Di Guo-Qing, Qin Zhao-Qi
Department of Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, PR China.
Noise Health. 2018 Jan-Feb;20(92):9-15. doi: 10.4103/nah.NAH_27_17.
The present study aimed to evaluate the influences of combined traffic noise (CTN) on the ability of learning and memory in mice.
The Institute of Cancer Research (ICR) mice were exposed to CTN from highways and high-speed railways for 42 days, whose day-night equivalent continuous A-weighted sound pressure level (L) was 70 dB(A). On the basis of behavioral reactions in Morris water maze (MWM) and the concentrations of amino acid neurotransmitters in the hippocampus, the impacts of CTN on learning and memory in mice were examined.
The MWM test showed that the ability of learning and memory in mice was improved after short-term exposure (6-10 days, the first batch) to 70 dB(A) CTN, which showed the excitatory effect of stimuli. Long-term exposure (26-30 days, the third batch; 36-40 days, the fourth batch) led to the decline of learning and memory ability, which indicated the inhibitory effect of stimuli. Assays testing amino acid neurotransmitters showed that the glutamate level of the experimental group was higher than that of the control group in the first batch. However, the former was lower than the latter in the third and fourth batches. Both, behavioral reactions and the concentrations of amino acid neurotransmitters, testified that short-term exposure and long-term exposure resulted in excitatory effect and inhibitory effect on the ability of learning and memory, respectively.
The effects of 70 dB(A) CTN on the ability of learning and memory were closely related to the exposure duration. Furthermore, those effects were regulated and controlled by the level of glutamate in the hippocampus.
本研究旨在评估交通混合噪声（CTN）对小鼠学习记忆能力的影响。
将癌症研究所（ICR）小鼠暴露于来自高速公路和高速铁路的CTN环境中42天，其昼夜等效连续A声级（L）为70分贝（A）。基于莫里斯水迷宫（MWM）中的行为反应以及海马体中氨基酸神经递质的浓度，检测CTN对小鼠学习记忆的影响。
MWM测试表明，短期暴露（6 - 10天，第一批）于70分贝（A）的CTN后，小鼠的学习记忆能力得到改善，显示出刺激的兴奋作用。长期暴露（26 - 30天，第三批；36 - 40天，第四批）导致学习记忆能力下降，表明刺激具有抑制作用。氨基酸神经递质检测显示，第一批实验小鼠的谷氨酸水平高于对照组。然而，第三批和第四批实验小鼠的谷氨酸水平低于对照组。行为反应和氨基酸神经递质浓度均证明，短期暴露和长期暴露分别对学习记忆能力产生兴奋作用和抑制作用。
70分贝（A）的CTN对学习记忆能力的影响与暴露持续时间密切相关。此外，这些影响受海马体中谷氨酸水平的调节和控制。
