急性低温低氧对大鼠下丘脑NOS及c-fos表达的影响

Effects of acute hypoxia and hypothermia on expression of c fos and NOS in the hypothalamus in rats *

目的：探讨急性低温低氧对大鼠下丘脑ＮＯＳ及ｃ－ｆｏｓ表达的影响。方法：用ｃ－ｆｏｓ免疫组化技术和ＮＡＤＰＨ－ｄ组化法研究急性低温低氧大鼠下丘脑内ｃ－ｆｏｓ原癌基因的表达、一氧化氮合酶（ＮＯＳ）的分布及两者的共存。结果：急性低温低氧组大鼠：①下丘脑内ｃ－ｆｏｓ表达明显增加，在许多核团呈恒定的核特异定位分布，其中室旁核、弓状核、腹内侧核、背内侧核表达最为强烈，乳头体前核、下丘脑后核有中等强度的表达，视上核偶有表达。②室旁核的大细胞部和视上核可见密集深染的ＮＯＳ阳性大细胞。③在室旁核的小细胞部及其附近的区域约有１０％～２０％的中小型ＮＯＳ阳性细胞同时表达ｃ－ｆｏｓ蛋白，其它部位偶见双染细胞。以上结果与对照组比较差异显著，而１ｄ组和３ｄ组之间无明显变化。结论：下丘脑内的特定核团可能参与低氧反应的整合。一氧化氮（ＮＯ）作为一种非经典的新型神经递质和信息分子可能与低氧反应有关。

Objective: To study the effects of acute hypoxia and hypothermia on the expression of c fos and NOS in the hypothalamus in rats. Mehtods: The effects of acute hypoxia and hypothermia on the expression of c fos and NOS were observed with c fos immunohistochemical and NADPH d histochemical staining. Results: The findings were as follows: ①c fos expression in the hypothalamus was significantly increased with a nucleus specific distribution especially in the paraventricular nucleus, arcuate mucleus, ventromedial nucleus and dorsomedial nucleus. ②Dense and deeply stained NOS positive cells were seen in the magnocellular region of the paraventricular nucleus and supoptic nucleus. ③In the parvocellular region of the paraventricular nucleus and in the adjacent periventricular region, about 10%～20% NOS positive cells were also stained by c fos immunohistochemistry. These findings were significantly different from those of the control but no evident difference was found between the One day and 3 day groups. Conclusion: Specific nuclei in the hypothalamus might take part in the adjustement of and adaptation to hypoxia and nitric oxide, an atypical new neurotransmitter and message molecule, may be related to the adaptation to hypoxia.