Blood flow to different skeletal muscle fiber types during contraction

1983 ◽  
Vol 245 (2) ◽  
pp. H265-H275 ◽  
Author(s):  
B. G. Mackie ◽  
R. L. Terjung

Blood flow to fast-twitch red (FTR), fast-twitch white (FTW), and slow-twitch red (STR) muscle fiber sections of the gastrocnemius-plantaris-soleus muscle group was determined using 15 +/- 3-microns microspheres during in situ stimulation in pentobarbital-anesthetized rats. Steady-state blood flows were assessed during the 10th min of contraction using twitch (0.1, 0.5, 1, 3, and 5 Hz) and tetanic (7.5, 15, 30, 60, and 120/min) stimulation conditions. In addition, an earlier blood flow determination was begun at 3 min (twitch series) or at 30 s (tetanic series) of stimulation. Blood flow was highest in the FTR (220-240 ml X min-1 X 100 g-1), intermediate in the STR (140), and lowest in the FTW (70-80) section during tetanic contraction conditions estimated to coincide with the peak aerobic function of each fiber type. These blood flows are fairly proportional to the differences in oxidative capacity among fiber types. Further, their absolute values are similar to those predicted from the relationship between blood flow and oxidative capacity found by others for dog and cat muscles. During low-frequency contraction conditions, initial blood flow to the FTR and STR sections were excessively high and not dependent on contraction frequency. However, blood flows subsequently decreased to values in keeping with the relative energy demands. In contrast, FTW muscle did not exhibit this time-dependent relative hyperemia. Thus, besides the obvious quantitative differences between skeletal muscle fiber types, there are qualitative differences in blood flow response during contractions. Our findings establish that, based on fiber type composition, a heterogeneity in blood flow distribution can occur within a whole muscle during contraction.

1997 ◽  
Vol 22 (4) ◽  
pp. 307-327 ◽  
Author(s):  
Robert S. Staron

This brief review attempts to summarize a number of studies on the delineation, development, and distribution of human skeletal muscle fiber types. A total of seven fiber types can be identified in human limb and trunk musculature based on the pH stability/ability of myofibrillar adenosine triphosphatase (mATPase). For most human muscles, mATPase-based fiber types correlate with the myosin heavy chain (MHC) content. Thus, each histochemically identified fiber has a specific MHC profile. Although this categorization is useful, it must be realized that muscle fibers are highly adaptable and that innumerable fiber type transients exist. Also, some muscles contain specific MHC isoforms and/or combinations that do not permit routine mATPase-based fiber typing. Although the major populations of fast and slow are, for the most part, established shortly after birth, subtle alterations take place throughout life. These changes appear to relate to alterations in activity and/or hormonal levels, and perhaps later in life, total fiber number. Because large variations in fiber type distribution can be found within a muscle and between individuals, interpretation of data gathered from human muscle is often difficult. Key words: aging, myosin heavy chains, myogenesis, myofibrillar adenosine triphosphate


2005 ◽  
Vol 25 (15) ◽  
pp. 6629-6638 ◽  
Author(s):  
Misook Oh ◽  
Igor I. Rybkin ◽  
Victoria Copeland ◽  
Michael P. Czubryt ◽  
John M. Shelton ◽  
...  

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.


1986 ◽  
Vol 251 (3) ◽  
pp. C395-C402 ◽  
Author(s):  
S. P. Kirkwood ◽  
E. A. Munn ◽  
G. A. Brooks

High-voltage electron microscopy at 1,500 kV was used to examine mitochondrial morphology in three skeletal muscles of the rat. The soleus, deep portion of the vastus lateralis, and superficial portion of the vastus lateralis muscles were examined to represent slow-twitch oxidative, fast-twitch oxidative, glycolytic, and fast-twitch glycolytic skeletal muscle fiber types, respectively. Muscle samples were removed from six female Wistar rats. The tissues were fixed using standard electron microscopic techniques and were sectioned transversely with respect to muscle fiber orientation to approximately 0.5-micron thickness. The sections were stained on grids with uranyl acetate and Reynolds' lead citrate. Results revealed a mitochondrial reticulum in all three skeletal muscle fiber types. Stereological analyses of the electron micrographs were performed to measure volume densities and surface-to-volume ratios of mitochondria in the muscle samples. Cross-sectional volume densities of mitochondria in the soleus (15.5 +/- 1%) and deep portion of the vastus lateralis (16.1 +/- 2%) were significantly greater (P less than 0.05) than in the superficial portion of the vastus lateralis (8.7 +/- 1%). Surface-to-volume ratios of mitochondria were not significantly different between fiber types. It was concluded that the mitochondria in mammalian limb skeletal muscle are a reticulum, or network.


2003 ◽  
Vol 100 (13) ◽  
pp. 7791-7796 ◽  
Author(s):  
J. V. Chakkalakal ◽  
M. A. Stocksley ◽  
M.-A. Harrison ◽  
L. M. Angus ◽  
J. Deschenes-Furry ◽  
...  

1996 ◽  
Vol 270 (4) ◽  
pp. C1067-C1074 ◽  
Author(s):  
P. C. Tullson ◽  
P. G. Arabadjis ◽  
K. W. Rundell ◽  
R. L. Terjung

Inosine 5'-monophosphate (IMP) reamination in skeletal muscle fiber sections of the rat hindlimb was studied. High IMP concentrations were established during ischemic contractions in each fiber section: 3.1, 2.8, or 0.6 mumol/g in the fast-twitch white (FTW), fast-twitch red (FTR), and slow-twitch red (STR) muscle sections, respectively. Thereafter blood flow was restored and stimulation was discontinued to allow reamination of IMP. After 0, 2, 5, 10, 15, or 20 min of recovery, muscle sections were freeze-clamped and analyzed for metabolite contents. IMP was nearly fully reaminated after 10 and 20 min of recovery in STR and FTR muscles, respectively. Reamination in TW fibers was delayed and slower, with only 50% of the IMP reaminated after 20 min of recovery. Significant recovery (approximately 75%) of phosphocreatine occurs in each fiber section before the onset of reamination. Reamination was also evaluated after high-speed treadmill running with or without inhibition of reamination by hadacidin. Running resulted in large accumulations of IMP in FTW and FTR fibers (3.5 and 1.4 mumul/g, respectively); IMP in FTR fibers was higher with hadacidin treatment. Reamination after running was much greater in FTR than in FTW fibers and was associated with recovery of phosphocreatine. After running, the purine degradation products inosine and hypoxanthine were increased in FTW and FTR fibers in normal and hadacidin-treated animals. Plasma inosine, hypoxanthine, and urate increased after exercise; concentrations continued to increase if reamination was inhibited by hadacidin. These results demonstrate that when muscle IMP is increased, subsequent degradation and loss of purines occur. Rapid reamination should minimize the quantity of purine lost from muscle and limit the metabolic cost of replenishing purines by the de novo synthesis or salvage pathways.


2015 ◽  
Vol 309 (7) ◽  
pp. F638-F647 ◽  
Author(s):  
Luz M. Acevedo ◽  
Alan Peralta-Ramírez ◽  
Ignacio López ◽  
Verónica E. Chamizo ◽  
Carmen Pineda ◽  
...  

This study describes fiber-type adaptations in hindlimb muscles, the interaction of sex, and the role of hypoxia on this response in 12-wk ⅚ nephrectomized rats (Nx). Contractile, metabolic, and morphological features of muscle fiber types were assessed in the slow-twitch soleus and the fast-twitch tibialis cranialis muscles of Nx rats, and compared with sham-operated controls. Rats of both sexes were considered in both groups. A slow-to-fast fiber-type transformation occurred in the tibialis cranialis of Nx rats, particularly in males. This adaptation was accomplished by impaired oxidative capacity and capillarity, increased glycolytic capacity, and no changes in size and nuclear density of muscle fiber types. An oxidative-to-glycolytic metabolic transformation was also found in the soleus muscle of Nx rats. However, a modest fast-to-slow fiber-type transformation, fiber hypertrophy, and nuclear proliferation were observed in soleus muscle fibers of male, but not of female, Nx rats. Serum testosterone levels decreased by 50% in male but not in female Nx rats. Hypoxia-inducible factor-1α protein level decreased by 42% in the tibialis cranialis muscle of male Nx rats. These data demonstrate that 12 wk of Nx induces a muscle-specific adaptive response in which myofibers do not change (or enlarge minimally) in size and nuclear density, but acquire markedly different contractile and metabolic characteristics, which are accompanied by capillary rarefaction. Muscle function and sex play relevant roles in these adaptations.


1993 ◽  
Vol 264 (5) ◽  
pp. C1246-C1251 ◽  
Author(s):  
P. G. Arabadjis ◽  
P. C. Tullson ◽  
R. L. Terjung

To determine the capacity for purine nucleotide degradation among skeletal muscle fiber types, we established energy-depleted conditions in muscles of the rat hindlimb by inducing muscle contraction during ischemia. After 5, 10, 15, or 20 min of ischemic contractions, representative muscle sections were freeze-clamped and analyzed for purine nucleotides, nucleosides, and bases. Fast-twitch muscle sections accumulated about fourfold more IMP than the slow-twitch red soleus muscle. Inosine begins to accumulate at < 0.5 mumol/g IMP in slow-twitch muscle and at approximately 2 mumol/g IMP in fast-twitch muscle. This suggests that inosine is formed intracellularly by 5'-nucleotidase acting on IMP and that the activity and/or substrate affinity of the 5'-nucleotidase present in slow-twitch muscle may be higher than in fast-twitch muscle. At similar concentrations of precursor IMP, slow-twitch muscle has a greater capacity for purine nucleoside formation and should be more dependent on salvage and de novo synthesis of purine for the maintenance of muscle adenine nucleotides. Fast-twitch muscles are better able to retain IMP for subsequent reamination due to their lower capacity to degrade IMP to inosine.


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