Spokes R A, Ghatei M A, Bloom S R
Department of Medicine, Royal Postgraduate Medical School, Hammersmith Hospital, London, England.
J Cardiovasc Pharmacol. 1989;13 Suppl 5:S191-2. doi: 10.1097/00005344-198900135-00053.
In an anesthetized rat, endothelin-1 (ET-1) causes a rapid, transient fall in blood pressure followed by a large, sustained rise. Rat endothelin-3 (ET-3) differs from porcine endothelin-1 (ET-1) by six amino acids and is 20 times less potent at contracting rat aortic strips. The comparative effects of ET-3 and ET-1 on blood pressure were studied in anesthetized rats in which the arterial blood pressure was continually monitored. Dose-response curves for the contraction of rat stomach strips, guinea pig ileum, and guinea pig trachea were also constructed. In the anesthetized rat, ET-3 was slightly (but not significantly) less potent than ET-1 at producing the transient blood pressure fall but was three times less potent at causing the subsequent rise. The two peptides were equipotent at contracting rat stomach strips but ET-3 was 10 times less potent at contracting the guinea pig ileum. Rat ET-3 was less potent at contracting the guinea pig trachea and had a lower maximal effect. These results suggest the existence of multiple receptor subtypes for ET.
在麻醉大鼠中，内皮素-1（ET-1）会导致血压迅速短暂下降，随后大幅持续上升。大鼠内皮素-3（ET-3）与猪内皮素-1（ET-1）有六个氨基酸不同，在使大鼠主动脉条收缩方面效力低20倍。在持续监测动脉血压的麻醉大鼠中研究了ET-3和ET-1对血压的比较作用。还构建了大鼠胃条、豚鼠回肠和豚鼠气管收缩的剂量反应曲线。在麻醉大鼠中，ET-3在产生短暂血压下降方面的效力略低于ET-1（但无显著差异），但在引起随后的血压上升方面效力低三倍。这两种肽在使大鼠胃条收缩方面效力相当，但ET-3在使豚鼠回肠收缩方面效力低10倍。大鼠ET-3在使豚鼠气管收缩方面效力较低，最大效应也较低。这些结果表明ET存在多种受体亚型。
