Myosin heavy chain composition in young and old rat skeletal muscle: effects of endurance exercise

1995 ◽  
Vol 78 (6) ◽  
pp. 2115-2120 ◽  
Author(s):  
V. K. Sullivan ◽  
S. K. Powers ◽  
D. S. Criswell ◽  
N. Tumer ◽  
J. S. Larochelle ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Exercise Training ◽  
Myosin Heavy Chain ◽  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Endurance Exercise ◽  
Heavy Chain ◽  
Medial Gastrocnemius ◽  
Type I ◽  
Succinate Dehydrogenase Activity

The objective of this study was to determine the effects of age and exercise on the myosin heavy chain (MHC) composition of skeletal muscle. Young (3 mo) and old (22 mo) female specific pathogen-free barrier-reared Fischer 344 rats were randomly assigned to young untrained or young trained and old untrained or old trained groups, respectively. Young trained and old trained animals performed endurance exercise training on a motorized treadmill for 8 wk. Succinate dehydrogenase activity and MHC isoforms were measured in the plantaris (Plan), lateral and medial gastrocnemius (Gast), and soleus (Sol) muscles. In sedentary animals, aging resulted in a decrease (P < 0.05) in type IIb MHC and an increase (P < 0.05) in type IIa MHC in both the Gast and Plan muscles. Also, aging resulted in a small but significant increase (approximately 4%; P < 0.05) in type I MHC in the Sol. Exercise training resulted in significant (P < 0.05) increases in Gast, Plan, and Sol succinate dehydrogenase activity in both young and old animals. Furthermore, exercise training resulted in a decrease (P < 0.05) in the percentage of type IIb MHC and an increase (P < 0.05) in the percentage of type IIa MHC in the Plan in both young and old animals. These data suggest that there is an age-related shift in locomotor muscle MHC isoforms from a faster to a slower isoform.

Effects of isometric training on skeletal myosin heavy chain expression

1998 ◽  
Vol 84 (6) ◽  
pp. 2036-2041 ◽  
Author(s):  
Fadia Haddad ◽  
Anqi X. Qin ◽  
Ming Zeng ◽  
Sam A. McCue ◽  
Kenneth M. Baldwin
Keyword(s):  
Skeletal Muscle ◽  
Resistance Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Training Programs ◽  
Training Session ◽  
Medial Gastrocnemius ◽  
Type I ◽  
Resistance Training Program ◽  
Relative Expression

This study tested the hypothesis that an isometric resistance-training program induces upregulation of slow myosin heavy chain (MHC) expression in a fast-twitch skeletal muscle. Thus we studied the effects of two resistance-training programs on rodent medial gastrocnemius (MG) muscle that were designed to elicit repetitive isometric contractions (10–12 per set; 4 sets per session) of different duration (8 vs. 5 s) and activation frequency (100 vs. 60 Hz) per contraction during each training session (total of 6 and 12 sessions). Results showed that both training paradigms produced significant increases in muscle weight (∼11–13%) after completion of training ( P < 0.05). Significant transformations in MHC expression occurred and involved specifically a decrease in the relative expression of the fast type IIb MHC and concomitant increased expression of the fast type IIx MHC. These adaptations were observed in both the “white” and “red” regions of the MG, and they occurred at both the mRNA and protein levels. These adaptations were detected after only six training sessions. Neither of the training programs produced any change in the relative expression of either the slow type I MHC or the moderately fast type IIa MHC, which can be upregulated in the red MG by chronic functional overload. These findings show that the isometric protocols used in this investigation were not sufficient to induce the hypothesized changes in the myosin heavy chain isoform expression in rodent skeletal muscle.

Interactive effects of emphysema and malnutrition on diaphragm structure and function

1994 ◽  
Vol 77 (2) ◽  
pp. 947-955 ◽  
Author(s):  
M. I. Lewis ◽  
S. A. Monn ◽  
W. Z. Zhan ◽  
G. C. Sieck
Keyword(s):  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Cross Sectional Area ◽  
Interactive Effects ◽  
Type I ◽  
Specific Force ◽  
Type Ii ◽  
Sectional Area ◽  
Succinate Dehydrogenase Activity ◽  
Cross Sectional

Interactive effects of emphysema (EMP) and prolonged nutritional deprivation (ND) on contractile, morphometric, and metabolic properties of hamster diaphragm muscle (DIA) were examined. Six months after induction of EMP (intratracheal elastase), saline-treated controls (CTL) and EMP hamsters of similar body weights were subjected to ND over 6 wk. Isometric contractile and fatigue properties of costal DIA were determined in vitro. DIA fibers were histochemically classified as type I or II, and fiber succinate dehydrogenase activity and cross-sectional area were determined using quantitative microscopic procedures. From histochemical sections, the number of capillaries per fiber (C/F) and per fiber cross-sectional area (C/A) were determined. ND resulted in progressive loss of body weight (ND-CTL, 23.8%; ND-EMP, 28.4%; P = NS). ND did not affect reduction in optimal length (Lo) of DIA fibers in EMP compared with CTL and ND-CTL hamsters. Maximum specific force (i.e., force/unit area) was reduced by approximately 25% in EMP animals compared with CTL. ND did not improve or exacerbate the reduction in specific force with EMP. ND attenuated improved fatigue resistance of DIA in EMP animals. No differences in fiber type proportions were noted among experimental groups. Significant atrophy of type I and II DIA fibers was noted after ND. Atrophy was proportionately greater in type II fibers of ND-EMP when referenced to EMP animals. Thus adaptive hypertrophy of type II DIA fibers in EMP animals was abolished. Fiber succinate dehydrogenase activity was significantly increased in type I and II fibers in EMP DIA. ND did not affect this metabolic adaptation of DIA fibers to persistent loads imposed by EMP.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracellular distribution of succinate dehydrogenase activity in skeletal muscle fibers of geese

1984 ◽  
Vol 62 (2) ◽  
pp. 235-240 ◽  
Author(s):  
H. J. Swatland
Keyword(s):  
Skeletal Muscle ◽  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Adenosine Triphosphatase ◽  
Muscle Fibers ◽  
Fiber Types ◽  
Succinate Dehydrogenase Activity ◽  
Individual Muscle ◽  
Concentric Zone ◽  
Pectoralis Muscles

Samples of iliotibialis anterior and pectoralis muscles were taken from five ganders (Anser domesticus). Serial transverse sections were reacted for succinate dehydrogenase (SDH) and alkali-stable adenosine triphosphatase (ATPase). The distribution of SDH activity within individual muscle fibers was measured with a scanning photometer. In many individual fibers, SDH activity was stronger in the periphery than in the axis. This gradient was steepest (−0.034 ± 0.019 absorbance units per concentric zone of 2 μm diameter measurements) in pectoralis fibers with strong SDH activity. In the pectoralis, radial gradients were correlated with fiber area so that the smallest fibers tended to have the steepest gradients of SDH activity. However, this relationship was reversed in fibers with strong ATPase and weak SDH activity in the iliotibialis anterior, and the largest fibers tended to have the steepest gradients. In all fiber types of both muscles, fibers with greater mean SDH activity tended to have steeper gradients.

scholarly journals Calcineurin plays a modulatory role in loading-induced regulation of type I myosin heavy chain gene expression in slow skeletal muscle

2009 ◽  
Vol 297 (4) ◽  
pp. R1037-R1048 ◽  
Author(s):  
Clay E. Pandorf ◽  
Weihua H. Jiang ◽  
Anqi X. Qin ◽  
Paul W. Bodell ◽  
Kenneth M. Baldwin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Fiber Type ◽  
Hindlimb Suspension ◽  
Chain Gene ◽  
Type I ◽  
Thyroid State

The role of calcineurin (Cn) in skeletal muscle fiber-type expression has been a subject of great interest because of reports indicating that it controls the slow muscle phenotype. To delineate the role of Cn in phenotype remodeling, particularly its role in driving expression of the type I myosin heavy chain (MHC) gene, we used a novel strategy whereby a profound transition from fast to slow fiber type is induced and examined in the absence and presence of cyclosporin A (CsA), a Cn inhibitor. To induce the fast-to-slow transition, we first subjected rats to 7 days of hindlimb suspension (HS) + thyroid hormone [triiodothyronine (T3)] to suppress nearly all expression of type I MHC mRNA in the soleus muscle. HS + T3 was then withdrawn, and rats resumed normal ambulation and thyroid state, during which vehicle or CsA (30 mg·kg−1·day−1) was administered for 7 or 14 days. The findings demonstrate that, despite significant inhibition of Cn, pre-mRNA, mRNA, and protein abundance of type I MHC increased markedly during reloading relative to HS + T3 ( P < 0.05). Type I MHC expression was, however, attenuated by CsA compared with vehicle treatment. In addition, type IIa and IIx MHC pre-mRNA, mRNA, and relative protein levels were increased in Cn-treated compared with vehicle-treated rats. These findings indicate that Cn has a modulatory role in MHC transcription, rather than a role as a primary regulator of slow MHC gene expression.

scholarly journals Assay of succinate dehydrogenase activity by the tetrazolium method: evaluation of an improved technique in skeletal muscle fractions.

1980 ◽  
Vol 28 (5) ◽  
pp. 408-412 ◽  
Author(s):  
J D Green ◽  
H T Narahara
Keyword(s):  
Skeletal Muscle ◽  
Ethyl Acetate ◽  
Succinate Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Inhibitory Effects ◽  
Succinate Dehydrogenase Activity ◽  
Low Concentrations ◽  
Mitochondrial Fractions ◽  
Mitochondrial Suspension ◽  
Improved Technique

An improved spectrophotometric method for measuring succinate dehydrogenase (EC 1.3.99.1) activity with the use of 2-(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT) is described. The procedure has been evaluated in mitochondrial fractions and homogenates of frog skeletal muscle. For mitochondrial suspensions, extraction of formazan with alcohol was found to be superior to extraction with ethyl acetate. For homogenates, complete extraction of formazan required sequential treatment with alcohol and ethyl acetate; the generally employed procedure of extracting once with ethyl acetate alone led to serious underestimation of the amount of formazan in the tissue. Observations of mitochondrial suspension incubated with various concentrations of INT led to the selection of 0.8 mM INT for optimal results. Higher concentrations, although commonly used, can exert undesirable inhibitory effects on succinate dehydrogenase activity, especially at low concentrations of mitochondria and after longer periods of incubation. The problem of instability of succinate dehydrogenase was solved by the addition of buffer at pH 7.5.

Polyadenylated RNA, actin mRNA, and myosin heavy chain mRNA in young and old human skeletal muscle

1996 ◽  
Vol 270 (2) ◽  
pp. E224-E229 ◽  
Author(s):  
S. Welle ◽  
K. Bhatt ◽  
C. Thornton
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Human Skeletal Muscle ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Type I ◽  
Polyadenylated Rna ◽  
Actin Mrna

The myofibrillar protein synthesis rate in old human skeletal muscle is slower than that in young adult muscle. To examine whether this difference in protein synthesis rate is explained by reduced availability of the mRNAs that encode the most abundant myofibrillar proteins, we determined relative hybridization signals from probes for actin mRNA, myosin heavy chain mRNA, and total polyadenylated RNA in vastus lateralis muscle biopsies taken from young (22- to 31-yr-old) and old (61- to 74-yr-old) human subjects. The mean fractional rate of myofibrillar synthesis was 38% slower in the older muscles, as determined by incorporation of a stable isotope tracer. Total actin and myosin heavy chain mRNAs, and polyadenylated RNA, were determined using slot-blot assays. Isoform-specific determinations of alpha-actin mRNA, type I myosin heavy chain mRNA, and type IIa myosin heavy chain mRNA were done with ribonuclease protection assays. Hybridization signals were expressed relative to tissue DNA content. There was no difference between age groups in total polyadenylated RNA or in any of the specific mRNAs. We conclude that the slower myofibrillar synthesis rate in older muscle is not caused by reduced mRNA availability.

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