ◽  
pp. 1125-1136 ◽  
Author(s):  
Olga M. Hernandez ◽  
Philippe R. Housmans ◽  
James D. Potter
Keyword(s):  
Muscle Contraction ◽  
Cardiac Muscle ◽  
Thin Filament ◽  
Thick Filament ◽  
Familial Hypertrophic Cardiomyopathy ◽  
Cardiac Muscle Contraction ◽  
Sensitivity Changes ◽  
Contraction And Relaxation

Cardiac muscle contraction depends on the tightly regulated interactions of thin and thick filament proteins of the contractile apparatus. Mutations of thin filament proteins (actin, tropomyosin, and troponin), causing familial hypertrophic cardiomyopathy (FHC), occur predominantly in evolutionarily conserved regions and induce various functional defects that impair the normal contractile mechanism. Dysfunctional properties observed with the FHC mutants include altered Ca2+ sensitivity, changes in ATPase activity, changes in the force and velocity of contraction, and destabilization of the contractile complex. One apparent tendency observed in these thin filament mutations is an increase in the Ca2+ sensitivity of force development. This trend in Ca2+ sensitivity is probably induced by altering the cross-bridge kinetics and the Ca2+ affinity of troponin C. These in vitro defects lead to a wide variety of in vivo cardiac abnormalities and phenotypes, some more severe than others and some resulting in sudden cardiac death.

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