The effect of a growth promoting drug, clenbuterol, on fibre frequency and area in hind limb muscles from young male rats

1986 ◽  
Vol 6 (3) ◽  
pp. 293-299 ◽  
Author(s):  
C. A. Maltin ◽  
M. I. Delday ◽  
P. J. Reeds
Keyword(s):  
Hind Limb ◽  
Extensor Digitorum Longus ◽  
Young Male ◽  
Extensor Digitorum ◽  
Male Rats ◽  
Cross Sectional ◽  
Limb Muscles ◽  
Fibre Number ◽  
Wet Weight ◽  
Growth Promoting

The effect of dietary administration of clenbuterol on soleus and extensor digitorum longus muscles was studied after 4 and 21 days. Both muscles showed an increase in wet weight with no significant change in total fibre number. After 4 days fibre cross-sectional areas were increased in soleus, but not in extensor digitorum longus, and after 21 days there was a change in fibre frequencies in extensor digitorum longus but not soleus muscles.

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 Early life undernutrition in rats

1982 ◽  
Vol 47 (3) ◽  
pp. 417-431 ◽  
Author(s):  
K. S. Bedi ◽  
A. R. Birzgalis ◽  
M. Mahon ◽  
J. L. Smart ◽  
A. C. Wareham
Keyword(s):  
Body Weight ◽  
Relative Frequency ◽  
Cross Sectional Area ◽  
Fibre Types ◽  
Male Rats ◽  
Sectional Area ◽  
Muscle Weight ◽  
Cross Sectional ◽  
Volume Proportion ◽  
Fibre Number

1. Male rats were undernourished either during the geslational and suckling periods or for a period of time immediately following weaning. Some rats were killed at the end of the period of undernutrition; others were nutritionally rehabilitated for lengthy periods of time before examination. Two muscles, the extensor digitorum longus (EDL) and soleus (SOL) were studied from each rat. Histochemically-stained transverse sections of these muscles were used to determine total number of fibres, the fibre cross-sectional areas and the relative frequency of the various fibre types.2. All rats killed immediately following undernutrition showed significant deficit sin body-weight, muscle weight and fibre cross-sectional area compared to age-matched controls.3. Animals undernourished during gestation and suckling and then fed normally for 5 months showed persistent and significant deficits in body-weight, muscle weight and total fibre number. There were also significant deficits in mean fibre cross-sectional area of each fibre type except for red fibres in the EDL. No difference in the volume proportion of connective tissue was found.4. Rats undernourished after weaning and then fed ad lib. for approximately 7 months had normal body-and muscle weights. Their muscles showed no significant differences in total fibre number, relative frequency of the various fibre types, fibre size or volume proportion of connective lissue.5. These results indicate that, although the effects on rat skeletal muscle of a period of undernutrition after weaning can be rectified, undernutrition before weaning causes lasting deficits.

scholarly journals The Effects of Calcium-β-Hydroxy-β-Methylbutyrate on Aging-Associated Apoptotic Signaling and Muscle Mass and Function in Unloaded but Nonatrophied Extensor Digitorum Longus Muscles of Aged Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Brian T. Bennett ◽  
Junaith S. Mohamed ◽  
Stephen E. Alway
Keyword(s):  
Muscle Mass ◽  
Satellite Cells ◽  
Muscle Function ◽  
Extensor Digitorum Longus ◽  
Cross Sectional Area ◽  
Extensor Digitorum ◽  
Aged Rats ◽  
Sectional Area ◽  
Cross Sectional ◽  
Apoptotic Signaling

Beta-hydroxy-beta-methylbutyrate (HMB), a naturally occurring leucine metabolite, has been shown to attenuate plantar flexor muscle loss and increase myogenic stem cell activation during reloading after a period of significant muscle wasting by disuse in old rodents. However, it was less clear if HMB would alter dorsiflexor muscle response to unloading or reloading when there was no significant atrophy that was induced by unloading. In this study, we tested if calcium HMB (Ca-HMB) would improve muscle function and alter apoptotic signaling in the extensor digitorum longus (EDL) of aged animals that were unloaded but did not undergo atrophy. The EDL muscle was unloaded for 14 days by hindlimb suspension (HS) in aged (34-36 mo.) male Fisher 344×Brown Norway rats. The rats were removed from HS and allowed normal cage ambulation for 14 days of reloading (R). Throughout the study, the rats were gavaged daily with 170 mg of Ca-HMB or water 7 days prior to HS, then throughout 14 days of HS and 14 days of recovery after removing HS. The animals’ body weights were significantly reduced by ~18% after 14 days of HS and continued to decline by ~22% during R as compared to control conditions; however, despite unloading, EDL did not atrophy by HS, nor did it increase in mass after R. No changes were observed in EDL twitch contraction time, force production, fatigue resistance, fiber cross-sectional area, or markers of nuclear apoptosis (myonuclei + satellite cells) after HS or R. While HS and R increased the proapoptotic Bax protein abundance, BCL-2 abundance was also increased as was the frequency of TUNEL-positive myonuclei and satellite cells, yet muscle mass and fiber cross-sectional area did not change and Ca-HMB treatment had no effect reducing apoptotic signaling. These data indicate that (i) increased apoptotic signaling preceded muscle atrophy or occurred without significant EDL atrophy and (ii) that Ca-HMB treatment did not improve EDL signaling, muscle mass, or muscle function in aged rats, when HS and R did not impact mass or function.

scholarly journals Different sensitivity of miniature endplate currents in rat external and internal intercostal muscles to the acetylcholinesterase inhibitor C-547 as compared with diaphragm and extensor digitorum longus

2009 ◽  
pp. 149-153
Author(s):  
K Petrov ◽  
I Kovyazina ◽  
V Zobov ◽  
E Bukharaeva ◽  
EE Nikolsky ◽  
...  
Keyword(s):  
Cholinesterase Inhibitor ◽  
Extensor Digitorum Longus ◽  
Acetylcholinesterase Inhibitor ◽  
Extensor Digitorum ◽  
Experimental Animals ◽  
Intercostal Muscles ◽  
Limb Muscles ◽  
Exercise Induced ◽  
28 Nm

Derivative of 6-methyluracil, selective cholinesterase inhibitor C547 potentiates miniature endplate currents (MEPCs) in rat external intercostal muscles (external ICM) more effectively than in internal intercostal muscles (internal ICM). Effect of the C-547 on intercostal muscles was compared with those on extensor digitorum longus (EDL) and diaphragm muscles. Half-effective concentrations for τ of MEPC decay arranged in increasing order were as follows: EDL, locomotor muscle, most sensitive = 1.3 nM, external ICM, inspiration muscle = 6.8 nM, diaphragm, main inspiration muscle = 28 nM, internal ICM, expiration muscle = 71 nM. External ICM might therefore be inhibited, similarly as the limb muscles, by nanomolar concentrations of the drug and do not participate in inspiration in the presence of the C-547. Moreover, internal ICM inhibition can hinder the expiration during exercise-induced fast breathing of C-547- treated experimental animals.

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.

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 Carbonic anhydrase activity in skeletal muscle fiber types, axons, spindles, and capillaries of rat soleus and extensor digitorum longus muscles.

1982 ◽  
Vol 30 (12) ◽  
pp. 1275-1288 ◽  
Author(s):  
D A Riley ◽  
S Ellis ◽  
J Bain
Keyword(s):  
Carbonic Anhydrase ◽  
Extensor Digitorum Longus ◽  
Muscle Fibers ◽  
Extensor Digitorum ◽  
Female Rats ◽  
Male Rats ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Slow Twitch ◽  
Fast Twitch

Carbonic anhydrase (CA) activities were studied in soluble extracts and cryostat sections of skeletal muscles from prepubertal and postpubertal rats. Acetazolamide inhibition was utilized to distinguish between activities of the acetazolamide-sensitive (CA I and II) and acetazolamide-resistant (CA III) forms of the enzyme. The inhibition studies indicated that fast-twitch oxidative-glycolytic muscle fibers contained both the sensitive and resistant forms of CA. Acetazolamide-sensitive activity was localized within muscle fibers, axons, myelin, and capillaries. Axoplasmic staining was restricted to subpopulations of myelinated axons in both the dorsal and ventral roots. Soleus muscles exhibited significantly greater activity of CA III than extensor digitorum longus muscles at all ages examined. CA III was richest in slow-twitch oxidative and intrafusal fibers. During puberty, soleus muscle fibers matured and converted from fast-twitch oxidative-glycolytic to slow-twitch oxidative fibers. There was a shift from the sensitive to the resistant form of CA; CA III activity increased about sevenfold. This activity peaked earlier in the muscles of female rats than male rats. These results demonstrated a complex distribution of CA isozymes in the neuromuscular system and pointed out that isozyme content depends on both the type of muscle and the age and sex of the animal.

Clenbuterol, a beta 2-agonist, retards atrophy in denervated muscles

1987 ◽  
Vol 252 (1) ◽  
pp. E152-E155 ◽  
Author(s):  
R. J. Zeman ◽  
R. Ludemann ◽  
J. D. Etlinger
Keyword(s):  
Extensor Digitorum Longus ◽  
Neuromuscular Diseases ◽  
Extensor Digitorum ◽  
Disuse Atrophy ◽  
Denervated Muscle ◽  
Cross Sectional ◽  
Beta 2 ◽  
Denervated Muscles ◽  
Gastrocnemius Muscles ◽  
Anterior Tibialis

Denervated soleus, anterior tibialis, and gastrocnemius muscles, but not the extensor digitorum longus, contained 95–110% more protein after 2–3 wk of treatment with the adrenergic beta 2-receptor agonist, clenbuterol, than denervated controls. In addition, the twofold difference in the protein content of denervated solei was paralleled by similar changes in contractile strength and muscle fiber cross-sectional area. In contrast, when the innervated contralateral muscles were examined, the extensor digitorum longus and anterior tibialis showed relatively small increases in protein of 32 and 19%, respectively, whereas the soleus and gastrocnemius were unaffected. The magnitude of the effects of clenbuterol in sparing the mass and functional capacity of denervated muscle suggests that this agent may be important in studies of neuromuscular diseases and disuse atrophy.

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.

Rat locomotory muscle fiber activity during trotting and galloping

1978 ◽  
Vol 44 (3) ◽  
pp. 358-363 ◽  
Author(s):  
T. E. Sullivan ◽  
R. B. Armstrong
Keyword(s):  
Rattus Norvegicus ◽  
Hind Limb ◽  
Fiber Type ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Glycogen Depletion ◽  
Active Muscle ◽  
Cross Sectional ◽  
Limb Muscles ◽  
Whole Muscle

This study was designed to investigate the hypothesis that the trot-gallop transition in running guadrupeds occurs when active cross-sectional areas of muscles or fiber populations within muscles, reach some critical point as animals increase speed within trotting. Rats (Rattus norvegicus) were used as experimental animals, and glycogen depletion was used to estimate patterns or fiber activity. Our results indicate that 1) the contribution to power output by the front limb muscles was less than that of the hind limb muscles during trotting and galloping; 2) the active cross-sectional area of plantaris muscles peaked immediately prior to the transition in gait; 3) the ankle plantar flexor group of muscles as a whole did not attain a maximum active cross-sectional area during fast trotting; and 4) no major discontinuities in whole muscle or fiber type glycogen depletion rates occurred across the gait change. Although these findings do not prove the hypothesis, they support the concept that the trop-gallop transition follows the attainment of peak active muscle cross-sectional areas as animals increase trotting speed.

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