延髓-小脑系的分支投射——荧光素双重标记法研究

THE DIVERGENT PROJECTIONS IN THE BULBO-CEREBELLAR SYSTEM——A DOUBLE FLUORESCEIN LABELING STUDY

本文报道用荧光素双重标记法研究大鼠延髓-小脑系的分支投射。将2％FB水溶液2μl注入左侧小脑半球前叶皮质,存活32小时后,将2％NY水溶液2μl注入右侧小脑半球前叶皮质,再存活16小时后,经心脏灌注磷酸盐缓冲的10％福尔马林,取小脑及延髓作恒冷箱连续切片,片厚20μm,隔片留1片作荧光显微镜检查。结果证实两侧小脑半球前叶间无往返的纤维联系,小脑半球前叶自延髓接受的传入投射比已知的要广泛得多。外侧网状核、腹侧网状亚核、中缝隐核、舌下神经前置核、楔外侧核、三叉神经脊束核及下橄榄核背侧副核内均有FB单标细胞、NY单标细胞及FB/NY双标细胞,除下橄榄核外,双标细胞占全部标记细胞的23％。以上结果表明:小脑自延髓接受多源性传入联系,而分支投射又使小脑的信息接受面进一步增大,使两侧小脑半球的活动同步化,从而有助于进行更完善的调节。

The divergent projections in the bulbo-cerebellar system of rats were studied by double fluorescein labeling method. 2 μ1 of 2％ Fast blue (FB)were injected into the cerebellar cortex of left anterior lobe, 32 hours later, 2 μl of 2％ Nuclear yellow (NY)were injected into the cerebellar cortex of right anteior lobe. The animals were allowed to survive 16 hours thereafter. Intracardiac perfusion were performed with 10％ formalin in 0.1 mol/L phosphate buffer. The cerebellum and medulla oblongata were removed and serial sections at 20 μm were cut by cryostat. One of every two sections was preserved for fluorescence microscopic observation. The results identified that there was no intereonnection between the anterior lobes of two cerebellar hemispheres and the anterior lobe of cerebellum received afferent projections from much more nuclei of the medulla oblongata than previous description. The FB or NY single labeled and FB/NY double labeled cells were observed in the nucleus reticularis lateralis, subnucleus reticularis ventralis, nucleus raphe obscurus, nucleus prepositus hypoglossi, nucleus cuneatus lateralis, nucleus spinalis nervi trigemini and nucleus olivaris aceessorius dorsalis. The double labeled cells accounted for 23％ of total labeled cells except the nucleus olivaris inferior. The results mentioned above suggested that the cerebellum receive multiple afferent connections originated from the medulla oblongata, and the divergent projections further amplify the information-receiving areas in the cerebellum, and synchronize the activities of both cerebellar hemispheres.