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Han S, Thoresen L, Jung JK, Zhu X, Thatte J, Solomon M, Gaidarov I, Unett DJ, Yoon WH, Barden J, Sadeque A, Usmani A, Chen C, Semple G, Grottick AJ, Al-Shamma H, Christopher R, Jones RM. Discovery of APD371: Identification of a Highly Potent and Selective CB 2 Agonist for the Treatment of Chronic Pain. ACS Med Chem Lett 2017; 8:1309-1313. [PMID: 29259753 DOI: 10.1021/acsmedchemlett.7b00396] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 11/30/2017] [Indexed: 11/30/2022] Open
Abstract
The discovery of a novel, selective and fully efficacious CB2 agonist with satisfactory pharmacokinetic and pharmaceutical properties is described. Compound 6 was efficacious in a rat model of osteoarthritis pain following oral administration and, in contrast to morphine, maintained its analgesic effect throughout a 5-day subchronic treatment paradigm. These data were consistent with our hypothesis that full agonist efficacy is required for efficient internalization and recycling of the CB2 receptor to avoid tachyphylaxis. Based on its overall favorable preclinical profile, 6 (APD371) was selected for further development for the treatment of pain.
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Affiliation(s)
- Sangdon Han
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Lars Thoresen
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Jae-Kyu Jung
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Xiuwen Zhu
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Jayant Thatte
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Michelle Solomon
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Ibragim Gaidarov
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - David J. Unett
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Woo Hyun Yoon
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Jeremy Barden
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Abu Sadeque
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Amin Usmani
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Chuan Chen
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Graeme Semple
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Andrew J. Grottick
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Hussein Al-Shamma
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Ronald Christopher
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
| | - Robert M. Jones
- Arena Pharmaceuticals, 6154 Nancy Ridge Drive, San Diego, California 92121, United States
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Lundell I, Rabe Bernhardt N, Johnsson AK, Larhammar D. Internalization studies of chimeric neuropeptide Y receptors Y1 and Y2 suggest complex interactions between cytoplasmic domains. ACTA ACUST UNITED AC 2011; 168:50-8. [DOI: 10.1016/j.regpep.2011.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 02/18/2011] [Accepted: 03/28/2011] [Indexed: 11/25/2022]
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Noble F, Roques BP. Protection of endogenous enkephalin catabolism as natural approach to novel analgesic and antidepressant drugs. Expert Opin Ther Targets 2007; 11:145-59. [PMID: 17227231 DOI: 10.1517/14728222.11.2.145] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The most efficient drugs to alleviate severe pain are opioid compounds. However, their chronic use could be associated with serious drawbacks, such as tolerance, respiratory depression and constipation. Therefore, there is a need for compounds able to efficiently alleviate inflammatory and neurogenic pain following chronic treatment. The discovery that the endogenous opioid peptides, enkephalins, are inactivated by two metallopeptidases, neutral endopeptidase and aminopeptidase N, which can be blocked by synthetic dual inhibitors, represents a promising way to develop 'physiological' analgesics devoid of morphine side effects. These dual inhibitors also have antidepressant-like properties through enkephalin-related activation of delta-opioid receptors. This is expected to reduce the emotional component of pain in humans. This article reviews the promising data obtained for future development of a new class of analgesic that could be of major interest in a number of severe and chronic pain syndromes.
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Liao D, Grigoriants OO, Loh HH, Law PY. Agonist-dependent postsynaptic effects of opioids on miniature excitatory postsynaptic currents in cultured hippocampal neurons. J Neurophysiol 2006; 97:1485-94. [PMID: 17122315 PMCID: PMC1796913 DOI: 10.1152/jn.00790.2006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Although chronic treatment with morphine is known to alter the function and morphology of excitatory synapses, the effects of other opioids on these synapses are not clear. Here we report distinct effects of several opioids (morphine, [d-ala(2),me-phe(4),gly(5)-ol]enkephalin (DAMGO), and etorphine) on miniature excitatory postsynaptic currents (mEPSCs) in cultured hippocampal neurons: 1) chronic treatment with morphine for >3 days decreased the amplitude, frequency, rise time and decay time of mEPSCs. In contrast, "internalizing" opioids such as etorphine and DAMGO increased the frequency of mEPSCs and had no significant effect on the amplitude and kinetics of mEPSCs. These results demonstrate that different opioids can have distinct effects on the function of excitatory synapses. 2) mu opioid receptor fused with green fluorescence protein (MOR-GFP) is clustered in dendritic spines in most hippocampal neurons but is concentrated in axon-like processes in striatal and corticostriatal nonspiny neurons. It suggests that MORs might mediate pre- or postsynaptic effects depending on cell types. 3) Neurons were cultured from MOR knock-out mice and were exogenously transfected with MOR-GFP. Chronic treatment with morphine suppressed mEPSCs only in neurons that contained postsynaptic MOR-GFP, indicating that opioids can modulate excitatory synaptic transmission postsynaptically. 4) Morphine acutely decreased mEPSC amplitude in neurons expressing exogenous MOR-GFP but had no effect on neurons expressing GFP. It indicates that the low level of endogenous MORs could only allow slow opioid-induced plasticity of excitatory synapses under normal conditions. 5) A theoretical model suggests that morphine might affect the function of spines by decreasing the electrotonic distance from synaptic inputs to the soma.
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Affiliation(s)
- Dezhi Liao
- Department of Neuroscience, The University of Minnesota, 321 Church Street S.E., Minneapolis, MN 55455, USA.
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Walwyn WM, Wei W, Xie CW, Chiu K, Kieffer BL, Evans CJ, Maidment NT. Mu opioid receptor-effector coupling and trafficking in dorsal root ganglia neurons. Neuroscience 2006; 142:493-503. [PMID: 16887280 DOI: 10.1016/j.neuroscience.2006.06.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Revised: 06/11/2006] [Accepted: 06/13/2006] [Indexed: 01/25/2023]
Abstract
Morphine induces profound analgesic tolerance in vivo despite inducing little internalization of the mu opioid receptor (muOR). Previously proposed explanations suggest that this lack of internalization could either lead to prolonged signaling and associated compensatory changes in downstream signaling systems, or that the receptor is unable to recycle and resensitize and so loses efficacy, either mechanism resulting in tolerance. We therefore examined, in cultured neurons, the relationship between muOR internalization and desensitization in response to two agonists, D-Ala2, N-MePhe4, Gly5-ol-enkephalin (DAMGO) and morphine. In addition, we studied the chimeric mu/delta opioid receptor (mu/ partial differentialOR) which could affect internalization and desensitization in neurons. Dorsal root ganglia neurons from muOR knockout mice were transduced with an adenovirus expressing either receptor and their respective internalization, desensitization and trafficking profiles determined. Both receptors desensitized equally, measured by Ca2+ current inhibition, during the first 5 min of agonist exposure to DAMGO or morphine treatment, although the mu/partial differentialOR desensitized more extensively. Such rapid desensitization was unrelated to internalization as DAMGO, but not morphine, internalized both receptors after 20 min. In response to DAMGO the mu/partial differentialOR internalized more rapidly than the muOR and was trafficked through Rab4-positive endosomes and lysosomal-associated membrane protein-1-labeled lysosomes whereas the muOR was trafficked through Rab4 and Rab11-positive endosomes. Chronic desensitization of the Ca2+ current response, after 24 h of morphine or DAMGO incubation, was seen in the DAMGO, but not morphine-treated, muOR-expressing cells. Such persistence of signaling after chronic morphine treatment suggests that compensation of downstream signaling systems, rather than loss of efficacy due to poor receptor recycling, is a more likely mechanism of morphine tolerance in vivo. In contrast to the muOR, the mu/partial differentialOR showed equivalent desensitization whether morphine or DAMGO treated, but internalized further with DAMGO than morphine. Such ligand-independent desensitization could be a result of the observed higher rate of synthesis and degradation of this chimeric receptor.
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MESH Headings
- Analgesics, Opioid/pharmacology
- Analysis of Variance
- Animals
- Animals, Newborn
- Baclofen/pharmacology
- Cells, Cultured
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalins/pharmacology
- Flow Cytometry/methods
- GABA Agonists/pharmacology
- Ganglia, Spinal/cytology
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Membrane Potentials/radiation effects
- Mice
- Mice, Knockout
- Morphine/pharmacology
- Neurons/drug effects
- Neurons/physiology
- Patch-Clamp Techniques/methods
- Protein Transport/drug effects
- Protein Transport/genetics
- Protein Transport/physiology
- Receptors, Opioid, mu/deficiency
- Receptors, Opioid, mu/physiology
- Time Factors
- Transfection/methods
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Affiliation(s)
- W M Walwyn
- Department of Psychiatry and Biobehavioral Sciences, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, NPI Box 77, 760 Westwood Plaza, Los Angeles, CA 90024-1759, USA.
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6
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Grecksch G, Bartzsch K, Widera A, Becker A, Höllt V, Koch T. Development of tolerance and sensitization to different opioid agonists in rats. Psychopharmacology (Berl) 2006; 186:177-84. [PMID: 16572262 DOI: 10.1007/s00213-006-0365-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2005] [Accepted: 01/13/2006] [Indexed: 10/24/2022]
Abstract
RATIONALE Despite numerous investigations, the mechanisms underlying the development of opioid tolerance are far from clear. However, several in vitro studies implicated a protective role of agonist-induced micro-opioid receptor endocytosis in the development of opioid tolerance. Moreover, we have recently demonstrated that the high-efficacy agonist etonitazene promotes rapid endocytosis of micro-opioid receptors, whereas the agonist morphine and the low-efficacy agonist buprenorphine fail to promote detectable receptor endocytosis in micro-opioid receptor expressing HEK293 cells. OBJECTIVES The present study explored the effects of these opioids on the development of tolerance and sensitization in rats in vivo. METHODS The opioid effects were quantified using the hot plate, electric tail root stimulation, and the locomotor activity chamber in male Wistar rats. Dose-response curves were generated for each test drug. To induce tolerance, equieffective doses of etonitazene, morphine, and buprenorphine were administered daily for 29 days. RESULTS We found that chronic treatment with the non-internalizing drugs buprenorphine and morphine resulted in a greater development of tolerance than etonitazene. In addition, the sensitization to the locomotor stimulant effect was high after buprenorphine and morphine, but was lacking after chronic etonitazene application. CONCLUSION The results support a role for the endocytotic potency of agonists in the development of tolerance and addiction during long-term opioid treatment.
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Affiliation(s)
- Gisela Grecksch
- Institute of Pharmacology and Toxicology, Faculty of Medicine, Otto-von-Guericke-University Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.
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