下丘脑室旁核内NPY神经元与CCK神经元相互关系的免疫电镜双标研究

DOUBLE LABELED IMMUNO-ELECTRON MICROSCOPIC STUDY ON THE RELATIONSHIP BETWEEN NPY-AND CCK-NEURONS IN THE HYPOTHALAMIC PARAVENTRICULAR NUCLEUS

应用包埋前免疫电镜双标技术对大鼠下丘脑室旁核的神经肽Y(NPY)和胆囊收缩素(CCK)神经元的相互关系进行了研究。用Norgren法进行免疫电镜双标染色。结果在电镜下观察到:在室旁核内侧部,NPY样免疫反应产物呈电子密度高的颗粒状或絮状,弥漫分布于胞浆;CCK样免疫反应产物则呈电子密度高的针状或块状,散在分布于胞浆,偶见于核内。有时,在一个神经末梢内既有浓重的颗粒状DAB反应产物,又有典型的针状TMB反应产物。在室旁核内,NPY和CCK神经元胞体互相混杂、交错存在,两者均为中等大细胞。在超微结构水平,NPY和CCK神经元的树突和轴突可由非NPY、非CCK神经末梢接受传入突触联系;CCK神经元的树突还可接受其他CCK神经末梢的传入性自调节突触;CCK神经元胞体可接受NPY神经末梢的传入性突触,后者的突触前成分内可能有CCK与NPY共存。

Using pre-embedding double labeled immuno-electron microscopic technique the relationship between NPY-and CCK-neurons in the paraventricular nucleus (PVN) of the rat hypothalamus was studied. The immunostaining procedure was carried out according to Norgren's method with some modifications. Under electron microscope it was observed that in the PVN the NPY-immunoreactive products distributed diffusely as high electron dense granular or flucculent deposits in the cytoplasm. Whereas the CCK-immunoreactive products distributed sparsely as high electron dense needle-or mass-like deposits in the cytoplasm. Occasionally, they appeared in the nucleus. Sometimes, heavy DAB granular reactive products and typical TMB needle-like deposits existed in the same nerve terminal. In the PVN, the NPY-and CCK-perikarya were interdigitated and both were mainly medium in size. The number of CCK-neurons was much more than that of NPY-neurons. At ultrastructural level the dendrites and axons of NPY-and CCK-neurons received afferent synapses from non-NPY, non-CCK nerve terminals; the dendrites of CCK-neurons might also received afferent autoregulatory synapses from other CCK-nerve terminals; the soma of CCK-neurons also received afferent synapses from NPY-nerve terminals, in the pre-synaptic element of which NPY and CCK might coexisted.