次声对大鼠学习记忆行为及海马和颞叶皮层5-HT、5-HTR的影响

Effects of infrasound on learning and memory and the expression of 5-hydroxy tryptamine and its receptor in hippocampi and temporal cortex of rats

目的探讨 8Hz次声对大鼠空间学习记忆行为的影响及其作用机制。方法大鼠分别暴露于 8Hz ,90dB、10 0dB或 13 0dB次声仓中 ,每日 2小时 ,之后进行Morris水迷宫训练 ,记录其找到隐匿站台的时间 ;第 6天训练结束后取脑并进行免疫组织化学染色 ,光镜下分析其海马及颞叶皮层 5 羟色胺 (5 HT)及5 羟色胺受体 (5 HTR)含量。结果次声组大鼠在水迷宫中逃离水难的时间均较对照组延长 (P =0 .0 10及P =0 .0 0 1,P =0 .0 0 0 ) ;次声组大鼠海马及颞叶皮层 5 HT、5 HTR含量均较对照组减少 (均P =0 .0 0 0 ) ;大鼠在水迷宫中找到隐匿站台的时间与其海马及颞叶皮层 5 HT、 5 HTR含量呈负相关。结论8Hz ,90dB、10 0dB及 13 0dB次声可使大鼠空间学习记忆能力降低 ,并且随次声声压级的增加其作用愈加明显 ,作用机制可能与海马及颞叶皮层 5 HT、5 HTR的减少有关。

ObjectiveTo investigate the effects of 8Hz infrasound on spatial learning ability of rats and its mechanism . MethodsMale SD rats were respectively exposed to 8Hz, 90dB?100dB or 130dB infrasound for 2 hours every day. All the rats were given Morris maze training as soon as taken out of the infrasonic depot each day for 6 days altogether. And at last the rat's brains were taken and given immunohistochemistrial straining for 5-hydroxy tryptamine(5-HT) and its receptor (5-HTR). The content of 5-HT and 5-HTR in hippocampi and temporal cortex were detected under an optical microscope. Results The infrasound groups show prolonged period in finding the hidden platform in Morris training( P =0.010, P = 0.001 and P =0.000). The hippocampi and temporal cortex of infrasound groups shown less positive cell of 5-HT and 5-HTR ( P =0.000) .The latent period of rats finding the hidden platform shows a negative correlation with the content of 5-HT and 5-HTR in hippocampus and temporal cortex.ConclusionsInfrasound of 8Hz, 90dB?100dB and 130dB could decrease the spatial learning ability of rats, and with the increasing of infrasound pressure , the effect become more obvious .The mechanism possibly related to the reduction of 5-HT and 5-HTR in hippocampus and temporal cortex.