Versatile Picklocks To Access All Opioid Receptors: Tuning the Selectivity and Functional Profile of the Cyclotetrapeptide c[Phe-d-Pro-Phe-Trp] (CJ-15,208)

Versatile Picklocks To Access All Opioid Receptors: Tuning the Selectivity and Functional Profile of the Cyclotetrapeptide c[Phe-<scp>d</scp>-Pro-Phe-Trp] (CJ-15,208) Nascent structure–activity relationship study of a diastereomeric series of kappa opioid receptor antagonists derived from CJ-15,208 The Macrocyclic Peptide Natural Product CJ-15,208 Is Orally Active and Prevents Reinstatement of Extinguished Cocaine-Seeking Behavior CJ-15,208, a Novel Kappa Opioid Receptor Antagonist from a Fungus, Ctenomyces serratus ATCC15502. Potent μ-Opioid Receptor Agonists from Cyclic Peptides Tyr-c[<scp>d</scp>-Lys-Xxx-Tyr-Gly]: Synthesis, Biological, and Structural Evaluation Opioid Activity Profiles of Oversimplified Peptides Lacking in the Protonable N-Terminus Synthesis and Evaluation of the Affinity toward μ-Opioid Receptors of Atypical, Lipophilic Ligands Based on the Sequencec[-Tyr-Pro-Trp-Phe-Gly-] Design, Synthesis, and Biological Evaluation of Novel Bifunctional C-Terminal-Modified Peptides for δ/μ Opioid Receptor Agonists and Neurokinin-1 Receptor Antagonists Endomorphin-1 Analogues Containing β-Proline Are μ-Opioid Receptor Agonists and Display Enhanced Enzymatic Hydrolysis Resistance Design and synthesis of conformationally constrained somatostatin analogs with high potency and specificity for .mu. opioid receptors