Tetrabranched Hetero-Conjugated Peptides as Bifunctional Agonists of the NOP and Mu Opioid Receptors

The general aim of the work was the validation of a new synthetic methodology designed for obtaining bifunctional heterotetrabranched peptide ligands. Applying an easily accessible synthetic route, we provided a small series of hetero-multimeric peptide conjugates targeting the nociceptin/orphanin FQ (N/OFQ) peptide receptors (NOP) and mu opioid receptors. Among these, H-PWT1-N/OFQ[Dmt(1)]dermorphin demonstrated a similar and high agonist potency at the NOP and mu receptors. The achieved results confirmed the robustness of the approach that is extremely versatile and virtually applicable to different peptide sequences whose pharmacological activity can be combined for generating dual acting multimeric compounds. These innovative pharmacological tools will be extremely helpful for investigating the consequences of the simultaneous activation and/or blockage of different peptidergic receptors.