Li Hongyan, Dokas Linda A, Godfrey Donald A, Rubin Allan M
Department of Neurology, Medical College of Ohio, Toledo, OH 43614-5907, USA.
J Vestib Res. 2002;12(4):167-83.
To determine if synaptic remodeling in the vestibular nuclear complex (VNC) may be involved in vestibular compensation, expressions of growth-associated protein-43 (GAP-43) and synaptosome-associated protein of 25 kDa (SNAP-25) were examined by immunoblotting and immunocytochemistry after unilateral vestibular ganglionectomy (UVG) in rats. GAP-43 expression increased bilaterally in the VNC after UVG, but more rapidly on the lesioned side, and remained high through 60 days. It was mainly associated with boutons at all survival times but was also present in some axonal processes and, at 7 days after UVG, in some somata. SNAP-25 expression also increased bilaterally, more rapidly on the lesioned side, but decreased bilaterally after peaking at 14 days. Its distribution in the VNC resembled that of GAP-43 but was more completely localized to boutons. Comparisons were made with auditory centers of the same rats, since the lesion also deafferented that system. Our results combined with those of previous studies suggest that degeneration of the vestibular nerve fibers is required for increased expression of GAP-43 in the VNC. The results suggest that axonal sprouting and synaptogenesis are involved in synaptic remodeling bilaterally in the rat VNC after UVG.
为了确定前庭神经核复合体（VNC）中的突触重塑是否可能参与前庭代偿，在大鼠单侧前庭神经节切除术（UVG）后，通过免疫印迹和免疫细胞化学检测生长相关蛋白43（GAP - 43）和25 kDa突触体相关蛋白（SNAP - 25）的表达。UVG后，VNC中GAP - 43的表达双侧增加，但在损伤侧增加得更快，并在60天内一直保持高水平。在所有存活时间，它主要与轴突终扣相关，但也存在于一些轴突过程中，并且在UVG后7天，存在于一些胞体中。SNAP - 25的表达也双侧增加，在损伤侧增加得更快，但在14天达到峰值后双侧下降。其在VNC中的分布与GAP - 43相似，但更完全地定位于轴突终扣。由于该损伤也使同一大鼠的听觉系统传入神经阻滞，因此与同一大鼠的听觉中枢进行了比较。我们的结果与先前研究的结果相结合表明，VNC中GAP - 43表达增加需要前庭神经纤维的退化。结果表明，轴突发芽和突触形成参与了UVG后大鼠VNC双侧的突触重塑。
