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Antonio T, Childers SR, Rothman RB, Dersch CM, King C, Kuehne M, Bornmann WG, Eshleman AJ, Janowsky A, Simon ER, Reith MEA, Alper K. Effect of Iboga alkaloids on µ-opioid receptor-coupled G protein activation. PLoS One 2013; 8:e77262. [PMID: 24204784 PMCID: PMC3818563 DOI: 10.1371/journal.pone.0077262] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 08/31/2013] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVE The iboga alkaloids are a class of small molecules defined structurally on the basis of a common ibogamine skeleton, some of which modify opioid withdrawal and drug self-administration in humans and preclinical models. These compounds may represent an innovative approach to neurobiological investigation and development of addiction pharmacotherapy. In particular, the use of the prototypic iboga alkaloid ibogaine for opioid detoxification in humans raises the question of whether its effect is mediated by an opioid agonist action, or if it represents alternative and possibly novel mechanism of action. The aim of this study was to independently replicate and extend evidence regarding the activation of μ-opioid receptor (MOR)-related G proteins by iboga alkaloids. METHODS Ibogaine, its major metabolite noribogaine, and 18-methoxycoronaridine (18-MC), a synthetic congener, were evaluated by agonist-stimulated guanosine-5´-O-(γ-thio)-triphosphate ([(35)S]GTPγS) binding in cells overexpressing the recombinant MOR, in rat thalamic membranes, and autoradiography in rat brain slices. RESULTS AND SIGNIFICANCE In rat thalamic membranes ibogaine, noribogaine and 18-MC were MOR antagonists with functional Ke values ranging from 3 uM (ibogaine) to 13 uM (noribogaine and 18MC). Noribogaine and 18-MC did not stimulate [(35)S]GTPγS binding in Chinese hamster ovary cells expressing human or rat MORs, and had only limited partial agonist effects in human embryonic kidney cells expressing mouse MORs. Ibogaine did not did not stimulate [(35)S]GTPγS binding in any MOR expressing cells. Noribogaine did not stimulate [(35)S]GTPγS binding in brain slices using autoradiography. An MOR agonist action does not appear to account for the effect of these iboga alkaloids on opioid withdrawal. Taken together with existing evidence that their mechanism of action also differs from that of other non-opioids with clinical effects on opioid tolerance and withdrawal, these findings suggest a novel mechanism of action, and further justify the search for alternative targets of iboga alkaloids.
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MESH Headings
- Animals
- Autoradiography
- Bridged-Ring Compounds/pharmacology
- CHO Cells
- Cricetulus
- Dose-Response Relationship, Drug
- Female
- Gene Expression
- Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology
- HEK293 Cells
- Humans
- Ibogaine/analogs & derivatives
- Ibogaine/pharmacology
- Organ Specificity
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, mu/agonists
- Receptors, Opioid, mu/antagonists & inhibitors
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
- Substance Withdrawal Syndrome/prevention & control
- Thalamus/drug effects
- Thalamus/metabolism
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Affiliation(s)
- Tamara Antonio
- Department of Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Steven R. Childers
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, United States of America
| | - Richard B. Rothman
- Translational Pharmacology Research Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland, United States of America
| | - Christina M. Dersch
- Translational Pharmacology Research Section, National Institute on Drug Abuse Intramural Research Program, Baltimore, Maryland, United States of America
| | - Christine King
- Department of Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Martin Kuehne
- Department of Chemistry, University of Vermont, Burlington, Vermont, United States of America
| | - William G. Bornmann
- Department of Experimental Therapeutics, University of Texas M. D. Anderson Cancer Center, Houston, Texas, United States of America
| | - Amy J. Eshleman
- Research Service, VA Medical Center, and Departments of Psychiatry and Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Aaron Janowsky
- Research Service, VA Medical Center, and Departments of Psychiatry and Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon, United States of America
| | - Eric R. Simon
- Department of Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Maarten E. A. Reith
- Department of Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Kenneth Alper
- Department of Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Neurology, New York University School of Medicine, New York, New York, United States of America
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Abstract
This paper is the twenty-fifth consecutive installment of the annual review of research concerning the endogenous opioid system, now spanning over a quarter-century of research. It summarizes papers published during 2002 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (Section 2), and the roles of these opioid peptides and receptors in pain and analgesia (Section 3); stress and social status (Section 4); tolerance and dependence (Section 5); learning and memory (Section 6); eating and drinking (Section 7); alcohol and drugs of abuse (Section 8); sexual activity and hormones, pregnancy, development and endocrinology (Section 9); mental illness and mood (Section 10); seizures and neurologic disorders (Section 11); electrical-related activity and neurophysiology (Section 12); general activity and locomotion (Section 13); gastrointestinal, renal and hepatic functions (Section 14); cardiovascular responses (Section 15); respiration and thermoregulation (Section 16); and immunological responses (Section 17).
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Affiliation(s)
- Richard J Bodnar
- Department of Psychology and Neuropsychology Doctoral Sub-Program, Queens College, City University of New York, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367, USA.
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