Riggs C E, Kilgour R D
Human Performance Laboratory, University of Arkansas, Fayetteville 72701.
J Sports Med Phys Fitness. 1991 Sep;31(3):442-6.
The effect of induced myocardial ischemia on cardiac glycogen utilization was investigated in trained and untrained male Sprague-Dawley rats. Following a 12 to 15 week endurance training program, myocardial ischemia was induced by ligation of the left coronary artery. Prior to and at 5 min intervals following ligation, affected tissues of five trained and untrained animals were removed, frozen in liquid nitrogen, and analyzed for glycogen and lactic acid. The glycogen content for both groups declined significantly (p less than 0.05) during the first 5 min, 38% and 15% for the trained and untrained, respectively, with a concomitant rise in the lactic acid of 150% and 40%. Overall, the cardiac lactate in the trained hearts was lower (p less than 0.05) than in untrained hearts but the pattern of response was the same. During the final 5 min of ischemia, cardiac glycogen rose in the trained hearts and declined in the sedentary hearts. The difference between the two groups at 30 min was significant (p less than 0.05). The results show that trained and untrained rat hearts utilize glycogen differently but produce similar quantities of lactic acid during brief periods of myocardial ischemia. Similar lactate despite greater glycogen utilization may indicate reduced anaerobic stress in the trained rat heart.
在经过训练和未经训练的雄性斯普拉格-道利大鼠中，研究了诱导性心肌缺血对心脏糖原利用的影响。经过12至15周的耐力训练计划后，通过结扎左冠状动脉诱导心肌缺血。在结扎前以及结扎后每隔5分钟，从五只经过训练和未经训练的动物身上取出受影响的组织，在液氮中冷冻，并分析糖原和乳酸含量。在最初的5分钟内，两组的糖原含量均显著下降（p小于0.05），经过训练的大鼠下降了38%，未经训练的大鼠下降了15%，同时乳酸含量分别上升了150%和40%。总体而言，经过训练的心脏中的心肌乳酸含量低于未经训练的心脏（p小于0.05），但反应模式相同。在缺血的最后5分钟内，经过训练的心脏中的心脏糖原含量上升，而久坐不动的心脏中的糖原含量下降。两组在30分钟时的差异显著（p小于0.05）。结果表明，经过训练和未经训练的大鼠心脏对糖原的利用方式不同，但在短暂的心肌缺血期间产生的乳酸量相似。尽管糖原利用率更高，但乳酸含量相似可能表明经过训练的大鼠心脏中的无氧应激降低。
