Hull A D, White C R, Pearce W J
Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, California 92350.
Placenta. 1994 Jun;15(4):365-75. doi: 10.1016/0143-4004(94)90004-3.
Endothelium derived relaxing factor (EDRF), now widely believed to be nitric oxide (NO), may play an important part in the control of fetoplacental vascular tone. To further explore this role we have determined the relaxation responses to exogenous NO and examined the temporal relationship between intracellular concentrations of cyclic GMP and vascular tone in isolated ring segments of human chorionic plate arteries. We have also determined the dose relations for the contractile agonists serotonin and the thromboxane analog U46619. Lastly, we have explored the relaxation responses to a wide range of agents known to elicit EDRF release in other vascular beds. Chorionic plate arteries relaxed significantly to exogenous NO with concomitant increases in cyclic guanosine monophosphate over basal values. ED50s for serotonin and U46619 were 1.48 x 10(-6) M and 3.39 x 10(-8) M respectively. The ED50 for NO derived from S-nitroso-N-acetyl-penicillamine was 1.28 x 10(-6) M. Endothelium-intact segments of chorionic plate arteries pre-contracted with either serotonin or U46619 failed to relax significantly to acetylcholine, adenosine diphosphate, A23187, bradykinin, and histamine and only minimally to substance P. We suggest that EDRF is likely to be important in the control of placental vascular tone, but that it is not possible to demonstrate its action in an unperfused experimental system.
内皮衍生舒张因子（EDRF），现在普遍认为是一氧化氮（NO），可能在胎儿胎盘血管张力的控制中起重要作用。为了进一步探究这一作用，我们测定了对外源性NO的舒张反应，并研究了人绒毛膜板动脉离体环段中细胞内环鸟苷酸浓度与血管张力之间的时间关系。我们还确定了收缩激动剂5-羟色胺和血栓素类似物U46619的剂量关系。最后，我们探究了对已知能在其他血管床中引发EDRF释放的多种药物的舒张反应。绒毛膜板动脉对外源性NO有显著舒张反应，同时环磷酸鸟苷相对于基础值增加。5-羟色胺和U46619的半数有效剂量（ED50）分别为1.48×10⁻⁶ M和3.39×10⁻⁸ M。来自S-亚硝基-N-乙酰青霉胺的NO的ED50为1.28×10⁻⁶ M。预先用5-羟色胺或U46619预收缩的绒毛膜板动脉内皮完整段对乙酰胆碱、二磷酸腺苷、A23187、缓激肽和组胺无显著舒张反应，对P物质仅有轻微舒张反应。我们认为EDRF可能在胎盘血管张力的控制中起重要作用，但在未灌注的实验系统中无法证明其作用。
