Correlations between MyoD, myogenin, SERCA1, SERCA2 and phospholamban transcripts during transformation of type-II to type-I skeletal muscle fibers

1997 ◽  
Vol 434 (2) ◽  
pp. 209-211 ◽  
Author(s):  
Ping Hu ◽  
K.-M. Zhang ◽  
Leon D. Wright ◽  
John A. Spratt ◽  
F. N. Briggs
2009 ◽  
Vol 107 (4) ◽  
pp. 1138-1143 ◽  
Author(s):  
Martijn A. Bekedam ◽  
Brechje J. van Beek-Harmsen ◽  
Willem van Mechelen ◽  
Anco Boonstra ◽  
Willem J. van der Laarse

The purpose of this study was to determine the myoglobin concentration in skeletal muscle fibers of chronic heart failure (CHF) patients and to calculate the effect of myoglobin on oxygen buffering and facilitated diffusion. Myoglobin concentration, succinate dehydrogenase (SDH) activity, and cross-sectional area of individual muscle fibers from the vastus lateralis of five control and nine CHF patients were determined using calibrated histochemistry. CHF patients compared with control subjects were similar with respect to myoglobin concentration: type I fibers 0.69 ± 0.11 mM (mean ± SD), type II fibers 0.52 ± 0.07 mM in CHF vs. type I fibers 0.70 ± 0.09 mM, type II fibers 0.49 ± 0.07 mM in control, whereas SDH activity was significantly lower in CHF in both fiber types ( P < 0.01). The myoglobin concentration in type I fibers was higher than in type II fibers ( P < 0.01). Consequently, the oxygen buffering capacity, calculated from myoglobin concentration/SDH activity was increased in CHF: type I fibers 11.4 ± 2.1 s, type II fibers 13.6 ± 3.9 s in CHF vs. type I fibers 7.8 ± 0.9 s, type II fibers 7.5 ± 1.0 s in control, all P < 0.01). The calculated extracellular oxygen tension required to prevent core anoxia (Po2crit) in muscle fibers was similar when controls were compared with patients in type I fibers 10.3 ± 0.9 Torr in CHF and 11.5 ± 3.3 Torr in control, but was lower in type II fibers of patients 6.1 ± 2.8 Torr in CHF and 14.7 ± 6.2 Torr in control, P < 0.01. The lower Po2crit of type II fibers may facilitate oxygen extraction from capillaries. Reduced exercise tolerance in CHF is not due to myoglobin deficiency.


1996 ◽  
Vol 84 (5) ◽  
pp. 1138-1147 ◽  
Author(s):  
Benoit M. Tavernier ◽  
Elie Haddad ◽  
Pascal J. Adnet ◽  
Toussaint S. Etchrivi ◽  
Dominique Lacroix ◽  
...  

Background Reports of the effects of halothane on isoform contractile proteins of striated muscles are conflicting. To determine whether halothane affects cardiac and skeletal contractile proteins differently, the authors examined the effects of two doses of halothane (0.44 and 1.26 mM, equivalent to 0.75 and 2.25 vol%, respectively) on the Ca++ sensitivity and maximal force in human skinned cardiac, type I (slow twitch), and type II (fast twitch) skeletal muscle fibers. Methods Left ventricular muscle strips and skeletal muscle biopsy specimens were obtained from eight and ten patients undergoing cardiac and orthopedic surgery, respectively. Sarcolemma and sarcoplasmic reticulum were destroyed with ethylene glycol bis (beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid plus Brij 58. Ca++ sensitivity was studied by observing the isometric tension developed by skinned fibers challenged with increasing concentrations of Ca++. Muscle fiber type was determined in each skeletal fiber by the difference in strontium-induced tension measurements. Results Halothane shifted the Ca++ tension curves toward higher Ca++ concentrations and increased the Ca++ concentrations for half-maximal activation in both cardiac and type I skeletal muscle fibers (from 1.96 microM and 1.06 microM under control conditions to 2.92 microM and 1.71 microM in presence of 0.75 vol% halothane, respectively) without changing the slope of this relationship (Hill coefficient). In contrast, no significant effect was observed in type II fibers. Halothane also decreased the maximal activated tension in the three groups of fibers with a lesser effect in type II fibers. Conclusions Halothane decreases Ca++ sensitivity and maximal force in human skinned cardiac and type I fibers at 20 degrees C. It is concluded that the negative inotropic effects of halothane depend on contractile proteins isoforms.


2020 ◽  
Vol 128 (5) ◽  
pp. 1207-1216 ◽  
Author(s):  
Cedric. R. Lamboley ◽  
David M. Rouffet ◽  
Travis L. Dutka ◽  
Michael J. McKenna ◽  
Graham D. Lamb

This study identified important cellular changes occurring in human skeletal muscle fibers following high-intensity intermittent exercise: 1) a decrease in contractile apparatus Ca2+ sensitivity in type I but not type II fibers, 2) a decrease in specific force only in type II muscle fibers, and 3) a redox-dependent increase in Ca2+ sensitivity occurring only in type II fibers, which would help maintain muscle performance by countering the normal metabolite-induced decline in Ca2+ sensitivity.


2011 ◽  
Vol 25 (S1) ◽  
Author(s):  
David M Gundermann ◽  
Dillon K Walker ◽  
Christopher S Fry ◽  
Jared M Dickinson ◽  
Micah J Drummond ◽  
...  

1988 ◽  
Vol 36 (7) ◽  
pp. 775-782 ◽  
Author(s):  
P Frémont ◽  
P M Charest ◽  
C Côté ◽  
P A Rogers

The objectives of the present study were to determine if carbonic anhydrase III (CA III) demonstrated a specific association for any particular organelle or structure of the skeletal muscle cell and to quantify the activity and content of this enzyme in different types of skeletal muscle fibers. Ultrastructural localization of CA III in the soleus (SOL), deep vastus lateralis (DVL), and superficial vastus lateralis (SVL), composed of predominantly type I, IIa, and IIb fibers, respectively, was performed using a high-resolution immunocytochemical technique and antibody specific for CA III on ultra-thin sections of skeletal muscle embedded in the water-soluble medium polyvinyl alcohol (PVA). The results indicated a uniform distribution of CA III within the sarcomere. Mitochondria, nuclei, triads, Z-, and M-bands were not specifically labeled. Immunoblotting of washed myofibril preparations did not show any detectable CA III associated with this structure. In addition to quantification of the immunogold labeling, CA III activity and content were assayed in the post-mitochondrial supernatant of the three muscles. In the SOL, these values were found to be 3.6-7.6 times higher than in the DVL. The SVL showed a labeling intensity slightly higher than background level, while the enzyme activity and content were indistinguishable from background levels. We therefore conclude that CA III is randomly distributed in the cytoplasm of the three muscle fiber types and that the relative CA III content and activity in the three muscles studied is SOL greater than DVL greater than SVL approximately equal to 0.


2005 ◽  
Vol 126 (5) ◽  
pp. 461-480 ◽  
Author(s):  
Lucas G. Prado ◽  
Irina Makarenko ◽  
Christian Andresen ◽  
Martina Krüger ◽  
Christiane A. Opitz ◽  
...  

The active and passive contractile performance of skeletal muscle fibers largely depends on the myosin heavy chain (MHC) isoform and the stiffness of the titin spring, respectively. Open questions concern the relationship between titin-based stiffness and active contractile parameters, and titin's importance for total passive muscle stiffness. Here, a large set of adult rabbit muscles (n = 37) was studied for titin size diversity, passive mechanical properties, and possible correlations with the fiber/MHC composition. Titin isoform analyses showed sizes between ∼3300 and 3700 kD; 31 muscles contained a single isoform, six muscles coexpressed two isoforms, including the psoas, where individual fibers expressed similar isoform ratios of 30:70 (3.4:3.3 MD). Gel electrophoresis and Western blotting of two other giant muscle proteins, nebulin and obscurin, demonstrated muscle type–dependent size differences of ≤70 kD. Single fiber and single myofibril mechanics performed on a subset of muscles showed inverse relationships between titin size and titin-borne tension. Force measurements on muscle strips suggested that titin-based stiffness is not correlated with total passive stiffness, which is largely determined also by extramyofibrillar structures, particularly collagen. Some muscles have low titin-based stiffness but high total passive stiffness, whereas the opposite is true for other muscles. Plots of titin size versus percentage of fiber type or MHC isoform (I-IIB-IIA-IID) determined by myofibrillar ATPase staining and gel electrophoresis revealed modest correlations with the type I fiber and MHC-I proportions. No relationships were found with the proportions of the different type II fiber/MHC-II subtypes. Titin-based stiffness decreased with the slow fiber/MHC percentage, whereas neither extramyofibrillar nor total passive stiffness depended on the fiber/MHC composition. In conclusion, a low correlation exists between the active and passive mechanical properties of skeletal muscle fibers. Slow muscles usually express long titin(s), predominantly fast muscles can express either short or long titin(s), giving rise to low titin-based stiffness in slow muscles and highly variable stiffness in fast muscles. Titin contributes substantially to total passive stiffness, but this contribution varies greatly among muscles.


1998 ◽  
Vol 84 (1) ◽  
pp. 229-235 ◽  
Author(s):  
L. V. Thompson ◽  
J. A. Shoeman

Thompson, L. V., and J. A. Shoeman. Contractile function of single muscle fibers after hindlimb unweighting in aged rats. J. Appl. Physiol. 84(1): 229–235, 1998.—This investigation determined how muscle atrophy produced by hindlimb unweighting (HU) alters the contractile function of single muscle fibers from older animals (30 mo). After 1 wk of HU, small bundles of fibers were isolated from the soleus muscles and the deep region of the lateral head of the gastrocnemius muscles. Single glycerinated fibers were suspended between a motor lever and force transducer, functional properties were studied, and the myosin heavy chain (MHC) composition was determined electrophoretically. After HU, the diameter of type I MHC fibers of the soleus declined (88 ± 2 vs. 80 ± 4 μm) and reductions were observed in peak active force (47 ± 3 vs. 28 ± 3 mg) and peak specific tension (Po; 80 ± 5 vs. 56 ± 5 kN/m2). The maximal unloaded shortening velocity increased. The type I MHC fibers from the gastrocnemius showed reductions in diameter (14%), peak active force (41%), and Po (24%), whereas the type IIa MHC fibers showed reductions in peak active force and Po. Thus 1 wk of inactivity has a significant effect on the force-generating capacity of single skeletal muscle fibers from older animals in a fiber type-specific manner (type I MHC > type IIa MHC > type I-IIa MHC). The decline in the functional properties of single skeletal muscle fibers in the older animals appears to be more pronounced than what has been reported in younger animal populations.


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