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Klein AK, Austin EW, Cunningham MJ, Dvorak D, Gatti S, Hulls SK, Kiss L, Kruegel AC, Marek GJ, Papp M, Sporn J, Hughes ZA. GM-1020: a novel, orally bioavailable NMDA receptor antagonist with rapid and robust antidepressant-like effects at well-tolerated doses in rodents. Neuropsychopharmacology 2024; 49:905-914. [PMID: 38177696 PMCID: PMC11039472 DOI: 10.1038/s41386-023-01783-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 01/06/2024]
Abstract
The NMDA receptor (NMDAR) antagonist ketamine has shown great potential as a rapid-acting antidepressant; however, its use is limited by poor oral bioavailability and a side effect profile that necessitates in-clinic dosing. GM-1020 is a novel NMDAR antagonist that was developed to address these limitations of ketamine as a treatment for depression. Here, we present the preclinical characterization of GM-1020 alongside ketamine, for comparison. In vitro, we profiled GM-1020 for binding to NMDAR and functional inhibition using patch-clamp electrophysiology. In vivo, GM-1020 was assessed for antidepressant-like efficacy using the Forced Swim Test (FST) and Chronic Mild Stress (CMS), while motor side effects were assessed in spontaneous locomotor activity and on the rotarod. The pharmacokinetic properties of GM-1020 were profiled across multiple preclinical species. Electroencephalography (EEG) was performed to determine indirect target engagement and provide a potentially translational biomarker. These results demonstrate that GM-1020 is an orally bioavailable NMDAR antagonist with antidepressant-like efficacy at exposures that do not produce unwanted motor effects.
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Affiliation(s)
| | | | | | - Dino Dvorak
- Gilgamesh Pharmaceuticals, New York, NY, USA
| | | | | | - Laszlo Kiss
- Gilgamesh Pharmaceuticals, New York, NY, USA
| | | | | | - Mariusz Papp
- Maj Institute of Pharmacology, Polish Academy of Sciences, Krakow, Poland
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Hill R, Sanchez J, Lemel L, Antonijevic M, Hosking Y, Mistry SN, Kruegel AC, Javitch JA, Lane JR, Canals M. Assessment of the potential of novel and classical opioids to induce respiratory depression in mice. Br J Pharmacol 2023; 180:3160-3174. [PMID: 37489013 PMCID: PMC10952895 DOI: 10.1111/bph.16199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 06/08/2023] [Accepted: 07/15/2023] [Indexed: 07/26/2023] Open
Abstract
BACKGROUND AND PURPOSE Opioid-induced respiratory depression limits the use of μ-opioid receptor agonists in clinical settings and is the main cause of opioid overdose fatalities. The relative potential of different opioid agonists to induce respiratory depression at doses exceeding those producing analgesia is understudied despite its relevance to assessments of opioid safety. Here we evaluated the respiratory depressant and anti-nociceptive effects of three novel opioids and relate these measurements to their in vitro efficacy. EXPERIMENTAL APPROACH Respiration was measured in awake, freely moving male CD-1 mice using whole body plethysmography. Anti-nociception was measured using the hot plate test. Morphine, oliceridine and tianeptine were administered intraperitoneally, whereas methadone, oxycodone and SR-17018 were administered orally. Receptor activation and arrestin-3 recruitment were measured in HEK293 cells using BRET assays. KEY RESULTS Across the dose ranges examined, all opioids studied depressed respiration in a dose-dependent manner, with similar effects at the highest doses, and with tianeptine and oliceridine showing reduced duration of effect, when compared with morphine, oxycodone, methadone and SR-17018. When administered at doses that induced similar respiratory depression, all opioids induced similar anti-nociception, with tianeptine and oliceridine again showing reduced duration of effect. These data were consistent with the in vitro agonist activity of the tested compounds. CONCLUSION AND IMPLICATIONS In addition to providing effective anti-nociception, the novel opioids, oliceridine, tianeptine and SR-17018 depress respiration in male mice. However, the different potencies and kinetics of effect between these novel opioids may be relevant to their therapeutic application in different clinical settings.
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Affiliation(s)
- Rob Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical CentreUniversity of NottinghamNottinghamUK
- Centre of Membrane Proteins and Receptors, Universities of Nottingham and BirminghamMidlandsUK
| | - Julie Sanchez
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical CentreUniversity of NottinghamNottinghamUK
- Centre of Membrane Proteins and Receptors, Universities of Nottingham and BirminghamMidlandsUK
| | - Laura Lemel
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical CentreUniversity of NottinghamNottinghamUK
- Centre of Membrane Proteins and Receptors, Universities of Nottingham and BirminghamMidlandsUK
| | - Mirjana Antonijevic
- Division of Biomolecular Science and Medicinal Chemistry, School of Pharmacy, University of Nottingham Biodiscovery InstituteUniversity ParkNottinghamUK
| | - Yselkla Hosking
- Division of Biomolecular Science and Medicinal Chemistry, School of Pharmacy, University of Nottingham Biodiscovery InstituteUniversity ParkNottinghamUK
| | - Shailesh N. Mistry
- Division of Biomolecular Science and Medicinal Chemistry, School of Pharmacy, University of Nottingham Biodiscovery InstituteUniversity ParkNottinghamUK
| | | | - Jonathan A. Javitch
- Departments of Psychiatry and Molecular Pharmacology and TherapeuticsColumbia University Vagelos College of Physicians & SurgeonsNew YorkNew YorkUSA
- Division of Molecular TherapeuticsNew York State Psychiatric InstituteNew YorkNew YorkUSA
| | - J. Robert Lane
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical CentreUniversity of NottinghamNottinghamUK
- Centre of Membrane Proteins and Receptors, Universities of Nottingham and BirminghamMidlandsUK
| | - Meritxell Canals
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical CentreUniversity of NottinghamNottinghamUK
- Centre of Membrane Proteins and Receptors, Universities of Nottingham and BirminghamMidlandsUK
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3
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Hill R, Kruegel AC, Javitch JA, Lane JR, Canals M. The respiratory depressant effects of mitragynine are limited by its conversion to 7-OH mitragynine. Br J Pharmacol 2022; 179:3875-3885. [PMID: 35297034 PMCID: PMC9314834 DOI: 10.1111/bph.15832] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/18/2022] [Accepted: 03/03/2022] [Indexed: 12/03/2022] Open
Abstract
Background and Purpose Mitragynine, the major alkaloid in Mitragyna speciosa (kratom), is a partial agonist at the μ opioid receptor. CYP3A‐dependent oxidation of mitragynine yields the metabolite 7‐OH mitragynine, a more efficacious μ receptor agonist. While both mitragynine and 7‐OH mitragynine can induce anti‐nociception in mice, recent evidence suggests that 7‐OH mitragynine formed as a metabolite is sufficient to explain the anti‐nociceptive effects of mitragynine. However, the ability of 7‐OH mitragynine to induce μ receptor‐dependent respiratory depression has not yet been studied. Experimental Approach Respiration was measured in awake, freely moving, male CD‐1 mice, using whole body plethysmography. Anti‐nociception was measured using the hot plate assay. Morphine, mitragynine, 7‐OH mitragynine and the CYP3A inhibitor ketoconazole were administered orally. Key Results The respiratory depressant effects of mitragynine showed a ceiling effect, whereby doses higher than 10 mg·kg−1 produced the same level of effect. In contrast, 7‐OH mitragynine induced a dose‐dependent effect on mouse respiration. At equi‐depressant doses, both mitragynine and 7‐OH mitragynine induced prolonged anti‐nociception. Inhibition of CYP3A reduced mitragynine‐induced respiratory depression and anti‐nociception without affecting the effects of 7‐OH mitragynine. Conclusions and Implications Both the anti‐nociceptive effects and the respiratory depressant effects of mitragynine are partly due to its metabolic conversion to 7‐OH mitragynine. The limiting rate of conversion of mitragynine into its active metabolite results in a built‐in ceiling effect of the mitragynine‐induced respiratory depression. These data suggest that such ‘metabolic saturation’ at high doses may underlie the improved safety profile of mitragynine as an opioid analgesic.
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Affiliation(s)
- Rob Hill
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, Universities of Nottingham and Birmingham, Midlands, UK
| | - Andrew C Kruegel
- Department of Chemistry, Columbia University, New York, New York, USA
| | - Jonathan A Javitch
- Departments of Psychiatry and Molecular Pharmacology and Therapeutics, Columbia University Vagelos College of Physicians & Surgeons, New York, New York, USA.,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, New York, USA
| | - J Robert Lane
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, Universities of Nottingham and Birmingham, Midlands, UK
| | - Meritxell Canals
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK.,Centre of Membrane Proteins and Receptors, Universities of Nottingham and Birmingham, Midlands, UK
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Chakraborty S, Uprety R, Slocum ST, Irie T, Le Rouzic V, Li X, Wilson LL, Scouller B, Alder AF, Kruegel AC, Ansonoff M, Varadi A, Eans SO, Hunkele A, Allaoa A, Kalra S, Xu J, Pan YX, Pintar J, Kivell BM, Pasternak GW, Cameron MD, McLaughlin JP, Sames D, Majumdar S. Oxidative Metabolism as a Modulator of Kratom's Biological Actions. J Med Chem 2021; 64:16553-16572. [PMID: 34783240 DOI: 10.1021/acs.jmedchem.1c01111] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The leaves of Mitragyna speciosa (kratom), a plant native to Southeast Asia, are increasingly used as a pain reliever and for attenuation of opioid withdrawal symptoms. Using the tools of natural products chemistry, chemical synthesis, and pharmacology, we provide a detailed in vitro and in vivo pharmacological characterization of the alkaloids in kratom. We report that metabolism of kratom's major alkaloid, mitragynine, in mice leads to formation of (a) a potent mu opioid receptor agonist antinociceptive agent, 7-hydroxymitragynine, through a CYP3A-mediated pathway, which exhibits reinforcing properties, inhibition of gastrointestinal (GI) transit and reduced hyperlocomotion, (b) a multifunctional mu agonist/delta-kappa antagonist, mitragynine pseudoindoxyl, through a CYP3A-mediated skeletal rearrangement, displaying reduced hyperlocomotion, inhibition of GI transit and reinforcing properties, and (c) a potentially toxic metabolite, 3-dehydromitragynine, through a non-CYP oxidation pathway. Our results indicate that the oxidative metabolism of the mitragynine template beyond 7-hydroxymitragynine may have implications in its overall pharmacology in vivo.
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Affiliation(s)
- Soumen Chakraborty
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, Missouri 63110, United States
| | - Rajendra Uprety
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Samuel T Slocum
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Takeshi Irie
- Department of Anesthesiology and Critical Care Medicine, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Valerie Le Rouzic
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Xiaohai Li
- Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Lisa L Wilson
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida 32610, United States
| | - Brittany Scouller
- Centre for Biodiscovery, School of Biological Science, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Amy F Alder
- Centre for Biodiscovery, School of Biological Science, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Andrew C Kruegel
- Department of Chemistry, Columbia University, New York 10027, United States
| | - Michael Ansonoff
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-8021, United States
| | - Andras Varadi
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Shainnel O Eans
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida 32610, United States
| | - Amanda Hunkele
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Abdullah Allaoa
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Sanjay Kalra
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Jin Xu
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Ying Xian Pan
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - John Pintar
- Department of Neuroscience and Cell Biology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854-8021, United States
| | - Bronwyn M Kivell
- Centre for Biodiscovery, School of Biological Science, Victoria University of Wellington, Wellington 6012, New Zealand
| | - Gavril W Pasternak
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York 10065, United States
| | - Michael D Cameron
- Department of Molecular Therapeutics, Scripps Research Institute, Jupiter, Florida 33458, United States
| | - Jay P McLaughlin
- Department of Pharmacodynamics, University of Florida, Gainesville, Florida 32610, United States
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York 10027, United States
| | - Susruta Majumdar
- Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, St. Louis, Missouri 63110, United States
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5
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Bhowmik S, Galeta J, Havel V, Nelson M, Faouzi A, Bechand B, Ansonoff M, Fiala T, Hunkele A, Kruegel AC, Pintar JE, Majumdar S, Javitch JA, Sames D. Site selective C-H functionalization of Mitragyna alkaloids reveals a molecular switch for tuning opioid receptor signaling efficacy. Nat Commun 2021; 12:3858. [PMID: 34158473 PMCID: PMC8219695 DOI: 10.1038/s41467-021-23736-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 05/13/2021] [Indexed: 12/25/2022] Open
Abstract
Mitragynine (MG) is the most abundant alkaloid component of the psychoactive plant material "kratom", which according to numerous anecdotal reports shows efficacy in self-medication for pain syndromes, depression, anxiety, and substance use disorders. We have developed a synthetic method for selective functionalization of the unexplored C11 position of the MG scaffold (C6 position in indole numbering) via the use of an indole-ethylene glycol adduct and subsequent iridium-catalyzed borylation. Through this work we discover that C11 represents a key locant for fine-tuning opioid receptor signaling efficacy. 7-Hydroxymitragynine (7OH), the parent compound with low efficacy on par with buprenorphine, is transformed to an even lower efficacy agonist by introducing a fluorine substituent in this position (11-F-7OH), as demonstrated in vitro at both mouse and human mu opioid receptors (mMOR/hMOR) and in vivo in mouse analgesia tests. Low efficacy opioid agonists are of high interest as candidates for generating safer opioid medications with mitigated adverse effects.
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Affiliation(s)
- Srijita Bhowmik
- Department of Chemistry, Columbia University, New York, NY, USA
| | - Juraj Galeta
- Department of Chemistry, Columbia University, New York, NY, USA
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences (IOCB Prague), 160 00, Prague 6, Czech Republic
| | - Václav Havel
- Department of Chemistry, Columbia University, New York, NY, USA
| | - Melissa Nelson
- Department of Psychiatry, and Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Abdelfattah Faouzi
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University School of Medicine, St Louis, MO, 63110, USA
- University of California San Diego, La Jolla, CA, 92161, USA
| | | | - Mike Ansonoff
- Department of Neuroscience and Cell Biology, Rutgers University, New Jersey, NJ, 08854, USA
| | - Tomas Fiala
- Department of Chemistry, Columbia University, New York, NY, USA
- Laboratory of Organic Chemistry, ETH Zürich, 8093, Zürich, Switzerland
| | - Amanda Hunkele
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University School of Medicine, St Louis, MO, 63110, USA
- Department of Neurology and Molecular Pharmacology, Memorial Sloan Kettering Cancer Center, New York, NY, 10021, USA
| | | | - John E Pintar
- Department of Neuroscience and Cell Biology, Rutgers University, New Jersey, NJ, 08854, USA
| | - Susruta Majumdar
- Center for Clinical Pharmacology, St Louis College of Pharmacy and Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Jonathan A Javitch
- Department of Psychiatry, and Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, NY, USA.
- NeuroTechnology Center at Columbia University, New York, NY, USA.
- The Zuckerman Mind Brain Behavior Institute at Columbia University, New York, NY, USA.
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Grundmann O, Babin JK, Henningfield JE, Garcia-Romeu A, Kruegel AC, Prozialeck WC, Raffa RB, Singh D, Smith KE. Kratom use in the United States: a diverse and complex profile. Addiction 2021; 116:202-203. [PMID: 32602213 PMCID: PMC7772230 DOI: 10.1111/add.15173] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 06/19/2020] [Indexed: 01/10/2023]
Affiliation(s)
- Oliver Grundmann
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, FL, USA
| | - Jane K. Babin
- The Law Office of Jane K. Babin, PC., San Diego, CA, USA
| | - Jack E. Henningfield
- PinneyAssociates, Bethesda, MD; and Department of Psychiatry and Human Services, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Albert Garcia-Romeu
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Walter C. Prozialeck
- Department of Pharmacology, College of Graduate Studies, Midwestern University, Downers Grove, IL, USA
| | - Robert B. Raffa
- Temple University School of Pharmacy, Philadelphia, PA, USA; and University of Arizona College of Pharmacy, Tucson AZ, USA
| | - Darshan Singh
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Penang, Malaysia
| | - Kirsten E. Smith
- National Institute on Drug Abuse Intramural Research Program, Baltimore, MD, USA
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7
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Grundmann O, Brown PN, Boyer EW, Swogger MT, Walsh Z, Prozialeck W, Kruegel AC, Veltri CA, Dudley S. Critique of "Kratom Use and Toxicities in the United States". Pharmacotherapy 2019; 39:1119-1120. [PMID: 31729073 DOI: 10.1002/phar.2336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/03/2019] [Indexed: 11/12/2022]
Affiliation(s)
- Oliver Grundmann
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, Florida
| | - Paula N Brown
- Centre for Applied Research & Innovation, BC Institute of Technology, Burnaby, British Columbia
| | - Edward W Boyer
- Department of Emergency Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
| | - Marc T Swogger
- Department of Psychiatry, University of Rochester Medical Center, Rochester, New York
| | - Zachary Walsh
- Department of Psychology, University of British Columbia, Kelowna, British Columbia
| | - Walter Prozialeck
- Department of Pharmacology, College of Graduate Studies, Midwestern University, Downers Grove, Illinois
| | - Andrew C Kruegel
- Department of Chemistry, Columbia University, New York, New York
| | - Charles A Veltri
- College of Pharmacy-Glendale, Midwestern University, Glendale, Arizona
| | - Steven Dudley
- Arizona Poison and Drug information Center, Tucson, Arizona
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Prozialeck WC, Avery BA, Boyer EW, Grundmann O, Henningfield JE, Kruegel AC, McMahon LR, McCurdy CR, Swogger MT, Veltri CA, Singh D. Kratom policy: The challenge of balancing therapeutic potential with public safety. Int J Drug Policy 2019; 70:70-77. [PMID: 31103778 PMCID: PMC7881941 DOI: 10.1016/j.drugpo.2019.05.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 04/01/2019] [Accepted: 05/03/2019] [Indexed: 02/07/2023]
Abstract
Kratom (Mitragyna speciosa) is a tree-like plant indigenous to Southeast Asia. Its leaves, and the teas brewed from them have long been used by people in that region to stave off fatigue and to manage pain and opioid withdrawal. Evidence suggests kratom is being increasingly used by people in the United States and Europe for the self-management of opioid withdrawal and treatment of pain. Recent studies have confirmed that kratom and its chemical constituents have potentially useful pharmacological actions. However, there have also been increasing numbers of reports of adverse effects resulting from use of kratom products. In August 2016, the US Drug Enforcement Administration announced plans to classify kratom and its mitragynine constituents as Schedule I Controlled Substances, a move that triggered a massive response from pro-kratom advocates. The debate regarding the risks, and benefits and safety of kratom continues to intensify. Kratom proponents tout kratom as a safer and less addictive alternative to opioids for the management of pain and opioid addiction. The anti-kratom faction argues that kratom, itself, is a dangerous and addictive drug that ought to be banned. Given the widespread use of kratom and the extensive media attention it is receiving, it is important for physicians, scientists and policy makers to be knowledgeable about the subject. The purpose of this commentary is to update readers about recent developments and controversies in this rapidly evolving area. All of the authors are engaged in various aspects of kratom research and it is our intention to provide a fair and balanced overview that can form the basis for informed decisions on kratom policy. Our conclusions from these analyses are: (a) User reports and results of preclinical studies in animals strongly suggest that kratom and its main constituent alkaloid, mitragynine may have useful activity in alleviating pain and managing symptoms of opioid withdrawal, even though well-controlled clinical trials have yet to be done. (b) Even though kratom lacks many of the toxicities of classic opioids, there are legitimate concerns about the safety and lack of quality control of purported "kratom" products that are being sold in the US. (c) The issues regarding the safety and efficacy of kratom and its mitragynine constituent can only be resolved by additional research. Classification of the Mitragyna alkaloids as Schedule I controlled substances would substantially impede this important research on kratom.
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Affiliation(s)
- Walter C Prozialeck
- Department of Pharmacology, Midwestern University, 555 31st Street, Downers Grove, IL 60515, USA.
| | - Bonnie A Avery
- Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA
| | - Edward W Boyer
- Department of Emergency Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Oliver Grundmann
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
| | - Jack E Henningfield
- Research, Health Policy and Abuse, Liability, Pinney Associates And Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of Medicine, 4800 Montgomery Lane, Suite 400, Bethesda, MD 20814, USA.
| | - Andrew C Kruegel
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027, USA.
| | - Lance R McMahon
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
| | - Christopher R McCurdy
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
| | - Marc T Swogger
- Department of Psychiatry, University of Rochester Medical Center, 300 Crittenden Blvd., Rochester, NY 14682, USA.
| | - Charles A Veltri
- Department of Pharmaceutical Sciences, Midwestern University, 19555 N. 59th Avenue, Glendale, AZ 85308, USA.
| | - Darshan Singh
- Centre for Drug Research, Universiti Sains Malaysia, Minden, Malaysia.
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9
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Kruegel AC, Grundmann O. The medicinal chemistry and neuropharmacology of kratom: A preliminary discussion of a promising medicinal plant and analysis of its potential for abuse. Neuropharmacology 2017; 134:108-120. [PMID: 28830758 DOI: 10.1016/j.neuropharm.2017.08.026] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/12/2017] [Accepted: 08/17/2017] [Indexed: 12/17/2022]
Abstract
The leaves of Mitragyna speciosa (commonly known as kratom), a tree endogenous to parts of Southeast Asia, have been used traditionally for their stimulant, mood-elevating, and analgesic effects and have recently attracted significant attention due to increased use in Western cultures as an alternative medicine. The plant's active alkaloid constituents, mitragynine and 7-hydroxymitragynine, have been shown to modulate opioid receptors, acting as partial agonists at mu-opioid receptors and competitive antagonists at kappa- and delta-opioid receptors. Furthermore, both alkaloids are G protein-biased agonists of the mu-opioid receptor and therefore, may induce less respiratory depression than classical opioid agonists. The Mitragyna alkaloids also appear to exert diverse activities at other brain receptors (including adrenergic, serotonergic, and dopaminergic receptors), which may explain the complex pharmacological profile of raw kratom extracts, although characterization of effects at these other targets remains extremely limited. Through allometric scaling, doses of pure mitragynine and 7-hydroxymitragynine used in animal studies can be related to single doses of raw kratom plant commonly consumed by humans, permitting preliminary interpretation of expected behavioral and physiological effects in man based on this preclinical data and comparison to both anecdotal human experience and multiple epidemiological surveys. Kratom exposure alone has not been causally associated with human fatalities to date. However, further research is needed to clarify the complex mechanism of action of the Mitragyna alkaloids and unlock their full therapeutic potential. This article is part of the Special Issue entitled 'Designer Drugs and Legal Highs.'
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Affiliation(s)
- Andrew C Kruegel
- Department of Chemistry, Columbia University, 3000 Broadway, New York, NY 10027, United States.
| | - Oliver Grundmann
- Department of Medicinal Chemistry, University of Florida, 1345 Center Drive, Gainesville, FL 32611, United States.
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Kruegel AC, Gassaway MM, Kapoor A, Váradi A, Majumdar S, Filizola M, Javitch JA, Sames D. Synthetic and Receptor Signaling Explorations of the Mitragyna Alkaloids: Mitragynine as an Atypical Molecular Framework for Opioid Receptor Modulators. J Am Chem Soc 2016; 138:6754-64. [PMID: 27192616 DOI: 10.1021/jacs.6b00360] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mu-opioid receptor agonists represent mainstays of pain management. However, the therapeutic use of these agents is associated with serious side effects, including potentially lethal respiratory depression. Accordingly, there is a longstanding interest in the development of new opioid analgesics with improved therapeutic profiles. The alkaloids of the Southeast Asian plant Mitragyna speciosa, represented by the prototypical member mitragynine, are an unusual class of opioid receptor modulators with distinct pharmacological properties. Here we describe the first receptor-level functional characterization of mitragynine and related natural alkaloids at the human mu-, kappa-, and delta-opioid receptors. These results show that mitragynine and the oxidized analogue 7-hydroxymitragynine, are partial agonists of the human mu-opioid receptor and competitive antagonists at the kappa- and delta-opioid receptors. We also show that mitragynine and 7-hydroxymitragynine are G-protein-biased agonists of the mu-opioid receptor, which do not recruit β-arrestin following receptor activation. Therefore, the Mitragyna alkaloid scaffold represents a novel framework for the development of functionally biased opioid modulators, which may exhibit improved therapeutic profiles. Also presented is an enantioselective total synthesis of both (-)-mitragynine and its unnatural enantiomer, (+)-mitragynine, employing a proline-catalyzed Mannich-Michael reaction sequence as the key transformation. Pharmacological evaluation of (+)-mitragynine revealed its much weaker opioid activity. Likewise, the intermediates and chemical transformations developed in the total synthesis allowed the elucidation of previously unexplored structure-activity relationships (SAR) within the Mitragyna scaffold. Molecular docking studies, in combination with the observed chemical SAR, suggest that Mitragyna alkaloids adopt a binding pose at the mu-opioid receptor that is distinct from that of classical opioids.
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Affiliation(s)
| | | | - Abhijeet Kapoor
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - András Váradi
- Department of Neurology, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | - Susruta Majumdar
- Department of Neurology, Memorial Sloan Kettering Cancer Center , New York, New York 10065, United States
| | - Marta Filizola
- Department of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai , New York, New York 10029, United States
| | - Jonathan A Javitch
- Division of Molecular Therapeutics, New York State Psychiatric Institute , New York, New York 10032, United States
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Gassaway MM, Jacques TL, Kruegel AC, Karpowicz RJ, Li X, Li S, Myer Y, Sames D. Deconstructing the Iboga Alkaloid Skeleton: Potentiation of FGF2-induced Glial Cell Line-Derived Neurotrophic Factor Release by a Novel Compound. ACS Chem Biol 2016; 11:77-87. [PMID: 26517751 DOI: 10.1021/acschembio.5b00678] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Modulation of growth factor signaling pathways in the brain represents a new experimental approach to treating neuropsychiatric disorders such as depression, anxiety, and addiction. Neurotrophins and growth factors exert synaptic, neuronal, and circuit level effects on a wide temporal range, which suggests a possibility of rapid and lasting therapeutic effects. Consequently, identification of small molecules that can either enhance the release of growth factors or potentiate their respective pathways will provide a drug-like alternative to direct neurotrophin administration or viral gene delivery and thus represents an important frontier in chemical biology and drug design. Glial cell line-derived neurotrophic factor (GDNF), in particular, has been implicated in marked reduction of alcohol consumption in rodent addiction models, and the natural product ibogaine, a substance used traditionally in ritualistic ceremonies, has been suggested to increase the synthesis and release of GDNF in the dopaminergic system in rats. In this report, we describe a novel iboga analog, XL-008, created by unraveling the medium size ring of the ibogamine skeleton, and its ability to induce release of GDNF in C6 glioma cells. Additionally, XL-008 potentiates the release of GDNF induced by fibroblast growth factor 2 (FGF2), another neurotrophin implicated in major depressive disorder, increasing potency more than 2-fold (from 7.85 ± 2.59 ng/mL to 3.31 ± 0.98 ng/mL) and efficacy more than 3-fold. The GDNF release by both XL-008 and the FGF2/XL-008 mixture was found to be mediated through the MEK and PI3K signaling pathways but not through PLCγ in C6 glioma cells.
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Affiliation(s)
- Madalee M. Gassaway
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Teresa L. Jacques
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Andrew C. Kruegel
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Richard J. Karpowicz
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Xiaoguang Li
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Shu Li
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Yves Myer
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Dalibor Sames
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
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Kruegel AC, Rakshit S, Li X, Sames D. Constructing Iboga alkaloids via C-H bond functionalization: examination of the direct and catalytic union of heteroarenes and isoquinuclidine alkenes. J Org Chem 2015; 80:2062-71. [PMID: 25633249 DOI: 10.1021/jo5018102] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The iboga alkaloids have attracted considerable attention in both the scientific community and popular media due to their reported ability to reverse or markedly diminish cravings for, and self-administration of, the major drugs of abuse. We have developed three new intramolecular C-H functionalization procedures leading to the core seven-membered ring of the iboga skeleton, a cyclization that proved to be highly challenging. The electrophilic palladium salt Pd(CH3CN)4(BF4)2 was effective for the cyclization of diverse N-(2-arylethyl)isoquinuclidines with yields of 10-35%. A two-step, bromination-reductive Heck reaction protocol was also effective for the synthesis of ibogamine in 42% yield. Finally, a direct Ni(0)-catalyzed C-H functionalization provided the benzofuran analogues of ibogamine (74%) and epi-ibogamine (38%). Although each approach suffers from significant shortcomings, in combination, the methods described provide practical routes to diverse ibogamine analogues.
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Affiliation(s)
- Andrew C Kruegel
- Department of Chemistry, Columbia University , New York, New York 10027, United States
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Gassaway MM, Rives ML, Kruegel AC, Javitch JA, Sames D. The atypical antidepressant and neurorestorative agent tianeptine is a μ-opioid receptor agonist. Transl Psychiatry 2014; 4:e411. [PMID: 25026323 PMCID: PMC4119213 DOI: 10.1038/tp.2014.30] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 03/26/2014] [Indexed: 12/12/2022] Open
Abstract
Current pharmacological treatments of depression and related disorders suffer from major problems, such as a low rate of response, slow onset of therapeutic effects, loss of efficacy over time and serious side effects. Therefore, there is an urgent need to explore new therapeutic approaches that address these issues. Interestingly, the atypical antidepressant tianeptine already meets in part these clinical goals. However, in spite of three decades of basic and clinical investigations, the molecular target of tianeptine, as well as its mechanism of action, remains elusive. Herein, we report the characterization of tianeptine as a μ-opioid receptor (MOR) agonist. Using radioligand binding and cell-based functional assays, including bioluminescence resonance energy transfer-based assays for G-protein activation and cAMP accumulation, we identified tianeptine as an efficacious MOR agonist (K(i Human) of 383±183 nM and EC(50 Human) of 194±70 nM and EC(50 Mouse) of 641±120 nM for G-protein activation). Tianeptine was also a full δ-opioid receptor (DOR) agonist, although with much lower potency (EC(50 Human) of 37.4±11.2 μM and EC(50 Mouse) of 14.5±6.6 μM for G-protein activation). In contrast, tianeptine was inactive at the κ-opioid receptor (KOR, both human and rat). On the basis of these pharmacological data, we propose that activation of MOR (or dual activation of MOR and DOR) could be the initial molecular event responsible for triggering many of the known acute and chronic effects of this agent, including its antidepressant and anxiolytic actions.
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Affiliation(s)
- M M Gassaway
- Department of Chemistry, Columbia University, New York, NY, USA
| | - M-L Rives
- Department of Psychiatry, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA
| | - A C Kruegel
- Department of Chemistry, Columbia University, New York, NY, USA
| | - J A Javitch
- Department of Psychiatry, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, USA,Department of Pharmacology, Columbia University, New York, NY, USA,Division of Molecular Therapeutics, New York State Psychiatric Institute, 1051 Riverside Drive, Unit 19, New York, NY 10032, USA. E-mail:
| | - D Sames
- Department of Chemistry, Columbia University, New York, NY, USA,Department of Chemistry, Columbia University, 3000 Broadway, MC3101, New York, NY 10027, USA. E-mail:
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