Catalase activity in skeletal muscle of varying fibre types

1981 ◽  
Vol 37 (1) ◽  
pp. 67-68 ◽  
Author(s):  
R. R. Jenkins
Keyword(s):  
Skeletal Muscle ◽  
Catalase Activity ◽  
Fibre Types

Histochemical differentiation of skeletal muscle in foetal and newborn mice

Development ◽  
1964 ◽  
Vol 12 (4) ◽  
pp. 759-767
Author(s):  
C. Wirsén ◽  
K. S. Larsson
Keyword(s):  
Skeletal Muscle ◽  
Muscle Development ◽  
Good Deal ◽  
Fibre Types ◽  
Muscle Bundle ◽  
Adult Skeletal Muscle ◽  
Newborn Mice ◽  
Longitudinal Splitting ◽  
Morphological Criteria ◽  
New Generation

In earlier investigations of muscle development, morphological criteria, such as diameter and staining with routine methods, have been used for classifying different fibre types. In human foetal muscle three fibre sizes are seen from the 15th week (Cuajunco, 1942). The largest fibres seem to be the centre of each primary muscle bundle. They were denoted as B fibres by Wohlfart (1937), who considered that they were also functionally different from the smaller ones forming around them. Tello (1922) and Cuajunco (1942) supported the widely held opinion that the smaller fibres are formed from the larger ones by longitudinal splitting. However, Couteaux (1941) claimed that the small fibres belong to a new generation differentiating from interstitial cells. Histochemical studies on foetal muscle are rare. However, during the last years a good deal of work has been carried out on the histochemistry of adult skeletal muscle.

Myofibril content of histochemical fibre types in rat skeletal muscle

1978 ◽  
Vol 63 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Kenneth F. Howells ◽  
Timothy C. Jordan ◽  
Jacqueline D. Howells
Keyword(s):  
Skeletal Muscle ◽  
Fibre Types ◽  
Rat Skeletal Muscle

Skeletal muscle fibre types and sizes in anorexia nervosa patients

1981 ◽  
Vol 1 (4) ◽  
pp. 395-403 ◽  
Author(s):  
B. Essén ◽  
L. Fohlin ◽  
G. Thorén ◽  
B. Saltin
Keyword(s):  
Skeletal Muscle ◽  
Anorexia Nervosa ◽  
Muscle Fibre ◽  
Skeletal Muscle Fibre ◽  
Fibre Types ◽  
Muscle Fibre Types

scholarly journals Regulation and role of hormone-sensitive lipase in rat skeletal muscle

2004 ◽  
Vol 63 (2) ◽  
pp. 309-314 ◽  
Author(s):  
Morten Donsmark ◽  
Jozef Langfort ◽  
Cecilia Holm ◽  
Thorkil Ploug ◽  
Henrik Galbo
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Energy Content ◽  
Hormone Sensitive Lipase ◽  
Fibre Types ◽  
Muscle Fibre Types ◽  
Muscle Fibres ◽  
Energy Store ◽  
Hormone Sensitive ◽  
Neutral Lipase

Intramyocellular triacylglycerol (TG) is an important energy store, and the energy content of this depot is higher than the energy content of the muscle glycogen depot. It has recently been shown that the mobilization of fatty acids from this TG pool may be regulated by the neutral lipase hormone-sensitive lipase (HSL). This enzyme is known to be rate limiting for intracellular TG hydrolysis in adipose tissue. The presence of HSL has been demonstrated in all muscle fibre types by Western blotting of muscle fibres isolated by collagenase treatment or after freeze-drying. The content of HSL varies between fibre types, being higher in oxidative fibres than in glycolytic fibres. When analysed under conditions optimal for“ HSL, neutral lipase activity in muscle can be stimulated by adrenaline as well as by contractions. These increases are abolished by the presence of anti-HSL antibody during analysis. Moreover, immunoprecipitation with affinity-purified anti-HSL antibody causes similar reductions in muscle HSL protein concentration and in measured neutral lipase responses to contractions. The immunoreactive HSL in muscle is stimulated by adrenaline via β-adrenergic activation of cAMP-dependent protein kinase (PKA). From findings in adipocytes it is likely that PKA phosphorylates HSL at residues Ser563, Ser659and Ser660. Contraction probably also enhances muscle HSL activity by phosphorylation, because the contraction-induced increase in HSL activity is elevated by the protein phosphatase inhibitor okadaic acid and reversed by alkaline phosphatase. A novel signalling pathway in muscle by which HSL activity may be stimulated by protein kinase C (PKC) via extracellular signal-regulated kinase (ERK) has been demonstrated. In contrast to previous findings in adipocytes, in muscle the activation of ERK is not necessary for stimulation of HSL by adrenaline. However, contraction-induced HSL activation is mediated by PKC, at least partly via the ERK pathway. In fat cells ERK is known to phosphorylate HSL at Ser600. Hence, phosphorylation of different sites may explain the finding that in muscle the effects of contractions and adrenaline on HSL activity are partially additive. In line with the view that the two stimuli act by different mechanisms, training increases contraction-mediated HSL activation but diminishes adrenaline-mediated HSL activation in muscle. In conclusion, HSL is present in skeletal muscle and can be activated by phosphorylation in response to both adrenaline and muscle contractions. Training increases contraction-mediated HSL activation, but decreases adrenaline-mediated HSL activation in muscle.

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