Capillary tortuosity in rat soleus muscle is not affected by endurance training

1989 ◽  
Vol 256 (4) ◽  
pp. H1110-H1116 ◽  
Author(s):  
D. C. Poole ◽  
O. Mathieu-Costello ◽  
J. B. West
Keyword(s):  
Exercise Training ◽  
Citrate Synthase ◽  
Metabolic Response ◽  
Oxidative Capacity ◽  
Treadmill Running ◽  
Female Rats ◽  
Capillary Length ◽  
Direct Function ◽  
Musculus Soleus ◽  
Muscle Changes

The total capillary length available for blood-tissue transfer is determined by the number and orientation of the capillaries. Therefore, whether capillary tortuosity changes with exercise training has important implications for peripheral gas exchange. To determine the effects of exercise training on capillary orientation and capillary length per volume of muscle fiber [Jv(c,f)] female rats were trained by treadmill running (30 m/min, up to 60 min/day, 5 days/wk) for 4 wk. Muscles from control and trained rats were perfusion fixed at sarcomere lengths (l) ranging from 1.59 to 2.15 microns, and morphometric techniques were used to estimate capillary orientation and Jv(c,f). Training increased (P less than 0.05) musculus soleus oxidative capacity 35% [as estimated from citrate synthase activity: 24.7 +/- 1.4 to 34.7 +/- 1.0 (SE) mumol.g-1.min-1], capillary-to-fiber ratio 30% (2.17 +/- 0.06 to 2.83 +/- 0.05), and Jv(c,f) 32% (1,886 +/- 73 to 2,496 +/- 180 mm-2). Capillary tortuosity (as determined from comparisons of transverse and longitudinal sections) was a direct function of l in control and trained rats and contributed 17-73% of capillary length above that estimated from capillary counts on transverse sections. We conclude that capillary tortuosity in m. soleus is unchanged by training. Therefore, Jv(c,f) increases as a consequence of increased capillary number. M. soleus citrate synthase activity is best correlated with Jv(c,f) and not with capillary counts on transverse sections. We hypothesize that training-induced muscle changes of capillary geometry improve O2 delivery to skeletal muscle and may therefore alter the metabolic response (e.g., lactate accumulation) to exercise after training.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of repetitive exercise on neonatal rat skeletal muscle oxidative capacity

1983 ◽  
Vol 54 (2) ◽  
pp. 530-535 ◽  
Author(s):  
A. M. MacIntosh ◽  
K. M. Baldwin
Keyword(s):  
Skeletal Muscle ◽  
Citrate Synthase ◽  
Maximal Oxygen Consumption ◽  
Oxidative Capacity ◽  
Treadmill Running ◽  
Neonatal Rat ◽  
Female Rats ◽  
Adult Rats ◽  
Male And Female Rats ◽  
Time Point

Since little is known about the training response to exercise in neonatal animals, this study was undertaken to elucidate the potential of oxidative system adaptations in developing skeletal muscle of rats during 50 days of daily treadmill running. The training regimen involved male and female rats (10 days old) initially running 0.1 mph, 0% grade, for 15 min. The program progressed to 1 mph, 25% grade, for 60 min by 50 days of age. At 25 days of age, pyruvate and palmitate oxidative capacity, and citrate synthase activity in red vastus muscle homogenates were elevated in the trained group (T) compared with age- and sex-matched controls (C). These increases were also observed for each subsequent time point tested and occurred in spite of the fact that the peak oxidative capacity of neonatal red vastus muscle was 46% greater than adult values. Further, trained animals tested at 45 days of age responded with a 12% increase in maximal oxygen consumption (Vo2max) compared with controls (P less than 0.05). Assays of muscle phosphofructokinase and of creatine phosphokinase activity conducted at this time point revealed no difference between T and C groups. Collectively, these data suggest that neonatal rats can be successfully trained and that they respond to an endurance-type program qualitatively similarly to adult rats.

scholarly journals Exercise training enhances white adipose tissue metabolism in rats selectively bred for low- or high-endurance running capacity

2013 ◽  
Vol 305 (3) ◽  
pp. E429-E438 ◽  
Author(s):  
Erin J. Stephenson ◽  
Sarah J. Lessard ◽  
Donato A. Rivas ◽  
Matthew J. Watt ◽  
Ben B. Yaspelkis ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Exercise Training ◽  
White Adipose Tissue ◽  
Citrate Synthase ◽  
Mitochondrial Protein ◽  
Treadmill Running ◽  
Endurance Running ◽  
Insulin Resistant ◽  
Disease States ◽  
Hcr Model

Impaired visceral white adipose tissue (WAT) metabolism has been implicated in the pathogenesis of several lifestyle-related disease states, with diminished expression of several WAT mitochondrial genes reported in both insulin-resistant humans and rodents. We have used rat models selectively bred for low- (LCR) or high-intrinsic running capacity (HCR) that present simultaneously with divergent metabolic phenotypes to test the hypothesis that oxidative enzyme expression is reduced in epididymal WAT from LCR animals. Based on this assumption, we further hypothesized that short-term exercise training (6 wk of treadmill running) would ameliorate this deficit. Approximately 22-wk-old rats (generation 22) were studied. In untrained rats, the abundance of mitochondrial respiratory complexes I–V, citrate synthase (CS), and PGC-1 was similar for both phenotypes, although CS activity was greater than 50% in HCR ( P = 0.09). Exercise training increased CS activity in both phenotypes but did not alter mitochondrial protein content. Training increased the expression and phosphorylation of proteins with roles in β-adrenergic signaling, including β3-adrenergic receptor (16% increase in LCR; P < 0.05), NOR1 (24% decrease in LCR, 21% decrease in HCR; P < 0.05), phospho-ATGL (25% increase in HCR; P < 0.05), perilipin (25% increase in HCR; P < 0.05), CGI-58 (15% increase in LCR; P < 0.05), and GLUT4 (16% increase in HCR; P < 0.0001). A training effect was also observed for phospho-p38 MAPK (12% decrease in LCR, 20% decrease in HCR; P < 0.05) and phospho-JNK (29% increase in LCR, 20% increase in HCR; P < 0.05). We conclude that in the LCR-HCR model system, mitochondrial protein expression in WAT is not affected by intrinsic running capacity or exercise training. However, training does induce alterations in the activity and expression of several proteins that are essential to the intracellular regulation of WAT metabolism.

Skeletal muscle biochemical adaptations to exercise training in miniature swine

1997 ◽  
Vol 82 (6) ◽  
pp. 1862-1868 ◽  
Author(s):  
Richard M. McAllister ◽  
Brian L. Reiter ◽  
John F. Amann ◽  
M. Harold Laughlin
Keyword(s):  
Skeletal Muscle ◽  
Antioxidant Enzymes ◽  
Lactate Dehydrogenase ◽  
Exercise Training ◽  
Endurance Exercise ◽  
Oxidative Capacity ◽  
Treadmill Running ◽  
Miniature Swine ◽  
Endurance Exercise Training ◽  
Hydroxyacyl Coa Dehydrogenase

McAllister, Richard M., Brian L. Reiter, John F. Amann, and M. Harold Laughlin. Skeletal muscle biochemical adaptations to exercise training in miniature swine. J. Appl. Physiol. 82(6): 1862–1868, 1997.—The primary purpose of this study was to test the hypothesis that endurance exercise training induces increased oxidative capacity in porcine skeletal muscle. To test this hypothesis, female miniature swine were either trained by treadmill running 5 days/wk over 16–20 wk (Trn; n = 35) or pen confined (Sed; n = 33). Myocardial hypertrophy, lower heart rates during submaximal stages of a maximal treadmill running test, and increased running time to exhaustion during that test were indicative of training efficacy. A variety of skeletal muscles were sampled and subsequently assayed for the enzymes citrate synthase (CS), 3-hydroxyacyl-CoA dehydrogenase, and lactate dehydrogenase and for antioxidant enzymes. Fiber type composition of a representative muscle was also determined histochemically. The largest increase in CS activity (62%) was found in the gluteus maximus muscle (Sed, 14.7 ± 1.1 μmol ⋅ min−1 ⋅ g−1; Trn, 23.9 ± 1.0; P < 0.0005). Muscles exhibiting increased CS activity, however, were located primarily in the forelimb; ankle and knee extensor and respiratory muscles were unchanged with training. Only two muscles exhibited higher 3-hydroxyacyl-CoA dehydrogenase activity in Trn compared with Sed. Lactate dehydrogenase activity was unchanged with training, as were activities of antioxidant enzymes. Histochemical analysis of the triceps brachii muscle (long head) revealed lower type IIB fiber numbers in Trn (Sed, 42 ± 6%; Trn, 10 ± 4; P < 0.01) and greater type IID/X fiber numbers (Sed, 11 ± 2; Trn, 22 ± 3; P < 0.025). These findings indicate that porcine skeletal muscle adapts to endurance exercise training in a manner similar to muscle of humans and other animal models, with increased oxidative capacity. Specific muscles exhibiting these adaptations, however, differ between the miniature swine and other species.

Insulin receptor binding and protein kinase activity in muscles of trained rats

1987 ◽  
Vol 252 (2) ◽  
pp. E170-E175
Author(s):  
G. L. Dohm ◽  
M. K. Sinha ◽  
J. F. Caro
Keyword(s):  
Insulin Sensitivity ◽  
Protein Kinase ◽  
Exercise Training ◽  
Insulin Receptor ◽  
Insulin Action ◽  
Kinase Activity ◽  
Insulin Receptors ◽  
Treadmill Running ◽  
Female Rats ◽  
Protein Kinase Activity

Exercise has been shown to increase insulin sensitivity, and muscle is quantitatively the most important tissue of insulin action. Since the first step in insulin action is the binding to a membrane receptor, we postulated that exercise training would change insulin receptors in muscle and in this study we have investigated this hypothesis. Female rats initially weighing approximately 100 g were trained by treadmill running for 2 h/day, 6 days/wk for 4 wk at 25 m/min (0 grade). Insulin receptors from vastus intermedius muscles were solubilized by homogenizing in a buffer containing 1% Triton X-100 and then partially purified by passing the soluble extract over a wheat germ agglutinin column. The 4 wk training regimen resulted in a 65% increase in citrate synthase activity in red vastus lateralis muscle, indicating an adaptation to exercise. Insulin binding by the partially purified receptor preparation s was approximately doubled in muscle of trained rats at all insulin concentrations, suggesting an increase in the number of receptors. Training did not alter insulin receptor structure as evidenced by electrophoretic mobility under reducing and nonreducing conditions. Basal insulin receptor protein kinase activity was higher in trained than untrained animals and this was likely due to the greater number of receptors. However, insulin stimulation of the protein kinase activity was depressed by training. These results demonstrate that endurance training does alter receptor number and function in muscle and these changes may be important in increasing insulin sensitivity after exercise training.

Downhill treadmill running trains the rat spinotrapezius muscle

2007 ◽  
Vol 102 (1) ◽  
pp. 412-416 ◽  
Author(s):  
S. A. Hahn ◽  
L. F. Ferreira ◽  
J. B. Williams ◽  
K. P. Jansson ◽  
B. J. Behnke ◽  
...  
Keyword(s):  
Citrate Synthase ◽  
Oxidative Capacity ◽  
Peak Oxygen Uptake ◽  
Microscopic Investigation ◽  
Treadmill Running ◽  
Whole Body ◽  
Initial Tension ◽  
Downhill Running ◽  
Health And Disease ◽  
Microcirculatory Function

There are currently no models of exercise that recruit and train muscles, such as the rat spinotrapezius, that are suitable for transmission intravital microscopic investigation of the microcirculation. Recent experimental evidence supports the concept that running downhill on a motorized treadmill recruits the spinotrapezius muscle of the rat. Based on these results, we tested the hypothesis that 6 wk of downhill running (−14° grade) for 1 h/day, 5 days/wk, at a speed of up to 35 m/min, would 1) increase whole body peak oxygen uptake (V̇o2 peak), 2) increase spinotrapezius citrate synthase activity, and 3) reduce the fatigability of the spinotrapezius during electrically induced 1-Hz submaximal tetanic contractions. Trained rats ( n = 6) elicited a 24% higher V̇o2 peak (in ml·min−1·kg−1: sedentary 58.5 ± 2.0, trained 72.7 ± 2.0; P < 0.001) and a 41% greater spinotrapezius citrate synthase activity (in μmol·min−1·g−1: sedentary 14.1 ± 0.7, trained 19.9 ± 0.9; P < 0.001) compared with sedentary controls ( n = 6). In addition, at the end of 15 min of electrical stimulation, trained rats sustained a greater percentage of the initial tension than their sedentary counterparts (control 34.3 ± 3.1%, trained 59.0 ± 7.2%; P < 0.05). These results demonstrate that downhill running is successful in promoting training adaptations in the spinotrapezius muscle, including increased oxidative capacity and resistance to fatigue. Since the spinotrapezius muscle is commonly used in studies using intravital microscopy to examine microcirculatory function at rest and during contractions, our results suggest that downhill running is an effective training paradigm that can be used to investigate the mechanisms for improved microcirculatory function following exercise training in health and disease.

Myosin heavy chain composition in the rat diaphragm: effect of age and exercise training

1992 ◽  
Vol 73 (4) ◽  
pp. 1282-1286 ◽  
Author(s):  
L. E. Gosselin ◽  
M. Betlach ◽  
A. C. Vailas ◽  
M. L. Greaser ◽  
D. P. Thomas
Keyword(s):  
Exercise Training ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Citrate Synthase ◽  
Relative Proportion ◽  
Maximal Oxygen Consumption ◽  
Age Groups ◽  
Treadmill Running ◽  
Age Related ◽  
Effects Of Aging

Increases in aerobic capacity in both young and senescent rats consequent to endurance exercise training are now known to occur not only in locomotor skeletal muscle but also in diaphragm. In the current study the effects of aging and exercise training on the myosin heavy chain (MHC) composition were determined in both the costal and crural diaphragm regions of female Fischer 344 rats. Exercise training [treadmill running at 75% maximal oxygen consumption (1 h/day, 5 day/wk, x 10 wk)] resulted in similar increases in plantaris muscle citrate synthase activity in both young (5 mo) and old (23 mo) trained animals (P < 0.05). Computerized densitometric image analysis of fast and slow MHC bands revealed the ratio of fast to slow MHC to be significantly higher (P < 0.005) in the crural compared with costal diaphragm region in both age groups. In addition, a significant age-related increase (P < 0.05) in percentage of slow MHC was observed in both diaphragm regions. However, exercise training failed to change the relative proportion of slow MHC in either the costal or crural region.

scholarly journals Short-term treadmill running in the rat: what kind of stressor is it?

2007 ◽  
Vol 103 (6) ◽  
pp. 1979-1985 ◽  
Author(s):  
David A. Brown ◽  
Micah S. Johnson ◽  
Casey J. Armstrong ◽  
Joshua M. Lynch ◽  
Nicholas M. Caruso ◽  
...  
Keyword(s):  
Acute Exercise ◽  
Citrate Synthase ◽  
Treadmill Running ◽  
Female Rats ◽  
Male Rats ◽  
Dependent Manner ◽  
Short Term ◽  
Male And Female ◽  
Physiological Variables ◽  
Systemic Stress

The use of short-term (1–5 days) treadmill running is becoming increasingly common as a model to study physiological adaptations following the exercise. Although the beneficial effects of acute exercise seem clear, a paucity of data exist describing potential markers of stress in response to forced running. We subjected male and female Sprague-Dawley rats to 0, 1, 2, 5, or 10 days of treadmill running. Twenty-four to 32 h after the last bout of exercise animals were killed and examined for training-induced changes in several physiological variables. No effect of skeletal citrate synthase activity was observed in the male animals after any duration, and only at 10 days of running did females show a significant increase in citrate synthase. Myocardial heat shock protein 72 (HSP72) content was higher in male rats than female rats, and exercise led to increased HSP72 in both sexes, although the time course was different between males and females. Animals displayed several markers of systemic stress in response to the treadmill running, and this was done in a sex-dependent manner. Serum corticosterone was significantly elevated in both sexes 24 h after exercise in three of four exercise groups. Corticosterone-binding globulin was higher in females, and decreased after running in female rats. Body and spleen weights decreased in males (but not females) in response to the exercise training, and running did not alter adrenal gland weights in either sex. These data indicate that in response to short-term treadmill running both male and female rats show signs of systemic stress, but that the pattern of changes occurs in a sex-specific manner.

scholarly journals Sarcolipin expression is not required for the mitochondrial enzymatic response to physical activity or diet

2017 ◽  
Vol 122 (5) ◽  
pp. 1276-1283
Author(s):  
Daniel Gamu ◽  
Anton Trinh ◽  
Val A. Fajardo ◽  
Eric Bombardier ◽  
A. Russell Tupling
Keyword(s):  
Exercise Training ◽  
Citrate Synthase ◽  
Oxidative Capacity ◽  
Metabolic Phenotype ◽  
High Fat ◽  
Muscle Oxidative Capacity ◽  
Plasmic Reticulum ◽  
Voluntary Running ◽  
Fat Feeding

In mice, transgenic manipulation of Ca2+-handling proteins is sufficient to alter the metabolic phenotype of muscle. We have previously shown that ablation of sarcolipin (SLN), a regulatory protein and uncoupler of sarco(endo)plasmic reticulum Ca2+-ATPases, leads to excessive diet-induced obesity and glucose intolerance in mice. However, it is unclear how loss of SLN per se affects muscle oxidative capacity and the ability of mitochondria to adapt to physiological stimuli, such as exercise training or calorie overload. To address this question, Sln−/− and wild-type (WT) littermates were given access to voluntary running wheels or underwent a treadmill training protocol for 8 wk. Furthermore, a separate group of mice were given a high-fat diet (42% kcal from fat for 8 wk) to determine whether the excessively obese phenotype of Sln−/− mice is associated with altered oxidative capacity. While voluntary running was insufficient to elicit mitochondrial adaptations, treadmill-trained mice showed significant increases ( P < 0.05) in the maximal activities of succinate dehydrogenase (+11%), citrate synthase (+12%), cytochrome oxidase (COX: +17%), along with increased protein expression of cytochrome c (+34%) and COX IV (+28%), which were irrespective of SLN expression. Lastly, no changes in the activities of mitochondrial marker enzymes existed with high-fat feeding, regardless of genotype. Together, these findings indicate that SLN is not required for the regulation of oxidative capacity in response to physiological stress, namely exercise or caloric surfeit. NEW & NOTEWORTHY Sarcolipin (SLN) has gained considerable attention for its uncoupling role of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA). Because of SLN’s ability to alter both cellular energy use and cytosolic [Ca2+], the potential exists for a regulatory role of mitochondrial biogenesis. Herein, we show skeletal muscle oxidative capacity to be unaltered in mice lacking SLN following exercise training or high-fat feeding. Our results contrast with published studies of SLN-overexpressing mice, possibly owing to supraphysiological uncoupling of SERCA.

Glucose transporters and maximal transport are increased in endurance-trained rat soleus

1992 ◽  
Vol 73 (2) ◽  
pp. 486-492 ◽  
Author(s):  
C. A. Slentz ◽  
E. A. Gulve ◽  
K. J. Rodnick ◽  
E. J. Henriksen ◽  
J. H. Youn ◽  
...  
Keyword(s):  
Training Program ◽  
Glucose Transport ◽  
Soleus Muscle ◽  
Protein Concentration ◽  
Citrate Synthase ◽  
Wheel Running ◽  
Contractile Activity ◽  
Treadmill Running ◽  
Female Rats ◽  
Transport Activity

Voluntary wheel running induces an increase in the concentration of the regulatable glucose transporter (GLUT4) in rat plantaris muscle but not in soleus muscle (K. J. Rodnick, J. O. Holloszy, C. E. Mondon, and D. E. James. Diabetes 39: 1425–1429, 1990). Wheel running also causes hypertrophy of the soleus in rats. This study was undertaken to ascertain whether endurance training that induces enzymatic adaptations but no hypertrophy results in an increase in the concentration of GLUT4 protein in rat soleus (slow-twitch red) muscle and, if it does, to determine whether there is a concomitant increase in maximal glucose transport activity. Female rats were trained by treadmill running at 25 m/min up a 15% grade, 90 min/day, 6 days/wk for 3 wk. This training program induced increases of 52% in citrate synthase activity, 66% in hexokinase activity, and 47% in immunoreactive GLUT4 protein concentration in soleus muscles without causing hypertrophy. Glucose transport activity stimulated maximally with insulin plus contractile activity was increased to roughly the same extent (44%) as GLUT4 protein content in soleus muscle by the treadmill exercise training. In a second set of experiments, we examined whether a swim-training program increases glucose transport activity in the soleus in the presence of a maximally effective concentration of insulin. The swimming program induced a 44% increase in immunoreactive GLUT4 protein concentration. Glucose transport activity maximally stimulated with insulin was 62% greater in soleus muscle of the swimmers than in untrained controls. Training did not alter the basal rate of 2-deoxyglucose uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochemical characterization of exercise-trained porcine myocardium

1991 ◽  
Vol 71 (1) ◽  
pp. 229-235 ◽  
Author(s):  
M. H. Laughlin ◽  
C. C. Hale ◽  
L. Novela ◽  
D. Gute ◽  
N. Hamilton ◽  
...  
Keyword(s):  
Exercise Training ◽  
Cardiac Muscle ◽  
Cardiac Tissue ◽  
Biochemical Characterization ◽  
Citrate Synthase ◽  
Oxidative Capacity ◽  
Miniature Swine ◽  
Metabolic System ◽  
Skeletal Muscle Myosin ◽  
Biochemical Systems

The purpose of this study was to determine whether cardiac biochemical adaptations are induced by chronic exercise training (ET) of miniature swine. Female Yucatan miniature swine were trained on a treadmill or were cage confined (C) for 16–22 wk. After training, the ET pigs had increased exercise tolerance, lower heart rates during exercise at submaximal intensities, moderate cardiac hypertrophy, increased coronary blood flow capacity, and increased oxidative capacity of skeletal muscle. Myosin from both the C and ET hearts was 100% of the V3 isozyme, and there were no differences between the myosin adenosine triphosphatase (ATPase) or myofibrillar ATPase activities of C and ET hearts. Also, the sarcoplasmic reticulum Ca(2+)-ATPase activity and Na(+)-Ca2+ exchange activity of sarcolemmal vesicles were the same in cardiac muscle of C and ET hearts. Finally, the glycolytic and oxidative capacity of ET cardiac muscle was not different from control, since phosphofructokinase, citrate synthase, and 3-hydroxyacyl-CoA dehydrogenase activities were the same in cardiac tissue from ET and C pigs. We conclude that endurance exercise training does not provide sufficient stress on the heart of a large mammal to induce changes in any of the three major cardiac biochemical systems of the porcine myocardium: the contractile system, the Ca2+ regulatory systems, or the metabolic system.

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