大鼠侧脑室注射甘珀酸后下丘脑视上核星形细胞和神经元对高渗刺激反应的影响

目的 观察大鼠侧脑室注射甘珀酸后下丘脑视上核星形细胞和神经元对高渗刺激反应的影响。方法 经侧脑室注射缝隙连接阻断剂甘珀酸(carbenoxolone,CBX)及尾静脉注射9％NaCl溶液后，用放射性免疫分析法测定大鼠血浆中加压素(VP)含量，免疫组织化学方法观察下丘脑视上核(SON)神经元的：Fos和星形细胞的Fos以及胶质原纤维酸性蛋白(GFAP)表达的变化。结果 1．未注射CBX组大鼠在高渗刺激后45min，血浆中VP的含量明显升高；SON中观察到GFAP／Fos阳性的星形细胞和Fos阳性神经元；2．GFAP／Fos阳性星形细胞高峰的出现早于Fos阳性神经元；3．向侧脑室注射CBX2h后，经尾静脉注射9％NaCl溶液，45Bin后血浆中的VP含量未升高，SON中GFAP／Fos阳性星形细胞的表达与未注射CBX组相同，Fos阳性神经元则显著减少。结论 SON的星形细胞对高渗刺激发生反应早于神经元，并可能通过缝隙连接影响神经元对渗透压的调节功能。

RESPONSE OF SON ASTROCYTES AND NEURONS TO HYPEROSMOTIC STIMULATION AFTER CARBENOXOLONE INJECTION INTO THE LATERAL VENTRICLE

Objective To observe the effection of carbennoxolone injection into the lateral ventricle on the reaction of SON astrocytes and neurons to hyperosmotic stimulation. Methods After injecting carbennoxolone(gap junction blocker,CBX) into lateral ventricle and injecting 9% NaCl into the femoral vein,radioimmunoassay was used to examine vasopression(VP) content in the blood plasma and immunohistochemistry used to observe glial fibrillary acidic protein(GFAP) and Fos expression in SON. Results 1.In the rats without CBX injection,the VP content increased significantly 45 minute after hyperosmotic stimulation.GFAP/Fos double positive immunoreactive (GFAP/Fos-ir) astrocytes and Fos-ir neurons were observed in SON.2.The peak time of GFAP/Fos-ir astrocytes appeared earlier than that of Fos-ir neurons. 3.Injecting CBX into the lateral ventricle followed by 9% NaCl injection into caudal vein 2 hours later.The VP content in blood plasm did not increase.GFAP/Fos-ir astrocytes in SON showed no difference while Fos-ir neurons obviously decreased than in the rats without CBX injection.Conclusion The present results indicated that SON astrocytes might communicate with neurons through gap junction and thus modulate neurons' function in osmotic regulation.