A series of [MeTyr1, MeArg7]-Dynorphin A (Dyn)(1-8)-OH analogues, modified at position 8 with various amino acids, is described. Their biological activities were determined in the three bioassays [guinea pig ileum (GPI), mouse vas deferens (MVD), and rabbit vas deferens (RVD)] and in the mouse tail-pinch test after subcutaneous administration. None of the analogues tested displayed more potent κ-opioid activity in the RVD than [MeTyr1, MeArg7, D-Leu8]-Dyn(1-8)-NHEt (1), which is a potent analgesic peptide with similar opioid receptor selectivity to that of Dyn.However, [MeTyr1, MeArg7, Melle8]-Dyn(1-8)-OH (11) showed about a twofold more potent analgesic effect than 1. Based on the obtained results it is conceivable that in the case of Dyn(1-8)-OH analogues both a lipophilic L-amino acid in position 8 and an unchanged 7-8 amide bond are essential to maintain potent κ-opioid activity.
本文描述了一系列[MeTyr1, MeArg7]-Dynorphin A (Dyn)(1-8)-OH类似物,在8号位上用不同的
氨基酸进行了修饰。在皮下给药后,通过三种
生物测定法(豚鼠回肠(G
PI)、小鼠输精管(MVD)和兔子输精管(RVD))和小鼠尾夹试验,确定了它们的
生物活性。在RVD中,所有测试的类似物都没有表现出比[MeTyr1, MeArg7, D-Leu8]-Dyn(1-8)-NHEt (1)更强的κ-阿片活性,而后者是一种强效镇痛肽,与Dyn具有相似的阿片受体选择性。然而,[MeTyr1, MeArg7, Melle8]-Dyn(1-8)-OH (11)的镇痛效果比1强约两倍。根据获得的结果,可以推断,在Dyn(1-8)-OH类似物中,8号位上的亲脂性L-
氨基酸和未改变的7-8号位酰胺键对于维持强效κ-阿片活性至关重要。