Strüder H K, Hollmann W, Platen P, Wöstmann R, Weicker H, Molderings G J
Institute of Sports Games, German Sport University, Cologne.
Eur J Appl Physiol Occup Physiol. 1999 Mar;79(4):318-24. doi: 10.1007/s004210050514.
The neurotransmitter serotonin (5-hydroxytryptamine, 5-HT) has been shown to modulate various physiological and psychological functions such as fatigue. Altered regulation of the serotonergic system has been suggested to play a role in response to exercise stress. In the present study, the influence was investigated of acute endurance exercise and short-term increase in the amount of training on the concentrations of the 5-HT precursor tryptophan (TRP), of prolactin (PRL) and of branched-chain amino acids (BCAA) in the blood, as well as on the binding of [3H]ketanserin to the serotonin-2A (5-HT2A) receptors on platelets. Nine healthy endurance-trained men were tested the day before (I) and after (II) a 9-day training programme. Samples of venous blood were drawn after an overnight fast and following 5 h of cycling. Fasted and post-exercise plasma concentrations of free TRP, BCAA and free TRP:BCAA ratio did not differ between I and II. A significant decrease of plasma BCAA (P < 0.01) and significant augmentations of plasma free TRP, free TRP:BCAA ratio and PRL (P < 0.01) were found post-exercise. The increase in plasma PRL was smaller in II compared with I. Acute endurance exercise reduced the density of platelet 5-HT2A receptor [3H]ketanserin binding sites at I and II (P < 0.05). The basal density of the binding sites and the affinity of [3H]ketanserin for these binding sites were unaffected by an increase in the amount of training. The present results support the hypothesis that acute endurance exercise may increase 5-HT availability. This was reflected in the periphery by increased concentration of the 5-HT precursor free TRP, by increased plasma PRL concentration, and by a reduction of 5-HT2A receptors on platelets. It remains to be resolved whether these alterations in the periphery occur in parallel with an increase in the availability of 5-HT in the brain.
神经递质血清素（5-羟色胺，5-HT）已被证明可调节多种生理和心理功能，如疲劳。血清素能系统调节的改变被认为在运动应激反应中起作用。在本研究中，调查了急性耐力运动和训练量短期增加对血液中5-HT前体色氨酸（TRP）、催乳素（PRL）和支链氨基酸（BCAA）浓度的影响，以及对血小板上[3H]酮色林与血清素-2A（5-HT2A）受体结合的影响。九名健康的耐力训练男性在9天训练计划前一天（I）和后一天（II）接受测试。在过夜禁食后和骑行5小时后采集静脉血样本。I和II之间，空腹和运动后血浆中游离TRP、BCAA以及游离TRP:BCAA比值无差异。运动后发现血浆BCAA显著降低（P < 0.01），血浆游离TRP、游离TRP:BCAA比值和PRL显著升高（P < 0.01）。与I相比，II中血浆PRL的升高幅度较小。急性耐力运动在I和II时均降低了血小板5-HT2A受体[3H]酮色林结合位点的密度（P < 0.05）。结合位点的基础密度以及[3H]酮色林对这些结合位点的亲和力不受训练量增加的影响。目前的结果支持急性耐力运动可能增加5-HT可用性的假设。这在周围表现为5-HT前体游离TRP浓度增加、血浆PRL浓度升高以及血小板上5-HT2A受体减少。外周的这些变化是否与大脑中5-HT可用性的增加同时发生仍有待解决。
