Cyclic AMP-induced enhancement of calcium accumulation by the sarcoplasmic reticulum with no modification of the sensitivity of the myofilaments to calcium in skinned fibres from a fast skeletal muscle

1978 ◽  
Vol 539 (2) ◽  
pp. 253-260 ◽  
Author(s):  
A FABIATO ◽  
F FABIATO
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Cyclic Amp ◽  
Skinned Fibres ◽  
Fast Skeletal Muscle ◽  
Calcium Accumulation

Cyclic AMP modulation of calcium accumulation by sarcoplasmic reticulum from fast skeletal muscle

1977 ◽  
Vol 468 (2) ◽  
pp. 188-193 ◽  
Author(s):  
Edward P. Bornet ◽  
Mark L. Entman ◽  
W.Barry Van Winkle ◽  
Arnold Schwartz ◽  
Dennis C. Lehotay ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Cyclic Amp ◽  
Fast Skeletal Muscle ◽  
Calcium Accumulation

Diaphragm tension reduced in dystrophic mice by an oxidant, hypochlorous acid

2010 ◽  
Vol 88 (2) ◽  
pp. 130-140
Author(s):  
Aude Lafoux ◽  
Alexandra Divet ◽  
Pascal Gervier ◽  
Corinne Huchet-Cadiou
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Hypochlorous Acid ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Diaphragm Muscle ◽  
Mdx Mouse ◽  
Mdx Mice ◽  
Skinned Fibres ◽  
Dystrophic Mice

In dystrophin-deficient skeletal muscle cells, in which Ca2+ homeostasis is disrupted and reactive oxygen species production is increased, we hypothesized that hypochlorous acid (HOCl), a strong H2O2-related free radical, damages contractile proteins and the sarcoplasmic reticulum. The aim of the present study was to investigate the effects of exposure to oxidative stress, generated by applying HOCl (100 µmol/L and 1 mmol/L), on the contractile function and sarcoplasmic reticulum properties of dystrophic mice. Experiments were performed on diaphragm muscle, which is severely affected in the mdx mouse, and the results were compared with those obtained in healthy (non-dystrophic) mice. In Triton-skinned fibres from C57BL/10 and mdx mice, 1 mmol/L HOCl increased myofibrillar Ca2+ sensitivity, but decreased maximal Ca2+-activated tension. In the presence of HOCl, higher concentrations of MgATP were required to produce rigor tensions. The interaction between HOCl and the Ca2+ uptake mechanisms was demonstrated using saponin-skinned fibres and sarcoplasmic reticulum vesicles. The results showed that HOCl, at micromolar or millimolar concentrations, can modify sarcoplasmic reticulum Ca2+ uptake and that this effect was more pronounced in diaphragm muscle from mdx mice. We conclude that in dystrophic diaphragm skeletal muscle cells, HOCl activates a cellular pathway that leads to an increase in the intracellular concentration of Ca2+.

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