In vitro O2 uptake and histochemical fiber type of resting hamster muscles

1984 ◽  
Vol 57 (1) ◽  
pp. 246-253 ◽  
Author(s):  
S. M. Sullivan ◽  
R. N. Pittman
Keyword(s):  
Surface Area ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Histochemical Staining ◽  
Striated Muscles ◽  
Type Composition ◽  
Slow Twitch ◽  
Pattern Number ◽  
Fast Twitch

In vitro oxygen consumption (VO2), histochemical fiber type, capillary arrangement, and muscle fiber geometry were measured in three hamster striated muscles. These muscles varied markedly in their histochemical fiber type composition (% by number): retractor (70% FG, fast-twitch, glycolytic; 16% FOG, fast-twitch, oxidative-glycolytic; 14% SO, slow-twitch, oxidative); soleus (57% FOG, 43% SO), and sartorius (98% FG, 2% FOG). Sartorius VO2 [0.80 +/- 0.034 (SE) ml O2 X min-1 X 100 g-1] was significantly different (P less than 0.01) from VO2 of retractor (0.89 +/- 0.038) and soleus (1.00 +/- 0.048).The number of capillaries around a fiber and the surface area/volume were greater for FOG and SO fibers than for FG fibers. Fibers of all types appeared to be roughly elliptical in shape. Capillaries were uniformly distributed around fibers in the soleus, but they were located more toward the ends of the major diameter in the retractor and sartorius. The results suggest a relationship among a fiber's oxidative capacity (based on its histochemical staining pattern), number of surrounding capillaries and surface area/volume. Furthermore, results suggest that VO2 and capillary spacing around a fiber may depend on fiber type.

Pretranslational regulation of myoglobin gene expression

1987 ◽  
Vol 252 (4) ◽  
pp. C450-C453 ◽  
Author(s):  
L. E. Underwood ◽  
R. S. Williams
Keyword(s):  
Gene Expression ◽  
Tibialis Anterior ◽  
Skeletal Muscles ◽  
Blot Hybridization ◽  
Oxidative Capacity ◽  
Striated Muscles ◽  
Mrna Content ◽  
Slow Twitch ◽  
Rna Probe ◽  
Fast Twitch

We have used blot hybridization techniques and a specific anti-sense RNA probe to determine whether variation in myoglobin gene expression among mammalian striated muscles is attributable to pretranslational regulatory events. We observed that myoglobin mRNA was expressed to approximately 10- and 5-fold greater levels, respectively, in cardiac and soleus (slow-twitch, oxidative, skeletal) muscles of adult rabbits than in tibialis anterior (fast-twitch, glycolytic, skeletal) muscles. Furthermore, when oxidative capacity of tibialis anterior muscles was increased by 21 days of indirect electrical stimulation, a model of exercise conditioning, myoglobin mRNA content increased approximately 15-fold. We conclude that pretranslational mechanisms are important in regulation of myoglobin gene expression in mammalian muscles.

scholarly journals Calcineurin Is Necessary for the Maintenance but Not Embryonic Development of Slow Muscle Fibers

2005 ◽  
Vol 25 (15) ◽  
pp. 6629-6638 ◽  
Author(s):  
Misook Oh ◽  
Igor I. Rybkin ◽  
Victoria Copeland ◽  
Michael P. Czubryt ◽  
John M. Shelton ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Oxidative Capacity ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Specific Expression ◽  
Interacting Protein ◽  
Type Composition ◽  
Slow Fiber ◽  
Fast Twitch

ABSTRACT Skeletal muscles are a mosaic of slow and fast twitch myofibers. During embryogenesis, patterns of fiber type composition are initiated that change postnatally to meet physiological demand. To examine the role of the protein phosphatase calcineurin in the initiation and maintenance of muscle fiber types, we used a “Flox-ON” approach to obtain muscle-specific overexpression of the modulatory calcineurin-interacting protein 1 (MCIP1/DSCR1), an inhibitor of calcineurin. Myo-Cre transgenic mice with early skeletal muscle-specific expression of Cre recombinase were used to activate the Flox-MCIP1 transgene. Contractile components unique to type 1 slow fibers were absent from skeletal muscle of adult Myo-Cre/Flox-MCIP1 mice, whereas oxidative capacity, myoglobin content, and mitochondrial abundance were unaltered. The soleus muscles of Myo-Cre/Flox-MCIP1 mice fatigued more rapidly than the wild type as a consequence of the replacement of the slow myosin heavy chain MyHC-1 with a fast isoform, MyHC-2A. MyHC-1 expression in Myo-Cre/Flox-MCIP1 embryos and early neonates was normal. These results demonstrate that developmental patterning of slow fibers is independent of calcineurin, while the maintenance of the slow-fiber phenotype in the adult requires calcineurin activity.

Slow to fast alterations in skeletal muscle fibers caused by clenbuterol, a beta 2-receptor agonist

1988 ◽  
Vol 254 (6) ◽  
pp. E726-E732 ◽  
Author(s):  
R. J. Zeman ◽  
R. Ludemann ◽  
T. G. Easton ◽  
J. D. Etlinger
Keyword(s):  
Muscle Fiber ◽  
Receptor Agonist ◽  
Fiber Type ◽  
Fiber Types ◽  
Cross Sectional ◽  
Type Composition ◽  
Slow Twitch ◽  
Beta 2 ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Chronic treatment of rats with clenbuterol, a beta 2-receptor agonist (8–12 wk), caused hypertrophy of histochemically identified fast- but not slow-twitch fibers within the soleus, while the mean areas of both fiber types were increased in the extensor digitorum longus (EDL). In contrast, treatment with the beta 2-receptor antagonist, butoxamine, reduced fast-twitch fiber size in both muscles. In the solei and to a lesser extent in the EDLs, the ratio of the number of fast- to slow-twitch fibers was increased by clenbuterol, while the opposite was observed with butoxamine. The muscle fiber hypertrophy observed in the EDL was accompanied by parallel increases in maximal tetanic tension and muscle cross-sectional area, while in the solei, progressive increases in rates of force development and relaxation toward values typical of fast-twitch muscles were also observed. Our results suggest a role of beta 2-receptors in regulating muscle fiber type composition as well as growth.

Biochemical and physiological changes in overloaded rat fast- and slow-twitch ankle extensors

1985 ◽  
Vol 59 (2) ◽  
pp. 639-646 ◽  
Author(s):  
R. R. Roy ◽  
K. M. Baldwin ◽  
T. P. Martin ◽  
S. P. Chimarusti ◽  
V. R. Edgerton
Keyword(s):  
Fiber Type ◽  
Relaxation Times ◽  
Glycogen Metabolism ◽  
Medial Gastrocnemius ◽  
Cross Sectional ◽  
Muscle Region ◽  
Type Composition ◽  
Contraction Times ◽  
Slow Twitch ◽  
Fast Twitch

The rat soleus (SOL) or medial gastrocnemius (MG) were chronically overloaded by removing their major synergists bilaterally. After 12–14 wks the overloaded SOL (OS) and overloaded MG (OMG) muscles had approximately 50% greater cross-sectional areas (CSA) than the controls. Maximum twitch (Pt) and tetanic (Po) tensions were approximately 46% larger in the OS compared with the normal SOL. The OMG produced 10 and 37% higher Pt and Po, respectively. Specific tension (Po/CSA) was not altered in either group (P greater than 0.05). Contraction times and half-relaxation times were unchanged. Myofibrillar and myosin ATPase specific activities indicated a shift toward that resembling a slower muscle in both the OS and the red portion but not the white portion of the OMG. Generally, markers of glycogen metabolism were reduced (P less than 0.05) in the same muscle areas that showed reduced ATPase activity. These biochemical results were consistent with the apparent histochemical conversion of fibers from fast-twitch, glycolytic----fast-twitch, oxidative-glycolytic----slow-twitch, oxidative types in these muscle areas. These results suggest that overloading either a fast- or slow-twitch plantarflexor results in an increase in muscle mass and maximum tension and in metabolic shifts that generally resemble those observed in a slower muscle. Further, the degree of adaptation appears to be related to the initial fiber type composition of the muscle and/or of the muscle region.

The effects of PGC-1α on control of microvascular Po2 kinetics following onset of muscle contractions

2014 ◽  
Vol 117 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Yutaka Kano ◽  
Shinji Miura ◽  
Hiroaki Eshima ◽  
Osamu Ezaki ◽  
David C. Poole
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Endurance Performance ◽  
Oxidative Capacity ◽  
Muscle Contractions ◽  
Peroxisome Proliferator ◽  
Peroxisome Proliferator Activated Receptor ◽  
Phosphorescence Quenching ◽  
Slow Twitch ◽  
Fast Twitch

During contractions, regulation of microvascular oxygen partial pressure (Pmvo2), which drives blood-myocyte O2 flux, is a function of skeletal muscle fiber type and oxidative capacity and can be altered by exercise training. The kinetics of Pmvo2 during contractions in predominantly fast-twitch muscles evinces a more rapid fall to far lower levels compared with slow-twitch counterparts. Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) improves endurance performance, in part, due to mitochondrial biogenesis, a fiber-type switch to oxidative fibers, and angiogenesis in skeletal muscle. We tested the hypothesis that improvement of exercise capacity by genetic overexpression of PGC-1α would be associated with an altered Pmvo2 kinetics profile of the fast-twitch (white) gastrocnemius during contractions toward that seen in slow-twitch muscles (i.e., slowed response kinetics and elevated steady-state Pmvo2). Phosphorescence quenching techniques were used to measure Pmvo2 at rest and during separate bouts of twitch (1 Hz) and tetanic (100 Hz) contractions in gastrocnemius muscles of mice with overexpression of PGC-1α and wild-type littermates (WT) mice under isoflurane anesthesia. Muscles of PGC-1α mice exhibited less fatigue than WT ( P < 0.01). However, except for the Pmvo2 response immediately following onset of contractions, WT and PGC-1α mice demonstrated similar Pmvo2 kinetics. Specifically, the time delay of the Pmvo2 response was shortened in PGC-1α mice compared with WT (1 Hz: WT, 6.6 ± 2.4 s; PGC-1α, 2.9 ± 0.8 s; 100 Hz: WT, 3.3 ± 1.1 s, PGC-1α, 0.9 ± 0.3 s, both P < 0.05). The ratio of muscle force to Pmvo2 was higher for the duration of tetanic contractions in PGC-1α mice. Slower dynamics and maintenance of higher Pmvo2 following muscle contractions is not obligatory for improved fatigue resistance in fast-twitch muscle of PGC-1α mice. Moreover, overexpression of PGC-1α may accelerate O2 utilization kinetics to a greater extent than O2 delivery kinetics.

Age and training alter collagen characteristics in fast- and slow-twitch rat limb muscle

1993 ◽  
Vol 75 (4) ◽  
pp. 1670-1674 ◽  
Author(s):  
S. D. Zimmerman ◽  
R. J. McCormick ◽  
R. K. Vadlamudi ◽  
D. P. Thomas
Keyword(s):  
Fiber Type ◽  
Treadmill Running ◽  
Interactive Effects ◽  
Maximal Aerobic Capacity ◽  
Fischer 344 ◽  
Type Composition ◽  
Degradation Rates ◽  
Slow Twitch ◽  
Fast Twitch ◽  
And Training

This study evaluated the single and interactive effects of age and training status on selected collagen parameters in two rodent locomotor skeletal muscles contrasting in fiber type composition. Gastrocnemius (GAST) and soleus (SOL) muscles from both trained (10 wk of daily treadmill running) and sedentary young adult (5-mo-old), middle-aged (15-mo-old), and old (23-mo-old) female Fischer 344 rats were evaluated for concentrations of collagen (measured by hydroxyproline concentration ([OH-Pro])) and of the predominant nonreducible lysine aldehyde-derived collagen cross-link hydroxylysylpyridinoline ([HP]). Maximal aerobic capacity was significantly elevated in all three trained groups compared with sedentary age-matched control groups. Slow-twitch SOL had a significantly higher [OH-Pro] than fast-twitch GAST (P < 0.05). Although aging had no effect on [OH-Pro] in GAST, in SOL a significant increase with age was seen (P < 0.02). In sedentary rats both GAST and SOL [HP] increased with age, with this increase being more pronounced for SOL. Additionally, although training had no effect on the aging-associated increase in GAST [HP], it prevented the rise seen in SOL. The observed training-induced reduction in SOL [HP] presumably reflects exercise recruitment and subsequent stimulation of collagen synthesis and degradation rates in this muscle. We conclude that both aging and training affect the extracellular matrix in rodent limb skeletal muscle.

Diaphragm arterioles are less responsive to α1- adrenergic constriction than gastrocnemius arterioles

2002 ◽  
Vol 92 (5) ◽  
pp. 1808-1816 ◽  
Author(s):  
Aaron Aaker ◽  
M. H. Laughlin
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Gastrocnemius Muscle ◽  
Fiber Type ◽  
Muscle Blood Flow ◽  
Oxidative Capacity ◽  
Receptor Stimulation ◽  
Exercise Induced ◽  
Fast Twitch

The sympathetic nervous system has greater influence on vascular resistance in low-oxidative, fast-twitch skeletal muscle than in high-oxidative skeletal muscle (17). The purpose of this study was to test the hypothesis that arterioles isolated from low-oxidative, fast-twitch skeletal muscle [the white portion of gastrocnemius (WG)] possess greater responsiveness to adrenergic constriction than arterioles isolated from high-oxidative skeletal muscle [red portion of the gastrocnemius muscle (RG) and diaphragm (Dia)]. Second-order arterioles (2As) were isolated from WG, RG, and Dia of rats and reactivity examined in vitro. Results reveal that Dia 2As constrict less to norepinephrine (NE) (10−9 to 10 −4 M) than 2As from RG and WG, which exhibited similar NE-induced constrictions. This difference was not endothelium dependent, because responses of denuded 2As were similar to those of intact arterioles. The blunted NE-induced constrictor response of Dia 2As appears to be the result of differences in α1-receptor effects because 1) arterioles from Dia also responded less to selective α1-receptor stimulation with phenylephrine than RG and WG arterioles; 2) arterioles from Dia, RG, and WG dilated similarly to isoproterenol (10−9 to 10−4 M) and did not respond to selective α2-receptor stimulation with UK-14304; and 3) endothelin-1 produced similar constriction in 2As from Dia, RG, and WG. We conclude that differences in oxidative capacity and/or fiber type composition of muscle tissue do not explain different NE responsiveness of Dia 2As compared with 2As from gastrocnemius muscle. Differences in α1-adrenergic constrictor responsiveness among arterioles in skeletal muscle may contribute to nonuniform muscle blood flow responses observed during exercise and serve to maintain blood flow to Dia during exercise-induced increases in sympathetic nerve activity.

Influence of fiber-type composition on recovery from tourniquet-induced skeletal muscle ischemia–reperfusion injury

2008 ◽  
Vol 33 (2) ◽  
pp. 272-281 ◽  
Author(s):  
Thomas J. Walters ◽  
John F. Kragh ◽  
David G. Baer
Keyword(s):  
Reperfusion Injury ◽  
Ischemia Reperfusion Injury ◽  
Contractile Function ◽  
Fiber Type ◽  
Ischemia Reperfusion ◽  
Fiber Types ◽  
Fiber Type Composition ◽  
Type Composition ◽  
Slow Twitch ◽  
Fast Twitch

This study was designed to determine if previously reported differences in the functional impairment of muscles composed of predominantly different fiber types occurs following extended periods of ischemia. We hypothesized that the soleus (Sol) muscle, a predominantly slow-twitch muscle, would be less vulnerable to tourniquet-induced ischemia–reperfusion than the plantaris (Plant), a predominantly fast-twitch muscle, as determined by the assessment of isometric contractile function. Male Sprague–Dawley rats were assigned to one of the following groups to undergo tourniquet application (TKA) (n = 6/group): 2 h TKA, 2 d recovery; 4 h TKA, 2 d recovery; 2 h TKA, 14 d recovery; or 4 h TKA, 14 d recovery. In situ isometric contractile properties were assessed in the predominantly slow-twitch Sol and the predominantly fast-twitch Plant; the contralateral muscle served as the internal control. At 2 d, muscle contraction could not be elicited via neural stimulation, but muscles did contract with direct stimulation, which indicates neural injury. This condition was resolved by day 14. At this time point, tetanic tension (Po) in the Plant was reduced by 45% and 69% in the 2 and 4 h groups, respectively. Po for the Sol was unaffected in the 2 h group, but was reduced by 30% in the 4 h group. The fatigue resistance of the Plant was increased 2 fold in the 4 h group and was unchanged in all other groups. These results demonstrate that vulnerability to tourniquet-induced ischemia–reperfusion injury is dramatically different with respect to muscle fiber-type composition.

Studies of the halothane-cooling contractures of skeletal muscle

1987 ◽  
Vol 65 (4) ◽  
pp. 697-703 ◽  
Author(s):  
Roberto T. Sudo ◽  
Gisele Zapata ◽  
Guilherme Suarez-Kurtz
Keyword(s):  
Skeletal Muscle ◽  
Synergistic Effects ◽  
Rabbit Muscle ◽  
Slow Twitch ◽  
Fast Twitch ◽  
Dose Dependent ◽  
Muscle Biopsies ◽  
Ca Homeostasis ◽  
Potential Use

The characteristics of transient contractures elicited by rapid cooling of frog or mouse muscles perfused in vitro with solutions equilibrated with 0.5–2.0% halothane are reviewed. The data indicate that these halothane-cooling contractures are dose dependent and reproducible, and their amplitude is larger in muscles containing predominantly slow-twitch type fibers, such as the mouse soleus, than in muscles in which fast-twitch fibers predominate, such as the mouse extensor digitorum longus. The halothane-cooling contractures are potentiated in muscles exposed to succinylcholine. The effects of Ca2+-free solutions, of the local anesthetics procaine, procainamide, and lidocaine, and of the muscle relaxant dantrolene on the halothane-cooling contractures are consistent with the proposal that the halothane-cooling contractures result from synergistic effects of halothane and low temperature on Ca sequestration by the sarcoplasmic reticulum. Preliminary results from skinned rabbit muscle fibers support this proposal. The halothane concentrations required for the halothane-cooling contractures of isolated frog or mouse muscles are comparable with those observed in serum of patients during general anesthesia. Accordingly, fascicles dissected from muscle biopsies of patients under halothane anesthesia for programmed surgery develop large contractures when rapidly cooled. The amplitude of these halothane-cooling contractures declined with the time of perfusion of the muscle fascicles in vitro with halothane-free physiological solutions. It is suggested that the halothane-cooling contractures could be used as a simple experimental model for the investigation of the effects of halothane on Ca homeostasis and contractility in skeletal muscle and for study of drugs of potential use in the management of the contractures associated with the halothane-induced malignant hyperthermia syndrome. It is shown that salicylates, but not indomethacin or mefenamic acid, inhibit the halothane-cooling contractures.

scholarly journals lncRNA-Six1 Is a Target of miR-1611 that Functions as a ceRNA to Regulate Six1 Protein Expression and Fiber Type Switching in Chicken Myogenesis

Cells ◽  
2018 ◽  
Vol 7 (12) ◽  
pp. 243 ◽  
Author(s):  
Manting Ma ◽  
Bolin Cai ◽  
Liang Jiang ◽  
Bahareldin Ali Abdalla ◽  
Zhenhui Li ◽  
...  
Keyword(s):  
Fiber Type ◽  
Muscle Fibers ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Proliferation And Differentiation ◽  
Slow Twitch Muscle ◽  
Fast Twitch Muscle ◽  
Slow Twitch ◽  
Slow Twitch Fibers ◽  
Fast Twitch

Emerging studies indicate important roles for non-coding RNAs (ncRNAs) as essential regulators in myogenesis, but relatively less is known about their function. In our previous study, we found that lncRNA-Six1 can regulate Six1 in cis to participate in myogenesis. Here, we studied a microRNA (miRNA) that is specifically expressed in chickens (miR-1611). Interestingly, miR-1611 was found to contain potential binding sites for both lncRNA-Six1 and Six1, and it can interact with lncRNA-Six1 to regulate Six1 expression. Overexpression of miR-1611 represses the proliferation and differentiation of myoblasts. Moreover, miR-1611 is highly expressed in slow-twitch fibers, and it drives the transformation of fast-twitch muscle fibers to slow-twitch muscle fibers. Together, these data demonstrate that miR-1611 can mediate the regulation of Six1 by lncRNA-Six1, thereby affecting proliferation and differentiation of myoblasts and transformation of muscle fiber types.

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