Structure-activity relationship, conformation and pharmacology studies of morphiceptin analogues--selective mu-opioid receptor ligands.

Morphiceptin (Tyr-Pro-Phe-Pro-NH(2)) is one of the most selective agonists for the mu-opioid receptor. In this review structure-activity relationships of morphiceptin analogues and studies resulting in defining low energy conformations are discussed. Finally, new developments in the control of tumour growth and cell proliferation by morphiceptin analogues are surveyed, which open future perspectives in the diagnosis and treatment of various cancers.