猫眶回向脑干的下行投射—WGA-HRP顺行追踪研究

THE CORTICAL DESCENDING PROJECTION FROM THE ORBITAL GYRUS TO THE BRAIN STEM IN THE CAT-BY WGA-HRP METHOD

为了探讨猫眶回至脑干下行投射的起源和终止部位,分别向眶回前部和后部注射WGA-HRP,追踪在脑干里的顺行标记终末支,结果如下:1.眶回前部注射,标记终未支见于三叉神经脊束核各亚核、感觉主核、孤束核和臂旁核等,而眶回后部注射,标记终末支多位于中脑中央灰质和臂旁核等。2.三叉神经感觉核簇由尾侧亚核吻部至感觉主核,于背侧部或背内侧部形成连续柱形标记区,其中吻侧亚核标记最密。孤束核的标记见于闩以上,吻侧部标记密集。臂旁核内的标记在眶回前部注射例多见于其内侧核;在眶回后部注射例,外侧核内标记稍多。中脑中央灰质里的标记区由尾向吻侧,逐渐由背外向腹外转移。3.各部的标记终末支主要见于注射同侧,对侧标记较少甚至没有。

WGA-HRP was injected into the anterior part(groupⅠ)or posterior part(groupⅡ)of the orbital gyrus in the cat,the cross sections of the brain stem were examined for the WGA-HRP labeled fibers and termi-nals with bright and dark rield microscopy.The results obtained were as follows:1.The labeled fibers and terminals in the brain stem in those cases injected WGA-HRP into anterior part were different from those injected into posterior part of the orbital gyrus.The labeled fibers and termi-nals of groupⅠwere seen in all subnuclei of the spinal trigeminal nucleus(Vo.Vi.Vc),principal sensory nucleus(Vp),nucleus of solitary tract(S),and parabrachial nucleus(Pb),and so on.The labeled fibers and terminals of groupⅡwere observed in the griseum centrale mes-encephali(Gem)and Pb,and so on.2.The labeling in the trigeminal sensory nuclear complex formed a continuous column rostro-caudally in its dorsal or dorso-medial part.Heavy labeling was seen in the Vo:the labeled fibers and terminals in S appeared slightly above the obex,being denser in its oral part;the labeled fibers and terminals of groupⅠwere mainly observed in the medial parabrachial nucleus(Pbm)and those of groupⅡin the lateral parabrachial nucleus(Pbl);tracing from the caudal to oral level of the Gem,we found the labeled fibers and terminals shifted from its dorso-lateral part to ventro-lateral part.3.The labeled fibers and terminals in all nuclei mentioned above were observed chiefly ipsilaterally,while on the contralateral side they were markedly less or even entirely absent,