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[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 x 20 d. P300 were recorded at parietal bone in rats. The Nissl body, NMDAR2B and [Ca2+]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 20th 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 Ca2+ in neurons increased markedly in NG.


CONCLUSION
Decreased Nissl body and NMDAR2B and increased [Ca2+]i in hippocampus in long-term noise exposed rats might cause the change of ERP P300.