Involvement of amino acid metabolite in skeletal muscle on the onset of exercise-induced central fatigue

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K01734
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Sports science
• Research Institution: Tokyo Medical University
• Principal Investigator: Miyazaki Teruo 東京医科大学, 医学部, 講師 (60532687)
• Co-Investigator(Kenkyū-buntansha): 本多 彰 東京医科大学, 医学部, 教授 (10468639) ; 大森 肇 筑波大学, 体育系, 教授 (20223969) ; 池上 正 東京医科大学, 医学部, 教授 (40439740)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 中枢性疲労 / 持久性運動 / エネルギー代謝 / 分岐鎖アミノ酸 / 骨格筋 / 脳

Outline of Final Research Achievements

In endurance exercise, 3-hydroxyisobutyrate（3HIB） that is a valine intermediate in muscular energy metabolism is excreted from the skeletal muscles. This study investigated the hypothesis that the 3HIB accumulated in brain might be one of the reasons to cause the central fatigue in exercise. In the results, 3HIB concentration in rat brain was significantly increased by treadmill exercise in a running time dependent manner, and there were significant correlation relationships in 3HIB concentration among skeletal muscles, serum and brains. In the rats with the significantly increased 3HIB in brain by its ip injection, the exercise performance was significantly decreased. This study suggested that the 3HIB accumulation in brain by endurance exercise might be one of the reasons for the exercise-induced central fatigue.

Free Research Field

栄養エネルギー代謝

Academic Significance and Societal Importance of the Research Achievements

運動誘発性の中枢性疲労の原因には，多くの説が唱えられているが，未だ明確に解明されていない。本研究では，骨格筋エネルギー代謝の変化に伴い骨格筋より放出されるアミノ酸中間代謝物が，脳内に取り込まれて蓄積し，運動パフォーマンスの低下をもたらした。そのため，本研究で得られた結果から，骨格筋のエネルギー代謝中間代謝物が，中枢性疲労の原因の１つである新たな可能性が示唆され，運動誘発性の中枢性疲労発症機序の解明に寄与する成果と考えられる。