大鼠下丘脑室旁核的神经支配

本文应用ＨＲＰ追踪、免疫细胞化学与电镜方法研究了大鼠下丘脑室旁核的神经支配。结果显示，中缝背核向室旁核投射的神经元中，部分为５－ＨＴ免疫反应阳性；被盖背外侧核的部分５－ＨＴ神经元也发出纤维投射至室旁核。将ＣＢ－ＨＲＰ注入第三脑室后，电镜下发现室旁核内ＥＶＫ免疫反应阳性树突接受ＨＲＰ反应阳性轴突形成突触，ＨＲＰ免疫反应阳性的树突与阴性轴突的传入形成突触，提示室旁核内ＥＮＫ神经元受触液神经元的突触调控，同时触液神经元又受到其他神经元的突触调控。

THE INNERVATIONS OF THE HYPOTHALAMIC PARAVENTRICULAR NUCLEUS IN THE RAT

The innervations of the hypothalamic paraventricular nucleus (PVN) in the rat were studied by means of HRP solution was injected unilaterally into PVN, the retrogradely labelled neurons were found in bilateral (predominantly ipsilateral) dorsal raphe nucleus (DR) and laterodorsal tegmental nucleus (LDTg). By combined method of HRP retrograde tracing and immunocytochemistry, HRP single-labelled neurons, 5-HT immunoreactive neurons and HRP/5-HT double-laabelled neurons were found in DR and LDTg. The double-labelled neurons were small or medium sizsed cells with round or elliptic somata.The results indicated that part of 5-HT-containing neurons in DR and LDTg projected to PVN.In another experiment, after injecting CB-HRP into the third ventricle, the sections were processed by immunoelectron microscopic technique. HRP reaction was demonstrated by molybdic acid-TMB method and ENK immunoreaction was demonstrated by chromogen DAB. Under electron microscope. it was observed. that in PVN the HRP reaction products appeared as highly electron dense needle-like or massive feature distributed in the perikarya, dendrites and axonal terminals whereas ENK-immunoreactive products as highly electron dense granular or flocculent materials precipitated at the periphery of the dendritic microtubules, on the outer membrane of mitochondria and in the matrix of perikaryon. It was interesting that in PVN ENK-like immunoreactive dendrites received asymmetric afferent axo-dendritic synapses from HRP reaction-positive axonal terminals. The presynaptic elements contained numerous small clear vesicles, part of which contacted presynaptic membrane. The synaptic cleft was about 20 nm in width and contained electron dense materials. In addition, some HRP reaction-positive dendrites as postsynaptic elements formed axo-dendritic synapses with negative axonal terminals. The results indicated that the ENK neurons of PVN received synaptic regulation from CSFcontacting neurons which in turn received synaptic regulation from other neurons. The above mentioned facts provided new ultrastructur I basis for the theory of the brain-cerebrospinal fluid neurohumoral circuit.