关键词：受体激动剂；副作用；医药；天花板效应
摘 要：Partial μ/κ opioid agonists produce analgesia and may have fewer side effects than full μ or κ agonists. Also, a ceiling effect has been observed with many μ/κ partial agonists, which may account for attenuation in side effects. Many benzomorphans, including cyclazocine and pentazocine, are mixed μ/κ partial agonists. Recent efforts have been focused on the synthesis of long-acting benzomorphans. Aminothiazolomorphinans are an example of novel morphinans having mixed κ and μ activity. The recognition of receptor dimerization and that μ and κ monomeric opioid receptors may be in close proximity lead to the synthesis of bivalent ligands. The two pharmacophores comprising the bivalent ligands determine their μ/κ pharmacological properties. Bivalent opioid ligands represent a relatively new class of opioid ligands.