College of Physical Education and Sports, Beijing Normal University , Beijing, 100875, China.
J Sports Sci Med. 2012 Jun 1;11(2):286-93. eCollection 2012.
The purpose of the study was to investigate the modulatory effect of changes of subthalamic nucleus (STN) activity on the development of central fatigue during exhausting exercise, and reveal the possible mechanism that might affect STN activity from the perspective of neurotransmitters. Rats were randomly divided into electrophysiology and microdialysis study groups. For electrophysiological study, electrical activity in sensorimotor cortex and STN were simultaneously recorded before, during and 90min after the exhausting exercise. For microdialysis study, extracellular fluid of STN was continuously collected with a microdialysis probe and glutamate (Glu), gamma-aminobutyric acid (GABA) levels were subsequently detected with high performance liquid chromatography (HPLC). The behavioral studies showed that rats ran well initiatively with the treadmill exercise in the beginning, 45 ± 11.5min later, movement capacity reduced obviously (which was termed as 'early fatigue'). Correspondingly, STN activity increased significantly compared with rest condition (p < 0.05), while, cortex activity decreased significantly (p < 0.05). Subsequently, rats continued their exercise with minor external stimulation till exhaustion. Cortex activity reached the minimum value under exhaustion condition, while STN activity changed insignificantly (p > 0.05). For microdialysis study, the dynamic change of Glu/GABA ratio was consistent with the change of STN activity during the development of 'early fatigue' rather than the development of exhaustion. In conclusion, the present study shows that, the development of the cortex fatigue during exhausting exercise consists of two phases, 'early fatigue' and exhaustion. Our results suggest that, dynamic changes of STN activity are closely relevant to the development of 'early fatigue' rather than exhaustion, and the changes of STN activity during the development of 'early fatigue' might be partly related to the variance of Glu and GABA levels in STN extracellular fluid. Key pointsThe development of the cortex fatigue during exhausting exercise consists of two phases, 'early fatigue' and exhaustion.Dynamic changes of STN activity are closely relevant to the development of 'early fatigue' rather than exhaustion.The changes of STN activity during the development of 'early fatigue' might be partly related to the variance of Glu and GABA levels in STN extracellular fluid.
研究目的在于探究苍白球内侧部（GPi）活动变化对力竭性运动中中枢疲劳发展的调制作用，并从神经递质角度揭示可能影响 GPi 活动的机制。将大鼠随机分为电生理和微透析研究组。电生理研究中，在力竭性运动前、运动中和运动后 90min 同步记录感觉运动皮层和 GPi 的电活动。微透析研究中，采用微透析探针持续采集 GPi 细胞外液，随后采用高效液相色谱（HPLC）检测谷氨酸（Glu）和γ-氨基丁酸（GABA）水平。行为学研究表明，大鼠开始在跑步机上运动时表现良好，45±11.5min 后运动能力明显降低（称为“早期疲劳”）。相应地，与静息状态相比，GPi 活动明显增加（p<0.05），而皮层活动明显降低（p<0.05）。随后，大鼠在外部刺激下继续运动直至力竭。在力竭状态下，皮层活动达到最低值，而 GPi 活动无明显变化（p>0.05）。对于微透析研究，Glu/GABA 比值的动态变化与“早期疲劳”发展过程中 GPi 活动的变化一致，而不是与力竭的发展一致。总之，本研究表明，力竭性运动中皮层疲劳的发展包括两个阶段，“早期疲劳”和力竭。我们的结果表明，GPi 活动的动态变化与“早期疲劳”的发展密切相关，而“早期疲劳”发展过程中 GPi 活动的变化可能部分与 GPi 细胞外液中 Glu 和 GABA 水平的变化有关。关键点力竭性运动中皮层疲劳的发展包括两个阶段，“早期疲劳”和力竭。GPi 活动的动态变化与“早期疲劳”的发展密切相关，而不是与力竭的发展密切相关。“早期疲劳”发展过程中 GPi 活动的变化可能部分与 GPi 细胞外液中 Glu 和 GABA 水平的变化有关。
