Voluntary Running Exercise Ameliorates Muscle Loss in Mice

2007 ◽  
Author(s):  
Andrea M. Hanson ◽  
Louis S. Stodieck ◽  
Virginia L. Ferguson
Keyword(s):  
Soleus Muscle ◽  
Fiber Type ◽  
Bed Rest ◽  
Muscle Loss ◽  
Running Exercise ◽  
Voluntary Running ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Both spaceflight and bed rest studies are known to cause substantial muscle loss in humans. Of particular interest in atrophy studies is the postural, slow-twitch fiber soleus muscle. It has been demonstrated that during periods of disuse, slow-twitch fibers undergo fiber type switching and morph into fast-twitch fibers [1]. Alternatively, when exercise is prescribed, there is switching of fast-to slow-twitch fibers [2], indicating a profound adaptability of the muscle to exercise.

scholarly journals lncRNA-Six1 Is a Target of miR-1611 that Functions as a ceRNA to Regulate Six1 Protein Expression and Fiber Type Switching in Chicken Myogenesis

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 243 ◽  
Author(s):  
Manting Ma ◽  
Bolin Cai ◽  
Liang Jiang ◽  
Bahareldin Ali Abdalla ◽  
Zhenhui Li ◽  
...  
Keyword(s):  
Fiber Type ◽  
Muscle Fibers ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Proliferation And Differentiation ◽  
Slow Twitch Muscle ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Emerging studies indicate important roles for non-coding RNAs (ncRNAs) as essential regulators in myogenesis, but relatively less is known about their function. In our previous study, we found that lncRNA-Six1 can regulate Six1 in cis to participate in myogenesis. Here, we studied a microRNA (miRNA) that is specifically expressed in chickens (miR-1611). Interestingly, miR-1611 was found to contain potential binding sites for both lncRNA-Six1 and Six1, and it can interact with lncRNA-Six1 to regulate Six1 expression. Overexpression of miR-1611 represses the proliferation and differentiation of myoblasts. Moreover, miR-1611 is highly expressed in slow-twitch fibers, and it drives the transformation of fast-twitch muscle fibers to slow-twitch muscle fibers. Together, these data demonstrate that miR-1611 can mediate the regulation of Six1 by lncRNA-Six1, thereby affecting proliferation and differentiation of myoblasts and transformation of muscle fiber types.

Slow to fast alterations in skeletal muscle fibers caused by clenbuterol, a beta 2-receptor agonist

1988 ◽  
Vol 254 (6) ◽  
pp. E726-E732 ◽  
Author(s):  
R. J. Zeman ◽  
R. Ludemann ◽  
T. G. Easton ◽  
J. D. Etlinger
Keyword(s):  
Muscle Fiber ◽  
Receptor Agonist ◽  
Fiber Type ◽  
Fiber Types ◽  
Cross Sectional ◽  
Type Composition ◽  
Slow Twitch ◽  
Beta 2 ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Chronic treatment of rats with clenbuterol, a beta 2-receptor agonist (8–12 wk), caused hypertrophy of histochemically identified fast- but not slow-twitch fibers within the soleus, while the mean areas of both fiber types were increased in the extensor digitorum longus (EDL). In contrast, treatment with the beta 2-receptor antagonist, butoxamine, reduced fast-twitch fiber size in both muscles. In the solei and to a lesser extent in the EDLs, the ratio of the number of fast- to slow-twitch fibers was increased by clenbuterol, while the opposite was observed with butoxamine. The muscle fiber hypertrophy observed in the EDL was accompanied by parallel increases in maximal tetanic tension and muscle cross-sectional area, while in the solei, progressive increases in rates of force development and relaxation toward values typical of fast-twitch muscles were also observed. Our results suggest a role of beta 2-receptors in regulating muscle fiber type composition as well as growth.

Influence of fiber type and muscle source on Ca2+ sensitivity of rat fibers

1989 ◽  
Vol 256 (2) ◽  
pp. C420-C427 ◽  
Author(s):  
B. Laszewski-Williams ◽  
R. L. Ruff ◽  
A. M. Gordon
Keyword(s):  
Calcium Concentration ◽  
Fiber Type ◽  
Calcium Sensitivity ◽  
One Dimensional ◽  
Protein Gel ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch ◽  
Adductor Longus

This study investigated the influence of muscle source and fiber type on the calcium sensitivity of skinned rat skeletal muscle fibers from predominantly slow muscles [soleus (SOL) and adductor longus (AL)], mixed muscle [posterior gracilis (PG)], and predominantly fast-twitch muscle [extensor digitorum longus (EDL)]. Fibers were characterized histochemically and by one-dimensional protein gel electrophoresis, and calcium-tension relationships were determined. Fiber type and muscle source had significant effects on the negative log of the calcium concentration associated with half-maximal tension (pCa1/2). Slow-twitch fibers had larger values of pCa1/2 than did fast-twitch fibers. Slow-twitch fibers from the predominantly slow muscles, SOL and AL, had similar values of pCa1/2 but slightly smaller values than from the mixed muscle, PG. Fast-glycolytic (FG) fibers from the predominantly fast muscle, EDL, had a higher pCa1/2 than fibers from the mixed fiber type muscle, PG. There were no differences between the pCa1/2 associated with FG and fast-oxidative-glycolytic fibers.

Molecular cloning and quantification of sarcoplasmic reticulum Ca(2+)-ATPase isoforms in rat muscles

1993 ◽  
Vol 264 (2) ◽  
pp. C333-C341 ◽  
Author(s):  
K. D. Wu ◽  
J. Lytton
Keyword(s):  
Fiber Type ◽  
Smooth Muscles ◽  
Full Length ◽  
Adult Rat ◽  
Mrna Ratio ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Quantitative Immunoblotting ◽  
Fast Twitch

A cDNA encoding the full-length adult rat fast-twitch muscle Ca(2+)-adenosinetriphosphatase (ATPase) was cloned. The deduced amino acid sequence of this molecule has 97 and 90% identity with those of rabbit fast-twitch muscle and chicken skeletal muscle Ca(2+)-ATPases, respectively. Specific probes from the 3'-untranslated region of each sarcoplasmic or endoplasmic reticulum Ca(2+)-ATPase (SERCA) gene product and full-length cRNA transcript standards were used to determine the quantity of mRNA encoding each isoform in various rat muscles. Quantitative immunoblotting was also used to determine the protein content of each SERCA isoform. Fast-twitch fibers expressed both SERCA1 mRNA and protein at a level two- to fivefold higher than SERCA2 was expressed in slow-twitch fibers. We observed a protein-to-mRNA ratio that varied from approximately 500,000 molecules per molecule in the fast-twitch muscles to approximately 200,000 in cardiac and smooth muscles. There was no difference, however, between the ratio for different isoforms in the same muscle. The content of Ca2+ pump in a given muscle therefore depends on at least three factors: 1) the efficiency of gene transcription and message stability (fiber type dependent), 2) the efficiency of translation and protein stability (muscle identity dependent), and 3) fiber composition of the muscle.

Contractile function of single muscle fibers after hindlimb suspension

1989 ◽  
Vol 66 (6) ◽  
pp. 2739-2749 ◽  
Author(s):  
P. R. Gardetto ◽  
J. M. Schluter ◽  
R. H. Fitts
Keyword(s):  
Contractile Function ◽  
Fiber Type ◽  
Muscle Fibers ◽  
Hindlimb Suspension ◽  
Type I ◽  
Single Muscle ◽  
Peak Tension ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch

The purpose of this investigation was to determine how muscle atrophy produced by the hindlimb suspension (HS) model alters the contractile function of slow- and fast-twitch single muscle fibers. After 2 wk of HS, small bundles of fibers were isolated from the soleus and the deep and superficial regions of the lateral and medial heads of the gastrocnemius, respectively. The bundles were placed in skinning solution and stored at -20 degrees C until studied. Single fibers were isolated and suspended between a motor arm and force transducer, the functional properties were studied, and subsequently the fiber type was established by myosin heavy chain (MHC) analysis on 1-D sodium dodecyl sulfate polyacrylamide gel electrophoresis. After HS, slow-twitch fibers of the soleus showed a significant reduction in fiber diameter (68 +/- 2 vs. 41 +/- 1 micron) and peak tension (1.37 +/- 0.01 vs. 0.99 +/- 0.06 kg/cm2), whereas the maximal shortening speed (Vmax) increased [1.49 +/- 0.11 vs. 1.92 +/- 0.14 fiber lengths (FL)/s]. A histogram showed two populations of fibers: one with Vmax values identical to control slow-twitch fibers and a second with significantly elevated Vmax values. This latter group frequently contained both slow and fast MHC protein isoforms. The pCa-force relation of the soleus slow-twitch fibers was shifted to the right; consequently, the free Ca2+ required for the onset of tension and for 50% of peak tension was significantly higher after HS. Slow-twitch fibers isolated from the gastrocnemius after HS showed a significant reduction in diameter (67 +/- 4 vs. 44 +/- 3 microns) and peak tension (1.2 +/- 0.06 vs. 0.96 +/- 0.07 kg/cm2), but Vmax was unaltered (1.70 +/- 0.13 vs. 1.65 +/- 0.18 FL/s). Fast-twitch fibers from the red gastrocnemius showed a significant reduction in diameter (59 +/- 2 vs. 49 +/- 3 microns) but no change in peak tension or Vmax. Fast-twitch fibers from the white superficial region of the medial head of the gastrocnemius were unaffected by HS. Collectively, these data suggest that the effects of HS on fiber function depend on the fiber type and location. Both slow-twitch type I and fast-twitch type IIa fibers atrophied; however, only slow-twitch fibers showed a decline in peak tension, and the increase in Vmax was restricted to a subpopulation of slow-twitch soleus fibers.

Effect of thin filament length on the force-sarcomere length relation of skeletal muscle

1991 ◽  
Vol 260 (5) ◽  
pp. C1060-C1070 ◽  
Author(s):  
H. L. Granzier ◽  
H. A. Akster ◽  
H. E. Ter Keurs
Keyword(s):  
Thin Filament ◽  
Sarcomere Length ◽  
Fiber Type ◽  
Thick Filament ◽  
Fiber Types ◽  
Single Region ◽  
Slow Twitch ◽  
The Difference ◽  
Slow Twitch Fibers ◽  
Fast Twitch

We studied a slow- and a fast-twitch muscle fiber type of the perch that have different thin filament lengths. The force-sarcomere length relations were measured, and it was tested whether their descending limbs were predicted by the cross-bridge theory. To determine the predicted relations, filament lengths were measured by electron microscopy. Measurements were corrected for shrinkage with the use of I-band and H-zone periodicities. Thick filament lengths of the two fiber types were found to be similar (1.63 +/- 0.06 and 1.64 +/- 0.10 microns for slow- and fast-twitch fibers, respectively), whereas the thin filament lengths were clearly different: 1.24 +/- 0.10 microns (n = 86) for the slow-twitch type and 0.94 +/- 0.04 microns (n = 94) for the fast type. The descending limbs of the two fiber types are therefore predicted to be shifted along the sarcomere length axis by approximately 0.6 microns. Sarcomere length was measured on-line by laser diffraction in a single region in the center of the fibers. The passive force-sarcomere strain relation increased much more steeply in the slow-twitch fibers. The descending limb of the active force-sarcomere length relation of fast twitch fibers was linear (r = 0.92), but was found at sarcomere lengths approximately 0.1 micron greater than predicted. The descending limb of the slow-twitch fibers was also linear (r = 0.87) but was now found at sarcomere lengths approximately 0.05 microns less than predicted. The difference in position of the descending limbs of the two fiber types amounted to 0.5 microns, approximately 0.1 micron less than predicted. The difference between measured and predicted descending limbs was statistically insignificant.

Na current density at and away from end plates on rat fast- and slow-twitch skeletal muscle fibers

1992 ◽  
Vol 262 (1) ◽  
pp. C229-C234 ◽  
Author(s):  
R. L. Ruff
Keyword(s):  
Skeletal Muscle ◽  
Current Density ◽  
Muscle Fibers ◽  
Postsynaptic Membrane ◽  
Na Current ◽  
End Plate ◽  
Skeletal Muscle Fibers ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Na current density and membrane capacitance were studied with the loose patch voltage clamp technique on rat fast- and slow-twitch skeletal muscle fibers at three different regions on the fibers: 1) the end plate border, 2) greater than 200 microns from the end plate (extrajunctional), and 3) on the end plate postsynaptic membrane. Fibers were treated with collagenase to improve visualization of the end plate and to enzymatically remove the nerve terminal. The capacitance of membrane patches was similar on fast- and slow-twitch fibers and patches of membrane on the end plate had twice the capacitance of patches elsewhere. For fast- and slow-twitch fibers, the sizes of the Na current normalized to the area of the patch were as follows: end plate greater than end plate border greater than extrajunctional. For both types of fibers, the amplitudes of the Na current normalized to the capacitance of the membrane patch were as follows: end plate approximately end plate border greater than extrajunctional. At each of the three regions, the Na current densities were larger on fast-twitch fibers and fast-twitch fibers had a larger increase in Na current density at the end plate border compared with extrajunctional membrane.

In vitro O2 uptake and histochemical fiber type of resting hamster muscles

1984 ◽  
Vol 57 (1) ◽  
pp. 246-253 ◽  
Author(s):  
S. M. Sullivan ◽  
R. N. Pittman
Keyword(s):  
Surface Area ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Histochemical Staining ◽  
Striated Muscles ◽  
Type Composition ◽  
Slow Twitch ◽  
Pattern Number ◽  
Fast Twitch

In vitro oxygen consumption (VO2), histochemical fiber type, capillary arrangement, and muscle fiber geometry were measured in three hamster striated muscles. These muscles varied markedly in their histochemical fiber type composition (% by number): retractor (70% FG, fast-twitch, glycolytic; 16% FOG, fast-twitch, oxidative-glycolytic; 14% SO, slow-twitch, oxidative); soleus (57% FOG, 43% SO), and sartorius (98% FG, 2% FOG). Sartorius VO2 [0.80 +/- 0.034 (SE) ml O2 X min-1 X 100 g-1] was significantly different (P less than 0.01) from VO2 of retractor (0.89 +/- 0.038) and soleus (1.00 +/- 0.048).The number of capillaries around a fiber and the surface area/volume were greater for FOG and SO fibers than for FG fibers. Fibers of all types appeared to be roughly elliptical in shape. Capillaries were uniformly distributed around fibers in the soleus, but they were located more toward the ends of the major diameter in the retractor and sartorius. The results suggest a relationship among a fiber's oxidative capacity (based on its histochemical staining pattern), number of surrounding capillaries and surface area/volume. Furthermore, results suggest that VO2 and capillary spacing around a fiber may depend on fiber type.

scholarly journals Comparative analysis of the transcriptomes of EDL, psoas, and soleus muscles from mice

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Pabodha Hettige ◽  
Uzma Tahir ◽  
Kiisa C. Nishikawa ◽  
Matthew J. Gage
Keyword(s):  
Skeletal Muscles ◽  
Striated Muscle ◽  
Fiber Type ◽  
Expression Patterns ◽  
Fiber Types ◽  
Muscle Adaptation ◽  
Myosin Heavy Chain Isoform ◽  
Genes Encoding ◽  
Slow Twitch ◽  
Fast Twitch

Abstract Background Individual skeletal muscles have evolved to perform specific tasks based on their molecular composition. In general, muscle fibers are characterized as either fast-twitch or slow-twitch based on their myosin heavy chain isoform profiles. This approach made sense in the early days of muscle studies when SDS-PAGE was the primary tool for mapping fiber type. However, Next Generation Sequencing tools permit analysis of the entire muscle transcriptome in a single sample, which allows for more precise characterization of differences among fiber types, including distinguishing between different isoforms of specific proteins. We demonstrate the power of this approach by comparing the differential gene expression patterns of extensor digitorum longus (EDL), psoas, and soleus from mice using high throughput RNA sequencing. Results EDL and psoas are typically classified as fast-twitch muscles based on their myosin expression pattern, while soleus is considered a slow-twitch muscle. The majority of the transcriptomic variability aligns with the fast-twitch and slow-twitch characterization. However, psoas and EDL exhibit unique expression patterns associated with the genes coding for extracellular matrix, myofibril, transcription, translation, striated muscle adaptation, mitochondrion distribution, and metabolism. Furthermore, significant expression differences between psoas and EDL were observed in genes coding for myosin light chain, troponin, tropomyosin isoforms, and several genes encoding the constituents of the Z-disk. Conclusions The observations highlight the intricate molecular nature of skeletal muscles and demonstrate the importance of utilizing transcriptomic information as a tool for skeletal muscle characterization.

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