Comparative biochemical and pharmacological characterization of a novel, NOP receptor selective hexapeptide, Ac-RYYRIR-ol.

Nociceptin/orphanin FQ (N/OFQ) is an endogenous neuropeptide, which is widely distributed in central and peripheral nervous system. Some N/OFQ sequence unrelated hexapeptides can effectively bind to the N/OFQ peptide (NOP) receptor and they were used as template for structure-activity studies that lead to discovery of the new NOP selective ligands. In the present study, the pharmacological profile of the novel hexapeptide Ac-RYYRIR-ol was investigated using various in vitro assays including receptor binding and G-protein activation in rat brain membranes, mouse and rat vas deferens, guinea pig ileum, mouse colon and Ca(2+) mobilization assay in chinese hamster ovary (CHO) cells co-expressing the human recombinant NOP receptor and the C-terminally modified Galpha(qi5) protein.

Structure-activity studies on the nociceptin/orphanin FQ receptor antagonist 1-benzyl-N-{3-[spiroisobenzofuran-1(3H),4'-piperidin-1-yl]propyl} pyrrolidine-2-carboxamide.

Twelve derivatives of the nociceptin/orphanin FQ (N/OFQ) receptor (NOP) antagonist 1-benzyl-N-{3-[spiroisobenzofuran-1(3H),4'-piperidin-1-yl]propyl} pyrrolidine-2-carboxamide (Comp 24) were synthesized and tested in binding experiments performed on CHO(hNOP) cell membranes. Among them, a novel interesting NOP receptor antagonist (compound 35) was identified by blending chemical moieties taken from different NOP receptor ligands. In vitro in various assays, Compound 35 consistently behaved as a pure, highly potent (pA(2) in the range 8.

Pharmacological characterization of the nociceptin/orphanin FQ receptor non peptide antagonist Compound 24.

Compound 24, 1-benzyl-N-[3-[spiroisobenzofuran-1(3H),4'-piperidin-1-yl]propyl] pyrrolidine-2-carboxamide was recently identified as a nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP) ligand. In this study, the in vitro and in vivo pharmacological profiles of Compound 24 were investigated. In vitro studies were performed measuring receptor and [(35)S]GTPgammaS binding and calcium mobilization in cells expressing the recombinant NOP receptor as well as using N/OFQ sensitive tissues.

Pharmacological profile of NOP receptors coupled with calcium signaling via the chimeric protein G alpha qi5.

In this study, the Galpha(qi5) protein was used to force the human nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor to signal through the Ca(2+) pathway in CHO cells. [Ca(2+)](i) levels were monitored using the fluorometer FlexStation II and the Ca(2+) dye Fluo 4 AM. Concentration response curves were generated with a panel of full and partial agonists, while NOP antagonists were assessed in inhibition-response curves.

Further studies on the pharmacological features of the nociceptin/orphanin FQ receptor ligand ZP120.

ZP120 is a nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP) ligand. In previous studies, the effects of ZP120 were found to be sensitive to J-113397 in mouse tissues while resistant to UFP-101 in rat tissues. The aim of this study was to further investigate the ZP120 pharmacological profile using mouse and rat preparations, J-113397 and UFP-101, as well as NOP receptor knockout (NOP(-/-)) mice.

In vitro and in vivo studies on UFP-112, a novel potent and long lasting agonist selective for the nociceptin/orphanin FQ receptor.

[(pF)Phe(4)Aib(7)Arg(14)Lys(15)]N/OFQ-NH(2) (UFP-112) has been designed as a novel ligand for the nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP) by combining into the same peptide different chemical modifications reported to increase N/OFQ potency. In vitro data obtained in the electrically stimulated mouse vas deferens demonstrated that UFP-112 behaved as a high potency (pEC(50) 9.43) full agonist at the NOP receptor.

Synthesis and biological activity of nociceptin/orphanin FQ analogues substituted in position 7 or 11 with Calpha,alpha-dialkylated amino acids.

Previous structure-activity and NMR studies on nociceptin/orphanin FQ (N/OFQ) demonstrated that Aib substitution of Ala(7) and/or Ala(11) increases the peptide potency through an alpha helix structure induction mechanism. On these bases we synthesised and evaluated pharmacologically in the mouse vas deferens assay a series of N/OFQ-NH(2) analogues substituted in position 7 and 11 with Calpha,alpha-disubstituted cyclic, linear and branched amino acids. None of the 20 novel N/OFQ analogues produced better results than [Aib(7)]N/OFQ-NH(2).

Pharmacological characterization of the nociceptin/orphanin FQ receptor antagonist SB-612111 [(-)-cis-1-methyl-7-[[4-(2,6-dichlorophenyl)piperidin-1-yl]methyl]-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ol]: in vitro studies.

The compound SB-612111 [(-)-cis-1-methyl-7-[[4-(2,6-dichlorophenyl)piperidin-1-yl]methyl]-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ol] was recently identified as a selective antagonist for the nociceptin/orphanin FQ (N/OFQ) peptide receptor (NOP). In the present study, the in vitro pharmacological profile of SB-612111 at human recombinant NOP receptors expressed in Chinese hamster ovary (CHO) cells [receptor binding, guanosine 5'-O-(3-[(35)S]thio)triphosphate (GTPgamma[(35)S]) binding, and cAMP level experiments] as well as at native NOP receptors expressed in peripheral (mouse and rat vas deferens, guinea pig ileum) and central (mouse cerebral cortex synaptosomes releasing [(3)H]5-HT) preparations was evaluated and compared with that of the standard nonpeptide antagonist (+/-)J-113397 [(+/-)-trans-1-[1-cyclooctylmethyl-3-hydroxymethyl-4-piperidyl]-3-ethyl-1,3-dihydro-2H-benzimidazol-2-one]. SB-612111 produced a concentration-dependent displacement of [(3)H]N/OFQ binding to CHO(hNOP) cell membranes, showing higher affinity and NOP selectivity over classical opioid receptors than (+/-)J-113397.