Sinzinger H, Feigl W
Wien Klin Wochenschr. 1985 Nov 8;97(21):817-9.
Prostacyclin is the most potent inhibitor of platelet aggregation and a very strong vasodilator. A few reports on a moderate vasoconstrictory response in certain vascular segments in various species have received less attention. We demonstrated recently that PGI2 dilates the arterial wall and has a constrictory effect on the venous wall. Normal and varicose human veins show a dose-dependent constrictory response to PGI2. Pretreatment of patients with 2.5 mg dihydroergotamine t.i.d. for 10 days increases venous PGI2 synthesis significantly. In vitro contractility response is identical in normal and varicose veins. Furthermore, no difference in contractility was registered in veins derived from treated and untreated patients. The significantly enhanced formation of PGI2 evoked by dihydroergotamine might be responsible for the tonisation of normal, healthy veins, as well as varicose veins.
前列环素是最有效的血小板聚集抑制剂，也是一种非常强效的血管扩张剂。关于不同物种某些血管段出现中度血管收缩反应的一些报道较少受到关注。我们最近证明，前列环素I2可扩张动脉壁，对静脉壁有收缩作用。正常和曲张的人静脉对前列环素I2呈剂量依赖性收缩反应。患者每日三次服用2.5毫克双氢麦角胺，持续10天，可显著增加静脉前列环素I2的合成。正常静脉和曲张静脉的体外收缩反应相同。此外，来自治疗和未治疗患者的静脉在收缩性方面没有差异。双氢麦角胺引起的前列环素I2形成显著增强，可能是正常健康静脉以及曲张静脉张力增加的原因。
