CONTRACTILE PROPERTIES AND ULTRASTRUCTURE OF EXTENSOR DIGITORUM LONGUS AND SOLEUS MUSCLES IN SPINAL CORD TRANSECTED RATS

1981 ◽  
Vol 59 (4) ◽  
pp. 393-404 ◽  
Author(s):  
DF Davey ◽  
C Dunlop ◽  
JFY Hoh ◽  
SYP Wong
Keyword(s):  
Spinal Cord ◽  
Extensor Digitorum Longus ◽  
Contractile Properties ◽  
Extensor Digitorum

Effects of endurance exercise-training on single-fiber contractile properties of insulin-treated streptozotocin-induced diabetic rats

2005 ◽  
Vol 99 (2) ◽  
pp. 472-478 ◽  
Author(s):  
Otto A. Sanchez ◽  
LeAnn M. Snow ◽  
Dawn A. Lowe ◽  
Robert C. Serfass ◽  
LaDora V. Thompson
Keyword(s):  
Exercise Training ◽  
Endurance Exercise ◽  
Extensor Digitorum Longus ◽  
Diabetic Rats ◽  
Contractile Properties ◽  
Extensor Digitorum ◽  
Single Fiber ◽  
Moderate Intensity ◽  
Specific Tension ◽  
Endurance Exercise Training

The purpose of this study was to characterize the contractile properties of individual skinned muscle fibers from insulin-treated streptozotocin-induced diabetic rats after an endurance exercise training program. We hypothesized that single-fiber contractile function would decrease in the diabetic sedentary rats and that endurance exercise would preserve the function. In the study, 28 rats were assigned to either a nondiabetic sedentary, a nondiabetic exercise, a diabetic sedentary, or a diabetic exercise group. Rats in the diabetic groups received subcutaneous intermediate-lasting insulin daily. The exercise-trained rats ran on a treadmill at a moderate intensity for 60 min, five times per week. After 12 wk, the extensor digitorum longus and soleus muscles were dissected. Single-fiber diameter, Ca2+-activated peak force, specific tension, activation threshold, and pCa50 as well as the myosin heavy chain isoform expression (MHC) were determined. We found that in MHC type II fibers from extensor digitorum longus muscle, diameters were significantly smaller from diabetic sedentary rats compared with nondiabetic sedentary rats ( P < 0.001). Among the nondiabetic rats, fiber diameters were smaller with exercise ( P = 0.038). The absolute force-generating capacity of single fibers was lower in muscles from diabetic rats. There was greater specific tension (force normalized to cross-sectional area) by fibers from the rats that followed an endurance exercise program compared with sedentary. From the results, we conclude that alterations in the properties of contractile proteins are not implicated in the decrease in strength associated with diabetes and that endurance-exercise training does not prevent or increase muscle weakness in diabetic rats.

Changes in isometric contractile properties of extensor digitorum longus and soleus muscles of C57BL/6J mice following denervation

1985 ◽  
Vol 63 (6) ◽  
pp. 681-686 ◽  
Author(s):  
D. M. S. Webster ◽  
B. H. Bressler
Keyword(s):  
Extensor Digitorum Longus ◽  
Marked Decrease ◽  
Age Groups ◽  
Contractile Properties ◽  
Extensor Digitorum ◽  
Contraction Time ◽  
Normal Response ◽  
Time To Peak ◽  
Generating Capacity ◽  
Wet Weight

In this study, conducted on mice of the C57BL/6J+/+ strain, we investigated the differential effects of denervation on the isometric contractile properties of the extensor digitorum longus (EDL) and soleus (SOL) muscles. The contractile properties were studied at 1, 28, 84, and 210 days following unilateral section of the sciatic nerve at 12 weeks of age. When isometric tetanus tension was expressed relative to wet weight, the denervated SOL showed an earlier and more pronounced loss in tension generating capacity than the EDL. Both the denervated SOL and EDL showed potentiation of the twitch tension at 28 days postdenervation. The time to peak twitch tension (TTP) and the time to half-relaxation (1/2RT) were prolonged by 28 days postdenervation in both muscles. This trend continued to the oldest age-groups studied in the EDL, but reached an apparent plateau in the SOL at 84 days postdenervation. In response to fatigue, the denervated SOL showed a marked decrease in resistance to fatigue at 1 day but a relatively normal response thereafter, whereas the denervated EDL showed an increase in resistance to fatigue at and beyond the 28-day period. In spite of the fact that the total contraction time of both muscles increased following denervation, the predominantly oxidative SOL remained a slower contracting muscle than the more glycolytic EDL.

scholarly journals Effects of Chronic Administration of Clenbuterol on Contractile Properties and Calcium Homeostasis in Rat Extensor Digitorum Longus Muscle

PLoS ONE ◽  
2014 ◽  
Vol 9 (6) ◽  
pp. e100281 ◽  
Author(s):  
Pascal Sirvent ◽  
Aymerick Douillard ◽  
Olivier Galbes ◽  
Christelle Ramonatxo ◽  
Guillaume Py ◽  
...  
Keyword(s):  
Calcium Homeostasis ◽  
Extensor Digitorum Longus ◽  
Chronic Administration ◽  
Extensor Digitorum Longus Muscle ◽  
Contractile Properties ◽  
Extensor Digitorum ◽  
Longus Muscle

Contractile properties of single-skinned skeletal muscle fibres of the extensor digitorum longus muscle of the Australian short-nosed echidna

2005 ◽  
Vol 53 (4) ◽  
pp. 237
Author(s):  
Anthony J. Bakker ◽  
Ann L. Parkinson ◽  
Stewart I. Head
Keyword(s):  
Skeletal Muscle ◽  
Extensor Digitorum Longus ◽  
Contractile Properties ◽  
Extensor Digitorum ◽  
Muscle Fibres ◽  
Force Response ◽  
Response Data ◽  
The Mean ◽  
Fast Twitch ◽  
Skeletal Muscle Fibres

Eutherian mammal fast-twitch muscle fibres share similar contractile activation properties, suggesting that these properties are highly conserved in mammals. To investigate this hypothesis, we examined the contractile properties of skeletal muscle from the order Monotremata, a mammalian order that separated from eutherians 150 million years ago. The Ca2+- and Sr2+-activation properties of single mechanically skinned skeletal muscle fibres from the extensor digitorum longus (EDL) muscle of the short-nosed echidna were determined. Sigmoidal curves fitted to force response data plotted as a function of pCa (–log[Ca2+]), had a mean slope of 4.32 ± 0.28 and a mean pCa50 and pCa10 value of 6.18 ± 0.01 and 6.41 ± 0.02 respectively (n = 20). The mean pSr50, pSr10 and slope values of curves fitted to the force-response data after activation with Sr2+ were 4.80 ± 0.03, 5.29 ± 0.07 and 2.75 ± 0.18 respectively (n = 20). The mean pCa50–pSr50 value for the echidna EDL fibres was 1.37 ± 0.04. In five of the echidna fibres, exposure to submaximal Ca2+ concentrations produced myofibrillar force oscillations (mean frequency, 0.13 ± 0.01 Hz), a phenomenon found only in eutherian slow and intermediate muscle fibres. These results show that echidna EDL fibres generally have similar contractile properties to eutherian fast-twitch skeletal muscle fibres, such as those found in the EDL of the rat.

Contractile properties of transplanted extensor digitorum longus muscles of cats

1980 ◽  
Vol 238 (3) ◽  
pp. C120-C126 ◽  
Author(s):  
J. A. Faulkner ◽  
J. H. Niemeyer ◽  
L. C. Maxwell ◽  
T. P. White
Keyword(s):  
Time Course ◽  
Extensor Digitorum Longus ◽  
Autologous Transplantation ◽  
Relaxation Times ◽  
Contractile Properties ◽  
Extensor Digitorum ◽  
Cross Sectional ◽  
Control Value ◽  
Time To Peak ◽  
Significant Difference

Following autologous transplantation of whole extensor digitorum longus (EDL) muscles of cats into the EDL site, we investigated the degree and time course of restoration of contractile properties of autografts toward control values. Isometric and isotonic contractile properties of 66 autografted EDL muscles were measured in situ from 40 to 440 days following transplantation. The control value for maximum tetanus tension (P0) was 27 N. The mean P0 for the autografts increased from 2% of control 40 days after transplantation to 26% 440 days after transplantation. When P0 was normalized per square centimeter of muscle fiber cross-sectional area, no significant difference was observed between the P0 of autografts (28 N/cm2) and controls. Compared to controls, autografts 40-179 days following transplantation had slower time to peak twitch tensions, half-relaxation times, and maximum velocities of shortening and smaller twitch-tetanus tension ratios. Between 180 and 440 days after transplantation, values for autografts approached control values. Autografts fatigued more than twice as rapidly as controls.

The effect of glutamine on locomotor performance and skeletal muscle myosins following spinal cord injury in rats

2006 ◽  
Vol 101 (4) ◽  
pp. 1045-1052 ◽  
Author(s):  
Jamie D. Golding ◽  
Sarah T. Rigley MacDonald ◽  
Bernhard H. J. Juurlink ◽  
Benjamin W. C. Rosser
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Functional Recovery ◽  
Extensor Digitorum Longus ◽  
Critical Role ◽  
Extensor Digitorum ◽  
Secondary Injury ◽  
Significant Difference ◽  
Cord Injury ◽  
Functional Scores

Following initial spinal cord injury (SCI), a cascade of pathological events, including oxidative stress, leads to secondary injury. Glutathione (GSH) plays a critical role in oxidant scavenging. Maintenance of GSH concentrations after SCI lessens secondary injury and improves recovery. Since glutamine promotes GSH synthesis, this nonessential amino acid was examined for therapeutic potential. Denervation alters the expression of myosin heavy chain (MHC) isoforms within skeletal muscles. The hypotheses of this study were that glutamine administration to SCI rats would lead to improved functional recovery and more preserved MHC phenotypes in representative locomotor muscles. Male Wistar rats were divided into four groups: healthy, sham with laminectomy, laminectomized SCI untreated, and laminectomized SCI treated with glutamine. Functional performance was measured weekly for 6 wk using Basso-Beattie-Bresnahan scale and angle board methods. MHC composition of rat soleus and extensor digitorum longus muscles was determined using SDS-PAGE. Glutamine-treated rats had significantly higher angle board scores ( P < 0.001) and Basso-Beattie-Bresnahan scores ( P < 0.01) than untreated SCI rats. Soleus of healthy rats contained 94% type 1 myosin isoform. Treated rats maintained 68%, which was significantly ( P < 0.001) greater than 28% in untreated rats. The extensor digitorum longus of healthy rats contained 55% type 2b myosin. There was a significant ( P < 0.001) decrease in this isoform following SCI, but no significant difference between treated and untreated groups. There were strong correlations between higher functional scores and more preserved MHC phenotypes. Our findings suggest glutamine improves functional recovery and helps preserve myosin profile by reducing secondary SCI, thereby maintaining more nerves.

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