Gayton R J
Nature. 1982 Jul 15;298(5871):275-6. doi: 10.1038/298275a0.
Since the enkephalins were first isolated a number of opioid peptides have been discovered, including a heptapeptide with the sequence Tyr-Gly-Gly-Phe-Met-Arg-Phe (Met-enkephalin-Arg6-Phe7). The heptapeptide was first isolated from chromaffin granules in bovine adrenal medulla, but using immunochemical techniques it has now been identified in human, rat and bovine brains. The C-terminal tetrapeptide of this molecule (Phe-Met-Arg-Phe) occurs in amidated form as the molluscan peptide FMRFamide. Antisera raised against FMRFamide have revealed immunoreactive material in the brains of several vertebrate species, including the rat where it occurs in nerve cell bodies and terminals. I now report that ionophoretically applied FMRFamide has an excitatory effect on rat medullary neurones which is unaffected by the opiate antagonist naloxone. In contrast, Met-enkephalin-Arg6-Phe7 and leucine-enkephalin (Leu-enkephalin) have predominantly depressant effects, which suggests that FMRFamide acts at a separate receptor.
自从脑啡肽首次被分离出来后，人们又发现了许多阿片样肽，包括一种七肽，其序列为Tyr-Gly-Gly-Phe-Met-Arg-Phe（甲硫氨酸脑啡肽-Arg6-Phe7）。这种七肽最初是从牛肾上腺髓质的嗜铬颗粒中分离出来的，但现在利用免疫化学技术已在人、大鼠和牛的大脑中鉴定出它。该分子的C末端四肽（Phe-Met-Arg-Phe）以酰胺化形式存在，即软体动物肽FMRF酰胺。针对FMRF酰胺产生的抗血清已在几种脊椎动物的大脑中揭示出免疫反应性物质，包括在大鼠大脑中，它存在于神经细胞体和终末。我现在报告，经离子电泳施加的FMRF酰胺对大鼠延髓神经元有兴奋作用，且不受阿片拮抗剂纳洛酮的影响。相比之下，甲硫氨酸脑啡肽-Arg6-Phe7和亮氨酸脑啡肽主要有抑制作用，这表明FMRF酰胺作用于一个独立的受体。
