L－精氨酸逆转一氧化氮抑制后的犬冠脉血流动力学改变和内皮素－1含量升高

观察了犬冠脉内灌注Ｎ－单甲基左旋精氨酸（Ｌ－ＮＭＭＡ）后再灌注Ｌ－精氨酸（Ｌ－Ａｒｇ）和单独灌注Ｌ－ＮＭＭＡ前后冠脉血流动力学、冠脉血流储备以及冠脉对不同浓度的乙酰胆碱（Ａｃｈ）反应的变化，同时用放免法测定冠脉前降支（ＬＡＤ）伴行静脉血中内皮素－１（ＥＴ－１）含量。结果发现，Ｌ－Ａｒｇ完全逆转了灌注Ｌ－ＮＭＭＡ引起的血流动力学改变，使心率回升，下降的基础冠脉流量（ＣＢＦ），从２０±８ｍｌ／ｍｉｎ回升至２８±７ｍｌ／ｍｉｎ，Ｐ＜０．０５），降低的冠脉储备恢复，从５１±１０ｍｌ／ｍｉｎ升至９４±１５ｍｌ／ｍｉｎ，Ｐ〈０．０１），ＥＴ－１的含量不再升高，从１５．５±３．０ｎｇ／Ｌ下降至５．０±２．０ｎｇ／Ｌ，Ｐ〈０．０１），Ａｃｈ介导的ＣＢＦ增加不再受到抑制（Ｐ〈０．０１）。结果提示提供外源性Ｌ－Ａｒｇ可增加一氧化氮（ＮＯ）的产生，使由于ＮＯ抑制而产生的血流动力学改变和ＥＴ－１升高发生逆转。

Effects of intracoronary L arginine on vasomotion and endothelium dependent responses of coronary arteries and endothelin 1 levels after inhibition of nitric oxide in coronary circulation in anesthetized dogs

Peak reactive hyperemic coronary blood flow ( CBF )following 15 s occlusion,resting CBF and CBF in response to acetylcholine(Ach) were observed both before and after a 5 mg / kg intracoronary infusion of N monomethly L arginine(L NMMA) and a 66 mg/ kg of L arginine(L Arg) in open chest anesthetized dogs,Meanwile,serial endothelin 1(ET 1) level was also obtained from the left interventricular vein and measured by radioimmuniassay. Results: L Arg completely reversed heart rate,resting CBF and CBF, and peak reactive hyperemic CBF was decreased by L NMMA. The increase in left interventricular vein blood ET 1 induced by L NMMA were not observed any more for 60min after L NMMA and L Arg infusion. L Arg also reversed the attenuated Ach stimulated endothelium dependent responses toward the levels before L NMMA infusion. These results suggested that a supply of exogenous L Arg could increase nitric oxide product,and reversed the change of hemodynamics and increased ET 1 levels after inhibition of nitric oxide.