噪声对海马CA3区神经元电活动及突触超微结构的影响

本文用电生理学方法及电镜技术研究105dB(A)白噪声对海马CA3区神经元电活动及突触超微结构的影响。结果表明:大鼠在强噪声暴露期间(5min),其神经元放电出现减频反应(占53.3％),增频反应(占20％)和基本无反应(占26.7％)。而强噪声定时重复暴露(每天1h共50天)后,单位放电频率极显著地低于对照组,以及高频单位消失而低频单位增加;同时,突触超微结构(大鼠和豚鼠)也出现小泡不集中于突触前膜和线粒体空泡化增多等不利于突触功能的变化。表明强噪声对海马CA3区神经元的影响是明显的,且以抑制性作用更为显著。本文结合本室以往工作进行讨论,认为噪声影响学习功能可能有通过影响海马的活动而作用的机制。

EFFECT OF EXPOSURE TO NOISE ON THE ELECTRCAL ACTIVITIES OF NEURONS AND THE ULTRASTRUCTURE OF SYNAPE IN HIPPOCAMPAL CA3 AREA

The effect of exposure to 105dB(A) white noise on the neural unit activity and the ultrastructure of synape of hippocampal CA3 area was studied in 27 rats and 5 guineapigs. The discharges of 108 units were recorded. The results have showed that there are three kinds of the response of these units during the exposure to noise for 5 min. They are : inhibition (53.3%, 16/30), excitation (20%, 6/30), and no reaction (26.7%, 8/30). And after repeated-timing exposure to noise (1 hour / day for 50 days), the frequency of neuronal firing was outstandingly lowered in rats and the ultrastructure of synape had some changes like degeneration.Previous studies have showed that learning is impaired significantly by noise, and suggested that the influence of noise upon learning is caused by the action of noise information on the cerebral cortex via assending activating system, interfering its normal integration. It has showed that hippocampus play an important role in learning and memory, and have rich association with reticular formation and cerebral cortex. Therefore we suggest that the influence of noise on the learning may be related to the effect of exposure to noise on the activity of neuron in hippocampus.