Potent μ-Opioid Receptor Agonists from Cyclic Peptides Tyr-c[d-Lys-Xxx-Tyr-Gly]: Synthesis, Biological, and Structural Evaluation

Potent μ-Opioid Receptor Agonists from Cyclic Peptides Tyr-c[<scp>d</scp>-Lys-Xxx-Tyr-Gly]: Synthesis, Biological, and Structural Evaluation Synthesis and activity profiles of novel cyclic opioid peptide monomers and dimers Synthesis and Evaluation of the Affinity toward μ-Opioid Receptors of Atypical, Lipophilic Ligands Based on the Sequencec[-Tyr-Pro-Trp-Phe-Gly-] Design and synthesis of conformationally constrained somatostatin analogs with high potency and specificity for .mu. opioid receptors Opioid Activity Profiles of Oversimplified Peptides Lacking in the Protonable N-Terminus Cyclic Enkephalin Analogues with Exceptional Potency and Selectivity for δ-Opioid Receptors Incorporation of a novel conformationally restricted tyrosine analog into a cyclic, .delta. opioid receptor selective tetrapeptide (JOM-13) enhances .delta. receptor binding affinity and selectivity Discovery of a Potent and Efficacious Peptide Derivative for δ/μ Opioid Agonist/Neurokinin 1 Antagonist Activity with a 2′,6′-Dimethyl-<scp>l</scp>-Tyrosine: In vitro, In vivo, and NMR-Based Structural Studies Endomorphin-1 Analogues Containing β-Proline Are μ-Opioid Receptor Agonists and Display Enhanced Enzymatic Hydrolysis Resistance A Cyclic Tetrapeptide (“Cyclodal”) and Its Mirror-Image Isomer Are Both High-Affinity μ Opioid Receptor Antagonists