Neural Control on the Activity of the Calcium-transport System in Sarcoplasmic Reticulum of Rat Skeletal Muscle

Nature ◽  
1973 ◽  
Vol 241 (5387) ◽  
pp. 285-286 ◽  
Author(s):  
A. MARGRETH ◽  
G. SALVIATI ◽  
U. CARRARO
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Transport System ◽  
Calcium Transport ◽  
Neural Control ◽  
Rat Skeletal Muscle

scholarly journals Characteristics of sarcoplasmic reticulum from normal and denervated rat skeletal muscle

1981 ◽  
Vol 200 (1) ◽  
pp. 11-15 ◽  
Author(s):  
G N Palexas ◽  
N Savage ◽  
H Isaacs
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Calcium Transport ◽  
Membrane Structure ◽  
Calcium Content ◽  
Heterogeneous Population ◽  
Rat Skeletal Muscle ◽  
Vesicle Size ◽  
Dependent Atpase

Denervation of rat skeletal muscle produces after 14 days a decrease in Ca2+ uptake of a heterogeneous population of sarcoplasmic-reticulum vesicles, when measured in the presence of oxalate. The Mg2+-dependent ATPase (Ca2+-independent) activity increased after the same period and the Ca2+ + Mg2+-dependent ATPase activity decreased. Concomitant with these changes, there was an increase in vesicle size and calcium content. The observations are discussed in terms of changes in altered membrane structure, manifested in the shift of the equilibrium of the ATPase from an enzyme involved in calcium transport to a phosphoenzyme giving rise to an increase in the Mg2+-dependent ATPase activity.

Ca2+ Uptake Coupled to Glycogen Phosphorolysis in the Glycogenolytic-Sarcoplasmic Reticulum Complex from Rat Skeletal Muscle

1996 ◽  
Vol 51 (7-8) ◽  
pp. 591-598 ◽  
Author(s):  
M. Nogues ◽  
A. Cuenda ◽  
F. Henao ◽  
C. Gutiérrez-Merino
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Glycogen Phosphorylase ◽  
Rat Skeletal Muscle ◽  
Subcellular Structure ◽  
Sequential Action ◽  
Physiological Conditions ◽  
Low Concentrations ◽  
Ischemic Muscle ◽  
Stimulation Of

Abstract The glycogenolytic-sarcoplasmic reticulum complex from rat skeletal muscle accumulates Ca2+ upon stimulation of glycogen phosphorolysis in the absence of added ATP. It is shown that an efficient Ca2+ uptake involves the sequential action of glycogen phosphorylase, phosphoglucomutase and hexokinase, which generate low concentrations of ATP (approximately 1 -2 μм) compartmentalized in the immediate vicinity of the sarcoplasmic reticulum Ca2+, Mg2+-ATPase (the Ca2+ pump). The Ca2+ uptake supported by glycogenolysis in this subcellular structure is strongly stimulated by micromolar concentrations of AMP, showing that the glycogen phosphorylase associated with this complex is in the dephosphorylated b form. The results point out that the flux through this compartmentalized metabolic pathway should be enhanced in physiological conditions leading to increased AMP concentrations in the sarcoplasm, such as long-lasting contractions and in ischemic muscle.

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