Effect of electrical stimulation patterns on glucose transport in rat muscles

1996 ◽  
Vol 271 (2) ◽  
pp. R426-R431 ◽  
Author(s):  
E. Johannsson ◽  
J. Jensen ◽  
K. Gundersen ◽  
H. A. Dahl ◽  
A. Bonen
Keyword(s):  
Extensor Digitorum Longus ◽  
Bolus Injection ◽  
Fold Increase ◽  
Transport Rate ◽  
Type I ◽  
Fiber Types ◽  
Glut 4 ◽  
Stimulation Period ◽  
Type I Fibers ◽  
White Gastrocnemius

Transport of 2-[3H]deoxy-D-glucose (2-DG) was investigated during supramaximal stimulations of different muscles. In addition, we varied the net stimulation time (NST). In different treatments, NST occupied either 5, 7.5, 10, 15, 20, 30, or 50% of a 20-min stimulation period. After a bolus injection of 3H-labeled 2-DG, the greatest transport occurred in the extensor digitorum longus. In red gastrocnemius (RG; type IIa fibers) and white gastrocnemius (WG; type IIb fibers), the 2-DG transport rate was highest at 10% NST (8- to 12-fold increase) and decreased thereafter. In soleus (type I fibers), the 2-DG transport increased from 5 to 50% NST. Below 30% NST, 2-DG transport was greater in RG and WG muscles than in soleus (P < 0.05). GLUT-4 and 2-DG transport were not correlated during the contractions. Therefore, the percent NST affects 2-DG transport differentially in muscles of varying fiber types, and the transport rate is not related to the GLUT-4 content of the muscles.

scholarly journals Treadmill Running Changes Endothelial Lipase Expression: Insights from Gene and Protein Analysis in Various Striated Muscle Tissues and Serum

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 906
Author(s):  
Agnieszka Mikłosz ◽  
Bartłomiej Łukaszuk ◽  
Adrian Chabowski ◽  
Jan Górski
Keyword(s):  
Protein Expression ◽  
Density Lipoprotein ◽  
Treadmill Running ◽  
Endothelial Lipase ◽  
Type I ◽  
Fiber Types ◽  
Gene And Protein Expression ◽  
Single Bout ◽  
The Impact ◽  
White Gastrocnemius

Endothelial lipase (EL) is an enzyme capable of HDL phospholipids hydrolysis. Its action leads to a reduction in the serum high-density lipoprotein concentration, and thus, it exerts a pro-atherogenic effect. This study examines the impact of a single bout exercise on the gene and protein expression of the EL in skeletal muscles composed of different fiber types (the soleus—mainly type I, the red gastrocnemius—mostly IIA, and the white gastrocnemius—predominantly IIX fibers), as well as the diaphragm, and the heart. Wistar rats were subjected to a treadmill run: 1) t = 30 [min], V = 18 [m/min]; 2) t = 30 [min], V = 28 [m/min]; 3) t = 120 [min], V = 18 [m/min] (designated: M30, F30, and M120, respectively). We established EL expression in the total muscle homogenates in sedentary animals. Resting values could be ordered with the decreasing EL protein expression as follows: endothelium of left ventricle > diaphragm > red gastrocnemius > right ventricle > soleus > white gastrocnemius. Furthermore, we observed that even a single bout of exercise was capable of inducing changes in the mRNA and protein level of EL, with a clearer pattern observed for the former. After 30 min of running at either exercise intensity, the expression of EL transcript in all the cardiovascular components of muscles tested, except the soleus, was reduced in comparison to the respective sedentary control. The protein content of EL varied with the intensity and/or duration of the run in the studied whole tissue homogenates. The observed differences between EL expression in vascular beds of muscles may indicate the muscle-specific role of the lipase.

scholarly journals Adrenergic control of vascular resistance varies in muscles composed of different fiber types: influence of the vascular endothelium

2011 ◽  
Vol 301 (3) ◽  
pp. R783-R790 ◽  
Author(s):  
Bradley J. Behnke ◽  
Robert B. Armstrong ◽  
Michael D. Delp
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Vascular Endothelium ◽  
Fold Increase ◽  
Male Rats ◽  
Type I ◽  
Fiber Types ◽  
Fast Twitch Muscle ◽  
Dose Responses ◽  
Fast Twitch

The influence of the sympathetic nervous system (SNS) upon vascular resistance is more profound in muscles comprised predominately of low-oxidative type IIB vs. high-oxidative type I fiber types. However, within muscles containing high-oxidative type IIA and IIX fibers, the role of the SNS on vasomotor tone is not well established. The purpose of this study was to examine the influence of sympathetic neural vasoconstrictor tone in muscles composed of different fiber types. In adult male rats, blood flow to the red and white portions of the gastrocnemius (GastRed and GastWhite, respectively) and the soleus muscle was measured pre- and postdenervation. Resistance arterioles from these muscles were removed, and dose responses to α1-phenylephrine or α2-clonidine adrenoreceptor agonists were determined with and without the vascular endothelium. Denervation resulted in a 2.7-fold increase in blood flow to the soleus and GastRed and an 8.7-fold increase in flow to the GastWhite. In isolated arterioles, α2-mediated vasoconstriction was greatest in GastWhite (∼50%) and less in GastRed (∼31%) and soleus (∼17%); differences among arterioles were abolished with the removal of the endothelium. There was greater sensitivity to α1-mediated vasoconstriction in the GastWhite and GastRed vs. the soleus, which was independent of whether the endothelium was present. These data indicate that 1) control of vascular resistance by the SNS in high-oxidative, fast-twitch muscle is intermediate to that of low-oxidative, fast-twitch and high-oxidative, slow-twitch muscles; and 2) the ability of the SNS to control blood flow to low-oxidative type IIB muscle appears to be mediated through postsynaptic α1- and α2-adrenoreceptors on the vascular smooth muscle.

Rostrocaudal pattern of fiber-type changes in an overloaded rat ankle extensor

1991 ◽  
Vol 71 (2) ◽  
pp. 558-564 ◽  
Author(s):  
P. F. Gardiner ◽  
B. J. Jasmin ◽  
P. Corriveau
Keyword(s):  
Fiber Type ◽  
Muscle Length ◽  
Similar Degree ◽  
Complex Nature ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Cross Sectional ◽  
Hypertrophic Response ◽  
Type I Fibers

Our aim was to quantify the overload-induced hypertrophy and conversion of fiber types (type II to I) occurring in the medial head of the gastrocnemius muscle (MG). Overload of MG was induced by a bilateral tenotomy/retraction of synergists, followed by 12–18 wk of regular treadmill locomotion (2 h of walking/running per day on 3 of 4 days). We counted all type I fibers and determined type I and II mean fiber areas in eight equidistant sections taken along the length of control and overloaded MG. Increase in muscle weights (31%), as well as in total muscle cross-sectional areas (37%) and fiber areas (type I, 57%; type II, 34%), attested to a significant hypertrophic response in overloaded MG. An increase in type I fiber composition of MG from 7.0 to 11.5% occurred as a result of overload, with the greatest and only statistically significant changes (approximately 70–100%) being found in sections taken from the most rostral 45% of the muscle length. Results of analysis of sections taken from the largest muscle girth showed that it significantly underestimated the extent of fiber conversion that occurred throughout the muscle as a whole. These data obtained on the MG, which possesses a compartmentalization of fiber types, support the notion that all fiber types respond to this model with a similar degree of hypertrophy. Also, they emphasize the complex nature of the adaptive changes that occur in these types of muscles as a result of overload.

Glucose transporter protein content and glucose transport capacity in rat skeletal muscles

1990 ◽  
Vol 259 (4) ◽  
pp. E593-E598 ◽  
Author(s):  
E. J. Henriksen ◽  
R. E. Bourey ◽  
K. J. Rodnick ◽  
L. Koranyi ◽  
M. A. Permutt ◽  
...  
Keyword(s):  
Protein Content ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Contractile Activity ◽  
Fiber Type ◽  
Linear Regression Analysis ◽  
Type I ◽  
Fiber Types ◽  
Transport Activity ◽  
Glut 4

The relationships among fiber type, glucose transporter (GLUT-4) protein content, and glucose transport activity stimulated maximally with insulin and/or contractile activity were studied by use of the rat epitrochlearis (15% type I-20% type II2a-65% type IIb), soleus (84-16-0%), extensor digitorum longus (EDL, 3-57-40%), and flexor digitorum brevis (FDB, 7-92-1%) muscles. Insulin-stimulated 2-deoxy-D-glucose (2-DG) uptake was greatest in the soleus, followed (in order) by the FDB, EDL, and epitrochlearis. On the other hand, contractile activity induced the greatest increase in 2-DG uptake in the FDB, followed by the EDL, soleus, and epitrochlearis. The effects of insulin and contractile activity on 2-DG uptake were additive in all the muscle preparations, with the relative rates being FDB greater than soleus greater than EDL greater than epitrochlearis. Quantitation of the GLUT-4 protein content with the antiserum R820 showed the following pattern: FDB greater than soleus greater than EDL greater than epitrochlearis. Linear regression analysis showed that whereas a relatively low and nonsignificant correlation existed between GLUT-4 protein content and 2-DG uptake stimulated by insulin alone, significant correlations existed between GLUT-4 protein content and 2-DG uptake stimulated either by contractions alone (r = 0.950) or by insulin and contractions in combination (r = 0.992). These results suggest that the differences in maximally stimulated glucose transport activity among the three fiber types may be related to differences in their content of GLUT-4 protein.

Gene Polymorphisms and Fiber-Type Composition of Human Skeletal Muscle

2012 ◽  
Vol 22 (4) ◽  
pp. 292-303 ◽  
Author(s):  
Ildus I. Ahmetov ◽  
Olga L. Vinogradova ◽  
Alun G. Williams
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fiber ◽  
Human Skeletal Muscle ◽  
Fiber Type ◽  
Vastus Lateralis Muscle ◽  
Type I ◽  
Fiber Types ◽  
Fiber Type Composition ◽  
Type Composition ◽  
Type I Fibers

The ability to perform aerobic or anaerobic exercise varies widely among individuals, partially depending on their muscle-fiber composition. Variability in the proportion of skeletal-muscle fiber types may also explain marked differences in aspects of certain chronic disease states including obesity, insulin resistance, and hypertension. In untrained individuals, the proportion of slow-twitch (Type I) fibers in the vastus lateralis muscle is typically around 50% (range 5–90%), and it is unusual for them to undergo conversion to fast-twitch fibers. It has been suggested that the genetic component for the observed variability in the proportion of Type I fibers in human muscles is on the order of 40–50%, indicating that muscle fiber-type composition is determined by both genotype and environment. This article briefly reviews current progress in the understanding of genetic determinism of fiber-type proportion in human skeletal muscle. Several polymorphisms of genes involved in the calcineurin–NFAT pathway, mitochondrial biogenesis, glucose and lipid metabolism, cytoskeletal function, hypoxia and angiogenesis, and circulatory homeostasis have been associated with fiber-type composition. As muscle is a major contributor to metabolism and physical strength and can readily adapt, it is not surprising that many of these gene variants have been associated with physical performance and athlete status, as well as metabolic and cardiovascular diseases. Genetic variants associated with fiber-type proportions have important implications for our understanding of muscle function in both health and disease.

Carnitine metabolism in human muscle fiber types during submaximal dynamic exercise

1996 ◽  
Vol 80 (3) ◽  
pp. 1061-1064 ◽  
Author(s):  
D. Constantin-Teodosiu ◽  
S. Howell ◽  
P. L. Greenhaff
Keyword(s):  
Muscle Fiber ◽  
Fiber Type ◽  
Vastus Lateralis ◽  
Group Formation ◽  
Free Carnitine ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Carnitine Metabolism ◽  
Type I Fibers

The effect of prolonged exhaustive exercise on free carnitine and acetylcarnitine concentrations in mixed-fiber skeletal muscle and in type I and II muscle fibers was investigated in humans. Needle biopsy samples were obtained from the vastus lateralis of six subjects immediately after exhaustive one-legged cycling at approximately 75% of maximal O2 uptake from both the exercised and nonexercised (control) legs. In the resting (control) leg, there was no difference in the free carnitine concentration between type I and II fibers (20.36 +/- 1.25 and 20.51 +/- 1.16 mmol/kg dry muscle, respectively) despite the greater potential for fat oxidation in type I fibers. However, the acetylcarnitine concentration was slightly greater in type I fibers (P < 0.01). During exercise, acetylcarnitine accumulation occurred in both muscle fiber types, but accumulation was greatest in type I fibers (P < 0.005). Correspondingly, the concentration of free carnitine was significantly lower in type I fibers at the end of exercise (P < 0.001). The sum of free carnitine and acetylcarnitine concentrations in type I and II fibers at rest was similar and was unchanged by exercise. In conclusion, the findings of the present study support the suggestion that carnitine buffers excess acetyl group formation during exercise and that this occurs in both type I and II fibers. However, the greater accumulation of acetylcarnitine in type I fibers during prolonged exercise probably reflects the greater mitochondrial content of this fiber type.

Fiber type-specific determinants of V maxfor insulin-stimulated muscle glucose uptake in vivo

2003 ◽  
Vol 284 (3) ◽  
pp. E541-E548 ◽  
Author(s):  
Hilary Ann Petersen ◽  
Patrick T. Fueger ◽  
Deanna P. Bracy ◽  
David H. Wasserman ◽  
Amy E. Halseth
Keyword(s):  
Glucose Uptake ◽  
Fiber Type ◽  
Type I ◽  
Fiber Types ◽  
Maximal Velocity ◽  
Glucose Flux ◽  
Steady State Levels ◽  
Type I Fibers ◽  
Relationship Of

The aim of this study was to determine barriers limiting muscle glucose uptake (MGU) during increased glucose flux created by raising blood glucose in the presence of fixed insulin. The determinants of the maximal velocity ( V max) of MGU in muscles of different fiber types were defined. Conscious rats were studied during a 4 mU · kg−1 · min−1insulin clamp with plasma glucose at 2.5, 5.5, and 8.5 mM. [U-14C]mannitol and 3- O-methyl-[3H]glucose ([3H]MG) were infused to steady-state levels ( t = −180 to 0 min). These isotope infusions were continued from 0 to 40 min with the addition of a 2-deoxy-[3H]glucose ([3H]DG) infusion. Muscles were excised at t = 40 min. Glucose metabolic index (Rg) was calculated from muscle-phosphorylated [3H]DG. [U-14C]mannitol was used to determine extracellular (EC) H2O. Glucose at the outer ([G]om) and inner ([G]im) sarcolemmal surfaces was determined by the ratio of [3H]MG in intracellular to EC H2O and muscle glucose. Rg was comparable at the two higher glucose concentrations, suggesting that rates of uptake near V max were reached. In summary, by defining the relationship of arterial glucose to [G]om and [G]im in the presence of fixed hyperinsulinemia, it is concluded that 1) V max for MGU is limited by extracellular and intracellular barriers in type I fibers, as the sarcolemma is freely permeable to glucose; 2) V max is limited in muscles with predominantly type IIb fibers by extracellular resistance and transport resistance; and 3) limits to Rg are determined by resistance at multiple steps and are better defined by distributed control rather than by a single rate-limiting step.

Effects of ACE inhibition and beta-blockade on skeletal muscle fiber types in dogs with moderate heart failure

1996 ◽  
Vol 270 (1) ◽  
pp. H115-H120 ◽  
Author(s):  
H. N. Sabbah ◽  
H. Shimoyama ◽  
V. G. Sharov ◽  
T. Kono ◽  
R. C. Gupta ◽  
...  
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Exercise Intolerance ◽  
Beta Blockade ◽  
Muscle Fiber Types ◽  
Type I ◽  
Fiber Types ◽  
Type Ii ◽  
Early Therapy ◽  
Type I Fibers

The proportion of slow-twitch, fatigue-resistant type 1 skeletal muscle (SM) fibers is often reduced in heart failure (HF), while the proportion of fatigue-sensitive type-II fibers increases. This maladaptation may be partially responsible for the exercise intolerance that characterize HF. In this study, we examined the effects of early monotherapy with the angiotensin-converting enzyme inhibor, enalapril, and the beta-blocker, metoprolol, on SM fiber type composition in 18 dogs with moderate HF produced by intracoronary microembolizations. HF dogs were randomized to 3 mo therapy with enalapril (10 mg twice daily), metoprolol (25 mg twice daily), or no treatment. Triceps muscle biopsies were obtained at baseline, before randomization, and at the end of 30 mo of therapy. Type I and type II SM fibers were differentiated by myofibrillar adenosinetriphosphatase (pH 9.4). In untreated dogs, the proportion of type I fibers was 27 +/- 1% before randomization and decreased to 23 +/- 1% (P < 0.05) at the end of 3 mo of follow up. In dogs treated with enalapril or metoprolol, the proportion of type I fibers was 30 +/- 4 and 28 +/- 2% before randomization and 33 +/- 4 and 33 +/- 1%, respectively, after 3 mo of therapy. In conclusion, in dogs with moderate HF, early therapy with enalapril or metoprolol prevents the progressive decline in the proportion of type I SM fibers.

scholarly journals Substrate profile in rat soleus muscle fibers after hindlimb unloading and fatigue

2000 ◽  
Vol 88 (2) ◽  
pp. 473-478 ◽  
Author(s):  
Varvara P. Grichko ◽  
Anne Heywood-Cooksey ◽  
Kameha R. Kidd ◽  
Robert H. Fitts
Keyword(s):  
Contractile Activity ◽  
Hindlimb Unloading ◽  
Type I ◽  
Fiber Types ◽  
Freeze Dried ◽  
Slow Type ◽  
Utilization Patterns ◽  
Rat Soleus Muscle ◽  
Type I Fibers ◽  
Gastrocnemius Muscles

Limb muscles from rats flown in space and after hindlimb unloading (HU) show an increased fatigability, and spaceflight has been shown to result in a reduced ability to oxidize fatty acids. The purpose of this investigation was to determine the effects of HU on the substrate content in fast- and slow-twitch fibers and to assess the substrate utilization patterns in single slow type I fibers isolated from control and HU animals. A second objective was to assess whether HU altered the ability of the heart or limb muscle to oxidize pyruvate or palmitate. After 2 wk of HU, single fibers were isolated from the freeze-dried soleus and gastrocnemius muscles. HU increased the glycogen content in all fiber types, and it increased lactate, ATP, and phosphocreatine in the slow type I fiber. After HU, the type I fiber substrate profile was shifted toward that observed in fast fibers. For example, fiber glycogen increased from 179 ± 16 to 285 ± 25 mmol/kg dry wt, which approached the 308 ± 23 mmol/kg dry wt content observed in the post-HU type IIa fiber. With contractile activity, the type I fiber from the HU animal showed a greater utilization of glycogen and accumulation of lactate compared with the control type I fiber. HU had no effect on the ability of crude homogenate or mitochondria fractions from the soleus or gastrocnemius to oxidize pyruvate or palmitate. The increased fatigability after HU may have resulted from an elevated glycolysis producing an increased cell lactate and a decreased pH.

Induction of beta-MHC transgene in overloaded skeletal muscle is not eliminated by mutation of conserved elements

1996 ◽  
Vol 271 (2) ◽  
pp. C690-C699 ◽  
Author(s):  
G. L. Tsika ◽  
J. L. Wiedenman ◽  
L. Gao ◽  
J. J. McCarthy ◽  
K. Sheriff-Carter ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Specific Activity ◽  
Fold Increase ◽  
Histochemical Staining ◽  
Type I ◽  
Plantaris Muscle ◽  
Mechanical Overload ◽  
Type I Fibers ◽  
Fast Twitch ◽  
Cat Expression

Mechanical overload leads to hypertrophy, increased type I fiber composition, and beta-myosin heavy chain (beta-MHC) induction in the fast-twitch plantaris muscle. To better understand the mechanism(s) involved in beta-MHC induction, we have examined inducible expression of transgenes carrying the simultaneous mutation of three DNA regulatory subregions [muscle CAT (MCAT), C-rich, and beta e3] in the context of either 5,600-base pair (bp; beta 5.6mut3) or 600-bp (beta 0.6mut3) beta-MHC promoter in overloaded plantaris muscles of transgenic mice. Protein extract from mechanically overloaded plantaris muscle of mice, harboring either mutant transgene beta 5.6mut3 or beta 0.6mut3, showed an unexpected 2.8- to 4.5-fold increase in chloramphenicol acetyltransferase (CAT) specific activity relative to their respective controls. Similar results were obtained with wild-type (wt) beta-MHC transgenes (beta 5.6wt, beta 0.6wt). Histochemical staining for both myofibrillar ATPase and CAT activity and CAT immunohistochemistry revealed a striking increase in type I fibers and that CAT expression was restricted to these fibers in overloaded plantaris muscle of beta 5.6mut3 transgenic mice. Our transgenic data suggest that beta-MHC transgenes, and perhaps the endogenous beta-MHC gene, are induced by mechanical overload via a mechanism(s) that does not exclusively require the MCAT, C-rich, or beta e3 subregions.

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