鸡海马结构向小脑各叶的直接投射——HRP逆行追踪法研究

Study on direct hippo-cerebellar projections from hippocampal formation in chickens with retrograde transport of horseradish peroxidase

采用HRP法逆行追踪鸡海马结构向小脑各叶投射的起始神经元。将50%HRP溶液分别引入鸡小脑Ⅳ、Ⅴ、Ⅵ、Ⅶ、Ⅷ、Ⅸ各叶,对端脑及间脑、脑干及小脑进行冰冻切片,TMB呈色,观察脑内标记细胞出现的位置。结果发现,除第Ⅸ叶外,注射小脑各叶双侧端脑海马结构的旁海马内侧区(APHm)出现大量标记细胞。在注射Ⅳ、Ⅴ、Ⅵ后偶尔在内侧隔核出现少量逆标细胞。随着注射点由Ⅳ叶到Ⅸ叶的后移,在APHm出现标记细胞的可能性渐小,而小脑前核,包括延髓大细胞网状核、下橄榄核、内外侧桥核、中脑的内侧螺旋核等标记的可能性相应地增大。隔核的标记细胞主要定位于外侧隔核。本研究结果表明,鸡存在海马向小脑的直接投射,这种投射主要终止于小脑的前叶、中叶。因为哺乳动物,鸡的隔核与海马有密切的联系。

To determine the existence and the topographic territories of direct hippo-cerebellar projections in chicken,50% HRP（horseradish peroxidase） was injected into the folia Ⅳ through Ⅸ of the cerebellum in chickens for retrograde tracing the origins of the telecephalic projection to the cerebellum.The results were as following：injection each folium except folium Ⅸ resulted in a large quantity of labeled neurons in the medial pars of parahippocampal area（APHm） of the bilateral hippocampal formation in telecephalon.In addition,after Ⅳ through Ⅵ folia injections small number of labelled neurons were occasionally found in the lateral septal nucleus.We also found that as the injection site shifted coudally from folium Ⅳ to Ⅸ,the possibility of the APHm being labeled granually declined,but that of the pre-cerebellar nuclei,including gigantocellular reticular nucleus of medulla oblongata,caudal olivary complex,lateral and medial pontine nuclei,medial spiriform nucleus of mesencephalon,increased respectively.The labeled neurons in the septal nuclei located mainly in the lateral septal nucleus.These results suggest that there are direct projections from the hippocampal formation to the rostral and intermedial lobi of the cerebellum in chicken,mainly origing from PHAm.As in mamanlian,the septal nucleus have tight connections with hippocampal formation in chickens.