Human vastus lateralis and soleus muscles display divergent cellular contractile properties
| Autor: | Emily Louis, Nicholas D. Luden, Scott Trappe, Todd A. Trappe, Kiril Minchev, Erik Hayes |
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| Rok vydání: | 2008 |
| Předmět: |
Adult
Male medicine.medical_specialty Physiology Vastus lateralis muscle Muscle Relaxation Genes MHC Class II Muscle Fibers Skeletal Skeletal muscle adaptation Genes MHC Class I chemical and pharmacologic phenomena Major histocompatibility complex Contractile Proteins Oxygen Consumption Physiology (medical) Internal medicine Myosin MHC class I medicine Humans Muscle Skeletal biology Skeletal muscle medicine.anatomical_structure Muscle relaxation Endocrinology Exercise and Respiratory Physiology biology.protein Female medicine.symptom Muscle contraction Muscle Contraction |
| Zdroj: | American journal of physiology. Regulatory, integrative and comparative physiology. 295(5) |
| ISSN: | 0363-6119 |
| Popis: | The purpose of this study was to investigate potential differences in single-fiber contractile physiology of fibers with the same myosin heavy chain isoform (MHC I and MHC IIa) originating from different muscles. Vastus lateralis (VL) and soleus biopsies were obtained from 27 recreationally active females (31 ± 1 yr, 59 ± 1 kg). A total of 943 single fibers (MHC I = 562; MHC IIa = 301) were isolated and examined for diameter, peak tension (Po), shortening velocity (Vo), and power. The soleus had larger ( P < 0.05) fibers (MHC I +18%; MHC IIa +19%), higher MHC I Vo (+13%), and higher MHC I Po (+18%) compared with fibers from the VL. In contrast, fibers from the VL had higher ( P < 0.05) specific tension (MHC I +18%; MHC IIa +20%), and MHC I normalized power (+25%) compared with the soleus. There was a trend for MHC IIa soleus fibers to have higher Vo [MHC IIa +13% ( P = 0.058)], whereas VL MHC IIa fibers showed a trend for higher normalized power compared with soleus fibers [MHC IIa +33% ( P = 0.079)]. No differences in absolute power were detected between muscles. These data highlight muscle-specific differences in single-fiber contractile function that should serve as a scientific basis for consideration when extending observations of skeletal muscle tissue from one muscle of interest to other muscles of origin. This is important when examining skeletal muscle adaptation to physical states such as aging, unloading, and training. |
| Databáze: | OpenAIRE |
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