title: In vivo and in vitro evaluation of novel μ-opioid receptor agonist compounds.
abstract: Opioids are the most effective and widely used drugs for pain treatment. Morphine is an archetypal opioid and is an opioid receptor agonist. Unfortunately, the clinical usefulness of morphine is limited by adverse effects such as analgesic tolerance and addiction. Therefore, it is important to study the development of novel opioid agonists as part of pain control. The analgesic effects of opioids are mediated by three opioid receptors, namely opioid μ-, δ-, and κ-receptors. They belong to the G protein-coupled receptor superfamily and are coupled to Gi proteins. In the present study, we developed a ligand screening system to identify novel opioid μ-receptor agonists that measures [(35)S]GTPγS binding to cell membrane fractions prepared from the fat body of transgenic silkworms expressing μ-receptor-Gi1α fusion protein. We screened the RIKEN Natural Products Depository (NPDepo) chemical library, which contains 5848 compounds, and analogs of hit compounds. We successfully identified a novel, structurally unique compound, that we named GUM1, with agonist activity for the opioid μ-receptor (EC50 of 1.2 µM). The Plantar Test (Hargreaves' Method) demonstrated that subcutaneous injection of 3mg/kg of GUM1 into wild-type rats significantly extended latency time. This extension was also observed in a rat model of morphine tolerance and was inhibited by pre-treatment of naloxone. The unique molecular skeleton of GUM1 makes it an attractive molecule for further ligand-opioid receptor binding studies.
authors.affiliation: Faculty of Science and Technology, Division of Molecular Science, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Nikaido
authors.affiliation: Faculty of Science and Technology, Division of Molecular Science, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Kurosawa
authors.affiliation: Faculty of Science and Technology, Division of Molecular Science, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Saikawa
authors.affiliation: Faculty of Science and Technology, Division of Molecular Science, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kuroiwa
authors.affiliation: Faculty of Science and Technology, Division of Molecular Science, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Chiharu
authors.initials: C
authors.lastname: Suzuki
authors.affiliation: Gunma Sericultural Technology Center, 1-1-1 Ohte-machi, Maebashi, Gunma 371-8570, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kuwabara
authors.affiliation: Department of Anesthesiology, Graduate School of Medicine, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Hazime
authors.initials: H
authors.lastname: Hoshino
authors.affiliation: Department of Anesthesiology, Graduate School of Medicine, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Obata
authors.affiliation: Department of Anesthesiology, Graduate School of Medicine, Gunma University, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Saito
authors.affiliation: Collaboration Promotion Unit, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Chemical Resource Development Research Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Tamio
authors.initials: T
authors.lastname: Saito
authors.affiliation: Chemical Resource Development Research Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Osada
authors.affiliation: Transgenic Silkworm Research Center, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Kobayashi
authors.affiliation: Transgenic Silkworm Research Center, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki 305-8634, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Sezutsu
authors.affiliation: Faculty of Science and Technology, Division of Molecular Science, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan. Electronic address: stakeda@gunma-u.ac.jp.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Takeda
mesh_terms: D000701:Analgesics, Opioid / Q000819:agonists / Q000494:pharmacology; D000818:Animals; D030801:Animals, Genetically Modified; D001596:Benzylamines / Q000819:agonists* / Q000494:pharmacology*; D001688:Biological Products / Q000494:pharmacology*; D012831:Bombyx; D004361:Drug Tolerance; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006801:Humans; D008297:Male; D010147:Pain Measurement / Q000187:drug effects; D011714:Pyrans / Q000819:agonists* / Q000494:pharmacology*; D011869:Radioligand Assay; D051381:Rats; D017450:Receptors, Opioid, mu / Q000819:agonists* / Q000235:genetics; D013462:Sulfur Radioisotopes / Q000378:metabolism
chemical_list: D000701:Analgesics, Opioid; D001596:Benzylamines; D001688:Biological Products; C000611307:GUM1 compound; C485764:OPRM1 protein, human; D011714:Pyrans; D017450:Receptors, Opioid, mu; D013462:Sulfur Radioisotopes; D016244:Guanosine 5'-O-(3-Thiotriphosphate)
keywords: Cross-tolerance; DAMGO (PubChem CID:5462471); High-throughput screening; Morphine (PubChem CID:5464110); NPD26 (PubChem CID:3129829); NPD3000 (PubChem CID:1788462); NPD48 (PubChem CID:3132838); NPD660, GUM1 (PubChem CID:3884637); NPD711 (PubChem CID:11870750); NPD85 (PubChem CID:78246253); Opioid receptor; Opioid rotation; Receptor-Gα fusion protein; TRV130 (PubChem CID:66553195); Transgenic silkworm