(NK-1)/EC50 (NK-3) = 0.44. In the rat vas deferens (RVD) assay, a typical NK-2 system, the pseudopeptide analogue 7 was (EC50 = 2 microM) 10-fold more potent than the parent peptide and 20-fold less potent than eledoisin, an NK-2 selective tachykinin. The pseudopeptide enkephalin analogue 17 had low biological activity when tested in the electrically induced GPI (EC50 = 2.3 microM) and was inactive in the
等规的亚甲氧基psi(
CH2O)功能被用作新型肽键替代物,并掺入到两个神经肽(物质P(
SP)和
脑啡肽)的序列中。
SP相关C端六肽[pGlu6]
SP6-11的拟肽类似物[pGlu6,Phe8 psi( )Gly9]
SP6-11(7)和[Leu5]
脑啡肽的两个拟肽类似物,[Tyr1 psi( )Gly2,合成了Leu5]
脑啡肽(11)和[Gly2 psi( )-Gly3,Leu5]
脑啡肽(17)。通过使用溶液中的常规偶联方法,将Nα-保护的伪二肽单元掺入合适的肽序列中。与母体肽[pGlu6]
SP6-11(
EC50 = 1.2 nM)相比,化合物7是一种有效的P物质激动剂(
EC50 = 4.8 nM),可刺激分离的豚鼠回肠(G
PI)的收缩。活性比
EC50(NK-1)/
EC50(NK-3)= 3.16表明,类似物7对G
PI的神经元(NK-3)比对肌肉(NK-1)速激肽受体更有效。