Intermittent cold exposure causes a muscle-specific shift in the fiber type composition in rats
| Autor: | T. J. Walters, S. H. Constable |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
Male
medicine.medical_specialty Physiology Cold exposure Citrate (si)-Synthase Myosins Acclimatization Body Temperature Rats Sprague-Dawley Extensor digitorum muscle Eating Oxygen Consumption Physiology (medical) Internal medicine medicine Animals Citrate synthase Fiber type composition Soleus muscle biology Histocytochemistry Chemistry Muscles musculoskeletal neural and ocular physiology Body Weight Metabolism Anatomy Hypothermia musculoskeletal system Rats Cold Temperature Endocrinology Body Composition biology.protein medicine.symptom |
| Zdroj: | Journal of Applied Physiology. 75:264-267 |
| ISSN: | 1522-1601 8750-7587 |
| DOI: | 10.1152/jappl.1993.75.1.264 |
| Popis: | We examined the effect of long-term intermittent cold exposure on the fiber type composition of the predominantly type I soleus and the predominantly type IIb extensor digitorum longus (EDL) muscles of rats. Cold exposure was accomplished by submerging the rats in shoulder-deep water, maintained at 20 +/- 0.5 degrees C, for 1 h/day, 5 days/wk, for < or = 19 wk. The efficacy of the treatment was tested by subjecting both groups to 20 degrees C water for 45 min while rectal temperature (Tre) and O2 consumption (VO2) were measured. The cold-exposed group displayed a 22% smaller reduction in Tre (P < 0.05) at the end of the exposure and 23% greater VO2 (P < 0.05) during the same period. Fiber type composition was determined using routine histochemical methods for myosin-adenosinetriphosphatase. In the soleus muscle of the cold-exposed rats, the number of type IIa fibers increased 156% (P < 0.05) and the number of type I fibers decreased 24% (P < 0.05). Cold exposure had no significant influence on the fiber type composition of the EDL muscle. Cold exposure resulted in an increase in citrate synthase activity of 20 and 22% in the soleus and EDL muscles, respectively (P < 0.05). The present study demonstrates that intermittent cold exposure induces a type I-to-type IIa transformation in the soleus muscle while having no influence on the EDL muscle. |
| Databáze: | OpenAIRE |
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