Synthesis and biological activity of new series of N-modified analogues of the N/OFQ(1-13)NH2 with aminophosphonate moiety.

New series of N-modified analogues of the N/OFQ(1-13)NH(2) with aminophosphonate moiety have been synthesized and investigated for biological activity. These peptides were prepared by solid-phase peptide synthesis-Fmoc-strategy. The N/OFQ(1-13)NH(2) analogues were tested for agonistic activity in vitro on electrically stimulated rat vas deferens smooth-muscle preparations isolated from Wistar albino rats.

Synthesis and biological activity of novel small peptides with aminophosphonates moiety as NOP receptor ligands.

The aim of the present study was the synthesis and the biological screening of new analogs of Ac-RYYRWK-NH2, modified at the N-terminal with 1-[(methoxyphosphono)methylamino]cycloalkanecarboxylic acids. The four newly synthesized ligands for the nociceptin/orphanin FQ (N/OFQ) receptor (NOP) have been prepared by solid-phase peptide synthesis--Fmoc-strategy. These compounds were tested for agonistic activity in vitro on electrically stimulated smooth-muscle preparations isolated from vas deferens of Wistar rats.

Synthesis and biological activity of nociceptin/orphanin FQ(1-13)NH2 analogues modified in 9 and/or 13 position.

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.