不同禁水时间老龄大鼠下丘脑大细胞分泌神经元的免疫电镜观察

The Immunoelectron Microscopic Observation of The Magnocellular Neurosecretory Neurons In The Hypothalamus of Aged Rat During Different Duration of Water Deprivation

电镜观察了不同禁水时间老龄大鼠下丘脑视上核和室旁核分泌神经元，即加压素和催产素神经元及胶质细胞的超微结构变化。结果显示：禁水６与１２ｈ后，上述两核团中的分泌神经元胞体增大，胞质中粗面内质网（ＲＥＲ）排列紧密且规则、高尔基（Ｇｏｌｇｉ）器的未成熟分泌颗粒及神经分泌颗粒增多、轴突内神经分泌颗粒少见；胶质细胞成份减少，突起回缩；相邻两神经元胞膜直接接触，质膜并列现象及突触增多。而在禁水２４ｈ后，神经元胞体内的神经分泌颗粒有减少，轴突中的神经分泌颗粒却增多并聚集成膨大区域。以上结果提示老龄大鼠视上核和室旁核的分泌神经元在禁水时其合成激素的功能是活跃的，而且催产素神经元的结构变化与加压素神经元结构变化是相似的。胶质细胞的结构变化为神经元质膜并列及突触的形式提供了有利条件。

The ultrastructural changes of the neurosecretory neurons-the vasopressin and Oxytocin neurons of the hypothalamic supraoptic and paraventricular nuclei(SON and PVN ) in the aged rats were observed by the immunoelectron microscopic technique.The results showed: after water deprivation for 6 and 12 h, the neurosecretory neuronal bodies became large, their RER arranged closely and regularly. Immature secretory granules of Golgi and neurosecretory granules (Nsgs) increased in number, But the number of Nsgs of axons in the neuropil did not increase . The processes of the glial cells were reduced and retracted from the components of neurosecretory neurons. The number of membrane apposition between adjacent neurosecretory neuron's soma and synaptic structure were increased. After 24h deprivation of water,the Nsgs and other organelles were reduced in the neurosecretory neuronal bodies,but it increased in the axons and accumulated in Herring bodies. The above results indicated: the functional activity of the neurosecretory neurons in the hypothalamic SON and PVN became active after water deprivation.The ultrastructural changes of the oxytocin neurons were similar to that of the vasopressin neurons. The glial processes retraction were advantageous to form the membrane apposition of neurons and synaptic structure.