急性低氧时豚鼠声信号传入的变化

本工作的目的是研究急性高原低氧对豚鼠听觉传入功能的影响。２０只豚鼠分为４组，分别接受模拟海拔高度为５０００、６０００、７０００和８００ｏｍ的急性低氧暴露，于不同时间测定听觉脑干诱发反应各波的潜伏期、峰间期、振幅和ＩＩＩ波的电反应阈（听阈）。结果如下：当升至预定的海拔高度和在低氧维持阶段，６０００ｍ以上组各波潜伏期延长，其中ＩＩ波变化更明显；回到海平面高度后逐渐恢复，１ｈ内基本可恢复正常；潜伏期变化的程度与海拔高度有关。在低氧阶段各波振幅普遍下降，回到海平面高度后逐渐回升，但恢复至正常所需时间较长。在升至预定的海拔高度和其后低氧维持阶段，各组动物的听阈均上升，脱离低氧后即可迅速恢复，１ｈ内可恢复正常。结果表明，急性高原低氧使听觉脑干传导时间延长，传入神经元兴奋性降低，听敏度下降，因而可以推测它能影响声信号的传入。

CHANGE OF TRANSMISSION OF SOUND SIGNAL DURING ACUTE EXPOSURE TO HYPOXIA

The purpose of this study was to observe the effects of acute hypoxia on the function of hear-ing transmission.Twenty guinea pigs were divided into 4 groups exposed to simulated aItitudes of5000m,6000m,7000m and 8 000m above sea level respectively.The latency,interpeak latencyand amplitude of waves of auditory brainstem evoked response and hearing threshold of wave IIIwere measured at different time points.The results were as follows:The latencv in groups of over6000m lengthened during exposure to hypoxia at the given height.Of the waves,wave II wasmost seriously affected.The latency recovered gradually after return to sea level and wasnormalized within 1 hour.The latency change was related to the elevation height.The amplitudeof all waves reduced during hypoxia and the recovery was slow.The hearing threshold rose in allgroups during hypoxic exposure and recovered rapidly to normal whithin 1 hour after return tosea level.The results show that acute altitude hypoxia can lengthen brainstem transmission time(BTT),reduce the excitability of afferent neuron and lower hearing sensitivity,suggesting that thetransmission of sound signal is affected.