Iadarola M J, Panula P, Majane E A, Yang Y T
Brain Res. 1985 Mar 18;330(1):127-34. doi: 10.1016/0006-8993(85)90013-7.
The regional quantitation, immunohistochemical localization and molecular heterogeneity of Met5-enkephalin-Arg6-Gly7-Leu8 were examined in rat spinal cord with a specific radioimmunoassay. A rostrocaudal gradient in Met5-enkephalin-Arg6-Gly7-Leu8 content was observed; the highest levels occurred in sacral cord. Dorsal cord content was higher than that of ventral cord at all spinal segments. Immunohistochemical staining supported and refined the latter observation: a dense network of perikarya and fibers was found in Laminae I and II of the dorsal horn. Cell bodies were frequently observed in lamina IV. Additional terminals were seen around the central canal and in the ventral gray matter, often outlining perikarya of motor neurons. Total Met5-enkephalin-Arg6-Gly7-Leu8 immunoreactivity could be fractionated into two main components using gel filtration chromatography. Nearly half of the total immuno-reactivity eluted as a high molecular weight peptide; the other half which co-eluted with Met5-enkephalin-Arg6-Gly7-Leu8 was further identified to be authentic Met5-enkephalin-Arg6-Gly7-Leu8 on reverse phase high pressure liquid chromatography. The present data, in conjunction with our previous study of Met5-enkephalin and Met5-enkephalin-Arg6-Phe7 indicates that all opioid peptides derived from preproenkephalin A are present in spinal cord and most likely are stored in the same neurons. Immunohistochemical localization of Met5-enkephalin-Arg6-Gly7-Leu8 in dorsal and ventral cord suggest a role for this peptide in both sensory and motor integration.
采用特异性放射免疫分析法，对大鼠脊髓中Met5-脑啡肽-Arg6-Gly7-Leu8的区域定量、免疫组化定位及分子异质性进行了研究。观察到Met5-脑啡肽-Arg6-Gly7-Leu8含量存在头-尾梯度变化；最高水平出现在骶髓。在所有脊髓节段，背侧脊髓的含量均高于腹侧脊髓。免疫组化染色支持并细化了后一观察结果：在背角的I层和II层发现了密集的胞体和纤维网络。在IV层经常观察到细胞体。在中央管周围和腹侧灰质中还可见到额外的终末，常围绕运动神经元的胞体。使用凝胶过滤色谱法，可将总的Met5-脑啡肽-Arg6-Gly7-Leu8免疫反应性分为两个主要成分。总免疫反应性中近一半以高分子量肽的形式洗脱；另一半与Met5-脑啡肽-Arg6-Gly7-Leu8共洗脱，经反相高压液相色谱进一步鉴定为 authentic Met5-脑啡肽-Arg6-Gly7-Leu8。本研究数据与我们先前对Met5-脑啡肽和Met5-脑啡肽-Arg6-Phe7的研究结果表明，所有源自前脑啡肽A的阿片肽均存在于脊髓中，且很可能储存在同一神经元中。Met5-脑啡肽-Arg6-Gly7-Leu8在背侧和腹侧脊髓中的免疫组化定位表明，该肽在感觉和运动整合中均发挥作用。
