高渗刺激后大鼠视上核星形胶质细胞和神经元的反应及其相互关系的光、电镜研究

目的探讨大鼠尾静脉注射高渗盐水(9％NaCl，5．5mL／kg)后，视上核(SON)内星形胶质细胞和神经元的可塑性反应及相互间的关系。方法用免疫组织化学和免疫电镜技术，观察刺激后15，45，90，180和360minSON内缝隙连接蛋白43(Cx43)和蛋白32(Cx32)的变化及超微结构。结果光镜下观察到Cx43阳性星形胶质细胞在15min出现，45min达到高峰；Cx32阳性神经元90min达到高峰。电镜下在SON内，观察到下列四种超微结构：(1)突触样结构(synapse like structure)，位于神经元的轴突末梢与Cx43阳性的星形胶质细胞突起之间；(2)三成分的突触复合体(tripartite synaptic structure)，由突触前膜、突触后膜和靠近此突触的星形胶质细胞突起共同组成；(3)同源性缝隙连接(gap junction，GJ)，位于星形胶质细胞突起之间，两侧均为Cx43；(4)“异源性缝隙连接样结构”(heterotypic gap junctions，HGJ)，是由Cx32阳性神经元和Cx43阳性星形胶质细胞突起组成的一种超微结构。结论高渗刺激后，SON内Cx43阳性星形胶质细胞和Cx32阳性神经元明显增加，前者出现和高峰的时间早于神经元；两者之间的HGJ数量明显增加，其他结构的数量变化不明显，因此两者可能是通过HGJ进行快速的信息交流。

The expression and relationship between astrocytes and neurons in the supraoptic nucleus after hyperosmotic stimuli by using light- and electron-microscopic techniques

Objective To investigate the plasticity changes and relationship between astrocytes and neurons in the supraoptic nucleus (SON) after hyperosmotic stimuli by injection trail vein of hyper-saline (9%NaCl,5.5 ml/kg). Methods Immunohistochemistry and immunoelectron- microscope methods were used to observe the expression of anti-connexin 43 and anti-connexin 32 after hyperosmotic stimuli at 15, 45, 90, 180, 360 min. Results Anti-Cx43-like immunoreactive-Li) astrocytes appeared at 15 minutes in SON, it peaked at 45 min; Cx32-Li peaked at 90min. Four kinds of special ultrastructures were found in SON by electron microscope: (1) the synapse-like structure, localized between neuron axons and processes of Cx43-Li astrocytes; (2) the tripartite synaptic structure, which were consisted of postsynaptic membrane, presynaptic membrane and astrocytes processes adjacent to the synapse; (3) the gap junction (GJ), composed of Cx43-Li membrane in both sides between astrocytes processes; (4) the heterotypic gap junctions (HGJ),which were consisted of Cx43-LI membrane on the side of astrocytes and Cx32-Li membrane on neurons. Conclusion Our results showed that after hyperosmotic stimuli, the number of Cx43-Li astrocytes and Cx32-Li neurons in SON increased significantly, appearance and peak Cx43-Li astrocytes was earlier than that of neurons, and number of HGJ also increased significantly, while number of other structures was not changed. It suggested that the signal may communicate quickly between SON astrocytes and neurons by means of HGJ.