Abstract
2-Methyl-N-((2′-(pyrrolidin-1-ylsulfonyl)biphenyl-4-yl)methyl)propan-1-amine (PF-04455242) is a novel κ-opioid receptor (KOR) antagonist with high affinity for human (3 nM), rat (21 nM), and mouse (22 nM) KOR, a ∼20-fold reduced affinity for human μ-opioid receptors (MORs; Ki = 64 nM), and negligible affinity for δ-opioid receptors (Ki > 4 μM). PF-04455242 also showed selectivity for KORs in vivo. In rats, PF-04455242 blocked KOR and MOR agonist-induced analgesia with ID50 values of 1.5 and 9.8 mg/kg, respectively, and inhibited ex vivo [3H](2-(benzofuran-4-yl)-N-methyl-N-((5S,7R,8R)-7-(pyrrolidin-1-yl)-1-oxaspiro[4.5]decan-8-yl)acetamide ([3H]CI977) and [3H](2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl) propanoyl]amino]propanoyl]amino]acetyl]-methylamino]-N-(2-hydroxyethyl)-3-phenylpropanamide ([3H]DAMGO) binding to KOR and MOR receptors with ID50 values of 2.0 and 8.6 mg/kg, respectively. An in vivo binding assay was developed using (-)-4-[3H]methoxycarbonyl-2-[(1-pyrrolidinylmethyl]-1-[(3,4-dichlorophenyl)acetyl]-piperidine ([3H]PF-04767135), a tritiated version of the KOR positron emission tomography ligand (-)-4-[11C]methoxycarbonyl-2-[(1-pyrrolidinylmethyl]-1-[(3,4-dichlorophenyl)acetyl]-piperidine ([11C]GR103545) in which PF-04455242 had an ID50 of 5.2 mg/kg. PF-04455242 demonstrated antidepressant-like efficacy (mouse forced-swim test), attenuated the behavioral effects of stress (mouse social defeat stress assay), and showed therapeutic potential in treating reinstatement of extinguished cocaine-seeking behavior (mouse conditioned place preference). KOR agonist-induced plasma prolactin was investigated as a translatable mechanism biomarker. Spiradoline (0.32 mg/kg) significantly increased rat plasma prolactin levels from 1.9 ± 0.4 to 41.9 ± 4.9 ng/ml. PF-04455242 dose-dependently reduced the elevation of spiradoline-induced plasma prolactin with an ID50 of 2.3 ± 0.1 mg/kg, which aligned well with the ED50 values obtained from the rat in vivo binding and efficacy assays. These data provide further evidence that KOR antagonists have potential for the treatment of depression and addiction disorders.
Footnotes
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.111.185108.
↵ The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.
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ABBREVIATIONS:
- GPCR
- G protein-coupled receptor
- CHO
- Chinese hamster ovary
- CPP
- conditioned place preference
- DOR
- δ-opioid receptor
- FST
- forced-swim test
- JVC
- jugular vein cannulation
- KOR
- κ-opioid receptor
- LC-MS/MS
- liquid chromatography/tandem mass spectrometry
- MOR
- μ-opioid receptor
- nor-BNI
- nor-binaltorphimine
- NAc
- nucleus accumbens
- PEI
- polyethylenimine
- PET
- positron emission tomography
- RO
- receptor occupancy
- RT
- room temperature
- SB
- specific binding
- SDS
- social defeat stress
- ANOVA
- analysis of variance
- HSD
- honestly significant difference
- PF-04455242
- 2-methyl-N-((2′-(pyrrolidin-1-ylsulfonyl)biphenyl-4-yl)methyl)propan-1-amine
- [3H]CI977
- [3H]2-(benzofuran-4-yl)-N-methyl-N-((5S,7R,8R)-7-(pyrrolidin-1-yl)-1-oxaspiro[4.5]decan-8-yl)acetamide
- [11C]GR103545
- (-)-4-[11C]methoxycarbonyl-2-[(1-pyrrolidinylmethyl]-1-[(3,4-dichlorophenyl)acetyl]-piperidine
- [3H]DAMGO
- [3H](2S)-2-[[2-[[(2R)-2-[[(2S)-2-amino-3-(4-hydroxyphenyl) propanoyl]amino]propanoyl]amino]acetyl]-methylamino]-N-(2-hydroxyethyl)-3-phenylpropanamide
- JDTic
- (3R)-7-hydroxy-N-((1S)-1-{[(3R,4R)-4-(3-hydroxyphenyl)-3,4-dimethylpiperidin-1-yl]methyl}-2-methylpropyl)-1,2,3,4-tetrahydroisoquinoline-3-carboxamide
- U50488H
- 2-(3,4-dichlorophenyl)-N-methyl-N-[(1R,2R)-2-pyrrolidin-1-ylcyclohexyl]acetamide; [3H]PF-04767135,(-)-4-[3H]methoxycarbonyl-2-[(1-pyrrolidinylmethyl]-1-[(3,4-dichlorophenyl)acetyl]-piperidine
- [3H]U69593
- [3H]N-methyl-2-phenyl-N-[(5R,7S,8S)-7-(pyrrolidin-1-yl)-1-oxaspiro[4.5]dec-8-yl]acetamide
- [35S]GTPγS
- [35S]guanosine 5′-[γ-thio]triphosphate.
- Received June 15, 2011.
- Accepted August 3, 2011.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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