Sequential increases in capillarization and mitochondrial enzymes in low-frequency-stimulated rabbit muscle

1998 ◽  
Vol 274 (3) ◽  
pp. C810-C818 ◽  
Author(s):  
Dejan Škorjanc ◽  
Frank Jaschinski ◽  
Georg Heine ◽  
Dirk Pette
Keyword(s):  
Citrate Synthase ◽  
Contractile Activity ◽  
Fiber Type ◽  
Low Frequency ◽  
Mitochondrial Enzymes ◽  
Rabbit Muscle ◽  
Mrna Levels ◽  
Metabolic Potential ◽  
Oxidative Potential ◽  
Time Pattern

To investigate temporal changes in capillarization and increases in mitochondrial enzyme activity, rabbit tibialis anterior muscles underwent chronic low-frequency stimulation for up to 50 days. Capillary density (CD), capillary-to-fiber ratio (C/F), intercapillary distance (ICD), and mean capillary area (MCA), as well as several other parameters of capillarization, were examined. In addition, tissue levels of mRNA specific to vascular endothelial growth factor (VEGF) were assessed by reverse transcriptase-polymerase chain reaction. Citrate synthase (CS) activity, a marker of aerobic-oxidative metabolic potential, was measured in the same muscles. Significant increases in CD and C/F, respectively, and decreases in ICD and MCA were observed after 2 days. These changes reached stable maxima by 14 days. The increases in capillarization occurred in a fiber-type-specific manner, affecting type IId fibers before types IIda and IIa. VEGF mRNA levels increased in a bimodal time pattern with a first elevation (2.5-fold) after 1 day and a second (9-fold) after 6–8 days. Increases in CS were first noted after 8 days. Obviously, increases in capillarization as induced by enhanced contractile activity precede increases in the aerobic-oxidative potential of energy metabolism.

scholarly journals Downregulation in muscle Na+-K+-ATPase following a 21-day expedition to 6,194 m

2000 ◽  
Vol 88 (2) ◽  
pp. 634-640 ◽  
Author(s):  
Howard Green ◽  
Brian Roy ◽  
Susan Grant ◽  
Margaret Burnett ◽  
Russ Tupling ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Succinic Dehydrogenase ◽  
Vastus Lateralis Muscle ◽  
Mitochondrial Enzymes ◽  
Succinic Dehydrogenase Activity ◽  
Oxidative Potential ◽  
Tissue Samples ◽  
Fiber Type Distribution

To investigate the hypothesis that acclimatization to altitude would result in a downregulation in muscle Na+-K+-ATPase pump concentration, tissue samples were obtained from the vastus lateralis muscle of six volunteers (5 males and 1 female), ranging in age from 24 to 35 yr, both before and within 3 days after a 21-day expedition to the summit of Mount Denali, Alaska (6,194 m). Na+-K+-ATPase, measured by the [3H]ouabain-binding technique, decreased by 13.8% [348 ± 12 vs. 300 ± 7.6 (SE) pmol/g wet wt; P< 0.05]. No changes were found in the maximal activities (mol ⋅ kg protein− 1 ⋅ h− 1) of the mitochondrial enzymes, succinic dehydrogenase (3.63 ± 0.20 vs. 3.25 ± 0.23), citrate synthase (4.76 ± 0.44 vs. 4.94 ± 0.44), and malate dehydrogenase (12.6 ± 1.8 vs. 12.7 ± 1.2). Similarly, the expedition had no effect on any of the histochemical properties examined, namely fiber-type distribution (types I, IIA, IIB, IC, IIC, IIAB), area, capillarization, and succinic dehydrogenase activity. Peak aerobic power (52.3 ± 2.1 vs. 50.6 ± 1.9 ml ⋅ kg− 1 ⋅ min− 1) and body mass (76.9 ± 3.7 vs. 75.5 ± 2.9 kg) were also unaffected. We concluded that acclimatization to altitude results in a downregulation in muscle Na+-K+-ATPase pump concentration, which occurs without changes in oxidative potential and other fiber-type histochemical properties.

scholarly journals Chronic low-frequency stimulation upregulates uncoupling protein-3 in transforming rat fast-twitch skeletal muscle

2004 ◽  
Vol 287 (6) ◽  
pp. R1419-R1426 ◽  
Author(s):  
Charles T. Putman ◽  
Walter T. Dixon ◽  
Jean A. Pearcey ◽  
Ian M. MacLean ◽  
Michelle J. Jendral ◽  
...  
Keyword(s):  
Protein Content ◽  
Citrate Synthase ◽  
Contractile Activity ◽  
Fiber Type ◽  
Uncoupling Protein ◽  
Low Frequency ◽  
Oxidative Capacity ◽  
Mitochondrial Density ◽  
Slow Fiber ◽  
Frequency Stimulation

The purpose of this investigation was to examine the temporal changes in uncoupling protein (UCP)-3 expression, as well as related adaptive changes in mitochondrial density and fast-to-slow fiber type transitions during chronically enhanced contractile activity. We examined the effects of 1–42 days of chronic low-frequency electrical stimulation (CLFS), applied to rat tibialis anterior (TA) for 10 h/day, on the expression of UCP-3 and concomitant changes in myosin heavy chain (MHC) protein expression and increases in oxidative capacity. UCP-3 protein content increased from 1 to 12 days, reaching 1.5-fold over control ( P < 0.0005); it remained elevated for up to 42 days. In contrast, UCP-3 mRNA decreased in response to CLFS, reaching a level that was threefold lower than control ( P < 0.0007). The activities of the mitochondrial reference enzymes citrate synthase (EC 4.1.3.7) and 3-hydroxyacyl-CoA-dehydrogenase (EC 1.1.1.35), which are known to increase in proportion to mitochondrial density, progressively increased up to an average of 2.3-fold ( P < 0.00001). These changes were accompanied by fast-to-slow fiber type transitions, characterized by a shift in the pattern of MHC expression ( P <0.0002): MHCI and MHCIIa expression increased by 1.7- and 4-fold, whereas MHCIIb displayed a 2.4-fold reduction. We conclude that absolute increases in UCP-3 protein content in the early adaptive phase were associated with the genesis of mitochondria containing a normal complement of UCP-3. However, during exposure to long-term CLFS, mitochondria were generated with a lower complement of UCP-3 and coincided with the emergence of a growing population of oxidative type IIA fibers.

Early muscular and metabolic adaptations to prolonged exercise training in humans

1991 ◽  
Vol 70 (5) ◽  
pp. 2032-2038 ◽  
Author(s):  
H. J. Green ◽  
S. Jones ◽  
M. E. Ball-Burnett ◽  
D. Smith ◽  
J. Livesey ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Creatine Phosphate ◽  
Area Ratio ◽  
Vastus Lateralis Muscle ◽  
Metabolic Potential ◽  
Oxidative Potential ◽  
Fiber Area ◽  
Glycerophosphate Dehydrogenase

A short-term training program involving 2 h of daily exercise at 59% of peak O2 uptake (VO2max) repeated for 10-12 consecutive days was employed to determine the significance of adaptations in energy metabolic potential on alterations in energy metabolism and substrate utilization in working muscle. The initial VO2max determined before training on the eight male subjects was 53.0 +/- 2.0 (SE) ml.kg-1.min-1. Analysis of samples obtained by needle biopsy from the vastus lateralis muscle before exercise (0 min) and at 15, 60, and 99 min of exercise indicated that on the average training resulted (P less than 0.05) in a 6.5% higher concentration of creatine phosphate, a 9.9% lower concentration of creatine, and a 39% lower concentration of lactate. Training had no effect on ATP concentration. These adaptations were also accompanied by a reduction in the utilization in glycogen such that by the end of exercise glycogen concentration was 47.1% higher in the trained muscle. Analysis of the maximal activities of representative enzymes of different metabolic pathways and segments indicated no change in potential in the citric acid cycle (succinate dehydrogenase, citrate synthase), beta-oxidation (3-hydroxyacyl CoA dehydrogenase), glucose phosphorylation (hexokinase), or potential for glycogenolysis (phosphorylase) and glycolysis (pyruvate kinase, phosphofructokinase, alpha-glycerophosphate dehydrogenase, lactate dehydrogenase). With the exception of increases in the capillary-to-fiber area ratio in type IIa fibers, no change was found in any fiber type (types I, IIa, and IIb) for area, number of capillaries, capillary-to-fiber area ratio, or oxidative potential with training.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Exercise Training-Induced PPARβ Increases PGC-1α Protein Stability and Improves Insulin-Induced Glucose Uptake in Rodent Muscles

Nutrients ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 652 ◽  
Author(s):  
Ju-Sik Park ◽  
John O. Holloszy ◽  
Kijin Kim ◽  
Jin-Ho Koh
Keyword(s):  
Cytochrome C ◽  
Exercise Training ◽  
Protein Stability ◽  
Glucose Uptake ◽  
Citrate Synthase ◽  
Peroxisome Proliferator ◽  
Mitochondrial Enzymes ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Peroxisome Proliferator Activated Receptor

This study aimed to investigate the long-term effects of training intervention and resting on protein expression and stability of peroxisome proliferator-activated receptor β/δ (PPARβ), peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC1α), glucose transporter type 4 (GLUT4), and mitochondrial proteins, and determine whether glucose homeostasis can be regulated through stable expression of these proteins after training. Rats swam daily for 3, 6, 9, 14, or 28 days, and then allowed to rest for 5 days post-training. Protein and mRNA levels were measured in the skeletal muscles of these rats. PPARβ was overexpressed and knocked down in myotubes in the skeletal muscle to investigate the effects of swimming training on various signaling cascades of PGC-1α transcription, insulin signaling, and glucose uptake. Exercise training (Ext) upregulated PPARβ, PGC-1α, GLUT4, and mitochondrial enzymes, including NADH-ubiquinone oxidoreductase (NUO), cytochrome c oxidase subunit I (COX1), citrate synthase (CS), and cytochrome c (Cyto C) in a time-dependent manner and promoted the protein stability of PPARβ, PGC-1α, GLUT4, NUO, CS, and Cyto C, such that they were significantly upregulated 5 days after training cessation. PPARβ overexpression increased the PGC-1α protein levels post-translation and improved insulin-induced signaling responsiveness and glucose uptake. The present results indicate that Ext promotes the protein stability of key mitochondria enzymes GLUT4, PGC-1α, and PPARβ even after Ext cessation.

Botulinum-induced muscle paralysis alters metabolic gene expression and fatigue recovery

1996 ◽  
Vol 270 (1) ◽  
pp. R238-R245 ◽  
Author(s):  
F. Gorin ◽  
K. Herrick ◽  
B. Froman ◽  
W. Palmer ◽  
R. Tait ◽  
...  
Keyword(s):  
Contractile Activity ◽  
Botulinum Toxin A ◽  
Tibialis Anterior Muscle ◽  
Low Frequency ◽  
Mrna Levels ◽  
Transcript Levels ◽  
Biochemical Alterations ◽  
Protein Levels ◽  
Metabolic Gene Expression ◽  
Fast Twitch

We evaluated the physiological, histochemical, and biochemical consequences of inhibiting contractile activity in rat skeletal muscles with botulinum toxin A (BTX). Contractile activity was entirely eliminated 12-18 h after a single, focal, intramuscular injection of BTX into the rat tibialis anterior muscle (TA). Neuromuscular transmission remained completely inhibited for 10-12 days, then slowly recovered. BTX-treated muscles exhibited a lower resistance to both high- and low-frequency fatigue at 7 and 14 days after injection, but contractile force recovered more rapidly in treated TA after fatigue. Treated TA showed a twofold increase in the activity of the triglyceride hydrolase enzyme lipoprotein lipase (LPL) and a comparable increase in the relative abundance of LPL steady-state mRNA. In contrast, there was a 28% reduction in protein levels of the muscle isozyme of glycogen phosphorylase (MGP) and a 70% decrease in relative MGP transcript levels. Similar changes in relative transcript levels of LPL and MGP were observed in the predominantly fast-twitch extensor digitorum longus after BTX injection, but relative LPL and MGP mRNA levels were not altered in predominantly slow-twitch soleus. Histochemical evidence indicated that fast-twitch glycolytic fibers had increased lipid content. These biochemical alterations were reversed 120 days after BTX treatment despite persistent atrophy.

Increased muscle oxidative potential following resistance training induced fibre hypertrophy in young men

2006 ◽  
Vol 31 (5) ◽  
pp. 495-501 ◽  
Author(s):  
Jason E. Tang ◽  
Joseph W. Hartman ◽  
Stuart M. Phillips
Keyword(s):  
Resistance Training ◽  
Muscle Fibre ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Atp Synthesis ◽  
Acid Oxidation ◽  
Mitochondrial Enzymes ◽  
Oxidative Potential ◽  
Cross Sectional ◽  
Resistance Training Program

Some evidence suggests that resistance training may lower relative muscle mitochondrial content via “dilution” of the organelle in a larger muscle fibre. Such an adaptation would reduce fatigue resistance, as well as compromise oxidative ATP synthesis and the capacity for fatty-acid oxidation. We investigated the effect of resistance training on mitochondrial enzymes of the citric acid cycle (citrate synthase; CS) and β-oxidation (β-hydroxyacyl CoA dehydrogenase; β-HAD), as well as markers of the potential for glucose phosphorylation (hexokinase; HK) and glycolysis (phosphofructokinase; PFK). Twelve untrained men (21.9 ± 0.5 y; 1.79 ± 0.03 m; 83.2 ± 3.2 kg) participated in a 12 week progressive resistance-training program. Muscle biopsies were taken from the vastus lateralis before (PRE) and after (POST) training. Training increased mean muscle fibre cross-sectional area (p < 0.05) and the activities of CS (PRE = 4.53 ± 0.44 mol·kg protein–1·h–1; POST = 5.63 ± 0.40 mol·kg protein–1·h–1; p < 0.001) and β-HAD (PRE = 2.55 ± 0.28 mol·kg protein–1·h–1; POST = 3.11 ± 0.21 mol·kg protein–1·h–1; p < 0.05). The activity of HK increased 42% (p < 0.05), whereas the activity of PFK remained unchanged. We conclude that resistance training provides a stimulus for improving muscle oxidative potential, as reflected by the increased activities of CS and β-HAD following resistance training induced hypertrophy.

Fiber type-specific expression of major proteolytic systems in fast- to slow-transforming rabbit muscle

2001 ◽  
Vol 280 (2) ◽  
pp. C239-C247 ◽  
Author(s):  
Karim R. Sultan ◽  
Bernd T. Dittrich ◽  
Elmi Leisner ◽  
Nina Paul ◽  
Dirk Pette
Keyword(s):  
Fiber Type ◽  
Low Frequency ◽  
Fiber Types ◽  
Rabbit Muscle ◽  
Calpain Activity ◽  
Specific Expression ◽  
Protein Conjugates ◽  
Protein Ubiquitination ◽  
Low Frequency Stimulation ◽  
Frequency Stimulation

The present study investigates the role of two major proteolytic systems in transforming rabbit and rat muscles. The fast-to-slow transformation of rabbit muscle by chronic low-frequency stimulation (CLFS) induces fast-to-slow transitions of intact, mature fibers and replacement of degenerating fibers by newly formed slow fibers. Ubiquitination, an indicator of the ATP-dependent proteasome system, and calpain activity were measured in homogenates of control and stimulated extensor digitorum longus muscles. Calpain activity increased similarly (∼2-fold) in stimulated rat and rabbit muscles. CLFS had no effect on protein ubiquitination in rat muscle but led to elevations in ubiquitin protein conjugates in rabbit muscle. Immunohistochemistry was used to study the distribution of μ-calpain and m-calpain and of ubiquitinated proteins in myosin heavy chain-based fiber types. The findings suggest that both proteolytic systems are involved in fiber transformation and replacement. Transforming mature fibers displayed increases in μ-calpain and accumulation of ubiquitin protein conjugates. The majority of these fibers were identified as type IIA. Enhanced ubiquitination was also observed in degenerating and necrotic fibers. Such fibers additionally displayed elevated m-calpain levels. Conversely, p94, the skeletal muscle-specific calpain, decayed rapidly after stimulation onset and was hardly detectable after 4 days of CLFS.

scholarly journals Transient regulation of c-fos, αB-crystallin, and hsp70 in muscle during recovery from contractile activity

1998 ◽  
Vol 274 (2) ◽  
pp. C341-C346 ◽  
Author(s):  
P. Darrell Neufer ◽  
George A. Ordway ◽  
R. Sanders Williams
Keyword(s):  
Citrate Synthase ◽  
Contractile Activity ◽  
Motor Nerve ◽  
Tibialis Anterior Muscle ◽  
Stress Protein ◽  
Low Frequency ◽  
Oxidative Capacity ◽  
Hsp70 Mrna ◽  
Genes Encoding ◽  
Αb Crystallin

Endurance exercise training increases the oxidative capacity of skeletal muscles, reflecting the induction of genes encoding enzymes of intermediary metabolism. To test the hypothesis that changes in gene expression may be triggered specifically during recovery from contractile activity, we quantified c-fos, αB-crystallin, 70-kDa heat shock protein (hsp70), myoglobin, and citrate synthase RNA in rabbit tibialis anterior muscle during recovery from intermittent (8 h/day), low-frequency (10 Hz) motor nerve stimulation. Recovery from a single 8-h bout of stimulation was characterized by large (>10-fold) transient increases in c-fos, αB-crystallin, and hsp70 mRNA. Similar changes were noted during recovery after 7 or 14 days of stimulation (8 h/day). Myoglobin and citrate synthase mRNA were also induced during recovery, but the changes were of lesser magnitude (2- to 2.5-fold) and were observed only following repeated bouts of muscle activity (7th or 14th day) that promoted sustained (>24 h) increases in these transcripts. These findings indicate that recovery from exercise is associated with specific transient changes in the expression of immediate early and stress protein genes, suggesting that the products of these genes may have specific roles in the remodeling process evoked by repeated bouts of contractile activity.

scholarly journals Differences in metabolic potential of skeletal muscle fibres and their significance for metabolic control

1985 ◽  
Vol 115 (1) ◽  
pp. 191-199
Author(s):  
P. D. Gollnick ◽  
M. Riedy ◽  
J. J. Quintinskie ◽  
L. A. Bertocci
Keyword(s):  
Skeletal Muscle ◽  
Contractile Activity ◽  
Work Capacity ◽  
Cellular Level ◽  
Muscle Fibres ◽  
Beta Oxidation ◽  
Metabolic Potential ◽  
Oxidative Potential ◽  
Skeletal Muscle Fibres

The role of an increase in oxidative potential of skeletal muscle in the enhanced work capacity and greater use of fat as a fuel after endurance training is discussed. Evidence is presented to illustrate that this adaptive response is probably expressed at the cellular level by a more rapid translocation into the mitochondria of the ADP generated during contractile activity. The consequence of this is a tighter control over the glycolytic process thereby creating more favourable conditions for the entry of acetyl units derived from beta-oxidation of fatty acids into the citric acid cycle.

PGC-1α and PGC-1β have both similar and distinct effects on myofiber switching toward an oxidative phenotype

2006 ◽  
Vol 291 (4) ◽  
pp. E807-E816 ◽  
Author(s):  
Ole Hartvig Mortensen ◽  
Lis Frandsen ◽  
Peter Schjerling ◽  
Erica Nishimura ◽  
Niels Grunnet
Keyword(s):  
Skeletal Muscle ◽  
Enzymatic Activity ◽  
Muscle Fiber ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Mrna Level ◽  
Creatine Kinase Activity ◽  
Negative Regulator ◽  
Peroxisome Proliferator ◽  
Mrna Levels

Peroxisome proliferator-activated receptor-γ coactivator-1α and -1β (PGC-1α and PGC-1β) were overexpressed by adenovirus-mediated gene transfer in cultures of primary rat skeletal muscle cells derived from neonatal myoblasts. Effects on muscle fiber type transition and metabolism were studied from days 5 to 22 of culture. PGC-1α and PGC-1β overexpression caused a three- to fourfold increase in mRNA level, a doubling of enzymatic activity of citrate synthase, a slight increase in short-chain acyl-CoA dehydrogenase mRNA, a doubling of the mRNA level, and a 30–50% increase in enzymatic activity of glyceraldehyde-3-phosphate dehydrogenase. Lactate dehydrogenase or creatine kinase activity was unchanged. PGC-1α enhanced glycogen buildup twofold at 5 or 25 mM glucose, whereas PGC-1β caused a decrease. Both PGC-1α and PGC-1β overexpression caused a faster maturation of myotubes, as seen by mRNA downregulation of the immature embryonal and perinatal myosin heavy-chain (MHC) isoforms. PGC-1α or PGC-1β overexpression enhanced mRNA of the slow oxidative-associated MHC isoform MHCIb and downregulated mRNA levels of the fast glycolytic-associated MHC isoforms MHCIIX and MHCIIB. Only PGC-1β overexpression caused an increase in mRNA of the intermediary fast oxidative-associated MHC isoform MHCIIA. PGC-1α or PGC-1β overexpression upregulated GLUT4 mRNA and downregulated myocyte enhancer factor 2C transcription factor mRNA; only PGC-1α overexpression caused an increase in the mRNA expression of TRB3, a negative regulator of insulin signaling. These results show that both PGC-1α and PGC-1β are involved in the regulation of skeletal muscle fiber transition and metabolism and that they have both overlapping and differing effects.

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