Endothelin-1 (ET-1) is a very potent vasoactive peptide released from endothelial cells, and ET-1 plays an important role in the maintenance and regulation of blood pressure in mammals. ET-1 signaling is mediated by two receptors: ETA and ETB. In mammals, ETA receptors are located on vascular smooth muscle where they mediate vasoconstriction. ETB receptors located on the endothelium mediate vasodilatation through the release of nitric oxide, whereas stimulation of ETB receptors placed on vascular smooth muscle leads to vasoconstriction. Less is known about ET-1 signaling in reptiles. In anaesthetized alligators, ET-1 elicits a biphasic blood pressure with a long-lasting initial decrease followed by a smaller increase in systemic blood pressure. In anaesthetized freshwater turtles, ET-1 causes a dose-dependent systemic vasodilatation mediated through ETB receptors. In the present study, we investigated the cardiovascular effects of ET-1 on the systemic and pulmonary vasculature of pythons. The presence of ETA and ETB receptors in the vasculature of pythons was verified by means of immunoblotting. Myography on isolated vessels revealed a dose-dependent vasoconstrictory response to ET-1 in both mesenteric and pulmonary arteries. Pressure measurements in recovered specimens revealed an ET-1-induced rise in systemic blood pressure supporting our in vitro findings. In conclusion, our study shows that ET-1 induces a strong pressor effect in the systemic circulation.

中文翻译：

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内皮素-1在球形蟒（Python Regius）中诱导强大的升压作用。

内皮素-1（ET-1）是一种从内皮细胞释放出来的非常有效的血管活性肽，ET-1在维持和调节哺乳动物的血压中起着重要的作用。ET-1信号传导由两种受体介导：ETA和ETB。在哺乳动物中，ETA受体位于血管平滑肌上，介导血管收缩。位于内皮上的ETB受体通过释放一氧化氮来介导血管舒张，而刺激放置在血管平滑肌上的ETB受体则导致血管收缩。关于爬行动物中的ET-1信号知之甚少。在麻醉的短吻鳄中，ET-1会引起双相性血压，且长期呈初始下降趋势，随后系统性血压上升幅度较小。在麻醉的淡水龟中 ET-1引起通过ETB受体介导的剂量依赖性全身性血管舒张。在本研究中，我们调查了ET-1对蟒蛇的全身和肺血管的心血管作用。通过免疫印迹证实了在蟒蛇的脉管系统中存在ETA和ETB受体。离体血管的肌电图显示肠系膜和肺动脉对ET-1的剂量依赖性血管收缩反应。回收标本中的压力测量结果表明，ET-1诱导的系统性血压升高支持了我们的体外研究结果。总之，我们的研究表明ET-1在体循环中诱导强大的升压作用。通过免疫印迹证实了在蟒蛇的脉管系统中存在ETA和ETB受体。离体血管的肌电图显示肠系膜和肺动脉对ET-1的剂量依赖性血管收缩反应。回收标本中的压力测量结果表明，ET-1诱导的系统性血压升高支持了我们的体外研究结果。总之，我们的研究表明ET-1在体循环中诱导强大的升压作用。通过免疫印迹证实了在蟒蛇的脉管系统中存在ETA和ETB受体。离体血管的肌电图显示肠系膜和肺动脉对ET-1的剂量依赖性血管收缩反应。回收标本中的压力测量结果表明，ET-1诱导的系统性血压升高支持了我们的体外研究结果。总之，我们的研究表明ET-1在体循环中诱导强大的升压作用。