Oxidative capacity varies along the length of healthy human tibialis anterior
| Autor: | Andreas Boss, Mark J. van Uden, Vincent Breukels, Linda Heskamp, Lauren J. Bains, Arend Heerschap |
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| Rok vydání: | 2018 |
| Předmět: |
Oxidative metabolism
medicine.diagnostic_test Physiology Spatially resolved Skeletal muscle Magnetic resonance imaging Isometric exercise 030218 nuclear medicine & medical imaging Phosphocreatine Incremental exercise 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Nuclear magnetic resonance medicine.anatomical_structure chemistry medicine Oxidative capacity 030217 neurology & neurosurgery |
| Zdroj: | The Journal of Physiology. 596:1467-1483 |
| ISSN: | 0022-3751 |
| DOI: | 10.1113/jp275009 |
| Popis: | KEY POINTS During exercise skeletal muscles use the energy buffer phosphocreatine. The post-exercise recovery of phosphocreatine is a measure of the oxidative capacity of muscles and is traditionally assessed by 31 P magnetic resonance spectroscopy of a large tissue region, assuming homogeneous energy metabolism. To test this assumption, we collected spatially resolved spectra along the length of human tibialis anterior using a home-built array of 31 P detection coils, and observed a striking gradient in the recovery rate of phosphocreatine, decreasing along the proximo-distal axis of the muscle. A similar gradient along this muscle was observed in signal changes recorded by 1 H muscle functional MRI. These findings identify intra-muscular variation in the physiology of muscles in action and highlight the importance of localized sampling for any methodology investigating oxidative metabolism of this, and potentially other muscles. ABSTRACT The rate of phosphocreatine (PCr) recovery (kPCr ) after exercise, characterizing muscle oxidative capacity, is traditionally assessed with unlocalized 31 P magnetic resonance spectroscopy (MRS) using a single surface coil. However, because of intramuscular variation in fibre type and oxygen supply, kPCr may be non-uniform within muscles. We tested this along the length of the tibialis anterior (TA) muscle in 10 male volunteers. For this purpose, we employed a 3T MR system with a 31 P/1 H volume transmit coil combined with a home-built 31 P phased-array receive probe, consisting of five coil elements covering the TA muscle length. Mono-exponential kPCr was determined for all coil elements after 40 s of submaximal isometric dorsiflexion (SUBMAX) and incremental exercise to exhaustion (EXH). In addition, muscle functional MRI (1 H mfMRI) was performed using the volume coil after another 40 s of SUBMAX. A strong gradient in kPCr was observed along the TA (P |
| Databáze: | OpenAIRE |
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