Nádasy G L, Székács B, Juhász I, Fehér J, Kovách A G, Monos E
Experimental Research Department, Semmelweis Medical University, Budapest, Hungary.
Acta Physiol Hung. 1991;78(1):77-87.
The present study was executed in order to get further data on the role of vessel wall constituents in prostanoid synthesis and on the effect of anorganic constituents on it. Prostacyclin and tromboxane production of rat aortic tissue slices with intact endothelium and after mechanical as well as chemical endothelium removal were studied. The effects of hypoxia and changes in the ionic milieu on the release of these prostanoids were also examined. The tissue slices were incubated in normal or in modified Krebs-Ringer solution, bubbled with 95% O2 and 5% CO2 (with the exception of the studies in hypoxic conditions). Prostacyclin and thromboxane release was determined by specific radioimmunoassay of the stable metabolites, 6-keto-PGF1 alpha and TxB2, from the incubation medium. 174 tissue samples obtained from 164 rats were studied. Mechanical removal of the endothelium increased prostacyclin production of the aortic segments about fivefolds from a basal rate of 52.9 +/- 19.4 ng/gr/min, while it had no significant effect on thromboxane release (basal rate 0.83 +/- 0.13 ng/gr/min). Treating the endothelium with 1.0 M HCl almost totally suppressed prostacyclin release. Lowering the partial oxygen tension of the incubation medium significantly decreased the production of prostacyclin, while release of TxB2 somewhat increased. Increasing the Ca2+ concentration of the medium between 0-5 mM the release of prostacyclin was augmented and the release of thromboxane was diminished. Potassium free medium caused a very large increase in prostacyclin release of the tissue slices. The results show that release of vasoactive prostanoids from isolated rat aortic wall is dependent not exclusively on the endothelium and that various methods of endothelium removal may have distinct influences on prostacyclin and thromboxane productions. The changes in anorganic constituents of the surrounding medium could massively affect prostacyclin and thromboxane production of rat aortic tissue. The alternative effects of the above listed treatments on the release of prostacyclin and thromboxane from the rat aortic wall suggest the existence of different mechanisms in the control of the production of the two major prostanoids possessing opposite physiological effects.
本研究旨在获取关于血管壁成分在前列腺素合成中的作用以及无机成分对其影响的更多数据。研究了完整内皮的大鼠主动脉组织切片以及机械和化学去除内皮后前列环素和血栓素的产生情况。还研究了缺氧和离子环境变化对这些前列腺素释放的影响。组织切片在正常或改良的 Krebs-Ringer 溶液中孵育，用 95% O₂ 和 5% CO₂ 鼓泡（缺氧条件下的研究除外）。通过对孵育介质中稳定代谢产物 6-酮-PGF1α 和 TxB2 的特异性放射免疫测定来确定前列环素和血栓素的释放。对从 164 只大鼠获得的 174 个组织样本进行了研究。机械去除内皮使主动脉段的前列环素产生量从基础速率 52.9±19.4 ng/gr/min 增加了约五倍，而对血栓素释放没有显著影响（基础速率 0.83±0.13 ng/gr/min）。用 1.0 M HCl 处理内皮几乎完全抑制了前列环素的释放。降低孵育介质的部分氧张力显著降低了前列环素的产生，而 TxB2 的释放略有增加。将介质中的 Ca²⁺ 浓度在 0 - 5 mM 之间增加，前列环素的释放增加，血栓素的释放减少。无钾培养基使组织切片的前列环素释放大幅增加。结果表明，离体大鼠主动脉壁中血管活性前列腺素的释放不仅取决于内皮，而且不同的内皮去除方法可能对前列环素和血栓素的产生有不同影响。周围介质无机成分的变化可大量影响大鼠主动脉组织中前列环素和血栓素的产生。上述处理对大鼠主动脉壁前列环素和血栓素释放的不同影响表明，在控制具有相反生理作用的两种主要前列腺素产生方面存在不同机制。
