Endothelium-dependent vasodilation in different rat hindlimb skeletal muscles

2003 ◽  
Vol 94 (5) ◽  
pp. 1777-1784 ◽  
Author(s):  
Richard M. McAllister
Keyword(s):  
Skeletal Muscles ◽  
Gastrocnemius Muscle ◽  
Perfusion Pressure ◽  
Fiber Type ◽  
Peak Effect ◽  
Variable Pressure ◽  
Constant Flow ◽  
Rat Skeletal Muscle ◽  
Type Composition ◽  
Muscle Groups

Few studies have examined potential for endothelium-dependent vasodilation in skeletal muscles of different fiber-type composition. We hypothesized that muscles composed of slow oxidative (SO)- and/or fast oxidative glycolytic (FOG)-type fibers have greater potential for endothelium-dependent vasodilation than muscles composed of fast glycolytic (FG)-type fibers. To test this hypothesis, the isolated perfused rat hindlimb preparation was used with a constant-flow, variable-pressure approach. Perfusion pressure was monitored continuously, and muscle-specific flows were determined by using radiolabeled microspheres at four time points: control, at peak effect of acetylcholine (ACh I; 1–2 × 10−4 M), at peak effect of ACh after infusion of an endothelial inhibitor (ACh II), and at peak effect of sodium nitroprusside (SNP; 4–5 × 10−4 M). Conductance was calculated by using pressure and flow data. In the SO-type soleus muscle, conductance increased with ACh and SNP, but the increase in conductance with ACh was partially abolished by the endothelial inhibitor N G-nitro-l-arginine methyl ester (control, 0.87 ± 0.19; ACh I, 2.07 ± 0.29; ACh II, 1.32 ± 0.15; SNP, 1.76 ± 0.19 ml · min−1 · 100 g−1 · mmHg−1; P < 0.05, ACh I and SNP vs. control). In the FOG-type red gastrocnemius muscle, similar findings were obtained (control, 0.64 ± 0.11; ACh I, 1.36 ± 0.21; ACh II, 0.73 ± 0.16; SNP, 1.30 ± 0.21 ml · min−1 · 100 g−1 · mmHg; P < 0.05, ACh I and SNP vs. control). In the FG-type white gastrocnemius muscle, neither ACh nor SNP increased conductance. Similar findings were obtained when muscles were combined into high- and low-oxidative muscle groups. Indomethacin had no effect on responses to ACh. These data indicate that endothelium-dependent vasodilation is exhibited by high-oxidative, but not low-oxidative, rat skeletal muscle. Furthermore, endothelium-dependent vasodilation in high-oxidative muscle appears to be primarily mediated by nitric oxide.

Parvalbumin content in striated muscles of the common shrew (Sorex araneus)

1998 ◽  
Vol 76 (12) ◽  
pp. 2194-2199 ◽  
Author(s):  
J Savolainen ◽  
M Vornanen
Keyword(s):  
Relaxation Time ◽  
Skeletal Muscles ◽  
Gastrocnemius Muscle ◽  
Fiber Type ◽  
Common Shrew ◽  
Isometric Contractions ◽  
Striated Muscles ◽  
Type Composition ◽  
The Common ◽  
Isometric Twitch

The parvalbumin content of mammalian muscles correlates positively with isometric relaxation rate and fiber type IIB frequency of the muscles but negatively with animal size. Since shrews are small-bodied animals with a relatively low number of type IIB fibers, it is of some interest to know how the parvalbumin content of shrew muscle correlates with the above factors. Parvalbumin content in heart, diaphragm, and gastrocnemius muscle of the common shrew, mouse, and rat was determined electrophoretically. Parvalbumin was not found in heart muscle of any species. Shrew diaphragm (0.29 ± 0.04 g/kg) had significantly less parvalbumin than mouse (0.63 ± 0.11 g/kg) or rat (0.54 ± 0.09 g/kg) diaphragm. Similarly, the parvalbumin content of shrew gastrocnemius muscle (0.28 ± 0.04 g/kg) was significantly lower than in that of mouse (2.88 ± 0.38 g/kg) or rat (0.96 ± 0.25 g/kg) gastrocnemius muscle. The isometric twitch of the gastrocnemius muscle was somewhat faster than the twitch of the diaphragm in all three species. The isometric contractions of shrew and mouse skeletal muscles were generally very similar in duration, with the exception of the relaxation time of the gastrocnemius muscle, which was shorter in the mouse. Diaphragm and gastrocnemius muscle of the rat were clearly slower than the respective muscles in the mouse or shrew with regard to both the contraction and relaxation phases. The half-relaxation time of isometric contractions correlated relatively weakly with parvalbumin content of the muscles (r = 0.40) but more strongly with their fiber IIB content (r = 0.81). The unexpectedly low parvalbumin content and relatively slow rate of contraction in shrew skeletal muscles are attributed to the exceptional fiber type composition, i.e., a high proportion of type IID fibers.

Na+-K+-ATPase properties in rat heart and skeletal muscle 3 mo after coronary artery ligation

2005 ◽  
Vol 99 (2) ◽  
pp. 656-664 ◽  
Author(s):  
D. J. Barr ◽  
H. J. Green ◽  
D. S. Lounsbury ◽  
J. W. E. Rush ◽  
J. Ouyang
Keyword(s):  
Coronary Artery ◽  
Skeletal Muscles ◽  
Left Main Coronary Artery ◽  
Fiber Type ◽  
Coronary Artery Ligation ◽  
Ouabain Binding ◽  
Artery Ligation ◽  
Adult Rats ◽  
Type Composition ◽  
Phosphatase Assay

This study was designed to determine whether chronic heart failure (CHF) results in changes in Na+-K+-ATPase properties in heart and skeletal muscles of different fiber-type composition. Adult rats were randomly assigned to a control (Con; n = 8) or CHF ( n = 8) group. CHF was induced by ligation of the left main coronary artery. Examination of Na+-K+-ATPase activity (means ± SE) 12 wk after the ligation measured, using the 3- O-methylfluorescein phosphatase assay (3- O-MFPase), indicated higher ( P < 0.05) levels in soleus (Sol) (250 ± 13 vs. 179 ± 18 nmol·mg protein−1·h−1) and lower ( P < 0.05) levels in diaphragm (Dia) (200 ± 12 vs. 272 ± 27 nmol·mg protein−1·h−1) and left ventricle (LV) (760 ± 62 vs. 992 ± 16 nmol·mg protein−1·h−1) in CHF compared with Con, respectively. Na+-K+-ATPase protein content, measured by the [3H]ouabain binding technique, was higher ( P < 0.05) in white gastrocnemius (WG) (166 ± 12 vs. 135 ± 7.6 pmol/g wet wt) and lower ( P < 0.05) in Sol (193 ± 20 vs. 260 ± 8.6 pmol/g wet wt) and LV (159 ± 10 vs. 221 ± 10 pmol/g wet wt) in CHF compared with Con, respectively. Isoform content in CHF, measured by Western blot techniques, showed both increases (WG; P < 0.05) and decreases (Sol; P < 0.05) in α1. For α2, only increases [red gastrocnemius (RG), Sol, and Dia; P < 0.05] occurred. The β2-isoform was decreased (LV, Sol, RG, and WG; P < 0.05) in CHF, whereas the β1 was both increased (WG and Dia; P < 0.05) and decreased (Sol and LV; P < 0.05). For β3, decreases ( P < 0.05) in RG were observed in CHF, whereas no differences were found in Sol and WG between CHF and Con. It is concluded that CHF results in alterations in Na+-K+-ATPase that are muscle specific and property specific. Although decreases in Na+-K+-ATPase content would appear to explain the lower 3- O-MFPase in the LV, such does not appear to be the case in skeletal muscles where a dissociation between these properties was observed.

scholarly journals Obesity-induced discrepancy between contractile and metabolic phenotypes in slow- and fast-twitch skeletal muscles of female obese Zucker rats

2017 ◽  
Vol 123 (1) ◽  
pp. 249-259 ◽  
Author(s):  
Luz M. Acevedo ◽  
Ana I. Raya ◽  
Rafael Ríos ◽  
Escolástico Aguilera-Tejero ◽  
José-Luis L. Rivero
Keyword(s):  
Muscle Mass ◽  
Skeletal Muscles ◽  
Fiber Type ◽  
Succinic Dehydrogenase ◽  
Zucker Rats ◽  
Fiber Types ◽  
Type Composition ◽  
Obese Zucker Rats ◽  
And Function ◽  
Fast Twitch

A clear picture of skeletal muscle adaptations to obesity and related comorbidities remains elusive. This study describes fiber-type characteristics (size, proportions, and oxidative enzyme activity) in two typical hindlimb muscles with opposite structure and function in an animal model of genetic obesity. Lesser fiber diameter, fiber-type composition, and histochemical succinic dehydrogenase activity (an oxidative marker) of muscle fiber types were assessed in slow (soleus)- and fast (tibialis cranialis)-twitch muscles of obese Zucker rats and compared with age (16 wk)- and sex (females)-matched lean Zucker rats ( n = 16/group). Muscle mass and lesser fiber diameter were lower in both muscle types of obese compared with lean animals even though body weights were increased in the obese cohort. A faster fiber-type phenotype also occurred in slow- and fast-twitch muscles of obese rats compared with lean rats. These adaptations were accompanied by a significant increment in histochemical succinic dehydrogenase activity of slow-twitch fibers in the soleus muscle and fast-twitch fiber types in the tibialis cranialis muscle. Obesity significantly increased plasma levels of proinflammatory cytokines but did not significantly affect protein levels of peroxisome proliferator-activated receptors PPARγ or PGC1α in either muscle. These data demonstrate that, in female Zucker rats, obesity induces a reduction of muscle mass in which skeletal muscles show a diminished fiber size and a faster and more oxidative phenotype. It was noteworthy that this discrepancy in muscle's contractile and metabolic features was of comparable nature and extent in muscles with different fiber-type composition and antagonist functions. NEW & NOTEWORTHY This study demonstrates a discrepancy between morphological (reduced muscle mass), contractile (shift toward a faster phenotype), and metabolic (increased mitochondrial oxidative enzyme activity) characteristics in skeletal muscles of female Zucker fatty rats. It is noteworthy that this inconsistency was comparable (in nature and extent) in muscles with different structure and function.

Downhill Running Excessive Training Inhibits Hypertrophy in Mice Skeletal Muscles with Different Fiber Type Composition

2015 ◽  
Vol 231 (5) ◽  
pp. 1045-1056 ◽  
Author(s):  
Alisson L. da Rocha ◽  
Bruno C. Pereira ◽  
José R. Pauli ◽  
Claudio T. de Souza ◽  
Giovana R. Teixeira ◽  
...  
Keyword(s):  
Skeletal Muscles ◽  
Fiber Type ◽  
Fiber Type Composition ◽  
Downhill Running ◽  
Type Composition

scholarly journals Acetylcholine and insulin‐mediated vasodilation in feed arteries and arterioles of rat skeletal muscle of different fiber type composition

2012 ◽  
Vol 26 (S1) ◽  
Author(s):  
Jaume Padilla ◽  
Nathan T Jenkins ◽  
Jeffrey S Martin ◽  
Jacqueline M Crissey ◽  
Shawn B Bender ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Fiber Type ◽  
Rat Skeletal Muscle ◽  
Fiber Type Composition ◽  
Type Composition ◽  
Feed Arteries

Progressive elevations in muscle blood flow during prolonged exercise in swine

1987 ◽  
Vol 63 (1) ◽  
pp. 285-291 ◽  
Author(s):  
R. B. Armstrong ◽  
M. D. Delp ◽  
E. F. Goljan ◽  
M. H. Laughlin
Keyword(s):  
Blood Flow ◽  
Prolonged Exercise ◽  
Fiber Type ◽  
Muscle Blood Flow ◽  
Miniature Swine ◽  
Time Period ◽  
Type Composition ◽  
Muscle Groups ◽  
Colonic Temperature ◽  
Over Time

Distribution of muscle blood flow has not been measured in man during prolonged exercise, but progressive elevations in skin flow coupled with constant cardiac output (QT) have suggested muscle blood flow may be compromised. However, previous experiments with rats demonstrated progressive increases in muscle blood flow over time during prolonged submaximal exercise. The present study was performed to study muscle blood flow in miniature swine during long-term exercise to shed light on this apparent anomaly. QT and distribution of QT were studied with radiolabeled microspheres while pigs ran on a level treadmill at a speed (10.5 km/h) requiring 71 +/- 4% of maximal O2 consumption (VO2 max). QT increased 23% from the 5th to the 30th min of exercise, whereas total skeletal muscle flow increased by 49%. Increases in flow in the muscles resulted from decreased resistance, since mean arterial pressure declined over this time period (-7%). In addition, the proportional increases in muscle flow were similar within synergistic muscle groups independent of fiber type composition (e.g., elbow extensors: 59–78%; elbow flexors: 26–40%). The factor that limited continued exercise appeared to be body temperature. Colonic temperature rose in linear fashion over time; the animals became exhausted at approximately 42 degrees C. These flow data are similar to previous findings in rats and indicate that during prolonged treadmill locomotion in quadrupedal animals muscle blood flow increases over time to near maximal levels.

Sign in / Sign up

Export Citation Format

Share Document