title: Synthesis and biological activity of nociceptin/orphanin FQ(1-13)NH2 analogues modified in 9 and/or 13 position.
abstract: The purpose of the present study was the synthesis and the biological screening of new analogues of N/OFQ(1-13)NH2, the minimal sequence maintaining the same activity as the natural peptide nociceptin. In order to investigate the role of Lys, we substituted Lys at positions 9 and/or 13 by Orn, Dab (diaminobutanoic acid) or Dap (diaminopropanoic acid). The new N/OFQ(1-13)NH2 analogues exerted strong and naloxone-resistant inhibition of electrically evoked contractions of rat vas deferens. Lys replacement with Orn maintained or even enhanced the inhibitory activity, while replacements with Dab and Dap decreased inhibitory activity.
authors.affiliation: Department of Organic Chemistry, University of Chemical Technology and Metallurgy, Sofia 1756, Bulgaria. e_naydenova@abv.bg
authors.forename: Emilia D
authors.initials: ED
authors.lastname: Naydenova
authors.forename: Vanya I
authors.initials: VI
authors.lastname: Zhivkova
authors.forename: Rositza N
authors.initials: RN
authors.lastname: Zamfirova
authors.forename: Lubomir T
authors.initials: LT
authors.lastname: Vezenkov
authors.forename: Yordanka G
authors.initials: YG
authors.lastname: Dobrinova
authors.forename: Polina I
authors.initials: PI
authors.lastname: Mateeva
mesh_terms: D018847:Opioid Peptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D011957:Receptors, Opioid / Q000187:drug effects
chemical_list: D018847:Opioid Peptides; D010446:Peptide Fragments; D011957:Receptors, Opioid; C439964:nociceptin (1-13) amide