一次性力竭运动过程中大鼠“黑质-丘脑-皮层”通路神经元相干性及递质动态变化

Dynamic changes of ‘substantianigra-ventralislateralis-cortex’ pathway neural activity coherence and neurotransmitters in rat during exhausting exercise

目的:通过观察一次性力竭运动过程中大鼠"黑质-丘脑-皮层"通路核团间神经元电活动的相干性及各核团神经递质谷氨酸(Glu)和γ-氨基丁酸(GABA)的浓度,探讨运动疲劳发生过程中大鼠"黑质-丘脑-皮层"通路神经元电活动的可能机制。方法:40只雄性Wistar大鼠,随机分为神经元电活动实时测定组、黑质网状部(SNr)神经元胞外神经递质实时测定组、丘脑腹外侧核(VL)神经元胞外神经递质实时测定组及皮层辅助运动区(SMA)神经元胞外神经递质实时测定组(n=10)。大鼠提供3级递增负荷跑台运动方案进行一次性力竭运动,通过自身对照,观察神经元电活动实时测定组大鼠SNr、VL及SMA神经元细胞在一次性力竭运动前、中、后神经元电活动的动态变化,同步、动态观察神经元胞外神经递质实时测定组大鼠一次性力竭运动前、中、后大鼠SNr、VL及SMA胞外Glu和GABA的浓度及其比值变化。结果:黑质网状部、丘脑腹外侧核局部场电与皮层脑电在力竭运动过程的不同阶段脑区之间神经元电活动,在0~30 Hz范围内均存在显著相干性。与安静状态相比较,自主运动期,大鼠黑质网状部神经元胞外Glu浓度、Glu/GABA比值均显著下降(P<0.05,P<0.01),GABA浓度则显著升高(P<0.05,P<0.01),而丘脑腹外侧核及皮层辅助运动区神经元胞外Glu浓度、Glu/GABA比值均显著升高(P<0.05,P<0.01),GABA浓度则显著下降(P<0.05,P<0.01);疲劳初期和力竭期,大鼠黑质网状部神经元胞外Glu浓度、Glu/GABA比值均显著升高(P<0.05,P<0.01),GABA浓度则显著下降(P<0.05,P<0.01),而丘脑腹外侧核及皮层辅助运动区神经元胞外Glu浓度、Glu/GABA比值均显著下降(P<0.05,P<0.01),GABA浓度则显著升高(P<0.05,P<0.01)。结论:大鼠在一次性力竭运动过程中"黑质-丘脑-皮层"通路各核团之间存在神经网络联系,该通路各核团神经递质Glu、GABA浓度的改变是导致其神经元电活动变化的因素之一。

Objective： To reveal the possible mechanism of changes of ＇substantianigra-ventralislateralis-cortex＇ pathway neural activity during one bout of exhausting exercise through observing the neural activity coherence between different nucleus and the concentration of extracellular glutamate （Glu） and gamma-aminobutyfic acid （GABA）. Methods： Male Wistar rats were randomly divided into neural activity real- time observation group, substantianigra （SNr） extracellular neurotransmitters observation group, ventralislateralis （VL） extracellular neuro-transmitters observation group and supplementary motor area （SMA） extracellular neurotransmitters observation group, 10 rats in each group. For rats of neural activity real-time observation group, by using LFPs and ECoG recording technique, and self-comparison, we simultaneously recorded the dynamic changes of neural activity of rat SNr, VL and SMA during one bout of exhausting exercise. The dynamic changes of extracellular Glu and GABA in rat SNr, VL and SMA were also observed through microdialysis combined high perfomlance liquid chromatography （HPLC） technique and self-comparison method. Results： Based on the behavioral performance, the exhausting exercise process could be divided into 5 different stages, the rest condition, auto exercise period, early fatigue period, exhaustion condition and recovery period. The elec-trophysiological study results showed that, the coherence between neural activity in rat SNr, VL and SMA was significant between 0-30 Hz during all the procedure of exhausting exercise. Compared with the rest condition, the microdialysis study showed that the Glu concentrations and Glu/GABA ratio in SNr were decreased significantly during automatic exercise period （ P 〈 0.05, P 〈 0.01 ）, the GABA concentrations were increased significantly （ P 〈 0.05, P 〈 0.01 ）, while, in VL and cortex, the Glu concentrations and Glu/GABA ratio were increased signiflcantly （ P 〈 0.05, P 〈0. 01 ）, the GABA concentrations were decreased significantly （ P 〈 0.05, P 〈0. 01 ）. Under early fatigue and exhaustion conditions, compared with the rest condition, the Glu concentrations and Glu/GABA ratio in SNr were increased significantly （ P 〈 0.05, P 〈0. 01 ）, the GABA concentrations were decreased significantly （ P 〈 0.05, P 〈 0.01 ）, while the Glu concentrations and Glu/GABA ratio in VL and cortex were decreased significantly （ P 〈 0.05, P 〈 0.01 ）, the GABA concentrations were increased significantly （ P 〈0. 05, P 〈 0.01 ）. Conclusion： The neural net work communication between ＇ substantianigra-ventralislateralis-cortex＇ pathway exists, changes of Glu and GABA in the nucelus of the pathway are one of the factors resulting in the changes of neural activity.