Biochemical properties of overloaded fast-twitch skeletal muscle

1982 ◽  
Vol 52 (2) ◽  
pp. 467-472 ◽  
Author(s):  
K. M. Baldwin ◽  
V. Valdez ◽  
R. E. Herrick ◽  
A. M. MacIntosh ◽  
R. R. Roy
Keyword(s):  
Skeletal Muscle ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Biochemical Properties ◽  
Female Rats ◽  
Surgical Removal ◽  
Fiber Types ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Myofibril Atpase

Previous studies suggest that fast-twitch skeletal muscle overloaded by surgical removal of synergists contains a greater percent of slow-twitch fibers than normal muscle. Therefore we examined subcellular systems known to represent biochemical properties of slow-twitch skeletal muscle by measuring myosin ATPase, Ca2+ regulation of myofibril ATPase, Ca2+ uptake of sarcoplasmic reticulum (SR), and marker enzymes of glycogenolysis in normal soleus (NS) and in normal (NP) and surgically overloaded (OP) plantaris muscles of adult female rats. The OP muscles were 65% larger than NP muscles (P less than 0.001). Specific activity of myosin and myofibril ATPase was approximately 25% lower in OP compared with NP muscle (P less than 0.05). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of myosin revealed the presence of more slow and less fast myosin light-chain components in OP muscles. Although SR of NP muscle took up more Ca2+ than OP muscle during the initial for both groups. Marker regulatory enzymes of glycogenolysis collectively were reduced by 40% in OP compared with NP muscle (P less than 0.001). Collectively the data are consistent with the concept that some muscle fiber types were converted from “fast” to “slow” in the OP muscle.

Expression of hybrid isomyosins in human skeletal muscle

1996 ◽  
Vol 271 (4) ◽  
pp. C1250-C1255 ◽  
Author(s):  
M. Wada ◽  
T. Okumoto ◽  
K. Toro ◽  
K. Masuda ◽  
T. Fukubayashi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Subunit Composition ◽  
Intact Muscle ◽  
Slow Twitch Muscle ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Fast Twitch

Myosin of human skeletal muscles was analyzed by means of several electrophoretic techniques. Myosin heavy chain (HC)-IIa-and HC-IIb-based isomyosins were identified by pyrophosphate-polyacrylamide gel electrophoresis (PP-PAGE). The electrophoretic mobilities of these fast-twitch muscle isomyosins differed in the order HC-IIa triplets < HC-IIb triplets. To determine the subunit composition of myosin molecules that function in intact muscle, two-dimensional electrophoresis in which the first and second dimensions were PP-PAGE and sodium dodecyl sulfate-PAGE, respectively, was also performed. Slow-twitch muscle isomyosin contained, in addition to slow-twitch light chain (LC) and HC-I isoforms, appreciable amounts of LC-2f, HC-IIa, and HC-IIb isoforms, and fast-twitch muscle isomyosin consisted of LC-2s and HC-I isoforms as well as fast-twitch LC and HC isoforms. Without consideration of HC- and slow-twitch alkali LC heterodimers, at least 31 possible isomyosins are derived from these findings on the subunit composition of isomyosins in human skeletal muscle.

Glutamine synthetase induction by glucocorticoids is preserved in skeletal muscle of aged rats

1996 ◽  
Vol 271 (6) ◽  
pp. E1061-E1066 ◽  
Author(s):  
D. Meynial-Denis ◽  
M. Mignon ◽  
A. Miri ◽  
J. Imbert ◽  
E. Aurousseau ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glutamine Synthetase ◽  
Skeletal Muscles ◽  
Female Rats ◽  
Mrna Levels ◽  
Aged Rats ◽  
Adult Rats ◽  
Adult Age ◽  
Slow Twitch ◽  
Fast Twitch

Glutamine synthetase (GS) is a glucocorticoid-inducible enzyme that has a key role for glutamine synthesis in muscle. We hypothesized that the glucocorticoid induction of GS could be altered in aged rats, because alterations in the responsiveness of some genes to glucocorticoids were reported in aging. We compared the glucocorticoid-induced GS in fast-twitch and slow-twitch skeletal muscles (tibialis anterior and soleus, respectively) and heart from adult (age 6-8 mo) and aged (age 22 mo) female rats. All animals received dexamethasone (Dex) in their drinking water (0.77 +/- 0.10 and 0.80 +/- 0.08 mg/day per adult and aged rat, respectively) for 5 days. Dex caused an increase in both GS activity and GS mRNA in fast-twitch and slow-twitch skeletal muscles from adult and aged rats. In contrast, Dex increased GS activity in heart of adult rats, without any concomitant change in GS mRNA levels. Furthermore, Dex did not affect GS activity in aged heart. Thus the responsiveness of GS to an excess of glucocorticoids is preserved in skeletal muscle but not in heart from aged animals.

Effect of exercise on lipoprotein lipase activity in rat heart and skeletal muscle

1975 ◽  
Vol 229 (2) ◽  
pp. 394-397 ◽  
Author(s):  
J Borensztajn ◽  
MS Rone ◽  
SP Babirak ◽  
JA McGarr ◽  
LB Oscai
Keyword(s):  
Skeletal Muscle ◽  
Lipoprotein Lipase ◽  
Lipase Activity ◽  
Plasma Triglyceride ◽  
Treadmill Running ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Lipoprotein Lipase Activity ◽  
Slow Twitch ◽  
Fast Twitch

Lipoprotein lipase activity was measured in the three skeletal muscle fiber types of untrained rats and in those of rats subjected to a 12-wk program of treadmill running. Lipoprotein lipase activity in slow-twitch red fibers was approximately 14- to 20-fold higher (P less than 0.001) than that in fast-twitch white and approximately 2-fold higher (P less than 0.001) than that in fast-twitch red fibers in the untrained animals. These results suggest that, in sedentary animals, mainly slow-twitch red and fast-twitch red fibers are capable of taking up plasma triglyceride fatty acids. Regularly performed endurance exercise resulted in significant increase (2- to 4.5-fold) in lipoprotein lipase activity in the three muscle fiber types examined. The increase in lipoprotein lipase activity in response to treadmill running suggests that exercise increases the capacity of these fibers to take up and oxidize plasma triglyceride fatty acids. Cardiac muscle did not undergo an exercise-induced increase in the levels of activity of lipoprotein lipase similar to that seen in skeletal muscle.

Effects of diabetes on protein synthesis in fast- and slow-twitch rat skeletal muscle

1980 ◽  
Vol 239 (1) ◽  
pp. E88-E95 ◽  
Author(s):  
K. E. Flaim ◽  
M. E. Copenhaver ◽  
L. S. Jefferson
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Peptide Chain ◽  
Fiber Types ◽  
Chain Initiation ◽  
Rapid Reversal ◽  
Slow Twitch ◽  
Fast Twitch

The effects of acute (2-day) and long-term (7-day) diabetes on rates of protein synthesis, peptide-chain initiation, and levels of RNA were examined in rat skeletal muscles that are known to have differing proportions of the three fiber types: fast-twitch white, fast-twitch red, and slow-twitch red. Short-term diabetes resulted in a 15% reduction in the level of RNA in all the muscles studied and an impairment in peptide-chain initiation in muscles with mixed fast-twitch fibers. In contrast, the soleus, a skeletal muscle with high proportions of slow-twitch red fibers, showed little impairment in initiation. When the muscles were perfused as a part of the hemicorpus preparation, addition of insulin to the medium caused a rapid reversal of the block in initiation in mixed fast-twitch muscles but had no effect in the soleus. The possible role of fatty acids in accounting for these differences is discussed. Long-term diabetes caused no further reduction in RNA, but resulted in the development of an additional impairment to protein synthesis that also affected the soleus and that was not corrected by perfusion with insulin. The defect resulting from long-term diabetes may involve elongation or termination reactions.

scholarly journals Strenuous Acute Exercise Induces Slow and Fast Twitch-Dependent NADPH Oxidase Expression in Rat Skeletal Muscle

Antioxidants ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 57 ◽  
Author(s):  
Juliana Osório Alves ◽  
Leonardo Matta Pereira ◽  
Igor Cabral Coutinho do Rêgo Monteiro ◽  
Luiz Henrique Pontes dos Santos ◽  
Alex Soares Marreiros Ferraz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Nadph Oxidase ◽  
Strenuous Exercise ◽  
Exercise Session ◽  
Type I ◽  
Fiber Types ◽  
Mrna Levels ◽  
Slow Twitch ◽  
Fast Twitch

The enzymatic complex Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase (NOx) may be the principal source of reactive oxygen species (ROS). The NOX2 and NOX4 isoforms are tissue-dependent and are differentially expressed in slow-twitch fibers (type I fibers) and fast-twitch fibers (type II fibers) of skeletal muscle, making them different markers of ROS metabolism induced by physical exercise. The aim of this study was to investigate NOx signaling, as a non-adaptive and non-cumulative response, in the predominant fiber types of rat skeletal muscles 24 h after one strenuous treadmill exercise session. The levels of mRNA, reduced glycogen, thiol content, NOx, superoxide dismutase, catalase, glutathione peroxidase activity, and PPARGC1α and SLC2A4 gene expression were measured in the white gastrocnemius (WG) portion, the red gastrocnemius (RG) portion, and the soleus muscle (SOL). NOx activity showed higher values in the SOL muscle compared to the RG and WG portions. The same was true of the NOX2 and NOX4 mRNA levels, antioxidant enzymatic activities, glycogen content. Twenty-four hours after the strenuous exercise session, NOx expression increased in slow-twitch oxidative fibers. The acute strenuous exercise condition showed an attenuation of oxidative stress and an upregulation of antioxidant activity through PPARGC1α gene activity, antioxidant defense adaptations, and differential gene expression according to the predominant fiber type. The most prominent location of detoxification (indicated by NOX4 activation) in the slow-twitch oxidative SOL muscle was the mitochondria, while the fast-twitch oxidative RG portion showed a more cytosolic location. Glycolytic metabolism in the WG portion suggested possible NOX2/NOX4 non-regulation, indicating other possible ROS regulation pathways.

scholarly journals Myosin content of individual human muscle fibers isolated by laser capture microdissection

2016 ◽  
Vol 310 (5) ◽  
pp. C381-C389 ◽  
Author(s):  
Charles A. Stuart ◽  
William L. Stone ◽  
Mary E. A. Howell ◽  
Marianne F. Brannon ◽  
H. Kenton Hall ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Light Chain ◽  
Type I ◽  
Fiber Types ◽  
Myosin Heavy Chains ◽  
Heavy Chains ◽  
Slow Twitch ◽  
Type I Fibers ◽  
Fast Twitch ◽  
Laser Capture

Muscle fiber composition correlates with insulin resistance, and exercise training can increase slow-twitch (type I) fibers and, thereby, mitigate diabetes risk. Human skeletal muscle is made up of three distinct fiber types, but muscle contains many more isoforms of myosin heavy and light chains, which are coded by 15 and 11 different genes, respectively. Laser capture microdissection techniques allow assessment of mRNA and protein content in individual fibers. We found that specific human fiber types contain different mixtures of myosin heavy and light chains. Fast-twitch (type IIx) fibers consistently contained myosin heavy chains 1, 2, and 4 and myosin light chain 1. Type I fibers always contained myosin heavy chains 6 and 7 (MYH6 and MYH7) and myosin light chain 3 (MYL3), whereas MYH6, MYH7, and MYL3 were nearly absent from type IIx fibers. In contrast to cardiomyocytes, where MYH6 (also known as α-myosin heavy chain) is seen solely in fast-twitch cells, only slow-twitch fibers of skeletal muscle contained MYH6. Classical fast myosin heavy chains (MHC1, MHC2, and MHC4) were present in variable proportions in all fiber types, but significant MYH6 and MYH7 expression indicated slow-twitch phenotype, and the absence of these two isoforms determined a fast-twitch phenotype. The mixed myosin heavy and light chain content of type IIa fibers was consistent with its role as a transition between fast and slow phenotypes. These new observations suggest that the presence or absence of MYH6 and MYH7 proteins dictates the slow- or fast-twitch phenotype in skeletal muscle.

Enhanced technique to measure proteins in single segments of human skeletal muscle fibers: fiber-type dependence of AMPK-α1 and -β1

2011 ◽  
Vol 110 (3) ◽  
pp. 820-825 ◽  
Author(s):  
Robyn M. Murphy
Keyword(s):  
Skeletal Muscle ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Significant Advance ◽  
Vastus Lateralis Muscle ◽  
Fiber Types ◽  
Freeze Dried ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Muscle Biopsies

Human physiological studies typically use skeletal muscle biopsies from the heterogeneous vastus lateralis muscle comprised of both fast-twitch and slow-twitch fiber types. It is likely that potential changes of physiological importance are overlooked because fiber-type specific responses may not be apparent in the whole muscle preparation. A technological advance in Western blotting is presented where proteins are analyzed in just one small segment (<2 mm) of individual fibers dissected from freeze-dried muscle samples using standard laboratory equipment. A significant advance is being able to classify every fiber at the level of both contractile (myosin heavy chain and tropomyosin) and sarcoplasmic reticulum [sarco(endo)plasmic reticulum Ca2+-ATPase type 1] properties and then being able to measure specific proteins in the very same segments. This removes the need to fiber type segments before further analyses and, as such, dramatically reduces the time required for sample collection. Compared with slow-twitch fibers, there was less AMP-activated protein kinase (AMPK)-α1 (∼25%) and AMPK-β1 (∼60%) in fast-twitch fibers from human skeletal muscle biopsies.

Expression of Titin in Skeletal Muscle Varies with Hind-Limb Unloading

2000 ◽  
Vol 2 (2) ◽  
pp. 107-115 ◽  
Author(s):  
Christine E. Kasper ◽  
Lin Xun
Keyword(s):  
Skeletal Muscle ◽  
Hind Limb ◽  
Laser Scanning ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Adult Rats ◽  
Single Fibers ◽  
Fast Twitch ◽  
Hind Limb Unloading ◽  
Antibody Localization

The effects of prolonged hind-limb unloading on titin antibody localization and expression of titin isozymes of single fibers from the synergistic slow-twitch soleus (SOL) and fast-twitch plantaris (PLN) of adult rats were studied after 14 and 28 days of hind-limb unloading (HU). Titin antibody localization and expression was not altered at 14 days of HU. However, there was a 4% loss in antibody to Z-band distance (Ab-Z) in the SOL and an increase of 8% in PLN Ab-Z after 28 days of HU. The titin and myosin heavy chain composition of single fibers and small bundles of fibers from control and unloaded muscles were examined using 2% to 12% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. There was a marked loss of relative amounts of titin in both SOL and PLN following 28 days of HU. As the protein loads for these measures were identical, the authors conclude that these findings represent an actual loss of titin density rather than a decreased value due to a loss of total muscle mass. Laser scanning densitometry of the titin bands show a marked decrease in density and molecular weight in unloaded SOL. In the PLN, marked losses of titin density were accompanied by decreased electrophoretic motility. The results demonstrate that the titin isoform composition and titin antibody localization of skeletal muscle is altered during hind-limb unloading. Furthermore, as titin is responsible for positional stability of the sarcomere and the fiber during contraction, change in isoforms during HU may predispose atrophied muscle to injury during reuse and recovery.

Time course adaptations in cardiac and skeletal muscle to different running programs

1977 ◽  
Vol 42 (2) ◽  
pp. 267-272 ◽  
Author(s):  
K. M. Baldwin ◽  
D. A. Cooke ◽  
W. G. Cheadle
Keyword(s):  
Skeletal Muscle ◽  
Steady State ◽  
Cardiac Muscle ◽  
High Speed ◽  
Time Course ◽  
Citrate Synthase ◽  
Biochemical Properties ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Fast Twitch

The effects of chronic “steady-state” and high-speed interval running were investigated on time-course changes in certain biochemical properties of cardiac and skeletal muscle fiber types of rats. Nine weeks of the interval program resulted in significant increased (15%) in both cardiac enlargement and ATPase activity of myofibrils; whereas increases in these parameters were only transient and not significant at the termination of the program involving steady-state running. Neither program induced appreciable alterations in citrate synthase and phosphofructokinase activity in cardiac muscle. In fast-twitch white fibers, “steady-state” training induced only a transient 45% increase in citrate synthase activity in contrast to a progressive twofold change with interval training. Both programs resulted in similar increases (45–50%) in citrate synthase activity in fast-twitch and slow-twitch red fibers. However, the patterns of increase for both fiber types differed between the two programs. These findings suggest that training programs incorporating elements of both “steady-state” incline and high-speed interval running can potentially induce respiratory enzyme adaptations in the greatest spectrum of rodent skeletal muscle fibers in addition to inducing adaptations to enhance contractile potential in cardiac muscle.

Uptake of chylomicron triglycerides by contracting skeletal muscle in rats

1980 ◽  
Vol 49 (5) ◽  
pp. 851-855 ◽  
Author(s):  
B. G. Mackie ◽  
G. A. Dudley ◽  
H. Kaciuba-Uscilko ◽  
R. L. Terjung
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Muscle Fiber Types ◽  
Muscle Stimulation ◽  
Fiber Types ◽  
Energy Needs ◽  
Red Muscle ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Fractional Uptake

The influence of muscle stimulation (3 Hz) on the uptake of exogenously administered chylomicron 14C-labeled triglycerides (14C-TG) in the three different muscle fiber types was evaluated in fed and fasted pentobarbital-anesthetized rats. The fractional uptake of 14C-TG in the nonstimulated muscles was lowest in the fast-twitch white, intermediate in the fast-twitch red, and highest in the slow-twitch red muscle fiber section. Fasting doubled the uptake in both high-oxidative red fibers. These 14C-TG uptakes were directly proportional (r = 0.993) to their respective activities of lipoprotein lipase in these fiber types of fed and fasted animals reported by others. Muscle stimulation caused a significant increase in the fractional 14C-TG uptake in all of the fiber types. Although the TG uptake could account for only a small fraction of the total energy needs of the working muscle, it could contribute to the turnover of endogenous TG, especially in the slow-twitch red fibers. Further, the estimated TG uptake rate is sufficient to replace endogenous TG loss with an overnight rest following exercise. These results suggest that plasma TG could play an important role in lipid metabolism, especially in the high-oxidative slow and fast muscle fiber types.

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