Plasticity of skeletal muscle: regenerating fibers adapt more rapidly than surviving fibers

1987 ◽  
Vol 62 (6) ◽  
pp. 2507-2511 ◽  
Author(s):  
C. M. Donovan ◽  
J. A. Faulkner
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscles ◽  
Fiber Type ◽  
Motor Nerve ◽  
Mammalian Skeletal Muscle ◽  
Recipient Site ◽  
Muscle Graft ◽  
Donor Muscle ◽  
High Degree ◽  
Fast Muscles

The properties of mammalian skeletal muscle demonstrate a high degree of structural and functional plasticity as evidenced by their adaptability to an atypical site after cross-transplantation and to atypical innervation after cross-innervation. We tested the hypothesis that, regardless of fiber type, skeletal muscles composed of regenerating fibers adapt more readily than muscles composed of surviving fibers when placed in an atypical site with atypical innervation. Fast muscles of rats were autografted into the site of slow muscles or vice versa with the donor muscle innervated by the motor nerve to the recipient site. Surviving fibers in donor muscles were obtained by grafting with vasculature intact (vascularized muscle graft), and regenerating fibers were obtained by grafting with vasculature severed (free muscle graft). Our hypothesis was supported because 60 days after grafting, transposed muscles with surviving fibers demonstrated only a slight change from the contractile properties and fiber typing of donor muscles, whereas transplanted muscles with regenerating fibers demonstrated almost complete change to those of the muscle formerly in the atypical site.

The Adaptive Potential of Skeletal Muscle Fibers

2002 ◽  
Vol 27 (4) ◽  
pp. 423-448 ◽  
Author(s):  
Dirk Pette
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Protein Isoforms ◽  
Mammalian Skeletal Muscle ◽  
Adaptive Potential ◽  
Hybrid Fibers ◽  
Neuromuscular Activity ◽  
Skeletal Muscle Fibers ◽  
Initial Location

Mammalian skeletal muscle fibers display a great adaptive potential. This potential results from the ability of muscle fibers to adjust their molecular, functional, and metabolic properties in response to altered functional demands, such as changes in neuromuscular activity or mechanical loading. Adaptive changes in the expression of myofibrillar and other protein isoforms result in fiber type transitions. These transitions occur in a sequential order and encompass a spectrum of pure and hybrid fibers. Depending on the quality, intensity, and duration of the alterations in functional demand, muscle fibers may undergo functional transitions in the direction of slow or fast, as well as metabolic transitions in the direction of aerobic-oxidative or glycotytic. The maximum range of possible transitions in either direction depends on the fiber phenotype and is determined by its initial location in the fiber spectrum. Key words: Ca-sequestering proteins, energy metabolism, fiber type transition, myofibrillar protein isofonns, myosin, neuromuscular activity

Plasticity in mammalian skeletal muscle

1977 ◽  
Vol 278 (961) ◽  
pp. 295-305 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Peripheral Nerve ◽  
Motor Nerve ◽  
Contractile Proteins ◽  
Biochemical Changes ◽  
Muscle Fibres ◽  
Mammalian Skeletal Muscle ◽  
Motor Innervation ◽  
Nerve Impulses ◽  
Contractile Characteristics

While it has been recognized for many years that different limb muscles belonging to the same mammal may have markedly differing contractile characteristics, it is only comparatively recently that it has been demonstrated that these differences depend upon the motor innervation. By appropriately changing the peripheral nerve innervating a mammalian skeletal muscle, it is possible to change dramatically the contractile behaviour of the reinnervated muscle. The manner by which the motor innervation determines the nature of a muscle fibre’s contractile machinery is not completely understood, but it appears that the number and pattern of motor nerve impulses reaching the muscle play an important role. The biochemical changes occurring within muscle fibres whose contractile properties have been modified by altered motor innervation include the synthesis of different contractile proteins.

scholarly journals Muscle-Derived Extracellular Signal-Regulated Kinases 1 and 2 Are Required for the Maintenance of Adult Myofibers and Their Neuromuscular Junctions

2015 ◽  
Vol 35 (7) ◽  
pp. 1238-1253 ◽  
Author(s):  
Bonnie Seaberg ◽  
Gabrielle Henslee ◽  
Shuo Wang ◽  
Ximena Paez-Colasante ◽  
Gary E. Landreth ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Tibialis Anterior ◽  
Neuromuscular Junctions ◽  
Germ Line ◽  
Fiber Type ◽  
Postnatal Growth ◽  
Mammalian Skeletal Muscle ◽  
Neuromuscular Synapses ◽  
Extracellular Signal

The Ras–extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway appears to be important for the development, maintenance, aging, and pathology of mammalian skeletal muscle. Yet no gene targeting ofErk1/2in muscle fibersin vivohas been reported to date. We combined a germ lineErk1mutation with Cre-loxPErk2inactivation in skeletal muscle to produce, for the first time, mice lacking ERK1/2 selectively in skeletal myofibers. Animals lacking muscle ERK1/2 displayed stunted postnatal growth, muscle weakness, and a shorter life span. Their muscles examined in this study, sternomastoid and tibialis anterior, displayed fragmented neuromuscular synapses and a mixture of modest fiber atrophy and loss but failed to show major changes in fiber type composition or absence of cell surface dystrophin. Whereas the lack of only ERK1 had no effects on the phenotypes studied, the lack of myofiber ERK2 explained synaptic fragmentation in the sternomastoid but not the tibialis anterior and a decrease in the expression of the acetylcholine receptor (AChR) epsilon subunit gene mRNA in both muscles. A reduction in AChR protein was documented in line with the above mRNA results. Evidence of partial denervation was found in the sternomastoid but not the tibialis anterior. Thus, myofiber ERK1/2 are differentially required for the maintenance of myofibers and neuromuscular synapses in adult mice.

scholarly journals Differential distribution of ryanodine receptor type 3 (RyR3) gene product in mammalian skeletal muscles

1996 ◽  
Vol 316 (1) ◽  
pp. 19-23 ◽  
Author(s):  
Antonio CONTI ◽  
L. GORZA ◽  
Vincenzo SORRENTINO
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Gene Product ◽  
Skeletal Muscles ◽  
Mammalian Species ◽  
Diaphragm Muscle ◽  
Muscle Fibres ◽  
Abdominal Muscles ◽  
Mammalian Skeletal Muscle ◽  
Specific Subset

Activation of intracellular Ca2+-release channels/ryanodine receptors (RyRs) is a fundamental step in the regulation of muscle contraction. In mammalian skeletal muscle, Ca2+-release channels containing the type 1 isoform of RyR (RyR1) open to release Ca2+ from the sarcoplasmic reticulum (SR) upon stimulation by the voltage-activated dihydropyridine receptor on the T-tubule/plasma membrane. In addition to RyR1, low levels of the mRNA of the RyR3 isoform have been recently detected in mammalian skeletal muscles. Here we report data on the distribution of the RyR3 gene product in mammalian skeletal muscles. Western-blot analysis of SR of individual muscles indicated that, at variance with the even distribution of the RyR1 isoform, the RyR3 content varies among different muscles, with relatively higher amounts being detected in diaphragm and soleus, and lower levels in abdominal muscles and tibialis anterior. In these muscles RyR3 was localized in the terminal cisternae of the SR. No detectable levels of RyR3 were observed in the extensor digitorum longus. Preferential high content of RyR3 in the diaphragm muscle was observed in several mammalian species. In situ hybridization analysis demonstrated that RyR3 transcripts are not restricted to a specific subset of skeletal-muscle fibres. Differential utilization of the RyR3 isoform in skeletal muscle may be relevant to the modulation of Ca2+ release with respect to specific muscle-contraction properties.

Insulin binding to individual rat skeletal muscles

1990 ◽  
Vol 259 (4) ◽  
pp. E517-E523 ◽  
Author(s):  
D. J. Koerker ◽  
I. R. Sweet ◽  
D. G. Baskin
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Binding Sites ◽  
Skeletal Muscles ◽  
Dissociation Constants ◽  
Binding Capacity ◽  
Fiber Type ◽  
Insulin Binding ◽  
Computer Assisted ◽  
Hindlimb Muscles

Studies of insulin binding to skeletal muscle, performed using sarcolemmal membrane preparations or whole muscle incubations of mixed muscle or typical red (soleus, psoas) or white [extensor digitorum longus (EDL), gastrocnemius] muscle, have suggested that red muscle binds more insulin than white muscle. We have evaluated this hypothesis using cryostat sections of unfixed tissue to measure insulin binding in a broad range of skeletal muscles; many were of similar fiber-type profiles. Insulin binding per square millimeter of skeletal muscle slice was measured by autoradiography and computer-assisted densitometry. We found a 4.5-fold range in specific insulin tracer binding, with heart and predominantly slow-twitch oxidative muscles (SO) at the high end and the predominantly fast-twitch glycolytic (FG) muscles at the low end of the range. This pattern reflects insulin sensitivity. Evaluation of displacement curves for insulin binding yielded linear Scatchard plots. The dissociation constants varied over a ninefold range (0.26-2.06 nM). Binding capacity varied from 12.2 to 82.7 fmol/mm2. Neither binding parameter was correlated with fiber type or insulin sensitivity; e.g., among three muscles of similar fiber-type profile, the EDL had high numbers of low-affinity binding sites, whereas the quadriceps had low numbers of high-affinity sites. In summary, considerable heterogeneity in insulin binding was found among hindlimb muscles of the rat, which can be attributed to heterogeneity in binding affinities and the numbers of binding sites. It can be concluded that a given fiber type is not uniquely associated with a set of insulin binding parameters that result in high or low binding.

scholarly journals The long noncoding RNA MyHC IIA/X-AS contributes to skeletal muscle myogenesis and maintains the fast fiber phenotype

2020 ◽  
Vol 295 (15) ◽  
pp. 4937-4949 ◽  
Author(s):  
Mingle Dou ◽  
Ying Yao ◽  
Lu Ma ◽  
Xiaoyu Wang ◽  
Xin'e Shi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Skeletal Muscles ◽  
Fiber Type ◽  
Muscle Fiber Type ◽  
Fast Fiber ◽  
Slow Type ◽  
Myhc Expression

Mammalian skeletal muscles comprise different types of muscle fibers, and this muscle fiber heterogeneity is generally characterized by the expression of myosin heavy chain (MyHC) isoforms. A switch in MyHC expression leads to muscle fiber–type transition under various physiological and pathological conditions, but the underlying regulator coordinating the switch of MyHC expression remains largely unknown. Experiments reported in this study revealed the presence of a skeletal muscle–specific antisense transcript generated from the intergenic region between porcine MyHC IIa and IIx and is referred to here as MyHC IIA/X-AS. We found that MyHC IIA/X-AS is identified as a long noncoding RNA (lncRNA) that is strictly expressed in skeletal muscles and is predominantly distributed in the cytoplasm. Genetic analysis disclosed that MyHC IIA/X-AS stimulates cell cycle exit of skeletal satellite cells and their fusion into myotubes. Moreover, we observed that MyHC IIA/X-AS is more enriched in fast-twitch muscle and represses slow-type gene expression and thereby maintains the fast phenotype. Furthermore, we found that MyHC IIA/X-AS acts as a competing endogenous RNA that sponges microRNA-130b (miR-130b) and thereby maintains MyHC IIx expression and the fast fiber type. We also noted that miR-130b was proved to down-regulate MyHC IIx by directly targeting its 3′-UTR. Together, the results of our study uncovered a novel pathway, which revealed that lncRNA derived from the skeletal MyHC cluster could modulate local MyHC expression in trans, highlighting the role of lncRNAs in muscle fiber–type switching.

A comparison of the antidotal effects of three oximes against an organophosphate on chick skeletal muscle

2021 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Skeletal Muscles ◽  
Motor Nerve ◽  
Toxic Effects ◽  
Hi 6 ◽  
Msec Duration ◽  
Organophosphorus Poisoning ◽  
Pre Treatment ◽  
Nerve Muscle ◽  
Time Of Administration

Background: One of the most toxic effects of organophosphorus poisoning (OP) is the paralysis of skeletal muscles. The oximes are a group of available antidotes. This study investigated the effects of different concentrations of paraoxon on the function of skeletal muscle and reversal or prevention of these effects by three different oximes (i.e., pralidoxime, obidoxime, and HI-6). Materials and Methods: This study was conducted based on the chicken biventer cervices (CBC) nerve-muscle preparation and the use of twitch tension recording technique. The twitches of the CBC were evoked by stimulating the motor nerve at 0.1 Hz with pulses of 0.2 msec duration and a voltage greater than that required to produce the maximum response. Moreover, twitches and contractures were recorded isotonically using Grass Biosystems. Results: Paraoxon at 0.1 µM induced a significant increase (more than 100%) in the twitch amplitude, while higher concentrations (0.3 and 1µM) induced partial or total contracture. Therefore, paraoxon at a concentration of 0.1 µ M was used to examine the capability of oximes to prevent or reverse its effects. Pralidoxime, obidoxime, and HI-6 dose-dependently prevented (when it was used as pre-treatment, 20 min before or at the same time of administration of the toxin) and reversed (when it was used as post-treatment, 20 min after the administration of the toxin) the effect of paraoxon. Conclusion: In conclusion, these results revealed that oximes were very useful in the prevention and reversal of the OP toxic effects on the skeletal muscle. Moreover, it was suggested that oximes were more effective when used as pre-treatment. Pralidoxime was more potent than obidoxime and HI-6. The HI-6, which is a newer oxime, was unexpectedly less effective than the other two.

scholarly journals p38 MAPK in Glucose Metabolism of Skeletal Muscle: Beneficial or Harmful?

2020 ◽  
Vol 21 (18) ◽  
pp. 6480 ◽  
Author(s):  
Eyal Bengal ◽  
Sharon Aviram ◽  
Tony Hayek
Keyword(s):  
Skeletal Muscle ◽  
Metabolic Syndrome ◽  
Glucose Metabolism ◽  
P38 Mapk ◽  
Glucose Intolerance ◽  
Skeletal Muscles ◽  
Fiber Type ◽  
Caloric Intake ◽  
Mitogen Activated Protein Kinase ◽  
Metabolic Adaptation

Skeletal muscles respond to environmental and physiological changes by varying their size, fiber type, and metabolic properties. P38 mitogen-activated protein kinase (MAPK) is one of several signaling pathways that drive the metabolic adaptation of skeletal muscle to exercise. p38 MAPK also participates in the development of pathological traits resulting from excessive caloric intake and obesity that cause metabolic syndrome and type 2 diabetes (T2D). Whereas p38 MAPK increases insulin-independent glucose uptake and oxidative metabolism in muscles during exercise, it contrastingly mediates insulin resistance and glucose intolerance during metabolic syndrome development. This article provides an overview of the apparent contradicting roles of p38 MAPK in the adaptation of skeletal muscles to exercise and to pathological conditions leading to glucose intolerance and T2D. Here, we focus on the involvement of p38 MAPK in glucose metabolism of skeletal muscle, and discuss the possibility of targeting this pathway to prevent the development of T2D.

Induction and maintenance of increased VEGF protein by chronic motor nerve stimulation in skeletal muscle

1998 ◽  
Vol 274 (3) ◽  
pp. H860-H867 ◽  
Author(s):  
Brian H. Annex ◽  
Carol E. Torgan ◽  
Pengnian Lin ◽  
Doris A. Taylor ◽  
Michael A. Thompson ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Nerve Stimulation ◽  
Skeletal Muscles ◽  
Motor Nerve ◽  
Capillary Density ◽  
Endothelial Cell Proliferation ◽  
Vascular Density ◽  
Oxidative Phenotype ◽  
Vegf Protein

Vascular endothelial growth factor (VEGF) causes endothelial cell proliferation in vitro and angiogenesis in vivo. Glycolytic skeletal muscles have a lower capillary density than oxidative muscles but can increase their capillary density and convert to a more oxidative phenotype when subject to chronic motor nerve stimulation (CMNS). We used Western analysis and immunohistochemical techniques to examine VEGF protein in a rabbit CMNS model of glycolytic skeletal muscle and in muscles with innate glycolytic versus oxidative phenotypes. VEGF protein per gram of total protein was increased in stimulated vs. control muscles 2.9 ± 1.0, 3.6 ± 1.3, 3.1 ± 0.5, 4.4 ± 1.6, and 2.7 ± 0.3 times after 3 ( n = 4), 5 ( n = 2), 10 ( n = 3), 21 ( n = 3), and 56 ( n = 2) days, respectively. VEGF protein was increased 3.1 ± 0.5 times ( P < 0.005) before (3, 5, and 10 days) and remained elevated 3.7 ± 1.0 times ( P < 0.05) after (21 and 56 days) the transition to an oxidative phenotype. By immunohistochemistry, VEGF protein was found primarily in the matrix between stimulated muscle fibers but not in the myocytes. In addition, VEGF protein was consistently lower in innate glycolytic compared with oxidative muscles. These findings suggest that VEGF plays a role in the alteration and maintenance of vascular density in mammalian skeletal muscles.

scholarly journals Transient neonatal exposure to hyperoxia, an experimental model of preterm birth, leads to skeletal muscle atrophy and fiber type switching

2021 ◽  
Author(s):  
Alyson Deprez ◽  
Zakaria Orfi ◽  
Alexandra Radu ◽  
Ying He ◽  
Daniela Ravizzoni Dartora ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Preterm Birth ◽  
Exercise Capacity ◽  
Skeletal Muscles ◽  
Fiber Type ◽  
Female Rats ◽  
Male Rats ◽  
Antioxidant Defenses ◽  
Increased Risk ◽  
And Function

Individuals born preterm show reduced exercise capacity and increased risk for pulmonary and cardiovascular diseases, but the impact of preterm birth on skeletal muscle, an inherently critical part of cardiorespiratory fitness, remains unknown. We evaluated the impacts of preterm birth-related conditions on the development, growth, and function of skeletal muscle using a recognized preclinical rodent model in which newborn rats are exposed to 80% oxygen from day 3 to 10 of life. We analyzed different hindlimb muscles of male and female rats at 10 days (neonatal), 4 weeks (juvenile) and 16 weeks (young adults). Neonatal high oxygen exposure increased the generation of reactive oxygen species and the signs of inflammation in skeletal muscles, which was associated with muscle fiber atrophy, fiber type shifting (reduced proportion of type I slow fibers and increased proportion of type IIb fast-fatigable fibers), and impairment in muscle function. These effects were maintained until adulthood. Fast-twitch muscles were more vulnerable to the effects of hyperoxia than slow-twitch muscles. Male rats, which expressed lower antioxidant defenses, were more susceptible than females to oxygen-induced myopathy. Overall, preterm birth-related conditions have long-lasting effects on the composition, morphology, and function of skeletal muscles; and these effects are sex-specific. Oxygen-induced changes in skeletal muscles could contribute to the reduced exercise capacity and to increased risk of diseases of preterm born individuals.

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