脉冲声暴露前后豚鼠耳蜗正、负和电位的变化

在豚鼠埋植慢性圆窗电极后,用短声诱发复合动作电位(CAP),用短纯音诱发动作电位-和电位(AP-SP)的复合波。观察脉冲声暴露前后SP^-和SP⁺相互关系及随恢复时间的变化.结果表明,SP^-的出现与CAP的阈移有关,当阈移≥30dB,即外毛细胞(OHC)损伤到一定程度时,SP^-出现率高;SP⁺下降越多,SP^-出现的幅度升高的愈多,反之亦然,提示在正常情况下,SP⁺对SP^-有抑制作用.OHC受损后,可能解除了这种抑制.所以作为重振现象指征的优势SP^-很可能是当OHC受损后,改变了内毛细胞(IHC)非线性特点所致。

Changes of positive and negative summating potential before and after impulse sound exposure in guinea pig cochlea

Compound action potential (CAP) and action potential-summating potential complex response (AP-SP) evoked by click and tone burst respectively were recorded from chronic electrode at round window in guinea pig. Corelations of positive summating potential (SP^-) and negative summating potential (SP^-) with recovery of them were observed before and after impulse noise exposure. The results show that the appearence of SP^- is related to CAP thresthold shift. The appearence of SP^- is more frequently than is in normal condition when auditory thresthold shift is equivatent to or over 30 dB. The lower the amplitude of SP⁺ is, the higher the amplitude of SP^-, and vice versa. It suggests that SP^- may be suppressed by SP⁺ in normal hearing. The suppression may be released if OHCs were injured. Dominent SP as the sign of recruitment may be induced by the change of nonlinear character of IHC following the damage of OHC.