Mosaic lectin and enzyme staining patterns in rat skeletal muscle.

We compared the localizations of lectin binding and activity for myosin ATPase and succinic dehydrogenase in sections of the gracilis, soleus, and masseter muscles from 10- and 60-day-old rats. In the 60-day-old rats, incubation of the muscle sections with the lectins ConA, GS-II, HPA, and jacalin gave rise to a mosaic staining pattern, especially in the gracilis muscle, in which the same fibers were strongly stained for ConA, GS-II, and HPA, whereas the staining with jacalin in these fibers was weak, and vice versa. There was no correspondence in the staining patterns for the enzymes and the lectins. In the masseter muscle only GS-II gave rise to distinct differences in the staining intensity between muscle fibers. In 10-day-old rats all fibers in the muscles were moderately stained with ConA, HPA, and jacalin, whereas a chessboard staining pattern could be observed after incubation with GS-II. In an extract of hindleg muscle from 60-day-old rats there was strong affinity for ConA and HPA and weak affinity for GS-II and jacalin, as shown by dot-blotting. After electrophoresis and blotting to nitrocellulose membranes, three muscle protein bands with apparent molecular weights of 100,000, 90,000, and 43,000 showed affinity for ConA, HPA, and GS-II, whereas no bands were jacalin positive. The complex lectin staining pattern in skeletal muscle might be related to development, specialization, and function of the muscles.

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Adaptation to prolonged starvation in the rat: curtailment of skeletal muscle proteolysis

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1981.241.4.e321 ◽

1981 ◽

Vol 241 (4) ◽

pp. E321-E327 ◽

Cited By ~ 10

Author(s):

M. N. Goodman ◽

M. A. McElaney ◽

N. B. Ruderman

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Early Event ◽

Body Protein ◽

Fed State ◽

Prolonged Starvation ◽

Obese Rats ◽

Old Rats

Previous studies have established that 16-wk-old nonobese and obese rats conserve body protein during prolonged starvation. To determine the basis for this, protein synthesis and degradation in skeletal muscle were evaluated in the isolated perfused hindquarters of these rats, in the fed state and when starved for 2, 5, 10, and 11 days. Rats aged 4 and 8 wk were used as a comparison. The results indicate that the response to starvation depends on several factors: the age of the rat, its degree of adiposity, and the duration of the fast. An early event in starvation was a decline in muscle protein synthesis. This occurred in all groups, albeit this reduction occurred more slowly in the older rats. A later response to starvation was an increase in muscle proteolysis. This occurred between 2 and 5 days in the 8-wk-old rats. In 16-wk-old rats it did not occur until between 5 and 10 days, and it was preceded by a period of decreased proteolysis. In 16-wk-old obese rats, a decrease in proteolysis persisted for upwards of 10 days and the secondary increase was not noted during the period of study. The data suggest that the ability of older and more obese rats to conserve body protein during starvation is due, in part, to a curtailment of muscle proteolysis. This adaptation seems to correlate with the availability of lipid fuels.

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Aging and acute exercise enhance free radical generation in rat skeletal muscle

Journal of Applied Physiology ◽

10.1152/jappl.1999.87.1.465 ◽

1999 ◽

Vol 87 (1) ◽

pp. 465-470 ◽

Cited By ~ 296

Author(s):

J. Bejma ◽

L. L. Ji

Keyword(s):

Skeletal Muscle ◽

Lipid Peroxidation ◽

Acute Exercise ◽

Muscle Protein ◽

Vastus Lateralis ◽

Age Groups ◽

Protein Carbonyl ◽

Biological Aging ◽

Young Rats ◽

Old Rats

Reactive oxygen species (ROS) are implicated in the mechanism of biological aging and exercise-induced oxidative damage. The present study examined the effect of an acute bout of exercise on intracellular ROS production, lipid and protein peroxidation, and GSH status in the skeletal muscle of young adult (8 mo, n = 24) and old (24 mo, n = 24) female Fischer 344 rats. Young rats ran on a treadmill at 25 m/min and 5% grade until exhaustion (55.4 ± 2.7 min), whereas old rats ran at 15 m/min and 5% grade until exhaustion (58.0 ± 2.7 min). Rate of dichlorofluorescin (DCFH) oxidation, an indication of ROS and other intracellular oxidants production in the homogenate of deep vastus lateralis, was 77% ( P < 0.01) higher in rested old vs. young rats. Exercise increased DCFH oxidation by 38% ( P < 0.09) and 50% ( P < 0.01) in the young and old rats, respectively. DCFH oxidation in isolated deep vastus lateralis mitochondria with site 1 substrates was elevated by 57% ( P < 0.01) in old vs. young rats but was unaltered with exercise. Significantly higher DCFH oxidation rate was also found in aged-muscle mitochondria ( P < 0.01), but not in homogenates, when ADP, NADPH, and Fe3+ were included in the assay medium without substrates. Lipid peroxidation in muscle measured by malondialdehyde content showed no age effect, but was increased by 20% ( P < 0.05) with exercise in both young and old rats. Muscle protein carbonyl formation was unaffected by either age or exercise. Mitochondrial GSH/ GSSG ratio was significantly higher in aged vs. young rats ( P < 0.05), whereas exercise increased GSSG content and decreased GSH/GSSG in both age groups ( P < 0.05). These data provided direct evidence that oxidant production in skeletal muscle is increased in old age and during prolonged exercise, with both mitochondrial respiratory chain and NADPH oxidase as potential sources. The alterations of muscle lipid peroxidation and mitochondrial GSH status were consistent with these conclusions.

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Trophic effects of skeletal muscle extracts on ventral spinal cord neurons in vitro: separation of a protein with morphologic activity from proteins with cholinergic activity.

The Journal of Cell Biology ◽

10.1083/jcb.101.4.1608 ◽

1985 ◽

Vol 101 (4) ◽

pp. 1608-1621 ◽

Cited By ~ 51

Author(s):

R G Smith ◽

J McManaman ◽

S H Appel

Keyword(s):

Skeletal Muscle ◽

Spinal Cord ◽

Lectin Binding ◽

Neurite Growth ◽

Factor Activity ◽

Spinal Cord Neurons ◽

Acetylcholine Synthesis ◽

Molecular Weights ◽

Multiple Species

Protein factors derived from skeletal muscle separately promote neurite elongation and acetylcholine synthesis in cultured rat ventral spinal neurons. Morphologic factor activity (neurite-inducing activity) is specifically found in rat skeletal muscle and cord neuron extracts, decreases with the postnatal age of the rats from which muscle extract is prepared, and increases in rat hindlimb muscle after 5 d of denervation. Cholinergic factor activity (acetylcholine synthesis-stimulating activity) is found in extracts of rat cerebral cortex and cardiac muscle in addition to spinal cord and skeletal muscle, increases with animal age, and decreases following 5 d of denervation. Biochemically, the factors responsible for these activities differ in their lability to denaturing conditions, apparent molecular weights, isoelectric points, and lectin-binding specificities. Under reducing conditions, morphologic activity is isolated in a single acidic glycoprotein with an Mr of 35,000, while acetylcholine synthesis-stimulating activity is found in multiple species of different molecular weights. Thus, acetylcholine synthesis-promoting activities and neurite growth-promoting activity appear to reside in different molecules. Significant purification of several of these factors has been achieved.

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Protein catabolism and impairment of skeletal muscle insulin signalling in heart failure

Clinical Science ◽

10.1042/cs20100363 ◽

2010 ◽

Vol 119 (11) ◽

pp. 465-466 ◽

Cited By ~ 2

Author(s):

P. Christian Schulze

Keyword(s):

Heart Failure ◽

Skeletal Muscle ◽

Muscle Protein ◽

Insulin Signalling ◽

Muscle Metabolism ◽

Exercise Intolerance ◽

Skeletal Muscle Protein ◽

Glucose And Lipid Metabolism ◽

Muscle Protein Metabolism ◽

And Function

Derangements in systemic and local metabolism develop in patients with CHF [chronic HF (heart failure)] and contribute to the progression of the disease. Impaired skeletal muscle metabolism, morphology and function leading to exercise intolerance are hallmarks of the syndrome of CHF. These changes result in abnormal glucose and lipid metabolism, and the associated insulin resistance, which contribute to progression of skeletal muscle catabolism and development of muscle atrophy in patients with advanced HF. In the present issue of Clinical Science, Toth and co-workers demonstrate the impairment of skeletal muscle protein metabolism in patients with HF, and specifically show an impaired anabolic response in the skeletal muscle of these patients following a period of nutritional deficiency.

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Skeletal muscle protein synthesis in adult and old rats

Reproduction Nutrition Development ◽

10.1051/rnd:19990134 ◽

1999 ◽

Vol 39 (1) ◽

pp. 98-99

Author(s):

I. Savary ◽

D. Dardevet ◽

E. Debras ◽

C. Sornet ◽

P. Patureau Mirand ◽

...

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Skeletal Muscle Protein ◽

Skeletal Muscle Protein Synthesis ◽

Old Rats

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Anabolic Properties of Mixed Wheat-Legume Pasta Products in Old Rats: Impact on Whole-Body Protein Retention and Skeletal Muscle Protein Synthesis

Nutrients ◽

10.3390/nu12061596 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1596 ◽

Cited By ~ 1

Author(s):

Insaf Berrazaga ◽

Jérôme Salles ◽

Karima Laleg ◽

Christelle Guillet ◽

Véronique Patrac ◽

...

Keyword(s):

Skeletal Muscle ◽

Protein Synthesis ◽

Muscle Mass ◽

Protein Quality ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Milk Proteins ◽

Skeletal Muscle Protein ◽

Skeletal Muscle Protein Synthesis ◽

Old Rats

The mechanisms that are responsible for sarcopenia are numerous, but the altered muscle protein anabolic response to food intake that appears with advancing age plays an important role. Dietary protein quality needs to be optimized to counter this phenomenon. Blending different plant proteins is expected to compensate for the lower anabolic capacity of plant-based when compared to animal-based protein sources. The objective of this work was to evaluate the nutritional value of pasta products that were made from a mix of wheat semolina and faba bean, lentil, or split pea flour, and to assess their effect on protein metabolism as compared to dietary milk proteins in old rats. Forty-three old rats have consumed for six weeks isoproteic and isocaloric diets containing wheat pasta enriched with 62% to 79% legume protein (depending on the type) or milk proteins, i.e., casein or soluble milk proteins (SMP). The protein digestibility of casein and SMP was 5% to 14% higher than legume-enriched pasta. The net protein utilization and skeletal muscle protein synthesis rate were equivalent either in rats fed legume-enriched pasta diets or those fed casein diet, but lower than in rats fed SMP diet. After legume-enriched pasta intake, muscle mass, and protein accretion were in the same range as in the casein and SMP groups. Mixed wheat-legume pasta could be a nutritional strategy for enhancing the protein content and improving the protein quality, i.e., amino acid profile, of this staple food that is more adequate for maintaining muscle mass, especially for older individuals.

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Effects of aging, exercise, and disease on force transfer in skeletal muscle

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00095.2015 ◽

2015 ◽

Vol 309 (1) ◽

pp. E1-E10 ◽

Cited By ~ 32

Author(s):

David C. Hughes ◽

Marita A. Wallace ◽

Keith Baar

Keyword(s):

Skeletal Muscle ◽

Muscle Protein ◽

Injury Rate ◽

Cytoskeletal Proteins ◽

Neural Activation ◽

Force Transmission ◽

Cross Sectional ◽

Force Transfer ◽

Effects Of Aging ◽

And Function

The loss of muscle strength and increased injury rate in aging skeletal muscle has previously been attributed to loss of muscle protein (cross-sectional area) and/or decreased neural activation. However, it is becoming clear that force transfer within and between fibers plays a significant role in this process as well. Force transfer involves a secondary matrix of proteins that align and transmit the force produced by the thick and thin filaments along muscle fibers and out to the extracellular matrix. These specialized networks of cytoskeletal proteins aid in passing force through the muscle and also serve to protect individual fibers from injury. This review discusses the cytoskeleton proteins that have been identified as playing a role in muscle force transmission, both longitudinally and laterally, and where possible highlights how disease, aging, and exercise influence the expression and function of these proteins.

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A postsynaptic Mr 58,000 (58K) protein concentrated at acetylcholine receptor-rich sites in Torpedo electroplaques and skeletal muscle.

The Journal of Cell Biology ◽

10.1083/jcb.104.6.1633 ◽

1987 ◽

Vol 104 (6) ◽

pp. 1633-1646 ◽

Cited By ~ 101

Author(s):

S C Froehner ◽

A A Murnane ◽

M Tobler ◽

H B Peng ◽

R Sealock

Keyword(s):

Skeletal Muscle ◽

Acetylcholine Receptor ◽

Muscle Protein ◽

Staining Intensity ◽

Neonatal Rat ◽

Diaphragm Muscle ◽

Mammalian Skeletal Muscle ◽

Rat Diaphragm ◽

Skeletal Muscle Protein ◽

Mouse Muscle

In the study of proteins that may participate in the events responsible for organization of macromolecules in the postsynaptic membrane, we have used a mAb to an Mr 58,000 protein (58K protein) found in purified acetylcholine receptor (AChR)-enriched membranes from Torpedo electrocytes. Immunogold labeling with the mAb shows that the 58K protein is located on the cytoplasmic side of Torpedo postsynaptic membranes and is most concentrated near the crests of the postjunctional folds, i.e., at sites of high AChR concentration. The mAb also recognizes a skeletal muscle protein with biochemical characteristics very similar to the electrocyte 58K protein. In immunofluorescence experiments on adult mammalian skeletal muscle, the 58K protein mAb labels endplates very intensely, but staining of extrasynaptic membrane is also seen. Endplate staining is not due entirely to membrane infoldings since a similar pattern is seen in neonatal rat diaphragm in which postjunctional folds are shallow and rudimentary, and in chicken muscle, which lacks folds entirely. Furthermore, clusters of AChR that occur spontaneously on cultured Xenopus myotomal cells and mouse muscle cells of the C2 line are also stained more intensely than the surrounding membrane with the 58K mAb. Denervation of adult rat diaphragm muscle for relatively long times causes a dramatic decrease in the endplate staining intensity. Thus, the concentration of this evolutionarily conserved protein at postsynaptic sites may be regulated by innervation or by muscle activity.

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Nutrition and microRNAs: Novel Insights to Fight Sarcopenia

Antioxidants ◽

10.3390/antiox9100951 ◽

2020 ◽

Vol 9 (10) ◽

pp. 951

Author(s):

Alessandra Barbiera ◽

Laura Pelosi ◽

Gigliola Sica ◽

Bianca Maria Scicchitano

Keyword(s):

Skeletal Muscle ◽

Muscle Mass ◽

Molecular Mechanisms ◽

Muscle Protein ◽

Low Grade ◽

Protein Homeostasis ◽

Dietary Interventions ◽

Physiological Processes ◽

Age Related ◽

And Function

Sarcopenia is a progressive age-related loss of skeletal muscle mass and strength, which may result in increased physical frailty and a higher risk of adverse events. Low-grade systemic inflammation, loss of muscle protein homeostasis, mitochondrial dysfunction, and reduced number and function of satellite cells seem to be the key points for the induction of muscle wasting, contributing to the pathophysiological mechanisms of sarcopenia. While a range of genetic, hormonal, and environmental factors has been reported to contribute to the onset of sarcopenia, dietary interventions targeting protein or antioxidant intake may have a positive effect in increasing muscle mass and strength, regulating protein homeostasis, oxidative reaction, and cell autophagy, thus providing a cellular lifespan extension. MicroRNAs (miRNAs) are endogenous small non-coding RNAs, which control gene expression in different tissues. In skeletal muscle, a range of miRNAs, named myomiRNAs, are involved in many physiological processes, such as growth, development, and maintenance of muscle mass and function. This review aims to present and to discuss some of the most relevant molecular mechanisms related to the pathophysiological effect of sarcopenia. Besides, we explored the role of nutrition as a possible way to counteract the loss of muscle mass and function associated with ageing, with special attention paid to nutrient-dependent miRNAs regulation. This review will provide important information to better understand sarcopenia and, thus, to facilitate research and therapeutic strategies to counteract the pathophysiological effect of ageing.

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Effect of fast dietary proteins on muscle protein synthesis rate and muscle strength in ad libitum-fed and energy-restricted old rats

British Journal Of Nutrition ◽

10.1017/s0007114511002182 ◽

2011 ◽

Vol 106 (11) ◽

pp. 1683-1690 ◽

Cited By ~ 14

Author(s):

Stéphane Walrand ◽

Aude Zangarelli ◽

Christelle Guillet ◽

Jérôme Salles ◽

Karine Soulier ◽

...

Keyword(s):

Protein Synthesis ◽

Muscle Strength ◽

Muscle Mass ◽

Muscle Protein ◽

Muscle Protein Synthesis ◽

Synthesis Rate ◽

Protein Synthesis Rate ◽

Old Rats ◽

And Function ◽

Muscle Protein Synthesis Rate

Sarcopenia is defined as age-related loss of muscle mass and strength. Energy restriction (ER) delays fibre loss by limiting the accumulated deleterious effects of reactive oxygen species on muscle. However, insufficient protein intake during ER might affect muscle mass and function. We hypothesised that ingestion of fast-digested proteins such as whey protein (WP) improves muscle protein synthesis and muscle strength in aged ER rats. The effect of WP or casein (CAS, slow protein) on muscle mass, protein synthesis and strength was evaluated in 21-month-old rats fed for 5 months either ad libitum (AL) or a 40 % protein and energy-restricted (PER) or 40 % AL-isonitrogenous ER diet. The nitrogen balance was reduced in PER-CAS rats only ( − 48 % v. AL-CAS). WP stimulated muscle protein synthesis rates compared with CAS in all groups (+21,+37 and +34 % in AL, PER and ER conditions, respectively). Muscle strength was higher in ER rats than in AL rats (+23 and +12 % for WP or CAS, respectively). Muscle performance tended to be greater in ER rats fed WP than in ER-CAS rats (P < 0·09). In conclusion, we observed that long-term ER combined with maintained protein intake had a beneficial impact on muscle protein synthesis rate and function during ageing.

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