title: Cyclic enkephalin analogs with exceptional potency at peripheral delta opioid receptors.
abstract: A series of super potent and delta-opioid-receptor-selective cyclic hexapeptides of the general formula [formula: see text] (where X is hydrogen or halogen) has been synthesized. The unsubstituted hexapeptide formula; see text: [Phe6]DPLCE) has extremely high potency at peripheral delta opioid receptors (IC50 value in the MVD assay is 0.016 nM) and in bioassays is the most selective compound in this series. The introduction of halogens in the phenyl ring of phenylalanine at position 4 led to significant changes in the selectivity and affinities at peripheral and central opioid receptors. In the binding studies, the most potent compound is the p-fluoro analog, whereas the most selective analog is the p-iodo-substituted peptide.
authors.affiliation: Department of Chemistry, University of Arizona, Tucson 85721.
authors.forename: H
authors.initials: H
authors.lastname: Bartosz-Bechowski
authors.forename: P
authors.initials: P
authors.lastname: Davis
authors.forename: T
authors.initials: T
authors.lastname: Zalewska
authors.forename: J
authors.initials: J
authors.lastname: Slaninova
authors.forename: F
authors.initials: F
authors.lastname: Porreca
authors.forename: H I
authors.initials: HI
authors.lastname: Yamamura
authors.forename: V J
authors.initials: VJ
authors.lastname: Hruby
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001812:Blood-Brain Barrier; D002462:Cell Membrane / Q000378:metabolism; D002531:Cerebellum / Q000378:metabolism; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003500:Cyclization; D004745:Enkephalins / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D006168:Guinea Pigs; D007082:Ileum / Q000502:physiology; D050356:Lipid Metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D010456:Peptides, Cyclic / Q000138:chemical synthesis* / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014649:Vas Deferens / Q000502:physiology
chemical_list: D004745:Enkephalins; D010456:Peptides, Cyclic; D017465:Receptors, Opioid, delta; C085405:tyrosyl-cyclo(penicillamyl-glycyl-4-iodophenylalanyl-cysteinyl)phenylalanine; C085404:tyrosyl-cyclo(penicillamyl-glycyl-phenylalanyl-cysteinyl)phenylalanine