目的：研究胰岛素诱导的急性低血糖应激对大鼠下丘脑增食欲素-A （ orexin-A）的表达影响。方法通过皮下注射胰岛素建立急性低血糖大鼠模型。采用免疫组织化学染色方法观察大鼠下丘脑 orexin-A 和 Fos 双标情况，并采用ELISA 方法对脑脊液中的 orexin-A 含量进行检测。结果禁食组、低血糖进食组和低血糖禁食组阳性神经元计数明显高于对照组（P＜0．05），但三组之间计数比较差异无统计学意义（P＞0．05）；Orexin-A /Fos 双标细胞率（双标细胞占 orexin-A 阳性细胞的百分率）在低血糖禁食组最高，与禁食组和低血糖进食组比较差异有统计学意义（P＜0．05）。 ELISA 检测结果显示，低血糖禁食组脑脊液中的 orexin-A 含量显著高于其它三组，差异有统计学意义（P＜0．05）。结论急性血糖的降低可以增强大鼠下丘脑中 orexin-A 的表达，而摄食行为可以抑制此调控效应。%Objective To explore the expression of orexin-A in insulin-induced acute hypoglycemia in rat hypothalamus .Methods The rat model of acute hypoglycemia was established by subcutaneous injection of insulin .We examined double labelling of orexin-A and Fos in rat hypothalamus by immunohistochemical staining and detected orexin-A level in cerebrospinal fluid (CSF) by ELISA assay .Results The number of orexin-A positive cell were increased in hypoglycemia of the fasting group ,hypoglycemia + feeding group , and hypoglycemia + fasting group than in the control group (P< 0 .05) ,but not significantly different a-mong these former three groups (P> 0 .05) .The double labeling rates for orexin-A and Fos (the percent-age of orexin-A /Fos double-labeled neurons to total orexin-A positive neurons) was significant higher in the hypoglycemia + fasting group than in the hypoglycemia + feeding and the fasting group .ELISA assay revealed that the orexin-A level of acute hypoglycemia rat with fasting in CSF was higher than in the other three groups (P< 0 .05) .Conclusion Orexin-A in rat hypothalamus can be stimulated by acute hypoglyce-mia ,but this modulation can be inhibited by signals related to feeding .
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