Bianchi G P, Grossi G, Bargossi A M
Department of Internal Medicine, Cardiology, Hepatology, University of Bologna, Italy.
J Sports Med Phys Fitness. 1997 Sep;37(3):194-9.
A laboratory-based model which links regional and central fatigue during physical exercise has not yet developed. Today we can assay the oxypurines, a specific and sensible marker of muscle cell-energy exhaustion during strenuous physical exercise, thus allowing us to insight in peripheral fatigue mechanisms. Prolonged physical exercise modifies plasma free amino acids and fatty acids levels, increases plasma free tryptophan (fTrp) and, conversely, probably serotonin, an amine involved in the genesis of central fatigue. We tried to verify if there is a correlation between central and peripheral fatigue.
We studied 29 male marathon runners before marathon, at the arrival, one and three days after the run.
Plasma samples were assayed for amino acids, fTrp serotonin, xanthine, hypoxanthine inosine, cortisol. Urine samples were assayed for serotonin and hydroxyin-doleacetic acid (5HIAA).
After the competition we observed a decrease in plasma fTrp but an increased ratio fTrp/sum of neutral amino acids with a normalization after 24 hours. No significant changes were observed in plasma and urinary serotonin and 5HIAA. Hypoxanthine and inosine increased at the end of the trial and returned to basal levels the day after. Cortisol increased at the end of the run but was reduced after 24 and 72 hours.
In our athletes we observed only indirect signs of fTrp involvement in the genesis of central fatigue. Oxypurines seem to be a good marker of regional muscular fatigue. Plasma cortisol expresses the stress reaction to the competition and its exhaustion after a prolonged physical exercise.
尚未建立起一种基于实验室的模型来关联体育锻炼期间的局部和中枢疲劳。如今，我们能够检测氧嘌呤，它是剧烈体育锻炼期间肌肉细胞能量耗竭的一种特异且灵敏的标志物，从而使我们能够深入了解外周疲劳机制。长时间体育锻炼会改变血浆游离氨基酸和脂肪酸水平，增加血浆游离色氨酸（fTrp），反之，可能还会增加血清素，一种与中枢疲劳发生有关的胺类物质。我们试图验证中枢疲劳与外周疲劳之间是否存在关联。
我们对29名男性马拉松运动员在马拉松比赛前、抵达终点时、赛后1天和3天进行了研究。
检测血浆样本中的氨基酸、fTrp、血清素、黄嘌呤、次黄嘌呤、肌苷、皮质醇。检测尿液样本中的血清素和5-羟吲哚乙酸（5HIAA）。
比赛后，我们观察到血浆fTrp下降，但fTrp与中性氨基酸总和的比值增加，24小时后恢复正常。血浆和尿液中的血清素及5HIAA未观察到显著变化。次黄嘌呤和肌苷在试验结束时增加，次日恢复至基础水平。皮质醇在跑步结束时增加，但在24小时和72小时后降低。
在我们的运动员中，我们仅观察到fTrp参与中枢疲劳发生的间接迹象。氧嘌呤似乎是局部肌肉疲劳的良好标志物。血浆皮质醇表达了对比赛的应激反应以及长时间体育锻炼后的疲劳状态。
