对速尿引起总和电位与蜗内电位不同变化的认识

Differences in furosemide induced changes of summating potential and endocochlear potential in guinea pigs

目的 研究SP的生理特性 ,探讨总和电位 (summatingpotential,SP)与蜗内电位(endocochlearpotential,EP)变化的关系。方法 实验使用 8只健康杂色豚鼠 ,经颈静脉注入速尿或速尿 小牛血清白蛋白混合液 ,同步观察SP与EP的改变。SP由 10 5dBpeSPL的交替极性短声诱发 ,面神经管电极记录 ;EP从耳蜗基底回记录。结果 用药前SP以 -SP为主 ,无 +SP或很小 ,用药后随着EP的快速下降 ,-SP振幅迅速变小、消失 ,+SP出现或振幅增大 ;随着EP恢复到一定值 ,+SP消失或变的很小 ,-SP重新出现、振幅逐渐增大 ,60min时EP与 -SP均恢复至用药前水平。结论 速尿引起SP两种成分 -SP与 +SP产生分离性改变 ,-SP振幅与EP幅值变化一致 ,而 +SP振幅与EP幅值变化相反。

Objective To investigate the physiological properties of summating potential (SP) and to compare the different changes between SP and endocochlear potential (EP) induced by Furosemide in guinea pigs Methods SP in response to clicks with alternative polarities at 105dB peSPL was recorded from a electrode in the facial nerve canal EP was measured with a glass microelectrode in the basal turn of the cochlea SP and EP were observed simultaneously and continuously after injection of Furosemide or the solution of Furosemide bovine serum albumin injected into the jugular vein of the animal Results Before furosemide application, only -SP could be recorded with small or without +SP After furosemide injection, EP declined dramatically followed by reduction of the -SP which quickly vanished, while +SP appeared or the amplitude increased When EP recovered to a certain level, +SP disappeared or dramatically decreased and then -SP reappeared The amplitude of -SP increased progressively with EP recovery Both -SP and EP recovered to the pre injected level in 60 min after the furosemide application Conclusion The results suggest that Furosemide induced distinct changes of -SP and +SP, the two components of SP The changes of -SP amplitude was consistent with that of the EP value, while the changes of +SP amplitude were contrary to that of the EP value