Nagase S, Miller J M, Dupont J, Lim H H, Sato K, Altschuler R A
Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, 1301 East Ann Street, Ann Arbor, MI 48109-0506, USA.
Hear Res. 2000 Sep;147(1-2):242-50. doi: 10.1016/s0378-5955(00)00134-9.
Fos immunoreactive (IR) staining was used to examine changes in excitatory neuronal activity in the rat inferior colliculus (IC) between normal hearing and 21 day deaf rats evoked by basal or apical monopolar cochlear electrical stimulation. The location of evoked Fos IR neurons was consistent with expected tonotopic areas. The number of Fos IR cells increased as stimulation intensity increased in both normal and 21 day deaf animals. Stimulation at 1. 5x threshold evoked fewer Fos IR cells in 21 day deafened animals compared to normal hearing animals. At 5x and above, however, significantly increased numbers of Fos IR neurons (in a larger grouping) were evoked in 21 day deafened animals compared to normal hearing animals. Another group of animals had 7 days of deafness followed by 14 days of chronic basal cochlear electrical stimulation. In this group basal monopolar stimulation at 5x evoked not only a greater number of Fos IR neurons, compared to normal hearing animals, but the location of their grouping was slightly shifted to a more dorso-lateral region in the contralateral IC, compared to the normal hearing and 21 day deaf groups. These observations indicate that both deafness and chronic electrical stimulation may alter central auditory processing.
采用Fos免疫反应性（IR）染色法，研究在正常听力大鼠与21日龄聋鼠中，基底或顶端单极耳蜗电刺激诱发的大鼠下丘（IC）兴奋性神经元活动的变化。诱发的Fos IR神经元的位置与预期的音频区域一致。在正常动物和21日龄聋鼠中，Fos IR细胞的数量均随刺激强度的增加而增加。与正常听力动物相比，1.5倍阈值刺激在21日龄聋鼠中诱发的Fos IR细胞较少。然而，在5倍及以上阈值刺激时，与正常听力动物相比，21日龄聋鼠中诱发的Fos IR神经元数量显著增加（在更大的区域）。另一组动物先经历7天耳聋，然后进行14天慢性基底耳蜗电刺激。在这组动物中，与正常听力动物相比，5倍阈值的基底单极刺激不仅诱发了更多的Fos IR神经元，而且与正常听力组和21日龄聋组相比，它们在对侧IC中的聚集位置略微向背外侧区域偏移。这些观察结果表明，耳聋和慢性电刺激都可能改变中枢听觉处理。
