高温环境下急性力竭运动对大鼠下丘脑单胺类神经递质的影响

目的:探讨高温条件下急性力竭运动对大鼠下丘脑单胺类神经递质的影响。方法:16只雄性SD大鼠经适应性跑台训练后随机分为常温运动组(E)和高温运动组(HE),每组8只。E组和HE组大鼠分别在常温环境(23℃,约50%相对湿度)和高温环境(33℃,约50%相对湿度)中进行一次性力竭跑台运动。两组大鼠均在急性力竭运动后即刻宰杀。记录大鼠实验前后肛温(Tr)变化及力竭运动时间,运用高效液相色谱法测试大鼠下丘脑单胺类神经递质。结果:HE组大鼠急性力竭运动时间显著小于E组(P<0.01),而Tr显著高于E组(P<0.01);HE组大鼠下丘脑去甲肾上腺素(NE)浓度显著高于E组(P<0.01);两组大鼠5羟色胺(5-HT)、多巴胺(DA)、5羟色胺与多巴胺比值(5HT/DA)之间无显著性差异(P>0.05),但HE组大鼠5-HT和DA代谢产物5羟色氨酸(5-HIAA)与3,4-二羟基苯乙酸(DOPAC)均显著低于E组(P<0.05)。结论:(1)高温环境明显降低大鼠运动能力,大鼠核心温度升高是影响高温环境中运动能力的关键性因素,而非下丘脑单胺类神经递质的变化。(2)高温环境在一定程度上减弱了力竭运动对大鼠下丘脑单胺类神经递质的影响。

Effect of Acute Exhausted Exercise in High Temperature Environment on Monoamine Neurotransmitters in Hypothalamus of Rats

Objective To investigate the effects of acute exhausted exercise in high temperature environment on monoamine neurotransmitters in hypothalamus of rats.Methods Sixteen Sprague-Dawley(SD) rats after adaptive treadmill training were randomly assigned to following two groups:exercise in normal environment group(E) and exercise in high temperature environment group(HE).Rats in the two groups ran on a treadmill to exhaustion respectively in a normal environment(23℃,～50%RH) or high temperature environment(33℃,～50%RH).All rats were killed immediately after exercise and their hypothalamuses were sampled.Immediate rectal temperatures(Tr) before and after exercise,and duration of exercise to exhaustion were recorded respectively.Monoamine neurotransmitters in hypothalamus of rats were determined by high performance liquid chromatography.Results Exercising duration of group HE was significantly shorter than that of group E(P < 0.01),while Tr of group HE was significantly higher than that of group E(P < 0.01).There was no significant difference in 5-hydroxytryptamine(5-HT),dopamine(DA) and ratio of 5-HT/DA between two groups.However,the metabolites of 5-HT and DA,including hydroxyindoleacetic acid(5-HIAA) and 3,4-dihydroxyphenylacetic acid(DOPAC) levels of group HE were significantly lower than those of group E(P < 0.05).Conclusions(1)Exercise capacity of rats in high temperature environment significantly reduced,in which elevated core temperature played more important role than the changes in monoamine neurotransmitters in hypothalamus.(2)High temperature weakened the effect of acute exhausted exercise on monoamine neurotransmitters of hypothalamus in rats.