一氧化氮在缺氧耐受形成中的作用

THE EFFECT OF NITRIC OXIDE ON GENERATION OF TOLERANCE EXPOSED TO HYPOXIA

分别给小鼠腹腔注射Ｌ－精氨酸（５０ｍｇ／ｋｇ）、Ｌ－精氨酸类似物Ｎω－ＮＩＴＲＯ－Ｌ－ＡＲＧＩＮＩＮＥ（５０ｍｇ／ｋｇ），３０ｍｉｎ后进行急性缺氧重复实验。结果发现，Ｌ－精氨酸、Ｌ－精氨酸类似物组第一次缺氧耐受性时间平均为１１ｍｉｎ、１６ｍｉｎ，分别近似于、高于盐水对照组小鼠的第一次平均耐受时间（１２ｍｉｎ）。Ｌ－精氨酸组、Ｌ－精氨酸类似物组第二、三、四次重复缺氧的耐受时间分别为其各自第一次缺氧耐受时间的２．０、２．７、３．１；２．６、３．７、４．９倍，分别略低于、明显高于对照组（对照组第二、三、四次重复缺氧的耐受时间分别为其第一次缺氧耐受时间的２．２、３．１、３．６倍）。用荧光方法测定正常对照组第一、二、三、四次缺氧组脑内一氧化氮的含量，结果发现，一次缺氧组一氧化氮含量明显高于正常对照组，二、三、四次缺氧组，一氧化氮含量比一次缺氧组明显回降，结果提示，脑内一氧化氮减少可能有助于缺氧耐受性的形成。

The mice were divided into 3 groups which were injected introperitoneally reagent, respectively,30 min prior to the onset exposed to hypoxia for four runs: (1)L Arginine (50mg/kg); (2) N ω Nitro L Arginine(50mg/kg); (3) saline solution (90mg/kg).The first tolerance time of hypoxia in group 1、group 2、 group 3 is 11min、16 min、12 min .The tolerance time of two、 three、 four runs hypoxia in group 1、 group 2、group 3 is 2.0、 2.7、 3.1;2.6、 3.7、 4.9;2.2、 3.1、 3.6 times as much as that in itself first hypoxia. We determined the contents of NO by fluorometric method in 5 groups. Result showed that NO contents in group 1 (hypoxia exposure for one run)is significantly higher than that in control group (without hypoxia exposure).The contents of NO in group 2、 group 3、group 4 (hypoxia exposure for two、 three、 four runs) tend to come close to normal level. The findings suggested that the decreasing of NO in brain play an important role in generation of tolerance exposed to hypoxia.