二聚化以及侧链和碳末端修饰的内吗啡肽类似物的构效关系研究

发布时间：2018-03-09 20:31

本文选题：内吗啡肽　切入点：阿片受体　出处：《兰州大学》2006年博士论文　论文类型：学位论文

【摘要】：内吗啡肽-1(EM-1,Tyr-Pro-Trp-Phe-NH_2)和内吗啡肽-2(EM-2,Tyr-Pro-Trp-Phe-NH_2)是1997年发现的对μ阿片受体有着高亲和性和选择性的内源性阿片肽,是公认的μ阿片受体的内源性配体。它们都具有强效的镇痛作用,但是同时又具有酶解稳定性差、不易透过血脑屏障和镇痛效果不能持久等缺点。因此我们通过合理设计,合成其类似物,以期在某些方面得到改善。我们的另外一个重要的目的就是研究它们跟阿片受体相互作用的构效关系,为基于内吗啡肽的镇痛新药的开发提供理论依据。类似物的改造方法主要是二聚化、侧链修饰和碳末端修饰。本论文除了对阿片类与内阿片肽尤其是内吗啡肽的研究现状做一个综述外,主要实验工作有: 1.使用液相多肽合成方法设计合成了内吗啡肽母体以及碳末端修饰的类似物共14个化合物;设计合成了侧链修饰的内吗啡肽和morphiceptin的类似物共12个化合物;设计合成了内吗啡肽-2和氮端片断的二聚体共14个化合物。所有类似物经过高效液相色谱或制备板纯化,分子量经质谱确证。 2.通过放射配体竞争结合实验测定了以上化合物对大鼠脑膜上μ和6阿片受体的亲和性和选择性;通过离体器官生物检定实验测定了它们在豚鼠回肠纵行肌(GPI)和小鼠输精管(MVD)上的活性;选择有代表性的化合物测定了小鼠热板模型上的镇痛活性和小鼠脑匀浆降解特性。通过以上实验,主要得出了以下结论: 1.内吗啡肽的碳末端酰胺为一较小的中性或弱碱性的基团时,能够使其更加倾向于跟μ阿片受体结合,较大的基团或酸性基团则会降低μ阿片受体亲和力,碳末端芳环的朝向能大大影响受体亲和力和选择性。 2.在内吗啡肽或morphiceptin的3位引入Hfe(2-amino-4-phenylbutanoic acid)或者4位引入Phg(phenylglycine)能够较好的模拟Phe的作用,D-Phg则效果不好,3位和4位的芳环在受体结合中所扮演的角色是不同的;3位引入Hfe的类似物能明显延长镇痛作用时间,内吗啡肽的主要在体降解位点在2,3位之间。 3.内吗啡肽二肽或三肽片断的二聚体能够增强单体的受体亲和力,内吗啡肽-2四肽二聚体随着连接子长度的延伸受体选择性呈现一种有规律的波动上升的趋势,在连接子长度为2和12个原子时,得到的类似物在MVD上表现出了很好的活性。因此,通过
[Abstract]:Endomorphin EM-1 (Tyr-Pro-Trp-Phe-NH2) and endomorphine (-2n) Tyr-Pro-Trp-Phe-NH2) were identified in 1997 as endogenous opioid peptides with high affinity and selectivity to 渭 opioid receptors, which are recognized as endogenous ligands of 渭 opioid receptors. But at the same time, it has some disadvantages, such as poor stability of enzymatic hydrolysis, not easy to penetrate the blood-brain barrier and no lasting analgesic effect, so we synthesize its analogues through reasonable design. In order to improve in some ways. Another important purpose of our study is to study the structure-activity relationship of their interaction with opioid receptors. It provides a theoretical basis for the development of new analgesic drugs based on endomorphin. Side chain modification and carbon terminal modification. In this thesis, in addition to a review of opioid and endopiotin, especially endomorphine peptides, the main experimental work is as follows:. 1. Fourteen compounds of endomorphine peptide matrix and carbon terminal modified analogues were designed and synthesized by using liquid phase peptide synthesis method, and 12 compounds of side chain modified endomorphine peptide and morphiceptin analogues were designed and synthesized. A total of 14 compounds of endomorphin 2 and N-terminal dimer were designed and synthesized. All analogues were purified by high performance liquid chromatography or preparation plate and their molecular weight was confirmed by mass spectrometry. 2. The affinity and selectivity of the above compounds to 渭 and 6-opioid receptors in rat meninges were determined by radioligand competitive binding assay. The activity of GPI in guinea pig ileum longitudinal muscle (GPI) and MVD in mouse vas deferens was determined by bioassay in vitro, and the analgesic activity and the degradation characteristics of mouse brain homogenate in hot plate model were determined by selecting representative compounds. Through the above experiments, the main conclusions are as follows:. 1.When endomorphine peptide carbon terminal amide is a small neutral or weak basic group, it is more inclined to bind to 渭 opioid receptor, while larger group or acidic group decreases 渭 opioid receptor affinity. The orientation of the aromatic ring at the end of carbon greatly affects the affinity and selectivity of the receptor. 2. The introduction of Hfe(2-amino-4-phenylbutanoic acidat 3 sites of morphine peptide or morphiceptin or the introduction of Ph phenylglycine glycine at 4 bit can simulate the effect of Phe better than D-Phg. The roles of 3 and 4 aromatic rings in receptor binding are different from those of Hfe at 3 and 4 positions. The analogue can obviously prolong the time of analgesic action, The main degradation sites of endomorphin were between 2 and 3. 3. The dimer of endomorphine peptide dipeptide or tripeptide fragment can enhance the receptor affinity of monomer, and the dimer of endomorphine peptide -2 tetrapeptide dimer increases with the extension of ligand length. When the length of the connectors is 2 and 12 atoms, the obtained analogue exhibits good activity on MVD.
【学位授予单位】：兰州大学
【学位级别】：博士
【学位授予年份】：2006
【分类号】：R341

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