Inoue Shino, Yamanaka Toshiaki, Kita Taizo, Nakashima Toshikatsu, Hosoi Hiroshi
Department of Otolaryngology, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8522, Japan.
Brain Res. 2003 Nov 21;991(1-2):78-83. doi: 10.1016/j.brainres.2003.08.002.
We investigated the changes in glutamate release from the ipsi- and contra-lesional medial vestibular nucleus (MVN) following unilateral labyrinthectomy (UL) by in vivo microdialysis study. The concentration of glutamate in the ipsi-lesional MVN was decreased until 4 h. Twelve hours after UL, the concentration of glutamate was restored back to the basal level, after which the release did not show any change between 24 and 48 h post-UL. In contrast, the concentration of glutamate in the contra-lesional MVN, which increased immediately after UL, decreased gradually to the basal level until 3-4 h post-UL, followed by no further change. The difference in the glutamate concentration between ipsi- and contra-lesional MVN increased immediately after UL and gradually decreased accompanied by a reduction in the frequency of nystagmus, although spontaneous nystagmus had not disappeared by the time the imbalance of glutamate release diminished. These results suggest that the imbalance of glutamate release between bilateral nuclei induced the nystagmus, and the change in release is concerned with the rapid development of vestibular compensation.
我们通过体内微透析研究，调查了单侧迷路切除术后，同侧和对侧内侧前庭核（MVN）谷氨酸释放的变化。同侧损伤的MVN中谷氨酸浓度在4小时内降低。迷路切除术后12小时，谷氨酸浓度恢复到基础水平，此后在术后24至48小时内释放未显示任何变化。相比之下，对侧损伤的MVN中谷氨酸浓度在迷路切除术后立即升高，在术后3至4小时逐渐降至基础水平，随后不再变化。同侧和对侧损伤的MVN之间谷氨酸浓度的差异在迷路切除术后立即增加，并随着眼球震颤频率的降低而逐渐减小，尽管在谷氨酸释放失衡消失时自发性眼球震颤尚未消失。这些结果表明，双侧核之间谷氨酸释放的失衡诱导了眼球震颤，释放的变化与前庭代偿的快速发展有关。
