scholarly journals Variant insertion of the fibularis tertius muscle is an evidence of the progressive evolutionary adaptation for the bipedal gait

2011 ◽  
Vol 1 (4) ◽  
pp. 81 ◽  
Author(s):  
Rashmoni Jana ◽  
Tara Sankar Roy
Keyword(s):  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Evolutionary Adaptation ◽  
Human Foot ◽  
Bipedal Gait ◽  
Recent Addition ◽  
Edl Muscle

Fibularis tertius (FT) is often considered as part of extensor digitorum longus (EDL) muscle. The muscle is absent in hominoid apes and with the acquisition of the bipedal gait; the muscle emerged as a recent addition in the human foot. From its various modes of insertions, it is evident that the muscles of the sole are in search of its distal attachment, which can best support the relatively weak human midfoot. We describe an unusual insertion of the muscle in support of this hypothesis.

scholarly journals Activity of mu- and m-calpain in regenerating fast and slow twitch skeletal muscles.

1996 ◽  
Vol 43 (4) ◽  
pp. 693-700 ◽  
Author(s):  
J Moraczewski ◽  
E Piekarska ◽  
M Zimowska ◽  
M Sobolewska
Keyword(s):  
Intracellular Calcium ◽  
Soleus Muscle ◽  
Muscle Regeneration ◽  
Skeletal Muscles ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Slow Twitch ◽  
Edl Muscle ◽  
Calpain Ii ◽  
Complete Regeneration

Calpains--non-lysosomal intracellular calcium-activated neutral proteinases, form a family consisting of several distinct members. Two of the isoenzymes: mu (calpain I) and m (calpain II) responded differently to the injury during complete regeneration of Extensor digitorum longus (EDL) muscle and partial regeneration of Soleus muscle. In the crushed EDL the level of m-calpain on the 3rd and 7th day of regeneration was higher than in non-operated muscles, whereas the activity of this calpain in injured Soleus decreased. The level of mu-calpain in EDL oscillated irregularly during regeneration whereas in Soleus of both injured and contralateral muscles its level rapidly rose. Our results support the hypothesis that m-calpain is involved in the process of fusion of myogenic cells whereas mu-calpain plays a significant but indirect role in muscle regeneration.

scholarly journals S1P3 receptor influences key physiological properties of fast-twitch extensor digitorum longus muscle

2016 ◽  
Vol 120 (11) ◽  
pp. 1288-1300 ◽  
Author(s):  
Elena Germinario ◽  
Michela Bondì ◽  
Francesca Cencetti ◽  
Chiara Donati ◽  
Marta Nocella ◽  
...  
Keyword(s):  
Extensor Digitorum Longus ◽  
The Body ◽  
Extensor Digitorum ◽  
Disuse Atrophy ◽  
Wild Type ◽  
Muscle Properties ◽  
Fatigue Development ◽  
Physiological Properties ◽  
Edl Muscle ◽  
Fast Twitch

To examine the role of sphingosine 1-phosphate (S1P) receptor 3 (S1P3) in modulating muscle properties, we utilized transgenic mice depleted of the receptor. Morphological analyses of extensor digitorum longus (EDL) muscle did not show evident differences between wild-type and S1P3-null mice. The body weight of 3-mo-old S1P3-null mice and the mean cross-sectional area of transgenic EDL muscle fibers were similar to those of wild-type. S1P3 deficiency enhanced the expression level of S1P1 and S1P2 receptors mRNA in S1P3-null EDL muscle. The contractile properties of S1P3-null EDL diverge from those of wild-type, largely more fatigable and less able to recover. The absence of S1P3 appears responsible for a lower availability of calcium during fatigue. S1P supplementation, expected to stimulate residual S1P receptors and signaling, reduced fatigue development of S1P3-null muscle. Moreover, in the absence of S1P3, denervated EDL atrophies less than wild-type. The analysis of atrophy-related proteins in S1P3-null EDL evidences high levels of the endogenous regulator of mitochondria biogenesis peroxisome proliferative-activated receptor-γ coactivator 1α (PGC-1α); preserving mitochondria could protect the muscle from disuse atrophy. In conclusion, the absence of S1P3 makes the muscle more sensitive to fatigue and slows down atrophy development after denervation, indicating that S1P3 is involved in the modulation of key physiological properties of the fast-twitch EDL muscle.

The effect of tri-iodothyronine on the membrane potential and intracellular sodium and potassium activities of rat soleus and extensor digitorum longus muscles

1993 ◽  
Vol 138 (3) ◽  
pp. 503-507 ◽  
Author(s):  
M. MacDermott
Keyword(s):  
Body Weight ◽  
Membrane Potential ◽  
Extensor Digitorum Longus ◽  
Weight Ratio ◽  
Extensor Digitorum ◽  
Heart Weight ◽  
Active Movement ◽  
Muscle Fibres ◽  
Muscle Types ◽  
Edl Muscle

ABSTRACT Tri-iodothyronine (T3) induces a considerable increase in the number of Na/K pump units in rat skeletal muscles, but this effect is more pronounced in red muscles, such as soleus, than in white muscles such as extensor digitorum longus (EDL). In the present study, the effect of T3 on the membrane potential (Em) and the intracellular activities of K+ and Na+ (aKi and aNai) in the two muscle types has been studied using microelectrodes. Hyperthyroidism was induced by seven subcutaneous injections of 50 μg T3 per 100 g body weight on alternate days. Following treatment of rats with T3, the mean T3 concentration in the serum was 8·4 ± 0·46 nmol/l (s.d.) compared with 1·1 ± 0·16 nmol/l in the serum of untreated control rats, and the heart weight/body weight ratio of the treated rats had increased from 0·29 ± 0·01 in control rats to 0·39 ± 0·02. In soleus muscle fibres from the T3-treated rats, the Em, aKi and aNai were unchanged, whereas, in EDL muscle fibres from these rats, the Em had depolarized by 2 mV (P<0·01) and aNai had increased by 2 mmol/l (P<0·05). Since T3 induces not only an increase in the number of pump units and active movement of Na+ and K+ but also an increase in the passive fluxes of these ions, the results are discussed in terms of these two opposing ionic movements. Journal of Endocrinology (1993) 138, 503–507

scholarly journals The passive mechanical properties of the extensor digitorum longus muscle are compromised in 2- to 20-mo-old mdx mice

2011 ◽  
Vol 110 (6) ◽  
pp. 1656-1663 ◽  
Author(s):  
Chady H. Hakim ◽  
Robert W. Grange ◽  
Dongsheng Duan
Keyword(s):  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Muscle Pathology ◽  
Mdx Mice ◽  
Myotendinous Junction ◽  
Muscle Rigidity ◽  
Dependent Manner ◽  
Stress Strain ◽  
Longus Muscle ◽  
Edl Muscle

Muscle rigidity and myotendinous junction (MTJ) deficiency contribute to immobilization in Duchenne muscular dystrophy (DMD), a lethal disease caused by the absence of dystrophin. However, little is known about the muscle passive properties and MTJ strength in a diseased muscle. Here, we hypothesize that dystrophin-deficient muscle pathology renders skeletal muscle stiffer and MTJ weaker. To test our hypothesis, we examined the passive properties of an intact noncontracting muscle-tendon unit in mdx mice, a mouse model for DMD. The extensor digitorum longus (EDL) muscle-tendon preparations of 2-, 6-, 14-, and 20-mo-old mdx and normal control mice were strained stepwisely from 110% to 160% of the muscle optimal length. The stress-strain response and failure position were analyzed. In support of our hypothesis, the mdx EDL preparation consistently developed higher stress before muscle failure. Postfailure stresses decreased dramatically in mdx but not normal preparations. Further, mdx showed a significantly faster stress relaxation rate. Consistent with stress-strain assay results, we observed significantly higher fibrosis in mdx muscle. In 2- and 6-mo-old mdx and 20-mo-old BL10 mice failure occurred within the muscle (2- to 14-mo-old BL10 preparations did not fail). Interestingly, in ≥14-mo-old mdx mice the failure site shifted toward the MTJ. Electron microscopy revealed substantial MTJ degeneration in aged but not young mdx mice. In summary, our results suggest that the passive properties of the EDL muscle and the strength of MTJ are compromised in mdx in an age-dependent manner. These findings offer new insights in studying DMD pathogenesis and developing novel therapies.

Impact of Diabetes on Microvascular PO2 and Tension in Rat Extensor Digitorum Longus (EDL) Muscle

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S222 ◽  
Author(s):  
Michael T. Paddock ◽  
Angela M. Ware ◽  
Carl E. Giacchi ◽  
William L. Sexton
Keyword(s):  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Edl Muscle

Properties of motor units in nerve-intact autografts of cat extensor digitorum longus muscles

1989 ◽  
Vol 62 (1) ◽  
pp. 231-238 ◽  
Author(s):  
T. G. Sandercock ◽  
C. Cote ◽  
J. A. Faulkner
Keyword(s):  
Extensor Digitorum Longus ◽  
Motor Units ◽  
Extensor Digitorum ◽  
Fatigue Properties ◽  
Specific Force ◽  
Mean Values ◽  
Control Value ◽  
Time To Peak ◽  
Significant Difference ◽  
Edl Muscle

1. In cats, isometric contractile properties were measured on five extensor digitorum longus (EDL) muscles and four EDL muscle grafts 150-270 days after autografting with nerves intact. Comparisons were made between the properties of whole muscles and grafts and between 36 motor units in control EDL muscles and 41 motor units in grafts. 2. The time-to-peak twitch force (TPT) of 23 +/- 1.7 (SE) ms for grafts was significantly prolonged compared with the value of 17 +/- 0.7 ms observed for whole EDL muscles. The mean values for the TPT of motor units were not different from the respective values for whole grafts or for whole muscles. The maximum specific force of whole grafts of 19.7 +/- 0.6 (SE) N/cm2 was significantly less than the control value of 23.6 +/- 0.6 N/cm2, an observation consistent with all previous data on the maximum specific force of grafts and control muscles. 3. Based on the presence or absence of sag and an index of fatigue, motor units were classified as fast fatigable (FF), fast intermediate (FI), fast fatigue-resistant (FR), and slow (S). Motor units were classified 33% FF, 22% FI, 27% FR, and 17% S in control muscles and 17% FF, 43% FI, 29% FR, and 12% S in autografted muscles. Compared with control muscles, the number of small FF units increased significantly in the autografts, but no significant difference was observed in the fatigue properties of motor units.(ABSTRACT TRUNCATED AT 250 WORDS)

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