EDRF对PE引起的大鼠主动脉缩血管效应的作用

EFFECTS OF EDRF ON THE VASOCONSTRICTOR ACTION OF PHENYLEPHRINE IN RAT AORTA

本文研究ＥＤＲＦ（ｅｎｄｏｔｈｅｌｉｕｍ－ｄｅｒｉｖｅｄｒｅｌａｘｉｎｇｆａｃｔｏｒ，ＥＤＲＦ）对ＰＥ（ｐｈｅｎｙｌｅｐｈｒｉｎｅ）引起的大鼠主动脉收缩反应的影响。内皮完整和去内皮的大鼠主动脉环悬挂于器官浴槽中，测定血管的张力和收缩速度的变化。所有的实验在消炎痛（ｉｎｄｏｍｅｔｈａｃｉｎ，１０μｍｏｌ／Ｌ）存在下进行。用美兰（ｍｅｔｈｙｌｅｎｅｂｌｕｅ，ＭＢ，１０μｍｏｌ／Ｌ）或左旋硝基精氨酸（ＮＧ－ｎｉｔｒｏ－Ｌ－ａｒｇｉｎｉｎｅ，Ｌ－ＮＮＡ，３０μｍｏｌ／Ｌ）处理内皮完整的大鼠主动脉环，ＰＥ的剂量－收缩张力曲线明显左移，ＥＣ３０值均降低５倍，最大反应比率分别为１．６±０．４和１．６±０．５。在去内皮的大鼠主动脉环中，经ＭＢ和Ｌ－ＮＮＡ处理后，仍可见ＥＣ３０下降３倍，最大反应比率均为１．０±０．２。后者可能与血管平滑肌产生少量ＥＤＲＦ有关。

The influence of endothelium derived relaxing factor (EDRF) on the vasoconstrictor effect of phenylephrine on rings of rat aorta was studied in this paper. Rings of rat aorta, with or without endothelium, were suspended in organ chambers for the measurement of contractive force and contractive speed. All experiments were performed in the presence of indomethacin (10μ mol/L) to prevent the production of vasoactive prostanoids. When the preparations with intact endothelium were treated with methylene blue (10μ mol/L), an inhibitor of the target enzyme of EDRF, or N G nitro L arginine(30μmol/L), an inhibitor of EDRF formation, dose contractive force curves of phenylephrine shifted to left: the EC 30 value decreased 5 fold and the maximal response ratios were 1 6±0 4 and 1 6±0 5(n=8) respectively. These results were similar to those observed after mechanical removal of the endothelium: a 3 fold decrease in the EC 30 value and the maximal response ratio was 1 0±0 2(n=8), The latter results may be related to a little EDRF produced by vascular smooth muscle.Our results suggest that the vasoconstrictive effect induced by phenylephrine may also be regulated by EDRF production from vascular endothelium and smooth muscle.