Distribution pattern of metorphamide compared with other opioid peptides from proenkephalin and prodynorphin in the bovine brain.
Distribution pattern of metorphamide compared with other opioid peptides from proenkephalin and prodynorphin in the bovine brain.
复制标题
美吗啡酰胺与来自脑啡肽原和强啡肽的其他阿片肽在牛脑中的分布模式比较。
DOI：
10.1111/j.1471-4159.1987.tb00946.x
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发表时间：
1987
影响因子：
4.7
通讯作者：
Weber,E
中科院分区：
文献类型：
--
作者：
Sonders,M;Weber,E
Metorphamide是一种含有[Met]-脑啡肽的阿片类八肽，具有C-末端α-酰胺基团。它来源于前脑啡肽原，是迄今为止唯一对μ阿片（吗啡）受体具有特别高亲和力、对K阿片受体亲和力稍低、对δ阿片受体亲和力相对较低的内源性阿片肽。用放射免疫分析法和色谱分离法测定了胃复安在牛尾状核、下丘脑、脊髓和垂体神经中间体中的浓度。将甲托啡胺浓度与相同提取物中来自前脑啡肽和强啡肽原的其他8种阿片肽浓度进行比较。其他阿片肽是来自脑啡肽原的[Met]-脑啡酰-Arg 6-Phe 7和[Met]-脑啡酰-Arg 6-Gly 7-Leu 8;来自强啡肽原的α-新内啡肽、β-新内啡肽、强啡肽A（1 - 8）、强啡肽A（1-17）和强啡肽B;以及[Leu]-脑啡肽，其可以衍生自任一前体。所有阿片肽存在于所有四个牛神经组织研究。甲托啡胺浓度低于其他前脑啡肽衍生的阿片肽的浓度。然而，它们与相同组织中前强啡肽衍生的阿片肽的浓度相似。观察到来自强啡肽原的阿片类药物在整个脑区的相对比例存在显著差异，这一发现表明差异的翻译后加工。脑啡肽原衍生的阿片类药物在脑区之间的比例差异不太明显。本研究的结果以及先前关于美托啡胺μ阿片受体结合和生物活性的发现表明，牛脑中美托啡胺的量足以使该肽成为具有生理学意义的内源性μ阿片受体配体的候选物。
Metorphamide is a [Met]‐enkephalin‐containing opioid octapeptide with a C‐terminal α‐amide group. It is derived from proenkephalin and is, so far, the only endogenous opioid peptide with a particularly high affinity for μ opioid (morphine) receptors, a somewhat lesser affinity forKopioid receptors, and a relatively low affinity for δ opioid receptors. The concentrations of metorphamide in the bovine caudate nucleus, the hypothalamus, the spinal cord, and the neurointermediate pituitary were determined by radioimmunoassay and chromatography separation procedures. Metorphamide concentrations were compared withthe concentrations of eight other opioid peptides from proenkephalin and prodynorphin in identical extracts. The other opioid peptides were [Met]‐enkephaIyl‐Arg6‐Phe7and [Met]‐enkephalyl‐Arg6‐Gly7‐Leu8from proenkephalin; α‐ neoendorphin, β‐neoendorphin, dynorphin A(l‐8), dynorphin A(1–17), and dynorphin B from prodynorphin; and [Leu]‐enkephalin, which can be derived from either precursor. All opioid peptides were present in all four bovine neural tissues investigated. Metorphamide concentrations were lower than the concentrations of the other proenkephalinderived opioid peptides. They were, however, similar to the concentrations of the prodynorphin‐derived opioid peptides in the same tissues. Marked differences in the relative ratios of the opioids derived from prodynorphin across brain regions were observed, a finding suggesting differential posttranslational processing. Differences in the ratios of the proenkephalin‐derived opioids across brain regions were less pronounced. The results from this study together with previous findings on metorphamide's μ opioid receptor binding and bioactivities suggest that the amounts of metorphamide in the bovine brain are sufficient to make this peptide a candidate for a physiologically significant endogenous μ opioid receptor ligand.