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Experimental Studies on mechanism underlying noise-induced Rearing disorder.

噪声引起的养育障碍机制的实验研究。

基本信息

批准号：
06671745
负责人：
YOSHIDA Masafumi
金额：
$ 1.02万
依托单位：
University of Occupational and Environmental Health
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

In the first year, cochlear microphonics (CM) in response to two tone stimuli as well as compound action potential (CAP) of the acoustic nerve were measured before and after exposure to 4kHz pure tone at 100dB SPL for 10min. The output of 2f1-f2 distortion product in the CM (CM-DP) were markedly reduced immediately after the exposure and then recovered gradually. The reduction and recovery in CM-DPs closely paralleled with those in the CAP.This may indicate that the affection of the outer hair cell (OHC) function plays an important role in developing the noise induced temporary threshold shift. The following study with administration of salicylate, which was known to interfere the electro-mechanical transduction (EMT) of OHCs, reveled the different alterations of the CM-DPs from those with sound exposure. From these results it is postulated that acoustic overstimulation affects the mechano-electrical transduction (MET) of OHC.In the following year, combined effects of loud sound and salicylate were studied. The effects were altered by changing the order in which the two agents were applied. The existing sound-induced damage attenuated the additional ototoxicity of salicylate, whereas attenuation did not occur when salicylate administration preceded sound exposure. From these results it is postulated that the MET holds dominant position over EMT in the cochlear transduction mechanism.Spontaneous electrical oscillations (AC potentials) were accidentally recorded from the cochlea of several animals without any exposure to sound or drugs. Close observations in the properties of the AC potentials indicated that the potentials were generated by the active mechanical vibration system at the area on the basilar membrane where the characteristic frequency corresponded to that of the potential.

第1年，在4kHz纯音、100dBSPL刺激10 min前后，分别测定耳蜗微音电位（CM）和听神经复合动作电位（CAP）。CM（CM-DP）2f 1-f2畸变产物的输出在照射后即刻明显减少，随后逐渐恢复。CM-DPs的降低和恢复与CAP的降低和恢复密切相关，这可能表明外毛细胞（OHC）功能的影响在噪声引起的暂时性阈移的发展中起重要作用。下面的研究与管理水杨酸，这是已知的干扰机电转导（EMT）的OHC，揭示了不同的改变CM-DP从那些声音暴露。从这些结果推测，声音过度刺激影响OHC的机械-电转换（MET）。在接下来的一年中，大声和水杨酸的联合作用进行了研究。通过改变这两种药剂的施用顺序来改变效果。现有的声音引起的损害衰减水杨酸盐的额外的耳毒性，而衰减没有发生水杨酸盐给药之前的声音曝光。从这些结果可以推测，MET在耳蜗传导机制中占主导地位，在没有任何声音或药物暴露的情况下，从几种动物的耳蜗意外记录到自发电振荡（AC电位）。对交流电位特性的密切观察表明，这些电位是由主动机械振动系统在基底膜上的特征频率与电位对应的区域产生的。