2周耐力训练削弱骨骼肌5′-一磷酸腺苷激活的蛋白激酶信号对急性运动的反应

目的:探讨2周耐力训练对大鼠一次急性运动骨骼肌5′-一磷酸腺苷激活的蛋白激酶(AMPK)信号的影响,分析骨骼肌AMPK信号对耐力训练的适应特点。方法:52只雄性SD大鼠分为训练和未训练两大组,训练组进行2周速度为18m/min、10%坡度、每天60min的耐力训练,结束后进行一次性大强度跑台运动(速度26m/min,10%坡度,60min);未训练组只进行一次性大强度跑台运动。两组分别于一次性运动前(安静时)、运动后即刻(0h)、1h和6h取材。使用高效液相色谱法(HPLC)测定AMP、ATP含量,放射性同位素方法测定AMPK活性。结果:与安静时相比,训练和未训练组大鼠一次性运动后即刻,腓肠肌AMP、AMP/ATP、AMPK分别增加42%、80%、80%和62%、89%、180%,均有统计学意义(P<0.01),AMP和AMP/ATP在运动后1h恢复,AMPK在运动后6h恢复;和未训练组相比,训练组一次性运动后即刻AMP和AMPK的增幅分别下降20%(P<0.05)和100%(P<0.01),但两组ATP和AMP/ATP在各时间点均无显著差异。结论:2周耐力训练削弱骨骼肌AMPK对急性运动的反应,其原因可能与AMP含量的增幅被削弱有关。

Endurance Training Attenuated the AMPK Signaling Response of Rat's Skeletal Muscle to Acute Exercise

Purpose To study the AMP and ATP contents,and 5'-AMP-activated protein kinase(AMPK)activity in gastrocnemius of rats during acute treadmill exercise.Methods Fifty two rats were randomly divided into two groups:sedentary group(NT,n=26)and training group(T,n=26).Group T completed 2-week endurance training on treadmill at the speed of 18m/min,10% slope,and 60 min per section.Both groups underwent a bout treadmill exercise at the speed of 26m/min,10% slope for 60 min.Materials were drawn at rest,immediate(0h),1h and 6h after exercise,respectively.AMP,ATP contents were determined by HPLC and AMPK activity by radio-isotope.Results Comparing with that at rest,AMP,AMP/ATP ratio and AMPK activity of group T and group NT were respectively increased 42%,80%,80% and 62%,89%,180%,respectively(P<0.01).AMP and AMP/ATP ratio returned to the levels at rest in 1h after exercise,but AMPK at 6h after exercise.Comparing with that in group NT,the amplification of AMP and AMPK of group T decreased 20%(P<0.05)and 100%(P<0.01),respectively,while ATP and AMP/ATP showed no significant deviation between group T and group NT.Conclusion 2-week endurance training attenuated AMPK signaling response of skeletal muscle during acute exercise through attenuating the amplification of AMP.