The Tenuissimus Muscle Preparation as a Model for Intravital Microscopic Studies of Skeletal Muscle Circulatory Function*

2015 ◽  
pp. 32-40 ◽  
Author(s):  
L. Lindbom ◽  
K.-E. Arfors
Keyword(s):  
Skeletal Muscle ◽  
Muscle Preparation ◽  
Microscopic Studies ◽  
Circulatory Function

Effect of electrical stimulation on intracellular triacylglycerol in isolated skeletal muscle

1990 ◽  
Vol 68 (1) ◽  
pp. 348-354 ◽  
Author(s):  
J. F. Hopp ◽  
W. K. Palmer
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Glucose Control ◽  
Muscle Preparation ◽  
Bicarbonate Buffer ◽  
Intermittent Stimulation ◽  
Flexor Digitorum Brevis ◽  
Muscle Groups ◽  
Flexor Digitorum

The contribution of intracellular triacylglycerol (TG) as a substrate for skeletal muscle during electrical stimulation is equivocal. Therefore, the purpose of this study was to investigate the effect of electrical stimulation on the TG content in the isolated intact rat flexor digitorum brevis skeletal muscle preparation by use of two different stimulation protocols. Muscles were electrically stimulated for 1 h either continuously at 1 Hz or intermittently (30 s on, 60 s off) at 5 Hz while incubated in 21 degrees C Krebs bicarbonate buffer (pH 7.4) that contained 11 mM glucose. Control muscles were either frozen immediately after excision or incubated for 1 h. TG content was significantly decreased (P less than 0.05) compared with control concentrations in both stimulated muscle groups, with the greatest reduction (60%) occurring after 5-Hz intermittent stimulation. These data indicate that intramuscular TG is hydrolyzed in response to electrical stimulation in the isolated flexor digitorum brevis muscle preparation. In addition, the type of stimulation (higher frequency intermittent vs. lower frequency continuous) employed influences the amount of intracellular TG hydrolyzed.

Effect of initial length on relations between oxygen uptake and load in dog muscle

1976 ◽  
Vol 230 (4) ◽  
pp. 1008-1012 ◽  
Author(s):  
WN Stainsby ◽  
JK Barclay
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Uptake ◽  
The Other ◽  
Mammalian Skeletal Muscle ◽  
Initial Length ◽  
Muscle Preparation ◽  
Optimal Length ◽  
Muscle Energetics ◽  
Isotonic Contractions ◽  
Fenn Effect

Oxygen uptake for brief tetanic contractions was calculated from measurements of blood flow and blood arteriovenous oxygen content differences. Each muscle preparation was pretested under isometric conditions to establish optimal length, Lo. After this one group of preparations performed afterload isotonic contractions at several loads with initial length, Li, less than Lo. The other groups of preparations performed similar contractions with Li greater than Lo. When Li was less than Lo, oxygen uptake for the highest load was always greater than oxygen uptake at the lowest load whereas intermediate loads were usually higher than both extremes. However, when Li was greater than Lo, oxygen uptake at the highest load was always less than oxygen uptake at the lowest load; again the intermediate loads were usually higher than both extremes. The data confirm and extend similar effects of initial length on heat production for contractions by amphibian muscles (7). It seems likely that the differences in initial lengths may account for the fact that the Fenn effect has not previously been observed in studies of mammalian skeletal muscle energetics.

Force development and metabolism in skeletal muscle of euthyroid and hypothyroid rats

1981 ◽  
Vol 97 (2) ◽  
pp. 221-225 ◽  
Author(s):  
M. E. Everts ◽  
C. van Hardeveld ◽  
H. E. D. J. Ter Keurs ◽  
A. A. H. Kassenaar
Keyword(s):  
Skeletal Muscle ◽  
Oxygen Consumption ◽  
Muscle Metabolism ◽  
Glucose Consumption ◽  
Triceps Surae ◽  
Active Force ◽  
Muscle Preparation ◽  
Force Development ◽  
Contraction Process ◽  
Triceps Surae Muscles

Abstract. The effects of thyroid hormone depletion on skeletal muscle metabolism in relation to force development were studied. For this purpose, the triceps surae muscles were perfused and stimulated at 5 Hz. The basal oxygen consumption of the skeletal muscle preparation was 50% lower in hypothyroid rats as compared with euthyroid rats. The results show that: 1. Active force development was the same in euthyroid and hypothyroid rats during 30 min of stimulation. 2. The increase in oxygen consumption during contraction was twice as high in the euthyroid group compared with the hypothyroid group. 3. Lactate release and glucose consumption were considerably higher in the euthyroid group than in the hypothyroid group during the last 15 min of stimulation. The data show that force development is not impaired in hypothyroid rats but, on the contrary, indicate that the contraction process proceeds more economically in hypothyroid rats than in euthyroid rats.

Δ Protein, a New Fibrous Protein of Skeletal Muscle: Preparation

1957 ◽  
Vol 188 (2) ◽  
pp. 205-211 ◽  
Author(s):  
William R. Amberson ◽  
John I. White ◽  
Howard B. Bensusan ◽  
Sylvia Himmelfarb ◽  
Brigitte E. Blankenhorn
Keyword(s):  
Skeletal Muscle ◽  
Ionic Strength ◽  
Electrophoretic Mobility ◽  
Protein A ◽  
High Ionic Strength ◽  
Partial Purification ◽  
Rabbit Muscle ◽  
Muscle Preparation ◽  
Preparative Electrophoresis ◽  
Fibrous Protein

Δ protein, a previously unreported fibrous protein with an electrophoretic mobility greater than that of myosin, is extracted from rabbit muscle by solutions of high ionic strength. This protein forms a complex with myosin, designated as Δ-myosin. Partial purification of Δ protein is achieved by two independent methods. In the first method alcohol fractionation is used. In the second, a solution of Salyrgan is used to dissociate the precipitated Δ-myosin complex. In each method further purification is obtained by preparative electrophoresis. Neither method yields a product which is entirely homogeneous. Tropomyosin is present as a contaminant in alcohol-fractionated preparations, and has been isolated and crystallized. All efforts to derive Δ protein from the previously known fibrous proteins of muscle have failed.

Leptin increases FA oxidation in lean but not obese human skeletal muscle: evidence of peripheral leptin resistance

2002 ◽  
Vol 283 (1) ◽  
pp. E187-E192 ◽  
Author(s):  
Gregory R. Steinberg ◽  
Michelle L. Parolin ◽  
George J. F. Heigenhauser ◽  
David J. Dyck
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Human Skeletal Muscle ◽  
Leptin Resistance ◽  
Muscle Preparation ◽  
Palmitate Oxidation ◽  
Obese Human

The adipocyte-derived hormone leptin has been shown to acutely increase fatty acid (FA) oxidation and decrease esterification in resting rodent skeletal muscle. However, the effects of leptin on human skeletal muscle FA metabolism are completely unknown. In these studies, we have utilized an isolated human skeletal muscle preparation combined with the pulse-chase technique to measure FA metabolism with and without leptin in lean and obese human skeletal muscle. Under basal conditions (in the absence of leptin), muscle from the obese demonstrated significantly elevated levels of total FA uptake (+72%, P = 0.038) and enhanced rates of FA esterification into triacylglycerol (+102%, P = 0.042) compared with lean subjects. In the presence of leptin, lean muscle had elevated rates of endogenous (+103%, P = 0.01) and exogenous (+150%, P = 0.03) palmitate oxidation. When the ratio of esterification to exogenous oxidation was examined, leptin reduced this ratio (−47%, P = 0.032), demonstrating the increased partitioning of FA toward oxidation and away from storage. Contrary to these findings in lean muscle, leptin had no effect on FA metabolism in skeletal muscle of the obese. This study provides the first evidence that leptin increases FA oxidation in skeletal muscle of lean, but not obese humans, thus demonstrating the development of leptin resistance in obese human skeletal muscle.

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