Oxidative capacity varies along the length of healthy human tibialis anterior
until further notice
SourceJournal of Physiology, 596, 8, (2018), pp. 1467-1483
Article / Letter to editor
Display more detailsDisplay less details
Journal of Physiology
SubjectRadboudumc 15: Urological cancers RIMLS: Radboud Institute for Molecular Life Sciences
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 5 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 < 0.001), being two times higher proximally vs. distally during SUBMAX and EXH. Statistical analysis showed that this gradient cannot be explained by pH variations. A similar gradient was seen in the slope of the initial post-exercise (1) H mfMRI signal change, which was higher proximally than distally in both the TA and the extensor digitorum longus (P < 0.001) and it strongly correlated with kPCr . The pronounced differences along the TA in functional oxidative capacity identify regional variation in the physiological demand of this muscle during everyday activities and have implications for the bio-energetic assessment of interventions to modify its performance and of neuromuscular disorders involving the TA. This article is protected by copyright. All rights reserved.
Upload full text
Use your RU credentials (u/z-number and password) to log in with SURFconext to upload a file for processing by the repository team.