L－精氨酸和N~G－甲基－L－精氨酸对血管内皮细胞释放EDRF的影响

通过培养的大鼠胸主动脉内皮细胞（ＣＥＣ）及胸主动脉环，利用生物分析法，探讨ＣＥＣ释放内皮源性舒张因子（ＥＤＲＦ／ＮＯ）的检测方法，影响ＥＤＲＦ／ＮＯ分泌的因素。发现单纯ＣＥＣ或经乙酰胆碱（Ａｃｈ）预处理的ＣＥＣ对去内皮血管环张力无明显影响；而经Ｌ－精氨酸（Ｌ－Ａｒｇ）或Ｌ－Ａｒｇ和Ａｃｈ预处理的ＣＥＣ可引起去内皮血管环产生明显舒张；ＮＧ－甲基－Ｌ－精氨酸和Ａｃｈ预处理的ＣＥＣ则引起去内皮血管环明显收缩。提示ＣＥＣ在基础状态和经Ａｃｈ预处理后，其合成和分泌ＥＤＲＦ／ＮＯ的能力很低或丧失，可能存在内源性ＥＤＲＦ／ＮＯ前体Ｌ－Ａｒｇ不足，供给外源性Ｌ－Ａｒｇ有增强ＣＥＣ合成和释放ＥＤＲＦ／ＮＯ的作用。在Ｌ－Ａｒｇ供给充足情况下，Ａｃｈ可进一步刺激ＣＥＣ释放ＥＤＲＦ／ＮＯ。

Effects of L-arginine and N-G-monomethyl-L-arginine on the release of endothelium-derived relaxing factor in cultured endothelial cells of rats

The purpose of our study was to look for a method for the detection of the release of the endothelium-derived relaxing factor(EDRF)by cultured endothelial cells(CECs)and the factors modulating the release of EDRF by CECs,The endothelial cells of the thoracic aorta of rats were cultured.The thoracic aortic ring of rats was isolated and the endothelium of the aortic ring was removed.The tension of this endothelium-removed aortic ring (ERAR)was determined after treated with various preparations of CEGs. It was found that pure CECs and CECs pretreated with acetylcholine(Ach)exerted no significant effect on the tension of ERAR;CECs pretreated with L-arginine(L-Arg)or L-Arg and Ach was able to result in marked vasodilatation of ERAR;CECs pretreated with NG-monomethyl-L-rginine and Ach could bring about marked vasoconstriction of ERAR. Our findings suggest that the ability of CECs to synthesize and release EDRF is quite low or is even lost under basic condition or after the pretreatment with Ach due to possibly a shortage of the endogenous precursor of EDRF but the synthesis of EDRF by CECs is significantly promoted by the provision of L-Arg and the addition of Ach after the provision of L-Arg can further increase the release of EDRF.