Chronic Hypobaric Hypoxia Increases Isolated Rat Fast-Twitch and Slow-Twitch Limb Muscle Force and Fatigue
| Autor: | Aidan Bradford, R El-Khoury, Ken D. O'Halloran |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Male
medicine.medical_specialty Physiology Isometric exercise Biology medicine.disease_cause Internal medicine Hyperventilation medicine Respiratory muscle Animals Respiratory system Hypoxia Muscle Skeletal Fatigue Specific force Extremities General Medicine Anatomy Hypoxia (medical) musculoskeletal system Rats Muscle Fibers Slow-Twitch Endocrinology Muscle Fibers Fast-Twitch medicine.symptom Oxidative stress Muscle Contraction Muscle contraction |
| Zdroj: | Scopus-Elsevier Europe PubMed Central |
| ISSN: | 1802-9973 0862-8408 |
| DOI: | 10.33549/physiolres.932140 |
| Popis: | Chronic hypoxia alters respiratory muscle force and fatigue, effects that could be attributed to hypoxia and/or increased activation due to hyperventilation. We hypothesized that chronic hypoxia is associated with phenotypic change in non-respiratory muscles and therefore we tested the hypothesis that chronic hypobaric hypoxia increases limb muscle force and fatigue. Adult male Wistar rats were exposed to normoxia or hypobaric hypoxia (PB=450 mm Hg) for 6 weeks. At the end of the treatment period, soleus (SOL) and extensor digitorum longus (EDL) muscles were removed under pentobarbitone anaesthesia and strips were mounted for isometric force determination in Krebs solution in standard water-jacketed organ baths at 25 °C. Isometric twitch and tetanic force, contractile kinetics, force-frequency relationship and fatigue characteristics were determined in response to electrical field stimulation. Chronic hypoxia increased specific force in SOL and EDL compared to age-matched normoxic controls. Furthermore, chronic hypoxia decreased endurance in both limb muscles. We conclude that hypoxia elicits functional plasticity in limb muscles perhaps due to oxidative stress. Our results may have implications for respiratory disorders that are characterized by prolonged hypoxia such as chronic obstructive pulmonary disease (COPD). |
| Databáze: | OpenAIRE |
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