Correlates of fatigue resistance in canine skeletal muscle stimulated electrically for up to one year
| Autor: | Stanley Salmons, W. A. Anderson, L. W. Stephenson, R. L. Hammond, B. R. Eisenberg, C. N. Mayne |
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| Rok vydání: | 1991 |
| Předmět: |
Male
medicine.medical_specialty Time Factors Physiology Stimulation Mitochondrion Biology Myosins Dogs Internal medicine Lipid droplet medicine Carnivora Citrate synthase Animals chemistry.chemical_classification Muscles Skeletal muscle Cell Biology Adaptation Physiological Electric Stimulation Citric acid cycle Microscopy Electron Endocrinology Enzyme medicine.anatomical_structure chemistry biology.protein |
| Zdroj: | The American journal of physiology. 261(2 Pt 1) |
| ISSN: | 0002-9513 |
| Popis: | In response to patterns of chronic electrical stimulation that increase its overall level of use, mammalian skeletal muscle becomes highly resistant to fatigue. The metabolic basis for this adaptation is well documented in the rabbit, but up to now it has not been possible to identify analogous changes in the dog. In this study, canine latissimus dorsi muscles were stimulated in situ for 2, 6 and 12 mo. Marked increases in fatigue resistance were consistently demonstrated. Citrate synthase and succinic dehydrogenase, conventionally used as markers of oxidative metabolism, did not increase in activity, but enzymes involved in major pathways supplying substrates to the tricarboxylic acid cycle increased up to threefold. Stimulation elevated the volume fraction of mitochondria 1.5-fold and that of lipid droplets 4.5-fold. After 6 mo of stimulation, mean fiber diameter had decreased by 30% and the area occupied by nonmuscle tissue had increased by 11%; these changes showed no further progression at 12 mo. Thus stimulated muscle becomes stably adapted to an increase in use, but the metabolic strategies for achieving increased fatigue resistance vary between species. |
| Databáze: | OpenAIRE |
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