scholarly journals Effects of a Bout of Downhill Running on Skeletal Muscle Function and Ca2+ Handling in Mouse Extensor Digitorum Longus Muscle

2018 ◽  
Vol 64 (Suppl.1) ◽  
pp. 146-146
Author(s):  
RYO KAKIGI ◽  
KYOKO NAKAMURA ◽  
HIROAKI ESHIMA ◽  
TOSHINORI YOSHIHARA ◽  
HISASHI NAITO
Keyword(s):  
Skeletal Muscle ◽  
Muscle Function ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Skeletal Muscle Function ◽  
Downhill Running ◽  
Longus Muscle

Myosin light chain phosphorylation-dephosphorylation in mammalian skeletal muscle

1982 ◽  
Vol 242 (3) ◽  
pp. C234-C241 ◽  
Author(s):  
D. R. Manning ◽  
J. T. Stull
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Extensor Digitorum Longus ◽  
Myosin Light Chain ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Mammalian Skeletal Muscle ◽  
Phosphate Content ◽  
Longus Muscle ◽  
Fast Twitch

Phosphorylation of the myosin light chain 2 (LC2) subunit was examined in rat fast-twitch and slow-twitch skeletal muscles in response to repetitive stimulation at 23 and 35 degrees C and on incubation of fast-twitch skeletal muscle with isoproterenol. After a 1-s tetany at 35 degrees C, LC2 phosphate content in extensor digitorum longus muscle increased rapidly and transiently from 0.21 to 0.51 mol phosphate/mol LC2. This pattern of phosphorylation was similar to that observed at 23 degrees C. Increases in LC2 phosphate content were dependent on the frequency and duration of stimulation. In soleus muscle LC2 phosphate content was minimal following a 1-s tetany but increased markedly following more prolonged tetanies. On incubation of extensor digitorum longus muscle with isoproterenol (20 microM), LC2 phosphate content did not change, whereas phosphorylase a levels increased. A positive correlation existed between LC2 phosphate content and potentiation of peak twitch tension in both types of muscles, suggesting a physiological function for LC2 phosphorylation.

Pattern of skeletal muscle regeneration after reautotransplantation of regenerated muscle

Development ◽  
1986 ◽  
Vol 92 (1) ◽  
pp. 1-10
Author(s):  
Adarshk Gulati
Keyword(s):  
Skeletal Muscle ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Skeletal Muscle Regeneration ◽  
Time Intervals ◽  
Muscle Weight ◽  
Longus Muscle ◽  
Conditioning Effect ◽  
Subsequent Regeneration

Autotransplantation of rat extensor digitorum longus muscle results in initial myofibre degeneration and subsequent regeneration from precursor myosatellite cells. To determine what effect a reinjury would have on the regenerative response, in the present,study, once transplanted and regenerated muscles were reinjured by reautotransplantion. In rats, four weeks after initial transplantation, when the regeneration was complete, the extensor digitorum longus muscle was transplanted again and the pattern of regeneration in reautotransplanted and once auto transplanted muscles was compared. Muscles were analysed 2, 4, 7, 14 and 30 days after autotransplantation and reautotransplantation. Both autotransplanted and reautotransplanted muscles underwent degeneration and regeneration; however, the pattern of regeneration in these two transplants was quite different. In autotransplants, a thin myogenic zone, marked by activated myoblasts, was first seen at 4 days. By 7 days the width of myogenic zone increased but still many degenerating myofibres were present in the central region of the muscle. By 14 days the muscle was filled with regenerated myotubes and myofibres. The reautotransplanted muscles underwent similar regenerative events; however, the rate of regeneration was considerably faster. The myogenic zone was apparent as early as 2 days and was much larger at 4 days, and by 7 days the entire muscle was filled with regenerated myotubes and myofibres which matured at later time intervals. Furthermore, the decrease in muscle weight in reautotransplanted muscles was not as much as that seen after autotransplantation. These findings reveal that not only is skeletal muscle capable of regeneration after a second injury, but the rate of this regeneration is much faster. This increased rate and recovery may be due to a conditioning effect of the first injury.

Catalase overexpression does not impair extensor digitorum longus muscle function in normal mice

2007 ◽  
Vol 36 (6) ◽  
pp. 833-841 ◽  
Author(s):  
Mingju Liu ◽  
Yongping Yue ◽  
Dejia Li ◽  
Dongsheng Duan
Keyword(s):  
Muscle Function ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Longus Muscle

scholarly journals Alpha 7 integrin preserves the function of the extensor digitorum longus muscle in dystrophin-null mice

2013 ◽  
Vol 115 (9) ◽  
pp. 1388-1392 ◽  
Author(s):  
Chady H. Hakim ◽  
Dean J. Burkin ◽  
Dongsheng Duan
Keyword(s):  
Muscular Dystrophy ◽  
Knockout Mice ◽  
Muscle Function ◽  
Extensor Digitorum Longus ◽  
Transmission Loss ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Force Transmission ◽  
Double Knockout ◽  
Longus Muscle

The dystrophin-associated glycoprotein complex (DGC) and the α7β1-integrin complex are two independent protein complexes that link the extracellular matrix with the cytoskeleton in muscle cells. These associations stabilize the sarcolemma during force transmission. Loss of either one of these complexes leads to muscular dystrophy. Dystrophin is a major component of the DGC. Its absence results in Duchenne muscular dystrophy (DMD). Because α7-integrin overexpression has been shown to ameliorate muscle histopathology in mouse models of DMD, we hypothesize that the α7β1-integrin complex can help preserve muscle function. To test this hypothesis, we evaluated muscle force, elasticity, and the viscous property of the extensor digitorum longus muscle in 19-day-old normal BL6, dystrophin-null mdx4cv, α7-integrin-null, and dystrophin/α7-integrin double knockout mice. While nominal changes were found in single knockout mice, contractility and passive properties were significantly compromised in α7-integrin double knockout mice. Our results suggest that DGC and α7β1-integrin complexes may compensate each other to maintain normal skeletal muscle function. α7β1-Integrin upregulation may hold promise to treat not only histological, but also physiological, defects in DMD.

Insulin does not hyperpolarize rat muscle by means of a ouabain-inhibitable process

1981 ◽  
Vol 241 (3) ◽  
pp. C145-C149 ◽  
Author(s):  
K. Zierler ◽  
E. Rogus
Keyword(s):  
Skeletal Muscle ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Electrogenic Pump ◽  
Rat Skeletal Muscle ◽  
Rat Muscle ◽  
Longus Muscle ◽  
Stimulation Of

Experiments were designed to test the hypothesis that insulin-induced hyperpolarization of rat skeletal muscle is mediated by stimulation of a ouabain-inhibitable electrogenic pump. Parallel experiments were carried out on rat caudofemoralis with isoproterenol, known to hyperpolarize rat skeletal muscle by stimulation of such a pump. Ouabain (10(-5) M) completely inhibited isoproterenol-induced hyperpolarization within 15 min but had no effect on half-maximal insulin-induced hyperpolarization. Ouabain (10(-6) M) inhibited isoproterenol effect by 60% during a period of 5–15 min. Ouabain (10(-4) M) had no effect on insulin-induced hyperpolarization within 10 min but depolarized during the next 10 min. In a separate series of studies in rat extensor digitorum longus muscle, 10(-5) M ouabain increased intracellular Na+ within 14 min. It is concluded that in rat caudofemoralis muscle, insulin-induced hyperpolarization is not mediated by a ouabain-inhibitable electrogenic pump.

Insulin sensitivity of rat skeletal muscle: effects of starvation and aging.

1979 ◽  
Vol 236 (5) ◽  
pp. E519 ◽  
Author(s):  
M N Goodman ◽  
N B Ruderman
Keyword(s):  
Skeletal Muscle ◽  
Glucose Uptake ◽  
Extensor Digitorum Longus ◽  
Glucose Utilization ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Low Concentrations ◽  
Longus Muscle ◽  
Relative Differences

The effects of starvation and of aging on the sensitivity of skeletal muscle to insulin were studied in the isolated perfused rat hindquarter preparation. As we have shown previously, starvation for 48 h had no effect on glucose uptake in hindquarters perfused with high levels of insulin (5 and 20 mU/ml). On the other hand, in the presence of physiological concentrations of insulin (50--200 muU/ml), glucose utilization was substantially greater in starved rats. Low concentrations of insulin had a greater effect on glucose uptake in fed young (100-g) than in fed older (350-g) rats. Starvation for 48 h enhanced glucose uptake in both young and older rats; however, the relative differences persisted. Starvation had similar effects on glucose utilization by the incubated soleus and extensor digitorum longus muscle. In addition, it augmented the stimulation by insulin of alpha-aminoisobutyric acid transport into the incubated extensor digitorum longus muscle. These results suggest that the in vitro sensitivity of skeletal muscle to physiological concentrations of insulin is enhanced during starvation. The basis for these findings and their physiological implications remain to be determined.

scholarly journals Defects in oxygen supply to skeletal muscle of prediabetic ZDF rats

2010 ◽  
Vol 298 (6) ◽  
pp. H1661-H1670 ◽  
Author(s):  
Christopher G. Ellis ◽  
Daniel Goldman ◽  
Madelyn Hanson ◽  
Alan H. Stephenson ◽  
Stephanie Milkovich ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Extensor Digitorum Longus ◽  
Regulatory System ◽  
Unknown Origin ◽  
Extensor Digitorum Longus Muscle ◽  
Extensor Digitorum ◽  
Resistance Arteries ◽  
Longus Muscle ◽  
Zucker Diabetic Fatty Rats

In humans, prediabetes is characterized by marked increases in plasma insulin and near normal blood glucose levels as well as microvascular dysfunction of unknown origin. Using the extensor digitorum longus muscle of 7-wk inbred male Zucker diabetic fatty rats fed a high-fat diet as a model of prediabetes, we tested the hypothesis that hyperinsulinemia contributes to impaired O2 delivery in skeletal muscle. Using in vivo video microscopy, we determined that the total O2 supply to capillaries in the extensor digitorum longus muscle of prediabetic rats was reduced to 64% of controls with a lower O2 supply rate per capillary and higher O2 extraction resulting in a decreased O2 saturation at the venous end of the capillary network. These findings suggest a lower average tissue Po2 in prediabetic animals. In addition, we determined that insulin, at concentrations measured in humans and Zucker diabetic fatty rats with prediabetes, inhibited the O2-dependent release of ATP from rat red blood cells (RBCs). This inability to release ATP could contribute to the impaired O2 delivery observed in rats with prediabetes, especially in light of the finding that the endothelium-dependent relaxation of resistance arteries from these animals is not different from controls and is not altered by insulin. Computational modeling confirmed a significant 8.3-mmHg decrease in average tissue Po2 as well as an increase in the heterogeneity of tissue Po2, implicating a failure of a regulatory system for O2 supply. The finding that insulin attenuates the O2-dependent release of ATP from RBCs suggests that this defect in RBC physiology could contribute to a failure in the regulation of O2 supply to meet the demand in skeletal muscle in prediabetes.

scholarly journals Identification in skeletal muscle of a distinct extracellular pool of amino acids, and its role in protein synthesis

1971 ◽  
Vol 121 (5) ◽  
pp. 817-827 ◽  
Author(s):  
R. C. Hider ◽  
E. B. Fern ◽  
D. R. London
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Incubation Medium ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Longus Muscle ◽  
Kinetics Of

1. The kinetics of radioactive labelling of extra- and intra-cellular amino acid pools and protein of the extensor digitorum longus muscle were studied after incubations with radioactive amino acids in vitro. 2. The results indicated that an extracellular pool could be defined, the contents of which were different from those of the incubation medium. 3. It was concluded that amino acids from the extracellular pool, as defined in this study, were incorporated directly into protein.

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