Short‐term training alters the control of mitochondrial respiration rate before maximal oxidative ATP synthesis. (2nd May 2013)

• Record Type: Journal Article
• Authors: Layec, G.; Haseler, L. J.; Hoff, J.; Hart, C. R.; Liu, X.; Le, Y.; Jeong, E.‐K.; Richardson, R. S.
• Is Part Of: Acta physiologica. Volume 208:Number 4(2013:Aug.)
• Page Start: 376
• Page End: 386
• Publication Date: 2013-05-02
• Subjects: Physiology -- Periodicals; Physiology -- Research -- Periodicals; 612
• DOI: 10.1111/apha.12103
• Languages: English
• ISSNs: 1748-1708

Abstract

<abstract abstract-type="main" xml:lang="en" id="apha12103-abs-0001"> <title>Abstract</title> <sec id="apha12103-sec-0001" sec-type="section"> <title>Aim</title> <p>Short‐term exercise training may induce metabolic and performance adaptations before any changes in mitochondrial enzyme potential. However, there has not been a study that has directly assessed changes in mitochondrial oxidative capacity or metabolic control as a consequence of such training <italic>in vivo</italic>. Therefore, we used <sup>31</sup>P‐magnetic resonance spectroscopy (<sup>31</sup>P‐MRS) to examine the effect of short‐term plantar flexion exercise training on phosphocreatine (PCr) recovery kinetics and the control of respiration rate.</p> </sec> <sec id="apha12103-sec-0002" sec-type="section"> <title>Method</title> <p>To this aim, we investigated 12 healthy men, experienced with this exercise modality (TRA), and 7 time‐control subjects (TC).</p> </sec> <sec id="apha12103-sec-0003" sec-type="section"> <title>Results</title> <p>After 5 days of training, maximum work rate during incremental plantar flexion exercise was significantly improved (<italic>P </italic><<italic> </italic>0.01). During the recovery period, the maximal rate of oxidative adenosine triphosphate synthesis (PRE: 28 ± 13 m<sc>m</sc> min<sup>−1</sup>; POST: 26 ± 15 m<sc>m</sc> min<sup>−1</sup>) and the PCr recovery time constant (PRE: 31 ± 19 s; POST: 29 ± 16) were not significantly altered. In contrast, the Hill coefficient (<italic>n</italic><sub>H</sub>) describing the co‐operativity between respiration rate and ADP was significantly increased in TRA (PRE: <italic>n</italic><sub>H</sub> = 2.7 ± 1.4; POST: <italic>n</italic><sub>H</sub> = 3.4 ± 1.9, <italic>P </italic><<italic> </italic>0.05). Meanwhile, there were no systematic variations in any of these variables in TC.</p> </sec> <sec id="apha12103-sec-0004" sec-type="section"> <title>Conclusion</title> <p>This study reveals that 5 days of training induces rapid adaptation in the allosteric control of respiration rate by ADP before any substantial improvement in muscle oxidative capacity occurs.</p> </sec> </abstract>