Jäger W, Goiny M, Herrera-Marschitz M, Flock A, Hökfelt T, Brundin L
Department of Physiology and Pharmacology, Huddinge University Hospital, Stockholm, Sweden.
Exp Brain Res. 1998 Aug;121(4):425-32. doi: 10.1007/s002210050477.
We have used the perfused guinea-pig temporal-bone preparation to study the sound-evoked efflux of aspartate and glutamate, which are putative afferent transmitters in the cochlea. The cochlea was stimulated with white noise at 89, 95, and 101 dB SPL. Cochlear function was monitored by recording the endocochlear potential, the cochlear microphonic, and the summating potential. In silence, there was a low basal efflux of both amino acids. A significant and intensity dependent sound-evoked efflux of aspartate was observed at all levels, whereas a significant efflux of glutamate was found only at the 101 dB SPL level. Immunohistochemistry of sections from the organ of corti showed an ubiquitous distribution of glutamate-like immunoreactivity in the sensory organ and ganglion, whereas aspartate-like immunoreactivity was found in the region of the inner hair cells and in the spiral ganglion. In view of these findings, we suggest that not only glutamate, but also aspartate may have a neurotransmitter role in the afferent pathway of the cochlea.
我们使用灌注的豚鼠颞骨制备物来研究天冬氨酸和谷氨酸的声诱发流出，这两种物质被认为是耳蜗中的传入递质。用89、95和101 dB SPL的白噪声刺激耳蜗。通过记录内淋巴电位、耳蜗微音器电位和总和电位来监测耳蜗功能。在安静状态下，两种氨基酸都有较低的基础流出量。在所有声压级下均观察到天冬氨酸有显著且与强度相关的声诱发流出，而仅在101 dB SPL水平发现谷氨酸有显著流出。对柯蒂氏器切片的免疫组织化学分析显示，感觉器官和神经节中普遍存在谷氨酸样免疫反应性，而在内毛细胞区域和螺旋神经节中发现了天冬氨酸样免疫反应性。鉴于这些发现，我们认为不仅谷氨酸，而且天冬氨酸可能在耳蜗的传入通路中具有神经递质作用。
