Structural and Biological Characterization of Elasmobranch Urotensins

术语“神经分泌”指的是某些神经 纤维释放生物活性物质进入血流 从而能够影响远距离目标的活动 机关 鱼类脊髓的下部含有 神经分泌系统。 神经合成两种肽 （小蛋白）称为尾加压素I和尾加压素II。 的 最早从硬骨鱼（硬骨鱼）中分离出尾加压素， 尽管进行了深入的研究，但它们在生理学中的重要性 这些鱼是不了解的。 康伦博士的实验室 Hazon提出了一种新的动物模型来研究 的生理作用。 我们将纯化尾加压素 I和II来自软骨的脊髓提取物 鱼，欧洲共同角鲨，并确定其化学 结构. 然后我们将合成几毫克的 肽，以确定它们在细胞中的生物学作用。 角鲨 使用自由游动的鱼， 在动脉插管，我们将研究的影响， 角鲨尿张素对血压和生产 类固醇. 角鲨的血，像其他的 鲨鱼家族，含有非常高浓度的尿素， 这对保持鱼的身体和 液体和周围的海水。 我们将调查 尿紧张素对尿素和其他血液指标的影响 角鲨体内的成分 我们会准备一条条光滑的 角鲨的各种器官和血管的肌肉， 研究尿紧张素的舒张或收缩能力 这些肌肉。 最后，我们希望能够深入了解 尿紧张素的作用，通过标记的分子与一个 放射性标记并确定角鲨的哪些器官 识别并结合肽。 我们希望通过这种方式 全面了解尿紧张素在调节 软骨鱼的生理学 这些知识将 在今后的调查中， 其他脊椎动物中的尿紧张素。

The term "neurosecretion" refers to the fact that certain nerve fibers release biologically active substances into the blood stream which are then able to influence the activities of distant target organs. The lower portion of the spinal cord of fishes contains such a neurosecretory system. The nerves synthesize two peptides (small proteins) known as urotensin I and urotensin II. The urotensins were first isolated from bony fishes (teleosts) but despite intensive study, their importance in the physiology of these fish is not understood. The laboratories of Dr. Conlon and Hazon are proposing a new animal model in which to investigate the physiological roles of the urotensins. We will purify urotensin I and II from an extract of the spinal cord of a cartilaginous fish, the European common dogfish and determine their chemical structures. We will then synthesize several milligrams of the peptides in order to determine their biological actions in the dogfish. Using free swimming fish that have been fitted with a cannula in an artery, we will investigate the effects of the dogfish urotensins on blood pressure and on the production of steroids. The blood of the dogfish, like other members of the shark family, contains a very high concentration of urea which is important in maintaining an equilibrium between the fish's body fluids and the surrounding sea water. We will investigate the effects of the urotensins upon the levels of urea and other blood constituents in the dogfish. We will prepare strips of smooth muscle from the various organs and blood vessels of the dogfish and study the abilities of the urotensins either to relax or contract these muscles. Finally, we hope to gain insight into the sites of action of the urotensins by tagging the molecules with a radioactive label and determining which organs in the dogfish recognize and bind the peptides. In this way, we hope to build up an overall picture of the roles of the urotensins in regulating the physiology of a cartilaginous fish. This knowledge will be valuable in future investigations that will assess the roles of the urotensins in other classes of vertebrate.