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.

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.

scholarly journals Early life undernutrition in rats

1982 ◽  
Vol 47 (3) ◽  
pp. 433-437 ◽  
Author(s):  
A. C. Wareham ◽  
M. Mahon ◽  
K.S Bedi ◽  
J. L. Smart
Keyword(s):  
Body Weight ◽  
Early Life ◽  
Extensor Digitorum Longus ◽  
Contractile Properties ◽  
Extensor Digitorum ◽  
Unit Weight ◽  
Pregnancy And Lactation ◽  
Wet Weight ◽  
Whole Muscle

1. The contractile properties of soleus and extensor digitorum longus muscles from animals at 12 months of age whose mothers had been undernourished during pregnancy and lactation (PU rats) have been compared with those of muscles from age-matched controls.2. Body-weight and muscle wet weight of PU rats was significantly reduced. Muscle: body-weight values were, however, no different from controls.3. No significant alterations in whole muscle speeds of contraction or relaxation could be delected when compared with those of age-matched controls.4. Twitch and tetanic forces of both SOL and EDL were greater per unit weight of muscle in PU rats. Apart from SOL twitch these differences were significant. The tetanus:twitch values were, however, not different.

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.

Muscular enlargement and number of fibers in skeletal muscles of rats

1981 ◽  
Vol 50 (5) ◽  
pp. 936-943 ◽  
Author(s):  
P. D. Gollnick ◽  
B. F. Timson ◽  
R. L. Moore ◽  
M. Riedy
Keyword(s):  
Skeletal Muscles ◽  
Extensor Digitorum Longus ◽  
Dry Weight ◽  
Extensor Digitorum ◽  
Surgical Ablation ◽  
Fiber Number ◽  
Wet Weight ◽  
The Difference ◽  
Total Muscle ◽  
Direct Counts

The effect of muscular enlargement produced by surgical ablation of a synergist and the combination of synergist ablation and exercise on the number of fibers in the soleus (S), plantaris (P), and extensor digitorum longus (EDL) muscles of the rat was studied. The number of fibers per muscle was determined by direct counts of individual fibers dissected from HNO3-treated muscles. Ablation of a synergist produced average enlargements of about 25, 45, and 29% for the S, P, and EDL muscles, respectively. Exercise and synergist ablation produced increases in wet weight to about 44 and 88% for the S and P muscles, respectively, whereas no further increases were observed in the EDL muscles. Intra-animal comparisons revealed that no differences existed for total fiber number or the incidence of fibers with bifurcations between the enlarged and contralateral control muscles. The difference in dry weight of fibers from the enlarged as compared with control muscles was closely correlated to differences in total muscle wet weight. These data demonstrate that hypertrophy rather than hyperplasia was responsible for increases from 10 to over 100% in the weight of skeletal muscles.

Effects of fatigue and recovery on contractile properties of frog muscle

1978 ◽  
Vol 45 (6) ◽  
pp. 899-902 ◽  
Author(s):  
R. H. Fitts ◽  
J. O. Holloszy
Keyword(s):  
Frog Muscle ◽  
Contractile Properties ◽  
Contraction Time ◽  
Anaerobic Conditions ◽  
Initial Value ◽  
Shortening Velocity ◽  
Tension Development ◽  
Generating Capacity ◽  
Frog Sartorius ◽  
Tetanic Tension

The contractile properties of frog sartorius muscles were evaluated during development of fatigue and recovery. Muscles were stimulated under anaerobic conditions at a rate of 30 stimuli/min. Twitch tension (Pt) decreased 59% and tetanic tension (Po) decreased 52% during 15 min of stimulation. Contraction time and one-half relaxation time increased markedly during the first 6 min and then leveld off. The peak rate of twitch tension development (dP/dt) progressively declined to 33% of its initial value. Maximum shortening velocity did not change significantly. Large increases in Pt and twitch dP/dt occurred during the first 15 s of recovery while Po did not increase significantly in this time. Thereafter, Pt, Po, and, dP/dt all progressively returned towards normal over 30 min. These results show that the initial rapid recovery in Pt is not due to an increase in the capacity to generate force. Po is a better indicator of the force-generating capacity of a muscle because, unlike Pt, it is not affected by changes in the rate of tension development.

Influence of spaceflight on rat skeletal muscle

1988 ◽  
Vol 65 (5) ◽  
pp. 2318-2325 ◽  
Author(s):  
T. P. Martin ◽  
V. R. Edgerton ◽  
R. E. Grindeland
Keyword(s):  
Atpase Activity ◽  
Extensor Digitorum Longus ◽  
Extensor Digitorum ◽  
Medial Gastrocnemius ◽  
Male Rats ◽  
Cross Sectional ◽  
Hindlimb Muscles ◽  
Wet Weight ◽  
Flight Muscles ◽  
Loss Of Mass

The size, succinate dehydrogenase (SDH) and alpha-glycerolphosphate dehydrogenase (GPD) activities, and alkaline myofibrillar adenosinetriphosphatase (ATPase) staining properties were determined from quantitative histochemical analyses of single fibers from five hindlimb muscles of six male rats exposed to a 7-day National Aeronautics and Space Administration spaceflight mission (SL-3). These same properties were determined in a group of ground-based control rats housed under simulated environmental conditions. The wet weight of each of the flight muscles was significantly reduced relative to control. However, the loss of mass varied from 36% in the soleus to 15% in the extensor digitorum longus. The cross-sectional areas of fibers in the flight muscles also were reduced, except for the dark ATPase fibers in the medial gastrocnemius. The greatest relative fiber atrophy occurred in the muscles with the highest proportion of light ATPase fibers. An increase in the percentage of dark ATPase fibers also was observed in flight muscles with a predominance of light ATPase fibers. Also, there was an increase in the biochemically determined myofibrillar ATPase activity of tissue sections of the flight soleus. No changes in histochemical or biochemical measures of ATPase activity were observed in the flight extensor digitorum longus. In general, the SDH activity of flight muscles was maintained, whereas GPD activity either was maintained or increased. Based on a metabolic profile of ATPase, SDH, and GPD, there was an increase in the proportion of fast oxidative-glycolytic fibers in some muscles.

scholarly journals Morphological observations and rates of protein synthesis in rat muscles incubated in vitro

1985 ◽  
Vol 232 (3) ◽  
pp. 927-930 ◽  
Author(s):  
C A Maltin ◽  
C I Harris
Keyword(s):  
Protein Synthesis ◽  
Extensor Digitorum Longus ◽  
Marked Decrease ◽  
Extensor Digitorum ◽  
Central Core ◽  
Phosphorylase Activity ◽  
Glucan Phosphorylase ◽  
Isolated Rat

Isolated soleus and extensor digitorum longus muscles from small (40 or 70 g) rats developed a central and substantial (13-57%) loss of glycogen and alpha-glucan phosphorylase activity after incubation for up to 2 h in vitro. The central ‘core’ of the muscles showed a marked decrease in the rate of protein synthesis. It is suggested that during brief periods of incubation the central core of isolated rat muscles becomes hypoxic, and that consequently the viability of such muscles must be in question.

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