Guo M, Ren T, Nuttall A L
Xijing Hospital, Fourth Military Medical University, Xi'an.
Zhonghua Er Bi Yan Hou Ke Za Zhi. 1997 Oct;32(5):259-63.
To investigate the electromotility of basilar membrane (BM) of guinea pigs in vivo, a couple of Platinum-iridium wire electrodes were placed into holes drilled in the scala vestibuli and scala tympani on the basal turn of cochlea separately. The organ of Corti was stimulated with rectangular direct current pulses. The displacement and velocity of BM were measured with Laser Doppler velocimeter. The results indicated that the displacement of BM elicited by current moved toward the scala where positive current was injected. The waveform of BM displacement was corresponding to the rectangular pulse of electric current step. Ringing responses could be seen at the onset and offset of current pulse that was the transient responses of outer hair cells. The frequency of the ringing was the same as that of characteristic frequency of partition in BM. It is supposed that the ringing of BM is an active process of depletive energy and participate with cochlear amplifier. In the insensitive cochlea or dead animal, direct current can still elicit a BM displacement but the ringing response is decreased or disappeared. This phenomenon is probably because of metabolic disturbance in damaged outer hair cells. The BM vibration induced by direct current is similar to that of induced by acoustic stimulation, which can transfer to other partition of BM by traveling wave. This characteristic has laid a foundation of electromotile hearing and electrically evoked otoacoustic emission.
为研究豚鼠体内基底膜（BM）的电运动，将一对铂铱丝电极分别置于耳蜗基底转前庭阶和鼓阶钻出的孔中。用矩形直流脉冲刺激柯蒂氏器。用激光多普勒测速仪测量基底膜的位移和速度。结果表明，电流引起的基底膜位移朝着注入正电流的蜗管移动。基底膜位移的波形与电流阶跃的矩形脉冲相对应。在电流脉冲的起始和结束时可看到振铃反应，这是外毛细胞的瞬态反应。振铃频率与基底膜中分区的特征频率相同。推测基底膜的振铃是一个消耗能量的主动过程，并参与耳蜗放大器的作用。在不敏感的耳蜗或死亡动物中，直流电仍可引起基底膜位移，但振铃反应减弱或消失。这种现象可能是由于受损外毛细胞的代谢紊乱所致。直流电诱发的基底膜振动与声刺激诱发的相似，可通过行波传递到基底膜的其他分区。这一特性为电动听力和电诱发耳声发射奠定了基础。
