A New Pain relief substance in spinal cord ; Parmacological Function and Metabolism of Spinorphin

本研究从牛脊髓中分离到一种脑啡肽降解酶的有效抑制剂，并对其氨基酸序列、药理作用和代谢进行了测定。这种新物质由七肽（Leu-Val-Val-Tyr-Pro-Trp-Thr）组成，我们将其命名为“Sinorphin”。从<50>弗罗姆脑中纯化得到的新物质对脑啡肽降解酶的抑制活性（IC_1），对氨肽酶为3.3 μ g/ml，对二肽氨肽酶为1.4 μ g/ml，对血管紧张素转换酶为2.4 μ g/ml，对脑啡肽酶为10 μ g/ml。该物质对纯化的肾和血液中的脑啡肽无抑制活性。Spinorphin对MVD（小鼠输精管）和GPI（豚鼠回肠）的电诱发浓度产生剂量相关抑制。脑池内注射Spinorphin（100-200 nmol/只）也产生剂量依赖性镇痛作用，镇痛作用在5 min内达高峰，15- 60 min后消失。纳洛酮可完全拮抗上述作用。当在人脊髓中孵育24小时时，大多数Spinorphin被降解。然而，约86%的Spinorphin是完整的HPLC孵育时，probestin，这是一种抑制剂的氨肽酶M.Spinorphin具有较高的抑制活性，对脑啡肽降解酶相比，各种水解产物。总之，阿片活性最重要的结构是Spinorphin。这表明，Spinorphin作为脑啡肽代谢在脊髓中的神经调质。

In this study, We isolated a potent inhibitor for enkephalin-degrading enzymes from the bovine spinal cord, and determined its amino-acid sequence, pharmacological function and metabolism. This new substance is composed of heptapeptide (Leu-Val-Val-Tyr-Pro-Trp-Thr), and has been named by us "Sinorphin". The inhibitory activity (IC_<50>) of this new substance toward enkephalin-degrading enzymes, purified frome monkey brain, was found to be 3.3ug/ml against aminopeptidase, 1.4ug/ml against dipeptidyl aminopeptidase, 2.4ug/ml against angiotensin-converting enzyme, and 10ug/ml against enkephalinase. This substance did not show inhibitory activity toward enkephalins purified kidney and blood. Spinorphin produces a dose-related inhibition of electrically evoked concentrations of both MVD(mouse vas deferens) and GPI(guinea-pig ileum). The intracisternally injected Spinorphin also produced a nalgesic effects in a dose-dependent manner, in dose of 100-200 nmol/mouse.The analgesic effect reached the maximum within 5 minand disapeard after 15-60min. These effects could be completely antagonised by naloxone. Most Spinorphin was degraded when incubated in the human spinal cord for 24hr. However, approximately 86% of the Spinorphin was intact on HPLC when incubated with probestin, which is an inhibitor of Aminopeptidase M.Spinorphin has a high inhibitory activity against enkephalin-degrading enzymes when compared to the various hydrolysis products. In conclusion, the most important structure for opioid activity is Spinorphin. It is suggested that Spinorphin acts as a neuromodulator of enkephalin metabolism in the spinal cord.