Endomorphin Analogues With Balanced Affinity For Both Mu- And Delta-Opioid Receptors

Analogues of endomorphin and tripeptides modified at positions 4 and 3, respectively, with various phenylalanine analogues were synthesized and their affinities for opioid receptors were evaluated. Most of the peptides exhibited potent mu-receptor affinity and selectivity, among them, compound 7 (Dmt-Pro-Tmp-Tmp-NH2) exhibited potent affinity for both mu- and delta-receptors (K-i mu = 0.47 nmol/L, K-i delta = 1.63 nmol/L). (C) 2011 Ting You Li. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.