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为了探讨神经垂体内后叶加压素（ＶＰ）释放的γ－氨基丁酸（ＧＡＢＡ）能神经调控，本研究用包埋前ＡＢＣ法结合免疫电镜双标技术，研究了大鼠神经垂体内ＶＰ能神经和ＧＡＢＡ能神经的超微结构分布及其相互联系。先用ＤＡＢ法显示ＧＡＢＡ免疫反应，然后用钼酸铵－ＴＭＢ法显示ＶＰ免疫反应，再用ＤＡＢ－氯化钴稳定后作免疫电镜包埋。电镜观察发现：在神经垂体内ＧＡＢＡ样免疫反应产物呈电子密度高的颗粒状沉淀，定位于神经末梢内的小清亮羹泡周围和线粒体膜上；ＶＰ样免疫反应产物呈电子密度高的不规则形块状或针状散在于神经分泌末梢内。ＧＡＢＡ样神经末梢分布于神经分泌末梢之间或紧贴毛细血管和垂体细胞，可与神经分泌末梢紧密接触甚至形成突触。ＶＰ样神经分泌末梢内含小透亮囊泡和大颗粒囊泡，并可与ＧＡＢＡ样轴突末梢形成突触。在这种情况下，ＧＡＢＡ样轴突为突触前成分，突触前、后膜呈对称性，突触间隙宽度小于２０ｎｍ，内含电子致密物质。以上结果证实，在大鼠神经垂体内ＶＰ释放受到ＧＡＢＡ神经的直接突触调控。
In order to investigate the GABAergic neurotransmission of vasopressin (VP) released from the neurohypophysis, we used the ABC method combined with immunoelectron microscopy to study the effects of VP Ultrastructure distribution of nerves and GABAergic nerves and their interconnections. GABA immunoassay was first displayed by DAB method, and then VP immunoreaction was shown by ammonium molybdate-TMB method, and then immobilized by DAB-cobalt chloride for immunoelectron microscopy. Electron microscopy showed that the GABA-like immunoreactive products in the neurohypophysis were electron-dense granular precipitates localized around the small clear bud vesicles and mitochondrial membrane within the nerve endings. The VP-like immunoreactive products showed high electron density irregularities Block-shaped or acicular scattered in the nerve endings. GABA-like nerve endings distributed between the nerve endings or close to the capillaries and pituitary cells, with close contact with the nerve endings or even the formation of synapses. VP-like neurosecretory terminals contain small translucent vesicles and large vesicles and form synapses with GABA-like axon tips. In this case, the GABA-like axon is a presynaptic component that is symmetrical at the anterior and posterior synapses with a synaptic cleft width of less than 20 nm containing electron-dense material. The above results confirm that the VP release in the rat neurohypophysis is directly regulated by the GABA nerve.