噪声暴露对大鼠事件相关电位P300的影响及其海马水平的机制

目的：研究噪声暴露对大鼠事件相关电位（ERP）的影响及海马水平的机制。方法：雄性SD大鼠,随机均分为正常对照组（C组）、噪声暴露组（N组）。暴露条件：105dB白噪声2．5h／d×20d。观察试验过程中第0、7、14和20d ERP各波的峰潜伏期以及峰峰幅度值,并检测海马神经元尼氏体、NMDAR2B及胞内钙浓度的变化。结果：在实验第14d、第20d,噪声暴露组动物ERP P3a、P3和P3b的峰潜伏期显著增长,而且在噪声暴露20d后,大鼠海马齿状回以及CA1区尼氏体显著减少（P〈0．01）,齿状回、CA1及CA3区NMDAB2B的免疫反应强度显著降低（P〈0．01）,神经元胞内钙浓度显著升高（P〈0．01）。结论：噪声暴露可致事件相关电位的改变,这可能与其海马神经元尼氏体、NMDAR2B以及胞内钙的变化有关。

Effects of noise exposure on event-related potential P300 and mechanism in hippocampus of rats

Aim： To study the effects of noise on event-related potential（ERP） and its mechanism in hippocampus in rats. Methods： Male SD rats were divided into 2 groups： control group（CG） and noise exposure group（NG）. The rats in NG were exposed to white noise 105 dB SPL for 2.5 h/d× 20 d. P300 were recorded at parietal bone in rats. The Nissl body, NMDAR2B and Ca^2＋ ]i of neurons in hippocampus were analyzed. Results： The peak latency（PL） of ERP P3a, P3 and P3b in NG were significantly longer than that in CG in the 14th and 20^th exposure day. The amount of Nissl body in dentate gyrus（DG） and CA1 region and NMDAR2B in DG, CA1 and CA3 region of hippocampus of NG were significantly decreased than those of CG as well, while the concentration of Ca^2 ＋ in neurons increased markedly in NG. Condution： Decreased Nissl body and NMDAR2B and increased Ca^2 ＋ ] i in hippocampus in long-term noise exposed rats might cause the change of ERP P300.