鸡圆窗埋植电极：听神经动作电位的长期记录方法

摘要

Objective　To record the electrocochleogram of chickens with better accuracy and stability, a technique of reliably recording cochlear potentials from a chronically implanted electrode was established. Methods　A cochlear deafferentation model was utilized to assess the validity of this technique. Twelve white Leghorn chickens were used as subjects. Cochlear action potential (CAP) recordings were taken immediately after implanting a silver balltipped electrode into the bony margin of the round window of left ears. Kainic acid (10μmol/ml×10μl) was then perfused into the scala tympani of six animals (KA group) to selectively damage the auditory nerve. The cochleae of other 6 birds remained intact (normal group). A series of CAP recordings were carried out at 1 day and 1, 2 and 4 weeks after the implantation and KA treatment.Results　Very stable CAP curves was obtained from both groups. Good reproducibility of the CAP curves were observed at different time points in the same animals.Conclusion　The electrode implantation site is relatively constant apart from the proximal end of the basilar papilla in comparison with the site of the conventional round window electrode. Furthermore, the ball-tip of the electrode is tightly fixed in the bone after the healing of wounded tissues. So, stable and reliable CAP curves are relatively easily recorded with the newly developed round window implanted electrode even several weeks after the operation.%目的为解决长期监测鸡听觉功能时通常使用的圆窗膜电极移位的问题，提高测试结果的稳定性，建立了一种新的电极埋植方法即“圆窗埋植电极”(round window implanted electrode)。并结合听觉传入神经病变模型评价该方法在实际使用中的稳定性。方法 12只白色Leghorn鸡平分为KA组(经鼓阶灌注kainic acid，选择性地破坏耳蜗传入神经树突)和正常组(不做耳蜗灌注)。暴露鸡的左侧圆窗，在其骨缘内钻孔后植入银球电极。测定电极植入后即刻(给药前)、1d和1，2，4周的听神经复合动作电位(CAP)。结果同一动物各次CAP波形重复性好，两组动物的振幅、潜伏期和听反应阈均达到满意的稳定性。讨论与传统的圆窗膜电极比较，圆窗埋植电极植入部位与基底膜的相对位置较恒定；组织愈合后，电极更不会移位，确保了测量数据的稳定性。结论该方法稳定可靠，改善了振幅的稳定性以后，使振幅成为听神经动作电位的一项灵敏而可靠的观察指标。本文详细介绍电极安装方法、检测结果，讨论与CAP记录有关的问题。