耐力训练及力竭运动对大鼠纹状体、中脑和下丘脑内单胺类神经递质的影响

Effects of endurance training and exhaustion treadmill running on monoamine neurotransmitters in striatum, midbrainand hypothalamus of rats

目的:运用单胺类神经递质比值和相关系数分析力竭性跑台运动对不同脑区单胺类神经递质相互关系的影响。方法:实验于2002-07/2003-07在南京体育学院和南京大学完成。选取8周龄雄性SD大鼠50只,随机分为5组:安静组(不训练);急性运动后即刻组(不训练,处死前进行急性力竭性跑台运动);急性运动后24h组(不训练,处死前一天进行急性力竭性跑台运动);耐力训练+急性运动后即刻组(实施耐力训练方案,最后进行急性力竭性跑台运动,并在运动后即刻处死);耐力训练+急性运动后24h组(实施耐力训练方案,最后进行急性力竭性跑台运动,并在运动后的24h处死);每组10只。耐力训练方案1次/d,6d/周。跑台速度由开始的10m/min逐渐增加到第4周30m/min,运动时间由30min/d增加到40min/d。急性力竭性跑台运动速度为28m/min,以动物不能坚持负荷跑速,滞跑道的后1/3处达3次以上,刺激驱赶无效(10s)为力竭标准。断头处死分离出纹状体、中脑及下丘脑,经处理后采用高效液相色谱-电化学检测法测定多巴胺、去甲肾上腺素及5-羟色胺含量。结果:50只SD大鼠均完成实验设计方案的实验,全部进入结果分析。①与安静组相比,力竭性跑台运动可使经训练和不经训练大鼠的下丘脑多巴胺/5-羟色胺、多巴胺/去甲肾上腺素比值显著性下降。②与安静组相比,急性运动后即刻组大鼠中脑去甲肾上腺素/5-羟色胺比值显著性升高;急性运动后24h组显著性低于急性运动后即刻组。③安静大鼠中脑内去甲肾上腺素与5-羟色胺的偏相关有显著性。不训练大鼠力竭性跑台运动后即刻下丘脑去甲肾上腺素与5-羟色胺的偏相关有显著性。不训练大鼠运动后24h中脑多巴胺与去甲肾上腺素及下丘脑去甲肾上腺素与5-羟色胺的偏相关有显著性。训练大鼠力竭性跑台运动后即刻下丘脑去甲肾上腺素与5-羟色胺的偏相关有显著性。结论:在运动至力竭时,中枢的抑制过程主要发生在纹状体,并由5-羟色胺、去甲肾上腺素和多巴胺同时起作用。力竭性运动后即刻中脑处于兴奋状态,运动会造成下丘脑持续的抑制作用。下丘脑内去甲肾上腺素与5-羟色胺可能相对成为一个独立于多巴胺的系统,共同调节其他递质或被其他递质调节,这种独立性因运动而表现显著。耐力训练可能提高纹状体、中脑多巴胺与去甲肾上腺素的平衡能力,而削弱5-羟色胺系统的抑制作用。

AIM： To analyze the effect of exhaustion treadmill running on the relationship of monoamine neurotransmitters in different brain regions by ratios of monoamine neurotransmitters and related coefficients. METHODS： The experiment was done from July 2002 to July 2003 in Nanjing Institute of Physical Education and Nanjing University. Fifty male SD rats of 8 weeks old were selected and divided into 5 groups randomly with 10 rats in each group： sedentary group （without training）, right after acute exercise group （without training, sacrificed right after acute exhaustion treadmill running）, 24 hours after acute exercise group （without training, sacrificed 24 hours later after acute exhaustion treadmill running）, right after acute exercise with training group （performance endurance training program, rats were sacrificed right after acute exhaustion treadmill running ）, 24 hours after acute exercise with training group （performance endurance training program, rats were sacrificed 24 hours after acute exhaustion treadmill running）. Endurance training program： once a day, 6 days a week. Speed increased from 10 m per minute at the first week to 30 m per minute at the 4^th week. Training time was that from 30 minutes per day at the first week to 40 minutes per day at the 4^th week. Acute exercise means an exhaustion treadmill running with the speed of 28 m per minute. The exhaustion standard was the rat could not keep the speed and stagnant stay in the 1/3 back part of the treadmill even with electricity stimulation for 10s more than 3 times. Rats were sacrificed with decollation. Striatum, midbrain and hypothalamus of the brain were separated. High-performance liquid chromatography with electrochemical detection was used to detect the levels of dopamine （DA）, norepinephrine （NE） and 5-hydrexytryptamine （5-HT）. RESULTS： Totally 50 SD rats were done the experimental program and involved in the result analysis. ① The results showed that exhaustion treadmill running could make the ratios of DA/5-HT and DA/NE in the hypothalamus of rats significantly decreased with or without prior endurance training as compared with the sedentary group.② The NE/5-HT ratio in the midbrain of the right after acute exercise group increased significantly as compared with the sedentary group, and the 24 hours after acute exercise group significantly decreased as compared with the right after acute exercise group. ③ The partial related coefficient between NE and 5- HT levels in the midbrain of the sedentary group was significant. The partial related coefficient between NE and 5-HT levels in the hypothalamus of the right after acute exercise group was significant. The partial related coefficient between DA and NE levels in the midbrain and the partial related coefficient between NE and 5-HT levels in the hypothalamus of 24 hours after acute exercise group were significant. The partial related coefficient between NE and 5-HT levels in the hypothalamus of the right after acute exercise with training group was significant. CONCLUSION： Central inhibition occurs mainly in the striatum, and 5- HT, NE and DA act simultaneously when running to exhaustion. The midbrain is in excitation after exhaustion treadmill running, while＇the hypothalamus is inhibited. NE and 5-HT in the hypothalamus may compose a system, relatively independent of DA, to adjust or be adjusted by other transmitters. This independence gets significant because of running. Endurance training may improve the balance between DA and NE in the striatum and the midbrain, while reduces the inhibition effect of 5-HT during exercise.