噪声暴露对大鼠学习记忆及海马氨基酸神经递质水平的影响

Effects of noise exposure on learning and memory and neurotransmitters of hippocampus in rats

目的研究噪声暴露对大鼠学习记忆及海马氨基酸神经递质的影响。方法雄性SD大鼠，随机分为正常对照组（C组）、Morris水迷宫训练组（M组）、噪声暴露组（N组）和噪声暴露后Morris水迷宫训练组（NM组）。暴露条件：105dB白噪声2．5Wd×20d。应用Morris水迷宫进行学习记忆测试。高效液相色谱法检测海马氨基酸类神经递质含量。结果在学习记忆测试第1，3天，NM组的逃避潜伏期为（38．25±10．72）s和（25．42±8．59）s，均显著高于M组的（26．91±9．25）s和（13．72±10．19）s（P〈0．05），在第2，4天，NM组的逃避潜伏期与M组相比也呈现升高趋势；NM组在目标象限停留时间及穿越原平台次数中的成绩[（20．22±9．16）s、（3．56±2．40）次]均显著低于M组[（36．25±13．13）s、（8．00±4．31）次]（P〈0．05）。N组和NM组海马谷氨酸含量[（13．76±1．09）μmol／g、（14．38±1．60）μmol／g]与C组和M组[（11．18±1．32）μmol／g、（10．84±1．03）μmol／g]相比均明显增加（P〈0．01），γ-氨基丁酸含量则明显下降（P〈0．05），天冬氨酸和甘氨酸含量各组间未见明显差别。结论噪声暴露可致大鼠学习记忆能力下降，这可能与其海马主要氨基酸神经递质含量改变有关。

Objective To study the effects of noise on learning and memory and neurotransmitters of hippocampus in rats. Methods Male SD rats were divided into four groups： control group（CG）, Morris water maze （MWM） training group（ MG）, noise exposure group（NG） and noise exposure plus MWM training group （NMG）. Character of noise exposure ：white noise105dB SPL,2.5h/d × 20d. Spatial learning and memory were assessed in hidden-plat-from-acquisition training and probe trial testing in MWM. HPLC were used to analyzed the concentration of amino acid neurotransmitters in hippocampus. Results The performance of NMG animals in hidden-platfrom-acquisition training and probe trial testing were worse than that in MG animals （ P 〈 0.05 ）. The concentrations of glutamate in hippocampus of NG and NMG animals were significantly higher than those of CG and MG animals（ P 〈 0.01 ）, while the concentration of GABA decreased markedly in NG and NMG animals （ P 〈 0.05 ）. Conclusion Increased glutamate and decreased GABA in hippocampus which developed in long-term noise exposed rats, might have caused the impairment of spatial learning and memory.