摘要:
To improve the structure-activity studies of the lead 6 opioid agonist H-Dmt-Tic-Asp*-Bid, we synthesized and pharmacologically characterized a series of analogues in which the side chain next to 1H-benzimidazole-2-yl (Bid) was substituted by those endowed with different chemical properties. Interesting results were obtained: (1) only Gly, Ala, and Asp resulted in delta agonism, (2) Phe yielded delta antagonism, (3) and all other residues except Glu (devoid of any activity) gave mu agonism.