Institute of Neuroscience, The Fourth Military Medical University, Xi'an, China.
J Neurosci Res. 2010 May 1;88(6):1364-73. doi: 10.1002/jnr.22297.
Acute hyperosmolarity induced a time-dependent expression of Fos protein in both neurons and astrocytes of the rat supraoptic nucleus, with peak Fos expression occurring at 45 min in astrocytes and at 90 min in neurons after hypertonic stimulation in vivo. To determine whether the two cell types were activated separately or in an integrated manner, animals were pretreated with fluorocitrate, a glial metabolic blocker or carbenoxolone, a gap junction blocker followed by an acute hypertonic stimulation similar to that of the controls. Antibodies against glial fibrillary acidic protein, connexin 43, vasopressin, and oxytocin were used in serial sections to identify the cellular elements of the supraoptic nucleus. It was found that interruption of astrocyte metabolism with fluorocitrate significantly reduced Fos protein expression in both astrocytes and neurons, whereas blockage of gap junctions with carbenoxolone clearly reduced Fos protein expression in neurons, but not in astrocytes. These results indicate that both neurons and astrocytes in the rat supraoptic nucleus are involved in regulating osmolarity. Astrocytes are activated first, whereas connexin 43 functional hemichannels in SON astrocytes are required for the subsequent activation of the neurons.
急性高渗诱导大鼠视上核神经元和星形胶质细胞中 Fos 蛋白的时间依赖性表达，在体内高渗刺激后 45 分钟星形胶质细胞和 90 分钟神经元中 Fos 表达达到峰值。为了确定这两种细胞类型是分别激活还是以整合方式激活，动物先用氟柠檬酸（一种星形胶质细胞代谢抑制剂）或 carbenoxolone（一种缝隙连接阻滞剂）预处理，然后进行类似于对照的急性高渗刺激。针对胶质纤维酸性蛋白、连接蛋白 43、血管加压素和催产素的抗体在连续切片中用于鉴定视上核的细胞成分。结果发现，用氟柠檬酸阻断星形胶质细胞代谢显著降低了星形胶质细胞和神经元中的 Fos 蛋白表达，而用 carbenoxolone 阻断缝隙连接明显降低了神经元中的 Fos 蛋白表达，但对星形胶质细胞没有影响。这些结果表明，大鼠视上核中的神经元和星形胶质细胞都参与了渗透压的调节。星形胶质细胞首先被激活，而 SON 星形胶质细胞中的连接蛋白 43 功能性半通道对于随后神经元的激活是必需的。
