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[Effects of direct current on vibration of cochlear basilar membrane]
1Department of Otorhinolaryngology, Zhujiang Hospital, First Military Medical University, Guangzhou 510282, China. guomengh@163.com
Objective:
To explore the effects of direct current on vibration of cochlear basilar membrane.
Methods:
A small hole with a diameter about 0.4 mm, which had the distance of 2.4 mm from round window niche, was made on cochlear basic turn of guinea pig for measuring the velocity of basilar membrane in vivo. On the superior and inferior edge of the measuring window, holes were made on the scala tympani and scala vestibuli for insert stimulating electrode that was made of platinum-iridium. The basilar membrane vibration was elicited by tone and the effect of direct current stimuli were observed by Laser Doppler interference velocimeter.
Results:
The velocity of basilar membrane vibration elicited with tone was increased significantly when positive current was delivered to scala vestibuli and the velocity was decreased on the contrary.
Conclusion:
The positive endolymphatic potential is essential for cochlea to transit sound to nerve impulse in physiological condition. It is benefit to enhance the gain of cochlear amplifier when the positive potential is increased on the top of outer hair cells, but the extrinsic negative potential should significantly decrease the gain of cochlear amplifier.