Newsholme E A, Blomstrand E
Department of Biochemistry, University of Oxford, United Kingdom.
Adv Exp Med Biol. 1995;384:315-20. doi: 10.1007/978-1-4899-1016-5_25.
In prolonged exercise the plasma level of branched-chain amino acids (BCAA) may fall and that of fatty acid increases: the latter increases the free tryptophan level, so that the plasma concentration ratio, free tryptophan/BCAA may increase leading to higher levels of tryptophan and therefore of 5-hydroxytryptamine (5-HT) in brain. The latter increases the activity of some 5-HT neurons in the brain which can cause sleep and which could, therefore, increase the mental effort necessary to maintain athletic activity. Drinks containing branched-chain amino acids should restore vigor to athletes whose performance is depressed by an excess of cerebral 5-HT. Recent work suggests that intake of branched-chain amino acids may improve performance in slower runners in the marathon and decrease perceived physical and mental exertion in laboratory experiments. This suggestion is supported by pharmacological manipulations that result in either increased or decreased physical performance.
在长时间运动中，支链氨基酸（BCAA）的血浆水平可能会下降，而脂肪酸水平会升高：后者会提高游离色氨酸水平，从而使血浆中游离色氨酸与支链氨基酸的浓度比升高，导致大脑中色氨酸水平升高，进而使5-羟色胺（5-HT）水平升高。后者会增加大脑中一些5-HT神经元的活性，这些神经元可导致睡眠，因此可能会增加维持运动活动所需的脑力。含有支链氨基酸的饮料应该能使那些因大脑中5-HT过多而表现下降的运动员恢复活力。最近的研究表明，摄入支链氨基酸可能会提高马拉松比赛中速度较慢的跑步者的成绩，并在实验室实验中降低主观的身心疲劳感。这一观点得到了药理学操作的支持，这些操作要么提高要么降低运动表现。
