McDonald John, Batuwangala Madura, Lambert David G
Department of Cardiovascular Sciences, Pharmacology and Therapeutics Group, Division of Anaesthesia, Critical Care and Pain Management, University of Leicester, LRI, Leicester, LE1 5WW, UK.
J Anesth. 2007;21(3):378-89. doi: 10.1007/s00540-007-0524-z. Epub 2007 Aug 1.
Urotensin II (U-II) is currently the most potent vasoconstrictor identified. This action is brought about via activation of a G(q/11)-protein coupled receptor (UT receptor). U-II activation of the UT receptor increases inositol phosphate turnover and intracellular Ca(2+). In addition to producing vasoconstriction, dilation and ionotropic effects have also been described. There is considerable variation in the responsiveness of particular vascular beds from the same and different species, including humans. Receptors for U-II are located peripherally on vascular smooth muscle (contractile responses) and endothelial cells (dilatory responses via nitric oxide). In humans, plasma U-II is elevated in heart failure, renal failure, liver disease, and diabetes. Iontophoresis of U-II in healthy volunteers produces vasodilation (of the forearm) while in patients with heart failure or hypertension a constriction is observed. To date there is only one clinical study using a UT receptor antagonist (palosuran) in diabetic patients with macroalbuminuria. This antagonist reduced albumin excretion, probably by increasing renal blood flow. Studies in other disease conditions are eagerly awaited. In summary, the U-II / UT receptor system has clinical potential, and for the anesthesiologist, this novel peptide-receptor system may be of use in the intensive care unit.
尾加压素II（U-II）是目前已确定的最有效的血管收缩剂。这种作用是通过激活G(q/11)蛋白偶联受体（UT受体）实现的。U-II对UT受体的激活会增加肌醇磷酸周转率和细胞内钙离子浓度。除了产生血管收缩作用外，还描述了其舒张和离子otropic效应。来自同一物种和不同物种（包括人类）的特定血管床的反应性存在很大差异。U-II的受体位于血管平滑肌外周（产生收缩反应）和内皮细胞（通过一氧化氮产生舒张反应）。在人类中，心力衰竭、肾衰竭、肝病和糖尿病患者的血浆U-II水平会升高。在健康志愿者中，U-II的离子电渗疗法会导致（前臂）血管舒张，而在心力衰竭或高血压患者中则观察到血管收缩。迄今为止，仅有一项针对患有大量蛋白尿的糖尿病患者使用UT受体拮抗剂（帕罗西汀）的临床研究。这种拮抗剂可能通过增加肾血流量来减少白蛋白排泄。人们急切期待在其他疾病状况下的研究。总之，U-II / UT受体系统具有临床应用潜力，对于麻醉医生而言，这个新型的肽-受体系统可能在重症监护病房中有用。
