Myotropic effects of proctolin analogues, modified in position 2 of the peptide chain, on the foregut of the locust Schistocerca gregaria
Myotropic effects of proctolin analogues, modified in position 2 of the peptide chain, on the foregut of the locust Schistocerca gregaria
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DOI：
10.1016/0022-1910(95)00130-1
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发表时间：
1996-05-01
影响因子：
2.2
通讯作者：
Konopinska, D
中科院分区：
文献类型：
--
作者：
Hinton, JM;Osborne, RH;Konopinska, D
Proctolin (H.Arg.Tyr.Leu.Pro.Thr.OH) 在 10(-8) M 至 2 x 10(-6) M 浓度范围内引起蝗虫 Schistocerca gregaria 分离前肠的剂量依赖性收缩，在评估的 10 个类似物中，[Phe(p-NH2)(2)]-、[Tyr(m-NH2)(2)]- 和[Phe(p-OEt)(2)]-proctolin 是剂量依赖性的上激动剂，而 [Phe(p-OMe)(2)]- 和 [L-DOPA(2)]-proctolin 仅在单剂量 5 x 10(-7) M 时才是上激动剂，剂量反应曲线的构建表明 [Phe(p-OMe)(2)]-、[L-DOPA(2)]-、 [Phe(p-NH2)(2)]-和[Phe(p-NO2)(2)]-proctolin 是部分激动剂，不能引起与母体五肽诱导的最大反应相当的反应。 [Cha(4-OMe)(2)]-、[Afb(p-OH)(2)]- 和 [Afb(p-NO2)(2)]-Proctolin 是弱激动剂，其内在活性分别相当于 proctolin、[α-Me-L-Tyr(2)]- 和 [Afb(p-NO2)(2)]-Proctolin 的 12.7%、7.9% 和 3.5% (10(-8) M -10(-6) M) 是 proctolin 诱导的组织收缩的有效非竞争性拮抗剂，当以 10(-6) M 剂量使用时，将应用的 proctolin 的最大反应分别降低至 16% 和 23%。通过对本研究中研究的类似物的肌向作用的分析，我们得出结论，proctolin 的激动作用取决于对位取代的 Phe 或间位取代的存在Tyr 位于肽链的 2 位，这些数据表明芳香环上理想的取代基是含有氧和氮原子的基团，版权所有 (C) 1996 Elsevier Science Ltd
Proctolin (H.Arg.Tyr.Leu.Pro.Thr.OH) caused dose-dependent contraction of the isolated foregut of the locust Schistocerca gregaria at concentrations ranging from 10(-8) M to 2 x 10(-6) M, Of the ten analogues evaluated, [Phe(p-NH2)(2)]-, [Tyr(m-NH2)(2)]- and [Phe(p-OEt)(2)]-proctolin are dose-dependent supra agonists while [Phe(p-OMe)(2)]- and [L-DOPA(2)]-proctolin are supra agonists only when applied at a single dose of 5 x 10(-7) M, Construction of dose response curves showed that [Phe(p-OMe)(2)]-, [L-DOPA(2)]-, [Phe(p-NH2)(2)]- and [Phe(p-NO2)(2)]-proctolin are partial agonists incapable of causing a maximum response equivalent to that induced by the parent pentapeptide. [Cha(4-OMe)(2)]-, [Afb(p-OH)(2)]- and [Afb(p-NO2)(2)]-Proctolin are weak agonists with intrinsic activities equivalent to only 12.7%, 7.9% and 3.5% respectively of that of proctolin, [alpha-Me-L-Tyr(2)]- and [Afb(p-NO2)(2)]-Proctolin (10(-8) M -10(-6) M) are potent non-competitive antagonists of proctolin induced tissue contraction, reducing the maximum response of applied proctolin to 16% and 23% respectively when used at a dose of 10(-6) M, From analysis of the myotropic effects of the analogues investigated in this study, we conclude that the agonist actions of proctolin are dependent on the presence of either a para substituted Phe or a meta substituted Tyr in position 2 of the peptide chain, These data show that the ideal substituents on the aromatic ring are groups containing oxygen and nitrogen atoms, Copyright (C) 1996 Elsevier Science Ltd