目的　探讨轴突导向分子EphA5在胚胎中脑神经上皮干细胞向靶组织纹状体特异性投射中的作用。 方法    自孕11 d大鼠取材胚胎中脑神经上皮干细胞并进行体外培养，应用免疫细胞化学的方法检测EphA5在神经上皮干细胞中的表达情况；取材鼠脑纹状体组织，应用冰冻切片、RT-PCR 及Western-blot等方法检测EphA5的配体Ephrin-A5的特异表达情况；将胚胎中脑神经上皮干细胞与新生鼠纹状体组织块联合培养，观察细胞的靶向生长情况。 结果　体外培养的胚胎中脑神经上皮干细胞可明显向纹状体生长并呈EphA5阳性，靶区纹状体组织中可检测到其配体Ephrin-A5高表达。  结论    轴突导向分子EphA5受体及其配体Ephrin-A5可介导胚胎中脑神经上皮干细胞向纹状体组织的靶向生长。

    Objective　To explore the effects of axon guidance molecular EphA5 on mesostriatal projection. Methods　Immunofluorescence staining was performed to examine the expression of EphA5 in embryonic neuroepithelial stem cells of mesencephalon and the expression of Ephrin-A5 in striatum, while, RT-PCR and Western-blot techniques were performed to detect the expression of mRNA and protein of Ephrin-A5 in striatum. Furthermore, neuroepithelial stem cells were co-cultured with striatum explants of newborn rat brains for exploring targeted growth of cultured cells.  Results　A great quantity of neuroepithelial stem cells were EphA5 positive, with the high expression of Ephrin-A5 in striatum. Co-cultured mesencephalon neuroepithelial stem cells extended towards the striatum. Conclusions    This study suggests that axon guidance molecular EphA5 receptor and its ligand Ephrin-A5 promotes the axon growth of neuroepithelial stem cells toward striatum during development, and these two molecules mediate the establishment of mesostriatal projection.