Role of CRP-positive cerebellar climbing fiber system on the development of vestibular compensation : An animal model study.

免疫组织化学研究表明，在共济失调突变型滚动小鼠名古屋（RMN）的前庭小脑中，促肾上腺皮质激素释放因子（CRF）阳性苔藓纤维和爬行纤维终末的数量增加。单极刷状细胞（UBC）是前庭小脑中的一类中间神经元，放大来自苔藓纤维的兴奋性输入。RNM组和对照组小鼠前庭小脑中钙视网膜蛋白（CR）阳性UBC的数量没有差异。但是，与CR阳性UBC紧密贴壁的CFR阳性苔藓纤维末端的数量在RMN中比对照组多5倍。本研究提示，与前庭小脑UBC接触的CRF阳性苔藓纤维终末可能对RMN的小脑共济失调有代偿作用，并试图阐明与前庭小脑UBC接触的CRF阳性苔藓纤维终末在前庭代偿发展中的作用。小鼠单侧小脑切除后，与前庭小脑UBC接触的CRF阳性苔藓纤维终末的数量没有变化。尽管RMN前庭小脑中CRF阳性攀爬纤维终末的数量增加，但小鼠单侧迷路切除术后前庭小脑中CRF阳性攀爬纤维终末的数量没有变化。这些结果提示，前庭小脑中CRF阳性苔藓纤维和爬行纤维在前庭代偿的发育中不起作用，相反，单侧前庭神经节切除后，同侧前庭内侧核中CRF阳性终末的数量减少，提示CRF影响前庭神经核中前庭代偿的发育，而不影响前庭小脑。

Role of CRP-positive cerebellar climbing fiber system in the development of vestibular compensationThe present immunohistochemical study demonstrated an increase in number of corticotropin-releasing factors (CRF)-positive mossy and climbing fiber terminals in the vestibulocerebellum in an ataxic mutant, rolling mouse Nagoya (RMN). Unipolar brush cells (UBCs), a class of interneurons in the vestibulocerebellum, amplifies excitatory inputs from mossy fibers. The number of calretinin (CR)-positive UBCs in the vestibulocerebellum was no different between RNM and the control mice. But, the number of CFR-positive mossy fiber terminals in closely apposition to CR-positive UBCs was 5-fold greater in RMN than in the controls. It is suggested that CRF-positive mossy fiber terminals in contact with UBCs in the vestibulocerebellum compensate the cerebellar ataxia in RMN.An attempt was made to clarify the roles of CRF-positive mossy fiber terminals in contact with UBCs in the vestibulocerebellum in the development of vestibular compensation. After unilateral labyrinthectomy in mice, there were no changes in number of CRF-positive mossy fiber terminals in contact with UBCs in the vestibulocerebellum. Although the number of CRF-positive climbing fiber terminals was increased in the vestibulocerebellum of RMN, there were no changes in number of CRF-positive climbing fiber terminals in the vestibulocerebellum after unilateral labyrinthectomy in mice. All these findings suggest that CRF-positive mossy and climbing fibers in the vestibulocerebellum do not play roles in the development of vestibular compensation.On the contrary, the number of CRF-positive terminals in the ipsilateral medial vestibular nucleus was decreased after unilateral labyrinthectomy in mice, suggesting that CRF affects the development of vestibular compensation in the vestibular nuclei, but not in the vestibulocerebellum.