大鼠嗅结节与黑质间的往返投射

将ＨＲＰ或ＷＧＡ－ＨＲＰ注入大白鼠一侧的嗅结节，凡注射涉及嗅结节的多形层者均在注射黑质致密部－Ａ８，Ａ９区出现标记细胞，标记细胞主要位于黑质致密部的内侧，其数量由内向外递减，黑质致密内部的标记细胞以吻侧１／３段最多，中１／３段次之，尾１／３段最少。在ＷＧＡ－ＨＲＰ注射区涉及嗅结节的多形层的各例，除看到黑质致密部中的标记细胞外，还可见密集的成串珠样和点状的标记终末，黑质致密部内的标记终末分布于吻尾方

RECIPROCAL PROJECTION BETWEEN OLFACTORY TUBERCLE AND SUBSTANTIA NIGRA IN RATS

The connections between the olfactory tubercle (OT) and the substantia nigra (SN) were studied with the method of retrograde and anterograde axonal transport of HRP or WGA-HRP in rats. The shape and distribution of retrogradely labelled cells and the density distribution of an-terogradely labelled terminals in the SN were analyzed. The labeled cells appeared in the ipsilat-eral parscompacta of the substantia nigra (SNc)- A8 and A9 areas following injecting HRP or WGA-HRP into the unilateral OT, in which the injected areas were located in the polymorphic layer of OT. The labelled cells were distributed mainly in the medial part and gradually decreased in the lateral part of SNc. The number of the labelled cells within SNc was the most in the rostal 1/3 part, less in the middle 1/3 part and the least in the caudal 1/3 part. In these WGA-HRP cases in which the injected areas were located in the polymorphic layer of OT. The densely labelled terminals with candia and dots in shape were also observed besides the labelled cells in SNc. The labelled terminals were distributed within the whole SNc. The density of labelled terminals in the rostal 2/3 part and in the medial part was higher than in the caudal 1/3 part and in the lateral part of SNc. In the cases in which the central injected areas located in the medial part of the OT the labelled terminals were more than those in the others. The results suggest that the projection to SNc mainly originate from the medial part of OT. These findings indicate that the connections between OT and SN were present in the reciprocal projection and the pathway between OT and SN may belong to one part of the extrapyramidal system.