摘要
目的探讨耳蜗内不同强度下高速率电刺激对大鼠下丘神经元兴奋性的影响。方法在刺激强度分别为电刺激听性脑干反应(electrically evoked auditory brainstem responses,EABR)阈上6dB和阈上12dB,用500pps和1000pps两种不同的电刺激速率急性刺激大鼠耳蜗,记录刺激2小时内及刺激停止后2小时内下丘神经元近场电位幅值。结果刺激强度为EABR阈上6dB时,应用500pps刺激速率,下丘神经元近场电位幅值在刺激过程中及刺激后2小时内都呈现上升趋势;应用1000pps刺激速率刺激2小时内,下丘神经元兴奋性有所下降,至刺激停止时为87%,但刺激停止后2小时内幅值不仅得到恢复,而且高于刺激前水平;予EABR阈上12dB强度电流刺激,在两种电刺激速率下,刺激后均可见下丘神经元反应幅值明显下降,速率越高下降越明显,恢复趋势越微弱。急性刺激停止时,500pps和1000pps刺激速率下丘神经元反应幅值分别下降52%、69%(P<0.05),刺激停止后120分钟,分别下降10%、59%。结论在较低电流强度(EABR阈上6dB)刺激下,高速率电刺激(1000pps)会导致下丘神经元兴奋性下降,但刺激停止后可恢复甚至高于刺激前水平;高强度、高速率电刺激会导致下丘神经元兴奋性下降,且刺激停止后恢复较慢;与听觉神经纤维相比,下丘神经元兴奋性受耳蜗内高速率电刺激的影响更大。
OBJECTIVE To assess the effect of high-rate stimulation with diferent intension on excitability of the inferior colliculus neuron. METHODS 2h acute electrical stimulation was performed with intensity of 6dB or 12dB above EABR threshold at different stimulus rates of 500pps,1000pps, the amplitudes of near-field potential of the inferior colliculus were recorded during the 2h stimulus period and 2h post-stimulus monitoring period. RESULTS While the acute stimulus intensity was kept constantly in the normal clinical level （6 dB above EABR threshold） with 500pps, the responses of inferior colliculus neurons rose during and after acute stimulation. With rate of 1000pps, the amplitude reduced to 87% at the end of stimulation, then recovered even higher than the level of pre-stimulus. While the acute stimulus intensity was kept constantly in the level of 12dB above EABR threshold, the amplitudes of the inferior colliculus reduced 52%, 69% compared with the pre-stimulus amplitude at the end of stimulation with 500 and 1000 pps respectively, and reduced 10%, 59% respectively 2h after stimulation. CONCLUSION The excitability of inferior colliculus neuron reduced at high-rate and low-intensity electrical stimulation, but could recover after the stimulation. The excitability of inferior colliculus neuron reduced manifestly at high-rate and high-intensity. The impact of intracochlear high rate electrical stimulation on excitability of inferior colliculus neuron was greater than that of auditory nerve.
出处
《中国耳鼻咽喉头颈外科》
北大核心
2009年第4期183-186,共4页
Chinese Archives of Otolaryngology-Head and Neck Surgery
基金
国家自然科学基金资助项目(30572028)
北京市自然科学基金资助项目(7032008)
北京市优秀人才资助项目(20081B0300300067)联合资助
关键词
大鼠
耳蜗
动物
实验
下丘
电刺激
Rats
Cochlea
Animals, Laboratoroy
Inferior Colliculus
Electric Stimulation
