title: Synthesis and changes in affinity for NOP and opioid receptors of novel hexapeptides containing β(2)-tryptophan analogues.
abstract: We report the synthesis and the biological activity of new analogues of Ac-RFMWMK-NH2 and Ac-RYYRWK-NH2, modified in position 4 and 5, respectively, with incorporation of newly synthesized β(2)-tryptophan analogues. Trp was substituted by the (S)-2-(1-methyl-1H-indol-3-yl)propionic residue or by (S)-2-(5-methoxy-1H-indol-3-yl)propionic residue. The biological activity (pEC50 and Emax) of these compounds was tested on electrically stimulated preparations of rat vas deferens. The 5-methoxy β-tryptophan group reverses the affinity of the compounds.
authors.affiliation: Institute of Neurobiology, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
authors.forename: Rositsa
authors.initials: R
authors.lastname: Zamfirova
authors.forename: Nikola
authors.initials: N
authors.lastname: Pavlov
authors.forename: Petar
authors.initials: P
authors.lastname: Todorov
authors.forename: Polina
authors.initials: P
authors.lastname: Mateeva
authors.forename: Jean
authors.initials: J
authors.lastname: Martinez
authors.forename: Monique
authors.initials: M
authors.lastname: Calmès
authors.forename: Emilia
authors.initials: E
authors.lastname: Naydenova
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D008297:Male; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011485:Protein Binding; D051381:Rats; D011957:Receptors, Opioid / Q000737:chemistry* / Q000378:metabolism; D014364:Tryptophan / Q000737:chemistry*; D014649:Vas Deferens / Q000187:drug effects; D000094942:Nociceptin Receptor
chemical_list: D009842:Oligopeptides; D011957:Receptors, Opioid; D014364:Tryptophan; D000094942:Nociceptin Receptor; C000722285:Oprl1 protein, rat