猫中缝核向嗅球的投射——HRP法研究

本研究用HRP逆轴突传递法观察了猫脑干中缝各核向嗅球的上行投射。实验证明,将HRP注入一侧嗅球后,标记细胞规律性地出现在上位脑干的各中缝核中,即中缝背核(RD)、中央上核(CS)、中间线形核(LI)和吻侧线形核(LR);下位脑干的中缝各核(中缝隐核、中缝苍白核,中缝大核和中缝桥核)全无标记。四个核中出现的标记细胞数各不相同,细胞的分布各有特点。RD中的标记细胞数是四个核中最多的,它们沿中线排列,主要集中于核的中、吻段,尾段极少。CS内的标记细胞数占第二位,仅见于核的尾段,吻段无标记。LI中的标记细胞最少,分散在核的全长。LR中的标记细胞不多,主要出现在同侧核的腹侧部。本研究支持文献中关于RD和CS与嗅球的上行联系的报导,证明了尚未见报导的LI和LR是嗅球传入纤维的另外来源。

PROJECTIONS FROM THE RAPHE NUCLEI TO THE OLFACTORY BULB IN THE CAT——HRP METHOD

The ascending projections from the raphe nuclei of the brain stcm in the cat were studied with the method of the retrograde transport of horseradish peroxidase and the shape and the distribution of the labeled cells in the raphe nuclei were analysed. It was demonstrated that following injecting HRP into one olfactory bulb the labeied cells appeared regularly in the nucleus raphe dorsalis (RD), the nucleus cen-tralis superior (CS), the nucleus linearis intermedius (LI) and the nucleus linearis rostralis (LR).The rest of the raphe nuclei were not labeled. The labeled cells in the four nuclei varied in number and had dif-ferent distribution patterns. The labeled cells in RD were most nume-rous of the four and distributcd along the midline, concentrated in its rostral and middle parts and few in its caudal part. The labeled cells in CS were second in number, presented only in its caudal half but not in its rostral half. The labeled cells in LI were the least and scattered in its whole extent. Less labeled cells were seen in LR and presented mainly in its ventral part ipsilaterally. Previous studies about the projections of the raphe nuclei to the olfactory bulb are reviewed and only RD and CS, no other raphe nuclei, have been reported to project to the olfactory bulb. This study agrees with the previous studies describing the projections of RD and CS to the olfactory bulb and suggests that LI and LR are the additional sources of the afferent fibers to the olfactory bulb.