Synthesis, conformational and pharmacological studies on dermorphin N-terminal tetrapeptide analogues

Dermorphin structure-activity relationships toward μ and δ opioid receptors were investigated using a series of synthetic peptides, in which the aromatic residues at positions 1 or/and 3 of the N-terminal tetrapeptide analogue H-Tyr-d-Arg-Phe-β-Ala-NH2 were replaced by unnatural or constrained amino acids.