An approach to understand the mechanism and pathogenesis of production and release of endothelium-derived relaxing factor by molecular and cellular biology technique.

1.血管内皮细胞产生和释放内皮源性舒张因子（EDRF）的机制我们测定了培养的牛主动脉内皮细胞磷脂酰肌醇周转和胞浆钙浓度。缓激肽以剂量依赖性方式诱导磷脂酰肌醇（PI）周转和细胞内钙释放以及细胞外钙内流。我们用生物测定的方法证明了EDRF是通过这个信号转导系统产生和释放的。此外，利用化学发光法测定一氧化氮（被认为是EDRF）对这一信号转导系统的研究也在进行中.溶血磷脂和修饰脂蛋白对EDRF产生和释放的影响（1）氧化型低密度脂蛋白（ox-LDL）抑制EDRF引起的血管舒张作用，其机制可能与ox-LDL中溶血磷脂酰胆碱（LPC）增加有关。我们证明，在培养的内皮细胞，氧化型低密度脂蛋白和LPC抑制PI营业额和缓激肽诱导的细胞内钙离子浓度依赖性的方式。因此，ox-LDL抑制EDRF产生或释放的机制之一是抑制该信号转导系统。(2)我们发现，高密度脂蛋白（HDL）和天然低密度脂蛋白（natural LDL）可降低ox-LDL对EDRF产生或释放的抑制作用，这是由于阻止了LPC从ox-LDL向内皮细胞的转移，并将转移的LPC从内皮细胞中清除。

1. The mechanism of production and release of endothelium-derived relaxing factor (EDRF) in vascular endothelial cellsWe measured both phosphatidyl inositol turnover and cytosolic calcium concentration in cultured bovine aortic endothelial cells. Bradykinin induced phosphatidyl inositol (PI) turnover and calcium release from intracellular store and influx of extracellular calcium in dose-dependent manners. We proved that EDRF was produced and released through this signal transduction system using bioassay method. Furthermore the investigation of this signal transduction system is now in proatess usincy measurement of nitric oxide, which is thought to be EDRF, with chemiluminescence mehtod.2. Effects of lysophospholipids and modified lipoproteins on the production and release of EDRF(1) We reported that oxidized low density lipoprotein (ox-LDL) inhibits the vasodilatation induced by EDRF which is released after agonist stimulation and that it is due to increased lysophosphatidylcholine (LPC) in ox-LDL. We demonstrated that in cultured endothelial cells, both ox-LDL and LPC inhibited PI turnover and elevation of cytosolic calcium induced by Bradykinin in dose-dependent manners. It was concluded that the inhibition of this signal transduction system is one of the mechanisms by which ox-LDL inhibits EDRF production or release.(2) We found that high density lipoprotein (HDL) and native LDL reduced the inhibitory effects of ox-LDL on EDRF production or release and that it was due to prevention of LPC transfer from ox-LDL to endothelial cells and removal of transferred LPC from endothelial ceIls.