Tryptophan replacement in the nociceptin/orphanin FQ receptor ligand Ac-RYYRWK-NH2

Authors :: Carra', Giacomo
Calo', Girolamo
Spagnolo, Barbara
Guerrini, Remo
Arduin, Marika
Marzola, Erika
Trapella, Claudio
Regoli, Domenico
Salvadori, Severo
Publication Year :: 2005
Publisher :: Blackwell Munksgaard:PO Box 2148, Periodicals Department, DK-1016 Copenhagen K Denmark:011 45 33 755913, EMAIL: agentservices@oxon.blackwellpublishing.com, INTERNET: http://www.blackwellmunksgaard.com, Fax: 011 45 77 333377, 2005.
Abstract: In the present study we describe the in vitro pharmacological characterization of the nociceptin/orphanin FQ (N/OFQ) receptor (NOP) ligand Ac-RYYRWK-NH2 and the synthesis and biological evaluation of 13 Trp5 substituted Ac-RYYRWK-NH2 analogs. Results indicate that Ac-RYYRWK-NH2 behaves as a highly potent and selective partial agonist at the NOP receptors and that the whole indole moiety of the Trp5 side chain is not required, being a phenyl-ethyl side chain already sufficient for maintaining high potency.

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