Effects Of Early Noise Exposure On Hippocampal LTP In Rats

There have been many studies on the effects of noise exposure on the auditory system.However,the auditory system is not isolated.It is linked to other systems or structures of the brain and therefore coordinated to complete specific functions.Thus,noise exposure may also affect other systems and their functions(such as hippocampus and learning and memory function)through these connections.In this study,we first examined behavioral consequences of early noise exposure on learning and memory by using rats as a research model.Morris water maze test showed that,compared with the control group,the average escape latency of the noise group in searching for hidden platforms and the latency for the first entry into the platform was prolonged.However,the duration in the target quadrant and swimming distance were decreased.The Y-maze test showed that the stay time and exploration distance of the noise group in the novel arm were lower than those in the control group.The T-maze test showed that animals in the noise group were also less performance score than those of the normal group while conducting the task.It has been shown that behavioural change are closely related to hippocampal synaptic plasticity in learning and memory.We therefore further examined the effect of early noise exposure on hippocampal LTP.The results showed that the amplitude of LTP in the hippocampus of noise group was decreased significantly compared with that recorded in the control group.These effects lasted for at least 2 months after the end of the noise exposure.The above results demonstrated the behavioral consequences of early noise exposure on learning and memory in rats,which may be related to noise-induced changes in hippocampal LTP.