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Neumann J, Hofmann B, Gergs U. Opposite Contractile Effects of Amphetamine-Related Hallucinogenic Drugs in the Isolated Human Atrium. Int J Mol Sci 2024; 25:8887. [PMID: 39201573 PMCID: PMC11354304 DOI: 10.3390/ijms25168887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2024] [Revised: 08/13/2024] [Accepted: 08/14/2024] [Indexed: 09/02/2024] Open
Abstract
The present study examined three hallucinogenic amphetamine derivatives, namely, 2,5-dimethoxy-4-iodoamphetamine (DOI) as well as 2,5-dimethoxy-4-methylamphetamine (DOM) and 4-methylmethcathinone (mephedrone). The objective of this study was to test the hypothesis that DOI, DOM, and mephedrone would increase the contractile force in isolated human atrial preparations in a manner similar to amphetamine. To this end, we measured contractile force under isometric conditions in electrically stimulated (1 Hz) human atrial preparations obtained during open surgery. DOI and DOM alone or in the presence of isoprenaline reduced the contractile force concentration-dependently in human atrial preparations. These negative inotropic effects of DOM and DOI were not attenuated by 10 µM atropine. However, mephedrone increased the contractile force in human atrial preparations in a concentration- and time-dependent manner. Furthermore, these effects were attenuated by the subsequent addition of 10 µM propranolol or pretreatment with 10 µM cocaine in the organ bath. Therefore, it can be concluded that amphetamine derivatives may exert opposing effects on cardiac contractile force. The precise mechanism by which DOI and DOM exert their negative inotropic effects remains unknown at present. The cardiac effects of mephedrone are probably due to the release of cardiac noradrenaline.
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Affiliation(s)
- Joachim Neumann
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany;
| | - Britt Hofmann
- Department of Cardiac Surgery, Mid-German Heart Center, University Hospital Halle, 06097 Halle, Germany;
| | - Ulrich Gergs
- Institute for Pharmacology and Toxicology, Medical Faculty, Martin Luther University Halle-Wittenberg, 06097 Halle, Germany;
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2
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Neumann J, Dhein S, Kirchhefer U, Hofmann B, Gergs U. Effects of congeners of amphetamine on the human heart. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:4615-4642. [PMID: 38340182 PMCID: PMC11166837 DOI: 10.1007/s00210-024-02983-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 01/28/2024] [Indexed: 02/12/2024]
Abstract
Central stimulatory and hallucinogenic drugs of abuse like amphetamine and most congeners of amphetamine can have cardiac harmful effects. These cardiac side effects can lead to morbidities and death. In this paper, we review current knowledge on the direct and indirect effects of these amphetamine congeners on the mammalian heart-more specifically, the isolated human heart muscle preparation. In detail, we address the question of whether and how these drugs affect cardiac contractility and their mechanisms of action. Based on this information, further research areas are defined, and further research efforts are proposed.
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Affiliation(s)
- Joachim Neumann
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Magdeburger Str. 4, 06112, D-06097, Halle, Germany.
| | - Stefan Dhein
- Rudolf-Boehm Institut für Pharmakologie und Toxikologie, Universität Leipzig, Härtelstraße 16-18, D-04107, Leipzig, Germany
| | | | - Britt Hofmann
- Cardiac Surgery, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097, Halle, Germany
| | - Ulrich Gergs
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, Magdeburger Str. 4, 06112, D-06097, Halle, Germany
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3
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Salinsky LM, Merritt CR, Zamora JC, Giacomini JL, Anastasio NC, Cunningham KA. μ-opioid receptor agonists and psychedelics: pharmacological opportunities and challenges. Front Pharmacol 2023; 14:1239159. [PMID: 37886127 PMCID: PMC10598667 DOI: 10.3389/fphar.2023.1239159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 09/28/2023] [Indexed: 10/28/2023] Open
Abstract
Opioid misuse and opioid-involved overdose deaths are a massive public health problem involving the intertwined misuse of prescription opioids for pain management with the emergence of extremely potent fentanyl derivatives, sold as standalone products or adulterants in counterfeit prescription opioids or heroin. The incidence of repeated opioid overdose events indicates a problematic use pattern consistent with the development of the medical condition of opioid use disorder (OUD). Prescription and illicit opioids reduce pain perception by activating µ-opioid receptors (MOR) localized to the central nervous system (CNS). Dysregulation of meso-corticolimbic circuitry that subserves reward and adaptive behaviors is fundamentally involved in the progressive behavioral changes that promote and are consequent to OUD. Although opioid-induced analgesia and the rewarding effects of abused opioids are primarily mediated through MOR activation, serotonin (5-HT) is an important contributor to the pharmacology of opioid abused drugs (including heroin and prescription opioids) and OUD. There is a recent resurgence of interest into psychedelic compounds that act primarily through the 5-HT2A receptor (5-HT 2A R) as a new frontier in combatting such diseases (e.g., depression, anxiety, and substance use disorders). Emerging data suggest that the MOR and 5-HT2AR crosstalk at the cellular level and within key nodes of OUD circuitry, highlighting a major opportunity for novel pharmacological intervention for OUD. There is an important gap in the preclinical profiling of psychedelic 5-HT2AR agonists in OUD models. Further, as these molecules carry risks, additional analyses of the profiles of non-hallucinogenic 5-HT2AR agonists and/or 5-HT2AR positive allosteric modulators may provide a new pathway for 5-HT2AR therapeutics. In this review, we discuss the opportunities and challenges associated with utilizing 5-HT2AR agonists as therapeutics for OUD.
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Affiliation(s)
| | | | | | | | - Noelle C. Anastasio
- Center for Addiction Sciences and Therapeutics and Department of Pharmacology and Toxicology, John Sealy School of Medicine, University of Texas Medical Branch, Galveston, TX, United States
| | - Kathryn A. Cunningham
- Center for Addiction Sciences and Therapeutics and Department of Pharmacology and Toxicology, John Sealy School of Medicine, University of Texas Medical Branch, Galveston, TX, United States
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4
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Vorobyeva N, Kozlova AA. Three Naturally-Occurring Psychedelics and Their Significance in the Treatment of Mental Health Disorders. Front Pharmacol 2022; 13:927984. [PMID: 35837277 PMCID: PMC9274002 DOI: 10.3389/fphar.2022.927984] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/06/2022] [Indexed: 12/20/2022] Open
Abstract
Classical psychedelics represent a family of psychoactive substances with structural similarities to serotonin and affinity for serotonin receptors. A growing number of studies have found that psychedelics can be effective in treating various psychiatric conditions, including post-traumatic stress disorder, major depressive disorder, anxiety, and substance use disorders. Mental health disorders are extremely prevalent in the general population constituting a major problem for the public health. There are a wide variety of interventions for mental health disorders, including pharmacological therapies and psychotherapies, however, treatment resistance still remains a particular challenge in this field, and relapse rates are also quite high. In recent years, psychedelics have become one of the promising new tools for the treatment of mental health disorders. In this review, we will discuss the three classic serotonergic naturally occurring psychedelics, psilocybin, ibogaine, and N, N-dimethyltryptamine, focusing on their pharmacological properties and clinical potential. The purpose of this article is to provide a focused review of the most relevant research into the therapeutic potential of these substances and their possible integration as alternative or adjuvant options to existing pharmacological and psychological therapies.
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Affiliation(s)
- Nataliya Vorobyeva
- Hive Bio Life Sciences Ltd., London, United Kingdom
- *Correspondence: Nataliya Vorobyeva,
| | - Alena A. Kozlova
- Department of Psychiatry and Psychotherapy, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
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5
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Kolaczynska KE, Luethi D, Trachsel D, Hoener MC, Liechti ME. Receptor Interaction Profiles of 4-Alkoxy-3,5-Dimethoxy-Phenethylamines (Mescaline Derivatives) and Related Amphetamines. Front Pharmacol 2022; 12:794254. [PMID: 35222010 PMCID: PMC8865417 DOI: 10.3389/fphar.2021.794254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/01/2021] [Indexed: 12/20/2022] Open
Abstract
3,4,5-Trimethoxyphenethylamine (mescaline) is a psychedelic alkaloid found in peyote cactus. Related 4-alkoxy-3,5-dimethoxy-substituted phenethylamines (scalines) and amphetamines (3C-scalines) are reported to induce similarly potent psychedelic effects and are therefore potential novel therapeutics for psychedelic-assisted therapy. Herein, several pharmacologically uninvestigated scalines and 3C-scalines were examined at key monoamine targets in vitro. Binding affinity at human serotonergic 5-HT1A, 5-HT2A, and 5-HT2C, adrenergic α1A and α2A, and dopaminergic D2 receptors, rat and mouse trace amine-associated receptor 1 (TAAR1), and human monoamine transporters were assessed using target specific transfected cells. Furthermore, activation of human 5-HT2A and 5-HT2B receptors, and TAAR1 was examined. Generally, scalines and 3C-scalines bound with weak to moderately high affinity to the 5-HT2A receptor (Ki = 150–12,000 nM). 3C-scalines showed a marginal preference for the 5-HT2A vs the 5-HT2C and 5-HT1A receptors whereas no preference was observed for the scalines. Extending the 4-alkoxy substituent increased 5-HT2A and 5-HT2C receptors binding affinities, and enhanced activation potency and efficacy at the 5-HT2A but not at the 5-HT2B receptor. Introduction of fluorinated 4-alkoxy substituents generally increased 5-HT2A and 5-HT2C receptors binding affinities and increased the activation potency and efficacy at the 5-HT2A and 5-HT2B receptors. Overall, no potent affinity was observed at non-serotonergic targets. As observed for other psychedelics, scalines and 3C-scalines interacted with the 5-HT2A and 5-HT2C receptors and bound with higher affinities (up to 63-fold and 34-fold increase, respectively) when compared to mescaline.
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Affiliation(s)
- Karolina E Kolaczynska
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Dino Luethi
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland.,Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | - Marius C Hoener
- Neuroscience Research, pRED, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Matthias E Liechti
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
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6
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Cao D, Yu J, Wang H, Luo Z, Liu X, He L, Qi J, Fan L, Tang L, Chen Z, Li J, Cheng J, Wang S. Structure-based discovery of nonhallucinogenic psychedelic analogs. Science 2022; 375:403-411. [PMID: 35084960 DOI: 10.1126/science.abl8615] [Citation(s) in RCA: 117] [Impact Index Per Article: 58.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Drugs that target the human serotonin 2A receptor (5-HT2AR) are used to treat neuropsychiatric diseases; however, many have hallucinogenic effects, hampering their use. Here, we present structures of 5-HT2AR complexed with the psychedelic drugs psilocin (the active metabolite of psilocybin) and d-lysergic acid diethylamide (LSD), as well as the endogenous neurotransmitter serotonin and the nonhallucinogenic psychedelic analog lisuride. Serotonin and psilocin display a second binding mode in addition to the canonical mode, which enabled the design of the psychedelic IHCH-7113 (a substructure of antipsychotic lumateperone) and several 5-HT2AR β-arrestin-biased agonists that displayed antidepressant-like activity in mice but without hallucinogenic effects. The 5-HT2AR complex structures presented herein and the resulting insights provide a solid foundation for the structure-based design of safe and effective nonhallucinogenic psychedelic analogs with therapeutic effects.
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Affiliation(s)
- Dongmei Cao
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Jing Yu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Huan Wang
- iHuman Institute, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
| | - Zhipu Luo
- Institute of Molecular Enzymology, School of Biology and Basic Medical Sciences, Soochow University, Suzhou, Jiangsu 215123, China
| | - Xinyu Liu
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Licong He
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Jianzhong Qi
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Luyu Fan
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Lingjie Tang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Zhangcheng Chen
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Jinsong Li
- State Key Laboratory of Cell Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
| | - Jianjun Cheng
- iHuman Institute, ShanghaiTech University, 393 Middle Huaxia Road, Shanghai 201210, China
| | - Sheng Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, China
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7
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Abstract
Hallucinogens, or psychedelics, are substances/drugs that have been used for over a millennium. The most well known are LSD, psilocybin, mescaline, and PCP. These substances may induce hallucinations as well as cause somatic and psychological symptoms. Because of the Controlled Substances Act of 1970, there has been very little research done to determine the long-term consequences or perhaps potential benefit of misuse and abuse of hallucinogens. Typically, these drugs are not abused but more often misused. Recently, there has been a renewed interest in these compounds, which may lead to possible therapeutic options.
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Affiliation(s)
- Wm Maurice Redden
- Division of Geriatric Psychiatry, Department of Psychiatry & Behavioral Neuroscience, St. Louis University School of Medicine, 1438 South Grand Boulevard, St Louis, MO 63104, USA.
| | - Saif-Ur-Rahman Paracha
- Division of Geriatric Psychiatry, Department of Psychiatry & Behavioral Neuroscience, St. Louis University School of Medicine, 1438 South Grand Boulevard, St Louis, MO 63104, USA
| | - Quratulanne Sheheryar
- Division of Geriatric Psychiatry, Department of Psychiatry & Behavioral Neuroscience, St. Louis University School of Medicine, 1438 South Grand Boulevard, St Louis, MO 63104, USA
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8
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Powell A, Ireland C, Lewis SJG. Visual Hallucinations and the Role of Medications in Parkinson's Disease: Triggers, Pathophysiology, and Management. J Neuropsychiatry Clin Neurosci 2021; 32:334-343. [PMID: 32374649 DOI: 10.1176/appi.neuropsych.19110316] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Visual hallucinations, which are part of the syndrome of Parkinson's disease (PD) psychosis, affect patients' quality of life and increase the likelihood of residential aged-care placement. The association between visual hallucinations and dopaminergic and other medications that are necessary for the symptomatic management of motor and other symptoms of PD is a common clinical dilemma. While dopaminergic medications have long been associated with PD psychosis, a clear causal link has not been established, and other neurotransmitter systems, particularly noradrenaline, serotonin, and acetylcholine, are implicated and important. A diverse range of demographic and disease-related risk factors, some being modifiable, highlight the complexity of potential underlying pathophysiological processes but also broaden practical options for prevention and treatment that can be multifaceted and individualized. The investigators reviewed the clinical features and epidemiology of visual hallucinations and PD, explored the pathological evidence for dysfunction of multiple neurotransmitter systems that may be relevant to these phenomena, and addressed the potential of medications commonly used in PD to either trigger or treat these symptoms.
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Affiliation(s)
- Alice Powell
- Parkinson's Disease Research Clinic, Brain and Mind Centre (Powell, Lewis), and Healthy Brain Ageing Program (Ireland), University of Sydney, Camperdown, New South Wales, Australia
| | - Catriona Ireland
- Parkinson's Disease Research Clinic, Brain and Mind Centre (Powell, Lewis), and Healthy Brain Ageing Program (Ireland), University of Sydney, Camperdown, New South Wales, Australia
| | - Simon J G Lewis
- Parkinson's Disease Research Clinic, Brain and Mind Centre (Powell, Lewis), and Healthy Brain Ageing Program (Ireland), University of Sydney, Camperdown, New South Wales, Australia
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9
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Waters K. Pharmacologic Similarities and Differences Among Hallucinogens. J Clin Pharmacol 2021; 61 Suppl 2:S100-S113. [PMID: 34396556 DOI: 10.1002/jcph.1917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 05/22/2021] [Indexed: 12/27/2022]
Abstract
Hallucinogens constitute a unique class of substances that cause changes in the user's thoughts, perceptions, and mood through various mechanisms of action. Although the serotonergic hallucinogens such as lysergic acid diethylamide, psilocybin, and N,N-dimethyltryptamine have been termed the classical hallucinogens, many hallucinogens elicit their actions through other mechanisms such as N-methyl-D-aspartate receptor antagonism, opioid receptor agonism, or inhibition of the reuptake of monoamines including serotonin, norepinephrine, and dopamine. The aim of this article is to compare the pharmacologic similarities and differences among substances within the hallucinogen class and their impact on physical and psychiatric effects. Potential toxicities, including life-threatening and long-term effects, will be reviewed.
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Affiliation(s)
- Kristin Waters
- School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA
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10
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Cumming P, Scheidegger M, Dornbierer D, Palner M, Quednow BB, Martin-Soelch C. Molecular and Functional Imaging Studies of Psychedelic Drug Action in Animals and Humans. Molecules 2021; 26:2451. [PMID: 33922330 PMCID: PMC8122807 DOI: 10.3390/molecules26092451] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/15/2021] [Accepted: 04/19/2021] [Indexed: 12/19/2022] Open
Abstract
Hallucinogens are a loosely defined group of compounds including LSD, N,N-dimethyltryptamines, mescaline, psilocybin/psilocin, and 2,5-dimethoxy-4-methamphetamine (DOM), which can evoke intense visual and emotional experiences. We are witnessing a renaissance of research interest in hallucinogens, driven by increasing awareness of their psychotherapeutic potential. As such, we now present a narrative review of the literature on hallucinogen binding in vitro and ex vivo, and the various molecular imaging studies with positron emission tomography (PET) or single photon emission computer tomography (SPECT). In general, molecular imaging can depict the uptake and binding distribution of labelled hallucinogenic compounds or their congeners in the brain, as was shown in an early PET study with N1-([11C]-methyl)-2-bromo-LSD ([11C]-MBL); displacement with the non-radioactive competitor ketanserin confirmed that the majority of [11C]-MBL specific binding was to serotonin 5-HT2A receptors. However, interactions at serotonin 5HT1A and other classes of receptors and pleotropic effects on second messenger pathways may contribute to the particular experiential phenomenologies of LSD and other hallucinogenic compounds. Other salient aspects of hallucinogen action include permeability to the blood-brain barrier, the rates of metabolism and elimination, and the formation of active metabolites. Despite the maturation of radiochemistry and molecular imaging in recent years, there has been only a handful of PET or SPECT studies of radiolabeled hallucinogens, most recently using the 5-HT2A/2C agonist N-(2[11CH3O]-methoxybenzyl)-2,5-dimethoxy- 4-bromophenethylamine ([11C]Cimbi-36). In addition to PET studies of target engagement at neuroreceptors and transporters, there is a small number of studies on the effects of hallucinogenic compounds on cerebral perfusion ([15O]-water) or metabolism ([18F]-fluorodeoxyglucose/FDG). There remains considerable scope for basic imaging research on the sites of interaction of hallucinogens and their cerebrometabolic effects; we expect that hybrid imaging with PET in conjunction with functional magnetic resonance imaging (fMRI) should provide especially useful for the next phase of this research.
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Affiliation(s)
- Paul Cumming
- Department of Nuclear Medicine, Bern University Hospital, CH-3010 Bern, Switzerland
- School of Psychology and Counselling, Queensland University of Technology, Brisbane 4059, Australia
| | - Milan Scheidegger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, CH-8032 Zurich, Switzerland; (M.S.); (D.D.); (B.B.Q.)
| | - Dario Dornbierer
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, CH-8032 Zurich, Switzerland; (M.S.); (D.D.); (B.B.Q.)
| | - Mikael Palner
- Odense Department of Clinical Research, University of Southern Denmark, DK-5000 Odense, Denmark;
- Department of Nuclear Medicine, Odense University Hospital, DK-5000 Odense, Denmark
- Neurobiology Research Unit, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark
| | - Boris B. Quednow
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital of the University of Zurich, CH-8032 Zurich, Switzerland; (M.S.); (D.D.); (B.B.Q.)
- Neuroscience Center Zurich, University of Zurich and Swiss Federal Institute of Technology Zurich, CH-8058 Zurich, Switzerland
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11
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Abstract
This paper introduces a new construct, the 'pivotal mental state', which is defined as a hyper-plastic state aiding rapid and deep learning that can mediate psychological transformation. We believe this new construct bears relevance to a broad range of psychological and psychiatric phenomena. We argue that pivotal mental states serve an important evolutionary function, that is, to aid psychological transformation when actual or perceived environmental pressures demand this. We cite evidence that chronic stress and neurotic traits are primers for a pivotal mental state, whereas acute stress can be a trigger. Inspired by research with serotonin 2A receptor agonist psychedelics, we highlight how activity at this particular receptor can robustly and reliably induce pivotal mental states, but we argue that the capacity for pivotal mental states is an inherent property of the human brain itself. Moreover, we hypothesize that serotonergic psychedelics hijack a system that has evolved to mediate rapid and deep learning when its need is sensed. We cite a breadth of evidences linking stress via a variety of inducers, with an upregulated serotonin 2A receptor system (e.g. upregulated availability of and/or binding to the receptor) and acute stress with 5-HT release, which we argue can activate this primed system to induce a pivotal mental state. The pivotal mental state model is multi-level, linking a specific molecular gateway (increased serotonin 2A receptor signaling) with the inception of a hyper-plastic brain and mind state, enhanced rate of associative learning and the potential mediation of a psychological transformation.
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Affiliation(s)
- Ari Brouwer
- Centre for Psychedelic Research, Imperial College London, London, United Kingdom
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12
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Marcher-Rørsted E, Halberstadt AL, Klein AK, Chatha M, Jademyr S, Jensen AA, Kristensen JL. Investigation of the 2,5-Dimethoxy Motif in Phenethylamine Serotonin 2A Receptor Agonists. ACS Chem Neurosci 2020; 11:1238-1244. [PMID: 32212672 DOI: 10.1021/acschemneuro.0c00129] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The 2,5-dimethoxyphenethylamine (2,5-PEA) scaffold is recognized as a motif conferring potent agonist activity at the serotonin 2A receptor (5-HT2AR). The 2,5-dimethoxy motif is present in several classical phenethylamine psychedelics such as 2,4,5- trimethoxyamphetamine (TMA-2), 2,5-dimethoxy-4-methylamphetamine (DOM), 2,5-dimethoxy-4-iodoamphetamine (DOI), 2,5- dimethoxy-4-bromoamphetamine (DOB), 2,5-dimethoxy-4-bromophenethylamine (2C-B), and 2,5-dimethoxy-4-iodophenethylamine (2C-I), and it has previously been suggested that this structural motif is essential for 5-HT2AR activation. In the present study, we present data that challenges this assumption. The 2- and 5-desmethoxy derivatives of 2C-B and DOB were synthesized, and their pharmacological profiles were evaluated in vitro at 5-HT2AR and 5-HT2CR in binding and functional assays and in vivo by assessing their induction of the head-twitch response in mice. Elimination of either the 2- or 5-methoxy group leads to a modest drop in binding affinity and functional potency at 5-HT2AR and 5-HT2CR, which was more pronounced upon removal of the 2-methoxy group. However, this trend was not mirrored in vivo, as removal of either methoxy group resulted in significant reduction in the ability of the compounds to induce the head-twitch response in mice. Thus, the 2,5-dimethoxyphenethylamine motif appears to be important for in vivo potency of phenethylamine 5-HT2AR agonists, but this does not correlate to the relative affinity and potency of the ligands at the recombinant 5-HT2AR.
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Affiliation(s)
- Emil Marcher-Rørsted
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Adam L. Halberstadt
- Department of Psychiatry, University of California San Diego, 9500 Gilman Dr., La Jolla 92093, California
| | - Adam K. Klein
- Department of Psychiatry, University of California San Diego, 9500 Gilman Dr., La Jolla 92093, California
| | - Muhammad Chatha
- Department of Psychiatry, University of California San Diego, 9500 Gilman Dr., La Jolla 92093, California
| | - Simon Jademyr
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Anders A. Jensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| | - Jesper L. Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
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13
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Zawilska JB, Kacela M, Adamowicz P. NBOMes-Highly Potent and Toxic Alternatives of LSD. Front Neurosci 2020; 14:78. [PMID: 32174803 PMCID: PMC7054380 DOI: 10.3389/fnins.2020.00078] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 01/20/2020] [Indexed: 12/29/2022] Open
Abstract
Recently, a new class of psychedelic compounds named NBOMe (or 25X-NBOMe) has appeared on the illegal drug market. NBOMes are analogs of the 2C family of phenethylamine drugs, originally synthesized by Alexander Shulgin, that contain a N-(2-methoxy)benzyl substituent. The most frequently reported drugs from this group are 25I-NBOMe, 25B-NBOMe, and 25C-NBOMe. NBOMe compounds are ultrapotent and highly efficacious agonists of serotonin 5-HT2A and 5-HT2C receptors (Ki values in low nanomolar range) with more than 1000-fold selectivity for 5-HT2A compared with 5-HT1A. They display higher affinity for 5-HT2A receptors than their 2C counterparts and have markedly lower affinity, potency, and efficacy at the 5-HT2B receptor compared to 5-HT2A or 5-HT2C. The drugs are sold as blotter papers, or in powder, liquid, or tablet form, and they are administered sublingually/buccally, intravenously, via nasal insufflations, or by smoking. Since their introduction in the early 2010s, numerous reports have been published on clinical intoxications and fatalities resulting from the consumption of NBOMe compounds. Commonly observed adverse effects include visual and auditory hallucinations, confusion, anxiety, panic and fear, agitation, uncontrollable violent behavior, seizures, excited delirium, and sympathomimetic signs such mydriasis, tachycardia, hypertension, hyperthermia, and diaphoresis. Rhabdomyolysis, disseminated intravascular coagulation, hypoglycemia, metabolic acidosis, and multiorgan failure were also reported. This survey provides an updated overview of the pharmacological properties, pattern of use, metabolism, and desired effects associated with NBOMe use. Special emphasis is given to cases of non-fatal and lethal intoxication involving these compounds. As the analysis of NBOMes in biological materials can be challenging even for laboratories applying modern sensitive techniques, this paper also presents the analytical methods most commonly used for detection and identification of NBOMes and their metabolites.
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Affiliation(s)
- Jolanta B Zawilska
- Department of Pharmacodynamics, Medical University of Łódź, Łódź, Poland
| | - Monika Kacela
- Department of Pharmacodynamics, Medical University of Łódź, Łódź, Poland
| | - Piotr Adamowicz
- Department of Forensic Toxicology, Institute of Forensic Research, Kraków, Poland
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Serotonin 2A receptors are a stress response system: implications for post-traumatic stress disorder. Behav Pharmacol 2020; 30:151-162. [PMID: 30632995 DOI: 10.1097/fbp.0000000000000459] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Serotonin, one of the first neurotransmitters to be identified, is an evolutionarily old molecule that is highly conserved across the animal kingdom, and widely used throughout the brain. Despite this, ascribing a specific set of functions to brain serotonin and its receptors has been difficult and controversial. The 2A subtype of serotonin receptors (5-HT2A receptor) is the major excitatory serotonin receptor in the brain and has been linked to the effects of drugs that produce profound sensory and cognitive changes. Numerous studies have shown that this receptor is upregulated by a broad variety of stressors, and have related 5-HT2A receptor function to associative learning. This review proposes that stress, particularly stress related to danger and existential threats, increases the expression and function of 5-HT2A receptors. It is argued that this is a neurobiological adaptation to promote learning and avoidance of danger in the future. Upregulation of 5-HT2A receptors during stressful events forms associations that tune the brain to environmental cues that signal danger. It is speculated that life-threatening situations may activate this system and contribute to the symptoms associated with post-traumatic stress disorder (PTSD). 3,4-Methylenedioxymethamphetamine, which activates 5-HT2A receptors, has been successful in the treatment of PTSD and has recently achieved status as a breakthrough therapy. An argument is presented that 3,4-methylenedioxymethamphetamine may paradoxically act through these same 5-HT2A receptors to ameliorate the symptoms of PTSD. The central thematic contention is that a key role of serotonin may be to function as a stress detection and response system.
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Mécanisme d’action de la pimavansérine : le nouvel antipsychotique pour traiter la psychose parkinsonienne. ANNALES MEDICO-PSYCHOLOGIQUES 2019. [DOI: 10.1016/j.amp.2019.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Sakloth F, Leggett E, Moerke MJ, Townsend EA, Banks ML, Negus SS. Effects of acute and repeated treatment with serotonin 5-HT2A receptor agonist hallucinogens on intracranial self-stimulation in rats. Exp Clin Psychopharmacol 2019; 27:215-226. [PMID: 30628811 PMCID: PMC6690189 DOI: 10.1037/pha0000253] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The prototype 5-HT2A receptor agonist hallucinogens LSD, mescaline, and psilocybin are classified as Schedule 1 drugs of abuse by the U.S. Drug Enforcement Administration. Accumulating clinical evidence has also suggested that acute or repeated "microdosing" with these drugs may have utility for treatment of some mental health disorders, including drug abuse and depression. The goal of the present study was to evaluate LSD, mescaline, and psilocybin effects on intracranial self-stimulation (ICSS), a procedure that has been used to evaluate abuse-related effects of other classes of abused drugs. Effects of repeated LSD were also examined to evaluate potential changes in its own effects on ICSS or changes in effects produced by the abused psychostimulant methamphetamine or the prodepressant kappa opioid receptor (KOR) agonist U69,593. Male Sprague-Dawley rats were implanted with microelectrodes targeting the medial forebrain bundle and trained to respond under a "frequency-rate" ICSS procedure, in which many drugs of abuse increase (or "facilitate") ICSS. In acute dose-effect and time-course studies, evidence for abuse-related ICSS facilitation was weak and inconsistent; the predominant effect of all 3 drugs was dose- and time-dependent ICSS depression. Repeated LSD treatment failed to alter either its own ICSS depressant effects or the abuse-related effects of methamphetamine; however, repeated LSD did attenuate ICSS depression by U69,593. These results extend those of previous preclinical studies to suggest weak expression of abuse-related effects by 5-HT2A agonist hallucinogens and provide supportive evidence for therapeutic effects of repeated LSD dosing to attenuate KOR-mediated depressant effects but not abuse potential of psychostimulants. (PsycINFO Database Record (c) 2019 APA, all rights reserved).
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Murnane KS, Guner OF, Bowen JP, Rambacher KM, Moniri NH, Murphy TJ, Daphney CM, Oppong-Damoah A, Rice KC. The adrenergic receptor antagonist carvedilol interacts with serotonin 2A receptors both in vitro and in vivo. Pharmacol Biochem Behav 2019; 181:37-45. [PMID: 30998954 DOI: 10.1016/j.pbb.2019.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 03/08/2019] [Accepted: 04/12/2019] [Indexed: 11/19/2022]
Abstract
There is increasing support for the potential clinical use of compounds that interact with serotonin 2A (5-HT2A) receptors. It is therefore of interest to discover novel compounds that interact with 5-HT2A receptors. In the present study, we used computational chemistry to identify critical ligand structural features of 5-HT2A receptor binding and function. Query of compound databases using those ligand features revealed the adrenergic receptor antagonist carvedilol as a high priority match. As carvedilol is used clinically for cardiovascular diseases, we conducted experiments to assess whether it has any interactions with 5-HT2A receptors. In vitro experiments demonstrated that carvedilol has high nanomolar affinity for 5-HT2A receptors. In vivo experiments demonstrated that carvedilol increases the ethanol-induced loss of the righting reflex and suppresses operant responding in mice, and that these effects are attenuated by pretreatment with the selective 5-HT2A receptor antagonist M100907. Moreover, carvedilol did not induce the head-twitch response in mice, suggesting a lack of psychedelic effects. However, carvedilol did not activate canonical 5-HT2A receptor signaling pathways and antagonized serotonin-mediated signaling. It also reduced the head-twitch response induced by 2,5-Dimethoxy-4-iodoamphetamine, suggesting potential in vivo antagonism, allosteric modulation, or functional bias. These data suggest that carvedilol has functionally relevant interactions with 5-HT2A receptors, providing a novel mechanism of action for a clinically used compound. However, our findings do not clearly delineate the precise mechanism of action of carvedilol at 5-HT2A receptors, and additional experiments are needed to elucidate the role of 5-HT2A receptors in the behavioral and clinical effects of carvedilol.
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Affiliation(s)
- Kevin Sean Murnane
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA.
| | - Osman F Guner
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA
| | - J Phillip Bowen
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA
| | - Kalyn M Rambacher
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA
| | - Nader H Moniri
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA
| | - Tyler J Murphy
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA; Department of Biology, Oglethorpe University, Atlanta, GA, USA
| | - Cedrick Maceo Daphney
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA
| | - Aboagyewaah Oppong-Damoah
- Department of Pharmaceutical Sciences, Mercer University College of Pharmacy, Mercer University Health Sciences Center, Atlanta, GA, USA
| | - Kenner C Rice
- Section on Drug Design and Synthesis, National Institute on Drug Abuse and Chemical Biology Research Branch, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
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Davis AK, Barsuglia JP, Lancelotta R, Grant RM, Renn E. The epidemiology of 5-methoxy- N, N-dimethyltryptamine (5-MeO-DMT) use: Benefits, consequences, patterns of use, subjective effects, and reasons for consumption. J Psychopharmacol 2018; 32:779-792. [PMID: 29708042 PMCID: PMC6248886 DOI: 10.1177/0269881118769063] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND/AIM 5-Methoxy- N,N-dimethyltryptamine (5-MeO-DMT) is a psychoactive compound found in several plants and in high concentrations in Bufo alvarius toad venom. Synthetic, toad, and plant-sourced 5-MeO-DMT are used for spiritual and recreational purposes and may have psychotherapeutic effects. However, the use of 5-MeO-DMT is not well understood. Therefore, we examined patterns of use, motivations for consumption, subjective effects, and potential benefits and consequences associated with 5-MeO-DMT use. METHODS Using internet-based advertisements, 515 respondents ( Mage=35.4. SD=11.7; male=79%; White/Caucasian=86%; United States resident=42%) completed a web-based survey. RESULTS Most respondents consumed 5-MeO-DMT infrequently (<once/year), for spiritual exploration, and had used less than four times in their lifetime. The majority (average of 90%) reported moderate-to-strong mystical-type experiences ( Mintensity=3.64, SD=1.11; range 0-5; e.g., ineffability, timelessness, awe/amazement, experience of pure being/awareness), and relatively fewer (average of 37%) experienced very slight challenging experiences ( Mintensity=0.95, SD=0.91; range 0-5; e.g., anxiousness, fear). Less than half (39%) reported repeated consumption during the same session, and very few reported drug craving/desire (8%), or legal (1%), medical (1%), or psychiatric (1%) problems related to use. Furthermore, of those who reported being diagnosed with psychiatric disorders, the majority reported improvements in symptoms following 5-MeO-DMT use, including improvements related to post-traumatic stress disorder (79%), depression (77%), anxiety (69%), and alcoholism (66%) or drug use disorder (60%). CONCLUSION Findings suggest that 5-MeO-DMT is used infrequently, predominantly for spiritual exploration, has low potential for addiction, and might have psychotherapeutic effects. Future research should examine the safety and pharmacokinetics of 5-MeO-DMT administration in humans using rigorous experimental designs.
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Affiliation(s)
- Alan K. Davis
- Behavioral Pharmacology Research Unit, Department of Psychiatry, Johns Hopkins School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD 21224 USA
| | | | - Rafael Lancelotta
- School of Counseling, Leadership, Advocacy, and Design, University of Wyoming, 1000 E. University Ave. Dept. 3374 Laramie, WY 82071 USA
| | - Robert M. Grant
- Department of Medicine, University of California, San Francisco, 1001 Potrero St, Building 100, Room 603, San Francisco, CA 94110 USA
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Pimavanserin for the treatment of Parkinson's disease psychosis: number needed to treat, number needed to harm, and likelihood to be helped or harmed. CNS Spectr 2018; 23:228-238. [PMID: 29098976 DOI: 10.1017/s1092852917000736] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Our aim was to describe the efficacy and tolerability of pimavanserin, a highly selective serotonin 5-HT2A receptor inverse agonist/antagonist indicated for the treatment of hallucinations and delusions associated with Parkinson's disease psychosis (PDP), using the metrics of number needed to treat (NNT) and number needed to harm (NNH). METHODS Categorical efficacy and tolerability data were extracted from the clinical trial databases of the double-blind placebo-controlled studies of pimavanserin in persons with PDP. NNT and NNH values were calculated with their respective 95% confidence intervals. The likelihood to be helped or harmed (LHH) was then calculated contrasting therapeutic response versus discontinuation because of an adverse event. RESULTS NNT values for pimavanserin 34 mg/d versus placebo for several definitions of clinical response are 10, and/or are not statistically significant, and/or show an advantage for pimavanserin over placebo (such as for postural hypotension). In terms of LHH, pimavanserin 34 mg/d is about five times more likely to result in clinical response (as measured by a ≥3 point decrease from baseline on the Scale for the Assessment of Positive Symptoms adapted for Parkinson's disease) versus discontinuation due to an adverse event. CONCLUSIONS Using the metrics of NNT, NNH, and LHH, pimavanserin 34 mg/d for the treatment of PDP appears to have a compelling benefit/risk profile.
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Schindler EAD, Wallace RM, Sloshower JA, D'Souza DC. Neuroendocrine Associations Underlying the Persistent Therapeutic Effects of Classic Serotonergic Psychedelics. Front Pharmacol 2018; 9:177. [PMID: 29545753 PMCID: PMC5838010 DOI: 10.3389/fphar.2018.00177] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 02/16/2018] [Indexed: 12/12/2022] Open
Abstract
Recent reports on the effects of psychedelic-assisted therapies for mood disorders and addiction, as well as the effects of psychedelics in the treatment of cluster headache, have demonstrated promising therapeutic results. In addition, the beneficial effects appear to persist well after limited exposure to the drugs, making them particularly appealing as treatments for chronic neuropsychiatric and headache disorders. Understanding the basis of the long-lasting effects, however, will be critical for the continued use and development of this drug class. Several mechanisms, including biological and psychological ones, have been suggested to explain the long-lasting effects of psychedelics. Actions on the neuroendocrine system are some such mechanisms that warrant further investigation in the study of persisting psychedelic effects. In this report, we review certain structural and functional neuroendocrinological pathologies associated with neuropsychiatric disorders and cluster headache. We then review the effects that psychedelic drugs have on those systems and provide preliminary support for potential long-term effects. The circadian biology of cluster headache is of particular relevance in this area. We also discuss methodologic considerations for future investigations of neuroendocrine system involvement in the therapeutic benefits of psychedelic drugs.
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Affiliation(s)
- Emmanuelle A D Schindler
- Department of Neurology, Yale School of Medicine, New Haven, CT, United States.,Department of Neurology, VA Connecticut Healthcare System, West Haven, CT, United States
| | - Ryan M Wallace
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States
| | - Jordan A Sloshower
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States.,Department of Psychiatry, VA Connecticut Healthcare System, West Haven, CT, United States
| | - Deepak C D'Souza
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, United States.,Department of Psychiatry, VA Connecticut Healthcare System, West Haven, CT, United States
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The renaissance in psychedelic research: What do preclinical models have to offer. PROGRESS IN BRAIN RESEARCH 2018; 242:25-67. [DOI: 10.1016/bs.pbr.2018.08.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Schneider RB, Iourinets J, Richard IH. Parkinson's disease psychosis: presentation, diagnosis and management. Neurodegener Dis Manag 2017; 7:365-376. [DOI: 10.2217/nmt-2017-0028] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Parkinson's disease is a neurodegenerative disorder characterized by motor and nonmotor symptoms. Psychosis is a common feature of Parkinson's disease. Parkinson's disease psychosis (PDP) encompasses minor phenomena (illusions, passage hallucinations and presence hallucinations), visual and nonvisual hallucinations and delusions. PDP is associated with reduced function and quality of life. The initial management approach should focus on identification and treatment of any contributory medical factors, reduction or discontinuation of medications with potential to induce or worsen psychosis, nonpharmacological strategies and consideration of acetylcholinesterase inhibitor treatment in the setting of dementia. Pimavanserin, quetiapine and clozapine may all be considered for use in PDP. In this review, we discuss the presentation, diagnosis and management of PDP.
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Affiliation(s)
- Ruth B Schneider
- Department of Neurology, University of Rochester School of Medicine & Dentistry, 265 Crittenden Blvd, Box MIND, Rochester, NY 14642, USA
| | - Julia Iourinets
- Department of Neurology, University of Rochester School of Medicine & Dentistry, 919 Westfall Rd, Bldg C, Rochester, NY 14618, USA
| | - Irene H Richard
- Department of Neurology, University of Rochester School of Medicine & Dentistry, 919 Westfall Rd, Bldg C, Rochester, NY 14618, USA
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Millière R. Looking for the Self: Phenomenology, Neurophysiology and Philosophical Significance of Drug-induced Ego Dissolution. Front Hum Neurosci 2017; 11:245. [PMID: 28588463 PMCID: PMC5441112 DOI: 10.3389/fnhum.2017.00245] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 04/25/2017] [Indexed: 12/17/2022] Open
Abstract
There is converging evidence that high doses of hallucinogenic drugs can produce significant alterations of self-experience, described as the dissolution of the sense of self and the loss of boundaries between self and world. This article discusses the relevance of this phenomenon, known as “drug-induced ego dissolution (DIED)”, for cognitive neuroscience, psychology and philosophy of mind. Data from self-report questionnaires suggest that three neuropharmacological classes of drugs can induce ego dissolution: classical psychedelics, dissociative anesthetics and agonists of the kappa opioid receptor (KOR). While these substances act on different neurotransmitter receptors, they all produce strong subjective effects that can be compared to the symptoms of acute psychosis, including ego dissolution. It has been suggested that neuroimaging of DIED can indirectly shed light on the neural correlates of the self. While this line of inquiry is promising, its results must be interpreted with caution. First, neural correlates of ego dissolution might reveal the necessary neurophysiological conditions for the maintenance of the sense of self, but it is more doubtful that this method can reveal its minimally sufficient conditions. Second, it is necessary to define the relevant notion of self at play in the phenomenon of DIED. This article suggests that DIED consists in the disruption of subpersonal processes underlying the “minimal” or “embodied” self, i.e., the basic experience of being a self rooted in multimodal integration of self-related stimuli. This hypothesis is consistent with Bayesian models of phenomenal selfhood, according to which the subjective structure of conscious experience ultimately results from the optimization of predictions in perception and action. Finally, it is argued that DIED is also of particular interest for philosophy of mind. On the one hand, it challenges theories according to which consciousness always involves self-awareness. On the other hand, it suggests that ordinary conscious experience might involve a minimal kind of self-awareness rooted in multisensory processing, which is what appears to fade away during DIED.
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Affiliation(s)
- Raphaël Millière
- Faculty of Philosophy, University of OxfordOxford, United Kingdom
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Abstract
Parkinson's disease psychosis (PDP) is theoretically a serotonin-dopamine imbalance syndrome due to disruption of the normal balance between the serotonergic and dopaminergic neurotransmitter systems in key brain circuits.
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Rickli A, Moning OD, Hoener MC, Liechti ME. Receptor interaction profiles of novel psychoactive tryptamines compared with classic hallucinogens. Eur Neuropsychopharmacol 2016; 26:1327-37. [PMID: 27216487 DOI: 10.1016/j.euroneuro.2016.05.001] [Citation(s) in RCA: 200] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/25/2016] [Accepted: 05/08/2016] [Indexed: 11/25/2022]
Abstract
The present study investigated interactions between the novel psychoactive tryptamines DiPT, 4-OH-DiPT, 4-OH-MET, 5-MeO-AMT, and 5-MeO-MiPT at monoamine receptors and transporters compared with the classic hallucinogens lysergic acid diethylamide (LSD), psilocin, N,N-dimethyltryptamine (DMT), and mescaline. We investigated binding affinities at human monoamine receptors and determined functional serotonin (5-hydroxytryptamine [5-HT]) 5-HT2A and 5-HT2B receptor activation. Binding at and the inhibition of human monoamine uptake transporters and transporter-mediated monoamine release were also determined. All of the novel tryptamines interacted with 5-HT2A receptors and were partial or full 5-HT2A agonists. Binding affinity to the 5-HT2A receptor was lower for all of the tryptamines, including psilocin and DMT, compared with LSD and correlated with the reported psychoactive doses in humans. Several tryptamines, including psilocin, DMT, DiPT, 4-OH-DiPT, and 4-OH-MET, interacted with the serotonin transporter and partially the norepinephrine transporter, similar to 3,4-methylenedioxymethamphetamine but in contrast to LSD and mescaline. LSD but not the tryptamines interacted with adrenergic and dopaminergic receptors. In conclusion, the receptor interaction profiles of the tryptamines predict hallucinogenic effects that are similar to classic serotonergic hallucinogens but also MDMA-like psychoactive properties.
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Affiliation(s)
- Anna Rickli
- Psychopharmacology Research, Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Olivier D Moning
- Psychopharmacology Research, Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Marius C Hoener
- Neuroscience Research, pRED, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Matthias E Liechti
- Psychopharmacology Research, Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland.
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Mechanism of action of pimavanserin in Parkinson's disease psychosis: targeting serotonin 5HT2A and 5HT2C receptors. CNS Spectr 2016; 21:271-5. [PMID: 27503570 DOI: 10.1017/s1092852916000407] [Citation(s) in RCA: 195] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Pimavanserin, a novel agent approved for the treatment of Parkinson's disease psychosis, has potent actions as an antagonist/inverse agonist at serotonin 5HT2A receptors and less potent antagonist/inverse agonist actions at 5HT2C receptors.
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mGlu5-GABAB interplay in animal models of positive, negative and cognitive symptoms of schizophrenia. Neurochem Int 2015; 88:97-109. [DOI: 10.1016/j.neuint.2015.03.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 03/17/2015] [Accepted: 03/23/2015] [Indexed: 11/19/2022]
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Optimising PET approaches to measuring 5-HT release in human brain. Synapse 2015; 69:505-11. [DOI: 10.1002/syn.21835] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 05/28/2015] [Accepted: 06/08/2015] [Indexed: 01/16/2023]
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Evaluation of the neurochemical effects of methoxetamine using brain microdialysis in mice. Forensic Toxicol 2015. [DOI: 10.1007/s11419-015-0267-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Halberstadt AL. Recent advances in the neuropsychopharmacology of serotonergic hallucinogens. Behav Brain Res 2015; 277:99-120. [PMID: 25036425 PMCID: PMC4642895 DOI: 10.1016/j.bbr.2014.07.016] [Citation(s) in RCA: 191] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 07/07/2014] [Accepted: 07/08/2014] [Indexed: 12/12/2022]
Abstract
Serotonergic hallucinogens, such as (+)-lysergic acid diethylamide, psilocybin, and mescaline, are somewhat enigmatic substances. Although these drugs are derived from multiple chemical families, they all produce remarkably similar effects in animals and humans, and they show cross-tolerance. This article reviews the evidence demonstrating the serotonin 5-HT2A receptor is the primary site of hallucinogen action. The 5-HT2A receptor is responsible for mediating the effects of hallucinogens in human subjects, as well as in animal behavioral paradigms such as drug discrimination, head twitch response, prepulse inhibition of startle, exploratory behavior, and interval timing. Many recent clinical trials have yielded important new findings regarding the psychopharmacology of these substances. Furthermore, the use of modern imaging and electrophysiological techniques is beginning to help unravel how hallucinogens work in the brain. Evidence is also emerging that hallucinogens may possess therapeutic efficacy.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States.
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Wieczorek PP, Witkowska D, Jasicka-Misiak I, Poliwoda A, Oterman M, Zielińska K. Bioactive Alkaloids of Hallucinogenic Mushrooms. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/b978-0-444-63462-7.00005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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D'Amico JM, Condliffe EG, Martins KJB, Bennett DJ, Gorassini MA. Recovery of neuronal and network excitability after spinal cord injury and implications for spasticity. Front Integr Neurosci 2014; 8:36. [PMID: 24860447 PMCID: PMC4026713 DOI: 10.3389/fnint.2014.00036] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 04/17/2014] [Indexed: 01/08/2023] Open
Abstract
The state of areflexia and muscle weakness that immediately follows a spinal cord injury (SCI) is gradually replaced by the recovery of neuronal and network excitability, leading to both improvements in residual motor function and the development of spasticity. In this review we summarize recent animal and human studies that describe how motoneurons and their activation by sensory pathways become hyperexcitable to compensate for the reduction of functional activation of the spinal cord and the eventual impact on the muscle. Specifically, decreases in the inhibitory control of sensory transmission and increases in intrinsic motoneuron excitability are described. We present the idea that replacing lost patterned activation of the spinal cord by activating synaptic inputs via assisted movements, pharmacology or electrical stimulation may help to recover lost spinal inhibition. This may lead to a reduction of uncontrolled activation of the spinal cord and thus, improve its controlled activation by synaptic inputs to ultimately normalize circuit function. Increasing the excitation of the spinal cord with spared descending and/or peripheral inputs by facilitating movement, instead of suppressing it pharmacologically, may provide the best avenue to improve residual motor function and manage spasticity after SCI.
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Affiliation(s)
- Jessica M D'Amico
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada
| | - Elizabeth G Condliffe
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada ; Department of Biomedical Engineering, University of Alberta Edmonton, AB, Canada ; Division of Physical Medicine and Rehabilitation, University of Alberta Edmonton, AB, Canada
| | - Karen J B Martins
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Physical Education and Recreation, University of Alberta Edmonton, AB, Canada
| | - David J Bennett
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Rehabilitation Medicine, University of Alberta Edmonton, AB, Canada
| | - Monica A Gorassini
- Centre for Neuroscience, University of Alberta Edmonton, AB, Canada ; Faculty of Medicine and Dentistry, University of Alberta Edmonton, AB, Canada ; Department of Biomedical Engineering, University of Alberta Edmonton, AB, Canada
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Halberstadt AL, Powell SB, Geyer MA. Role of the 5-HT₂A receptor in the locomotor hyperactivity produced by phenylalkylamine hallucinogens in mice. Neuropharmacology 2013; 70:218-27. [PMID: 23376711 DOI: 10.1016/j.neuropharm.2013.01.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 12/20/2012] [Accepted: 01/12/2013] [Indexed: 01/12/2023]
Abstract
The 5-HT₂A receptor mediates the effects of serotonergic hallucinogens and may play a role in the pathophysiology of certain psychiatric disorders, including schizophrenia. Given these findings, there is a need for animal models to assess the behavioral effects of 5-HT₂A receptor activation. Our previous studies demonstrated that the phenylalkylamine hallucinogen and 5-HT₂A/₂C agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) produces dose-dependent effects on locomotor activity in C57BL/6J mice, increasing activity at low to moderate doses and reducing activity at high doses. DOI did not increase locomotor activity in 5-HT₂A knockout mice, indicating the effect is a consequence of 5-HT₂A receptor activation. Here, we tested a series of phenylalkylamine hallucinogens in C57BL/6J mice using the Behavioral Pattern Monitor (BPM) to determine whether these compounds increase locomotor activity by activating the 5-HT₂A receptor. Low doses of mescaline, 2,5-dimethoxy-4-ethylamphetamine (DOET), 2,5-dimethoxy-4-propylamphetamine (DOPR), 2,4,5-trimethoxyamphetamine (TMA-2), and the conformationally restricted phenethylamine (4-bromo-3,6-dimethoxybenzocyclobuten-1-yl)methylamine (TCB-2) increased locomotor activity. By contrast, the non-hallucinogenic phenylalkylamine 2,5-dimethoxy-4-tert-butylamphetamine (DOTB) did not alter locomotor activity at any dose tested (0.1-10 mg/kg i.p.). The selective 5-HT₂A antagonist M100907 blocked the locomotor hyperactivity induced by mescaline and TCB-2. Similarly, mescaline and TCB-2 did not increase locomotor activity in 5-HT₂A knockout mice. These results confirm that phenylalkylamine hallucinogens increase locomotor activity in mice and demonstrate that this effect is mediated by 5-HT₂A receptor activation. Thus, locomotor hyperactivity in mice can be used to assess phenylalkylamines for 5-HT₂A agonist activity and hallucinogen-like behavioral effects. These studies provide additional support for the link between 5-HT₂A activation and hallucinogenesis.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0804, USA.
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Jang JW, Kim MS, Cho YS, Cho AE, Pae AN. Identification of structural determinants of ligand selectivity in 5-HT₂ receptor subtypes on the basis of protein-ligand interactions. J Mol Graph Model 2012; 38:342-53. [PMID: 23085173 DOI: 10.1016/j.jmgm.2012.06.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 06/07/2012] [Accepted: 06/13/2012] [Indexed: 11/24/2022]
Abstract
Drug selectivity is one of the most critical improvement steps in drug development. The 5-hydroxytryptamine 2 (5-HT₂) receptor has 3 subtypes that exhibit different pharmacological functions. Because of their high amino acid sequence similarity, designing small molecules that selectively activate only 1 receptor among the 3 subtypes is difficult. We performed homology modeling of the 5-HT₂ receptor subtypes using the β₂-adrenergic receptor as a template to identify differences in active sites that may influence 5-HT₂ receptor agonist selectivity. A subset of selective 5-HT₂ agonists was docked into the modeled protein structures to investigate their interactions with each receptor. Subtype-specific active site residues at positions xl2.54, 5.39, and 5.46 interacted differently with each ligand. Molecular dynamics simulations revealed that position 5.46 of the 5-HT(2A) receptor interacted more favorably with selective 5-HT(2A) agonists than with selective 5-HT(2B) agonists. These computationally obtained insights provided clues to improving agonist selectivity for specific pharmacological action at 5-HT₂ receptors.
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Affiliation(s)
- Jae Wan Jang
- Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology, PO Box 131, Cheongryang, Seoul 130-650, Republic of Korea
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Canal CE, Morgan D. Head-twitch response in rodents induced by the hallucinogen 2,5-dimethoxy-4-iodoamphetamine: a comprehensive history, a re-evaluation of mechanisms, and its utility as a model. Drug Test Anal 2012; 4:556-76. [PMID: 22517680 DOI: 10.1002/dta.1333] [Citation(s) in RCA: 144] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 01/09/2012] [Accepted: 01/10/2012] [Indexed: 11/06/2022]
Abstract
Two primary animal models persist for assessing hallucinogenic potential of novel compounds and for examining the pharmacological and neurobiological substrates underlying the actions of classical hallucinogens, the two-lever drug discrimination procedure and the drug-induced head-twitch response (HTR) in rodents. The substituted amphetamine hallucinogen, serotonin 2 (5-HT(2) ) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI) has emerged as the most popular pharmacological tool used in HTR studies of hallucinogens. Synthesizing classic, recent, and relatively overlooked findings, addressing ostensibly conflicting observations, and considering contemporary theories in receptor and behavioural pharmacology, this review provides an up-to-date and comprehensive synopsis of DOI and the HTR model, from neural mechanisms to utility for understanding psychiatric diseases. Also presented is support for the argument that, although both the two-lever drug discrimination and the HTR models in rodents are useful for uncovering receptors, interacting proteins, intracellular signalling pathways, and neurochemical processes affected by DOI and related classical hallucinogens, results from both models suggest they are not reporting hallucinogenic experiences in animals.
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Affiliation(s)
- Clint E Canal
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL 32610, USA.
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Trachsel D. Fluorine in psychedelic phenethylamines. Drug Test Anal 2012; 4:577-90. [DOI: 10.1002/dta.413] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 12/13/2011] [Accepted: 12/13/2011] [Indexed: 12/15/2022]
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Halberstadt AL, Geyer MA. Multiple receptors contribute to the behavioral effects of indoleamine hallucinogens. Neuropharmacology 2011; 61:364-81. [PMID: 21256140 PMCID: PMC3110631 DOI: 10.1016/j.neuropharm.2011.01.017] [Citation(s) in RCA: 241] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2010] [Revised: 12/03/2010] [Accepted: 01/10/2011] [Indexed: 10/18/2022]
Abstract
Serotonergic hallucinogens produce profound changes in perception, mood, and cognition. These drugs include phenylalkylamines such as mescaline and 2,5-dimethoxy-4-methylamphetamine (DOM), and indoleamines such as (+)-lysergic acid diethylamide (LSD) and psilocybin. Despite their differences in chemical structure, the two classes of hallucinogens produce remarkably similar subjective effects in humans, and induce cross-tolerance. The phenylalkylamine hallucinogens are selective 5-HT(2) receptor agonists, whereas the indoleamines are relatively non-selective for serotonin (5-HT) receptors. There is extensive evidence, from both animal and human studies, that the characteristic effects of hallucinogens are mediated by interactions with the 5-HT(2A) receptor. Nevertheless, there is also evidence that interactions with other receptor sites contribute to the psychopharmacological and behavioral effects of the indoleamine hallucinogens. This article reviews the evidence demonstrating that the effects of indoleamine hallucinogens in a variety of animal behavioral paradigms are mediated by both 5-HT(2) and non-5-HT(2) receptors.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States.
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Huot P, Fox SH, Brotchie JM. The serotonergic system in Parkinson's disease. Prog Neurobiol 2011; 95:163-212. [PMID: 21878363 DOI: 10.1016/j.pneurobio.2011.08.004] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/05/2011] [Accepted: 08/15/2011] [Indexed: 01/23/2023]
Abstract
Although the cardinal manifestations of Parkinson's disease (PD) are attributed to a decline in dopamine levels in the striatum, a breadth of non-motor features and treatment-related complications in which the serotonergic system plays a pivotal role are increasingly recognised. Serotonin (5-HT)-mediated neurotransmission is altered in PD and the roles of the different 5-HT receptor subtypes in disease manifestations have been investigated. The aims of this article are to summarise and discuss all published preclinical and clinical studies that have investigated the serotonergic system in PD and related animal models, in order to recapitulate the state of the current knowledge and to identify areas that need further research and understanding.
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Affiliation(s)
- Philippe Huot
- Toronto Western Research Institute, MCL 11-419, Toronto Western Hospital, University Health Network, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8
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Abstract
3,4-Methylenedioxymethamphetamine (MDMA) or 'ecstasy' has been associated with memory deficits during abstinence and intoxication. The human neuropharmacology of MDMA-induced memory impairment is unknown. This study investigated the role of 5-HT(2A) and 5-HT(1A) receptors in MDMA-induced memory impairment. Ketanserin is a 5-HT(2A) receptor blocker and pindolol a 5-HT(1A) receptor blocker. It was hypothesized that pretreatment with ketanserin and pindolol would protect against MDMA-induced memory impairment. Subjects (N=17) participated in a double-blind, placebo-controlled, within-subject design involving six experimental conditions consisting of pretreatment (T1) and treatment (T2). T1 preceded T2 by 30 min. T1-T2 combinations were: placebo-placebo, pindolol 20 mg-placebo, ketanserin 50 mg-placebo, placebo-MDMA 75 mg, pindolol 20 mg-MDMA 75 mg, and ketanserin 50 mg-MDMA 75 mg. Memory function was assessed at Tmax of MDMA by means of a word-learning task (WLT), a spatial memory task and a prospective memory task. MDMA significantly impaired performance in all memory tasks. Pretreatment with a 5-HT(2A) receptor blocker selectively interacted with subsequent MDMA treatment and prevented MDMA-induced impairment in the WLT, but not in the spatial and prospective memory task. Pretreatment with a 5-HT(1A) blocker did not affect MDMA-induced memory impairment in any of the tasks. Together, the results demonstrate that MDMA-induced impairment of verbal memory as measured in the WLT is mediated by 5-HT(2A) receptor stimulation.
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Dougherty JP, Aloyo VJ. Pharmacological and behavioral characterization of the 5-HT2A receptor in C57BL/6N mice. Psychopharmacology (Berl) 2011; 215:581-93. [PMID: 21340474 DOI: 10.1007/s00213-011-2207-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 01/27/2011] [Indexed: 11/30/2022]
Abstract
RATIONALE The serotonin (5-HT) 2A receptor is implicated in numerous psychiatric disorders, making it an important, clinically relevant target. Despite the availability of transgenic mouse lines, the native mouse 5-HT(2A) receptor is not well-characterized. OBJECTIVES The goals of the current study were to determine 5-HT(2A) and 5-HT(2C) receptor densities in mouse cortex, establish a pharmacological profile of the mouse 5-HT(2A) receptor, and determine the effects of chronic drug treatment on 5-HT(2A) receptor density and 5-HT(2A) receptor-mediated behavior. METHODS Receptor densities were determined in cortex and frontal cortex via saturation binding assays using [(3)H]ketanserin or [(3)H]mesulergine. A pharmacological profile was established by displacing [(3)H]ketanserin binding with several ligands. Chronic treatment with 5-HT(2A/2C) receptor agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI), 5-HT(2A) receptor antagonist, MDL 11939, or vehicle was followed by 5-HT(2A) receptor density determination. Head twitch responses (HTRs) were counted on select days. RESULTS Mice had high 5-HT(2A), but low 5-HT(2C) receptor densities. Ligand binding affinities for mouse 5-HT(2A) receptors correlated with rat, but not rabbit or human, affinities. Chronically DOI-treated mice displayed reduced HTRs and 5-HT(2A) receptor density compared to saline-treated mice. Receptor density was unchanged following chronic treatment with MDL 11939. CONCLUSIONS The current study provides some basic information about mouse 5-HT(2A) and 5-HT(2C) receptors and provides comparisons to rats, rabbits, and humans. The current chronic agonist treatment study demonstrated an important similarity between the 5-HT(2A) receptor in mice, rats, and rabbits, while antagonist treatment revealed an interesting difference from previous studies in rabbits.
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Affiliation(s)
- John P Dougherty
- Drexel University College of Medicine, Philadelphia, PA 19102, USA.
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Salvinorin A fails to substitute for the discriminative stimulus effects of LSD or ketamine in Sprague–Dawley rats. Pharmacol Biochem Behav 2010; 96:260-5. [DOI: 10.1016/j.pbb.2010.05.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 05/05/2010] [Accepted: 05/12/2010] [Indexed: 11/17/2022]
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Halberstadt AL, Geyer MA. LSD but not lisuride disrupts prepulse inhibition in rats by activating the 5-HT(2A) receptor. Psychopharmacology (Berl) 2010; 208:179-89. [PMID: 19937319 PMCID: PMC2797624 DOI: 10.1007/s00213-009-1718-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 10/27/2009] [Indexed: 11/27/2022]
Abstract
RATIONALE Compounds that activate the 5-HT(2A) receptor, such as lysergic acid diethylamide (LSD), act as hallucinogens in humans. One notable exception is the LSD congener lisuride, which does not have hallucinogenic effects in humans even though it is a potent 5-HT(2A) agonist. LSD and other hallucinogens have been shown to disrupt prepulse inhibition (PPI), an operational measure of sensorimotor gating, by activating 5-HT(2A) receptors in rats. OBJECTIVE We tested whether lisuride disrupts PPI in male Sprague-Dawley rats. Experiments were also conducted to identify the mechanism(s) responsible for the effect of lisuride on PPI and to compare the effects of lisuride to those of LSD. RESULTS Confirming a previous report, LSD (0.05, 0.1, and 0.2 mg/kg, s.c.) reduced PPI, and the effect of LSD was blocked by pretreatment with the selective 5-HT(2A) antagonist MDL 11,939. Administration of lisuride (0.0375, 0.075, and 0.15 mg/kg, s.c.) also reduced PPI. However, the PPI disruption induced by lisuride (0.075 mg/kg) was not blocked by pretreatment with MDL 11,939 or the selective 5-HT(1A) antagonist WAY-100635 but was prevented by pretreatment with the selective dopamine D(2)/D(3) receptor antagonist raclopride (0.1 mg/kg, s.c). CONCLUSIONS The effect of LSD on PPI is mediated by the 5-HT(2A) receptor, whereas activation of the 5-HT(2A) receptor does not appear to contribute to the effect of lisuride on PPI. These findings demonstrate that lisuride and LSD disrupt PPI via distinct receptor mechanisms and provide additional support for the classification of lisuride as a non-hallucinogenic 5-HT(2A) agonist.
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Affiliation(s)
- Adam L. Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093 USA
| | - Mark A. Geyer
- Department of Psychiatry-0804, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0804 USA
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Abstract
The US Food and Drug Administration (FDA) have suggested that fatal serotonin syndrome (SS) is possible with selective serotonin reuptake inhibitors (SSRIs) and triptans: this warning affects millions of patients as these drugs are frequently given simultaneously. SS is a complex topic about which there is much misinformation. The misconception that 5-HT1A receptors can cause serious SS is still widely perpetuated, despite quality evidence that it is activation of the 5-HT2A receptor that is required for serious SS. This review considers SS involving serotonin agonists: ergotamine, lysergic acid diethylamide, bromocriptine, and buspirone, as well as triptans, and reviews the experimental foundation underpinning the latest understanding of SS. It is concluded that there is neither significant clinical evidence, nor theoretical reason, to entertain speculation about serious SS from triptans and SSRIs. The misunderstandings about SS exhibited by the FDA, and shared by the UK Medicines and Healthcare products Regulatory Agency (in relation to methylene blue), are an important issue with wide ramifications.
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Hasler F, Studerus E, Lindner K, Ludewig S, Vollenweider FX. Investigation of serotonin-1A receptor function in the human psychopharmacology of MDMA. J Psychopharmacol 2009; 23:923-35. [PMID: 18635693 DOI: 10.1177/0269881108094650] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Serotonin (5-HT) release is the primary pharmacological mechanism of 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') action in the primate brain. Dopamine release and direct stimulation of dopamine D2 and serotonin 5-HT2A receptors also contributes to the overall action of MDMA. The role of 5-HT1A receptors in the human psychopharmacology of MDMA, however, has not yet been elucidated. In order to reveal the consequences of manipulation at the 5-HT1A receptor system on cognitive and subjective effects of MDMA, a receptor blocking study using the mixed beta-adrenoreceptor blocker/5-HT1A antagonist pindolol was performed. Using a double-blind, placebo-controlled within-subject design, 15 healthy male subjects were examined under placebo (PL), 20 mg pindolol (PIN), MDMA (1.6 mg/kg b.wt.), MDMA following pre-treatment with pindolol (PIN-MDMA). Tasks from the Cambridge Neuropsychological Test Automated Battery were used for the assessment of cognitive performance. Psychometric questionnaires were applied to measure effects of treatment on core dimensions of Altered States of Consciousness, mood and state anxiety. Compared with PL, MDMA significantly impaired sustained attention and visual-spatial memory, but did not affect executive functions. Pre-treatment with PIN did not significantly alter MDMA-induced impairment of cognitive performance and only exerted a minor modulating effect on two psychometric scales affected by MDMA treatment ('positive derealization' and 'dreaminess'). Our findings suggest that MDMA differentially affects higher cognitive functions, but does not support the hypothesis from animal studies, that some of the MDMA effects are causally mediated through action at the 5-HT1A receptor system.
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Affiliation(s)
- F Hasler
- Department of Clinical Research, Heffter Research Center, University Hospital of Psychiatry, Zürich, Switzerland.
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Gatch MB, Rutledge MA, Carbonaro T, Forster MJ. Comparison of the discriminative stimulus effects of dimethyltryptamine with different classes of psychoactive compounds in rats. Psychopharmacology (Berl) 2009; 204:715-24. [PMID: 19288085 PMCID: PMC2865430 DOI: 10.1007/s00213-009-1501-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2008] [Accepted: 02/22/2009] [Indexed: 12/25/2022]
Abstract
RATIONALE There has been increased recreational use of dimethyltryptamine (DMT), but little is known of its discriminative stimulus effects. OBJECTIVES The present study assessed the similarity of the discriminative stimulus effects of DMT to other types of hallucinogens and to psychostimulants. METHODS Rats were trained to discriminate DMT from saline. To test the similarity of DMT to known hallucinogens, the ability of (+)-lysergic acid diethylamide (LSD), (-)-2,5-dimethoxy-4-methylamphetamine (DOM), (+)-methamphetamine, or (+/-)3,4-methylenedioxymethyl amphetamine (MDMA) to substitute in DMT-trained rats was tested. The ability of DMT to substitute in rats trained to discriminate each of these compounds was also tested. To assess the degree of similarity in discriminative stimulus effects, each of the compounds was tested for substitution in all of the other training groups. RESULTS LSD, DOM, and MDMA all fully substituted in DMT-trained rats, whereas DMT fully substituted only in DOM-trained rats. Full cross-substitution occurred between DMT and DOM, LSD and DOM, and (+)-methamphetamine and MDMA. MDMA fully substituted for (+)-methamphetamine, DOM, and DMT, but only partially for LSD. In MDMA-trained rats, LSD and (+)-methamphetamine fully substituted, whereas DMT and DOM did not fully substitute. No cross-substitution was evident between (+)-methamphetamine and DMT, LSD, or DOM. CONCLUSIONS DMT produces discriminative stimulus effects most similar to those of DOM, with some similarity to the discriminative stimulus effects of LSD and MDMA. Like DOM and LSD, DMT seems to produce predominately hallucinogenic-like discriminative stimulus effects and minimal psychostimulant effects, in contrast to MDMA which produced hallucinogen- and psychostimulant-like effects.
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Affiliation(s)
- Michael B Gatch
- Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107-2699, USA.
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Capela JP, Carmo H, Remião F, Bastos ML, Meisel A, Carvalho F. Molecular and Cellular Mechanisms of Ecstasy-Induced Neurotoxicity: An Overview. Mol Neurobiol 2009; 39:210-71. [DOI: 10.1007/s12035-009-8064-1] [Citation(s) in RCA: 210] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 02/27/2009] [Indexed: 11/29/2022]
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S(-)Propranolol as a discriminative stimulus and its comparison to the stimulus effects of cocaine in rats. Psychopharmacology (Berl) 2009; 203:369-82. [PMID: 18795268 DOI: 10.1007/s00213-008-1317-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Accepted: 08/22/2008] [Indexed: 10/21/2022]
Abstract
RATIONALE Racemic propranolol (PRO), a beta-adrenoceptor antagonist, has been evaluated as a test agent but not as a discriminative stimulus. Its S(-) stereoisomer is thought to subserve the effects of (+/-)PRO. MATERIALS AND METHODS Rats were trained to discriminate S(-)PRO (5 mg/kg) from saline in a two-lever food-reinforced operant conditioning task. RESULTS The S(-)PRO stimulus was shown to be centrally mediated, dose-related, time dependent, and stereoselective: S(-)PRO (ED(50) = 2.2 mg/kg) was twice as potent as (+/-)PRO and approximately four times as potent as R(+)PRO. The S(-)PRO stimulus generalized fully to the beta-adrenoceptor agent pindolol, the alpha(1)-adrenoceptor agonist methoxamine, cocaine, and the serotonergic agents TFMPP and RU 24969; partial generalization occurred to (-)ephedrine and nisoxetine but not to fenfluramine or 5-OMe DMT. The S(-)PRO stimulus was blocked completely (and competitively) when prazosin, an alpha(1)-adrenoceptor antagonist, was given in combination with the training dose of S(-)PRO. Moreover, prazosin exerted antagonism of the S(-)PRO-like effect of (+/-)PRO or R(+)PRO but produced only partial antagonism of the S(-)PRO-like effect of cocaine. In a second study, rats were trained to discriminate 8 mg/kg of cocaine from saline. The cocaine stimulus generalized to S(-)PRO, (+/-)PRO, and R(+)PRO. Prazosin partially attenuated the stimulus effect of cocaine (8 mg/kg) but completely blocked the cocaine-like effects of (+/-), S(-), and R(+)PRO. CONCLUSIONS PRO and cocaine exhibited cross-substitution, but their stimulus effects were antagonized differentially by prazosin. PRO (and its optical isomers) can exert a stimulus effect that is based, at least in part, on increased alpha(1)-adrenoceptor activity. PRO might be better characterized as an adrenoceptor partial agonist.
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Halberstadt AL, Buell MR, Masten VL, Risbrough VB, Geyer MA. Modification of the effects of 5-methoxy-N,N-dimethyltryptamine on exploratory behavior in rats by monoamine oxidase inhibitors. Psychopharmacology (Berl) 2008; 201:55-66. [PMID: 18604652 PMCID: PMC2929165 DOI: 10.1007/s00213-008-1247-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 06/18/2008] [Indexed: 10/21/2022]
Abstract
RATIONALE The hallucinogenic tea known as ayahuasca is made from a combination of psychoactive plants that contribute the active components N,N-dimethyltryptamine (DMT) and 5-methoxy-DMT (5-MeO-DMT), as well as the monoamine oxidase (MAO) inhibitors (MAOIs) harmine and harmaline for oral activity. OBJECTIVE The present study examined the effects of 5-MeO-DMT in combination with MAOIs in rats using the behavioral pattern monitor, which enables analyses of patterns of locomotor activity and exploration. Interaction studies using the serotonin (5-HT)(1A) antagonist WAY-100635 (1.0 mg/kg) and the 5-HT(2A) antagonist MDL 11,939 (1.0 mg/kg) were also performed to assess the respective contributions of these receptors to the behavioral effects of 5-MeO-DMT in MAOI-treated animals. RESULTS 5-MeO-DMT (0.01, 0.1, and 1.0 mg/kg) decreased locomotor activity and investigatory behavior. In rats pretreated with a behaviorally inactive dose of harmaline (0.1 mg/kg), 1.0 mg/kg 5-MeO-DMT had biphasic effects on locomotor activity, initially reducing locomotion and then increasing activity as time progressed. The ability of harmaline to shift 5-MeO-DMT to a biphasic locomotor pattern was shared by the selective MAO(A) inhibitor clorgyline, whereas the selective MAO(B) inhibitor (-)-deprenyl was ineffective. The late hyperactivity induced by the combination of 1.0 mg/kg 5-MeO-DMT and 0.3 mg/kg clorgyline was blocked by pretreatment with MDL 11,939. Pretreatment with WAY-100635 failed to attenuate either the early hypoactivity or the late hyperactivity. CONCLUSIONS The ability of harmaline to modify the behavioral effects of 5-MeO-DMT is mediated by the inhibition of MAO(A). Furthermore, 5-HT(2A) receptors are responsible for the late hyperactivity induced by 5-MeO-DMT in the presence of MAO(A) inhibitors.
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MESH Headings
- DOM 2,5-Dimethoxy-4-Methylamphetamine/pharmacology
- Animals
- Behavior, Animal
- Behavioral Research/instrumentation
- Clorgyline/pharmacology
- Dose-Response Relationship, Drug
- Drug Administration Schedule
- Drug Interactions
- Drug Therapy, Combination
- Exploratory Behavior/drug effects
- Harmaline/pharmacology
- Hyperkinesis/chemically induced
- Male
- Methoxydimethyltryptamines/chemistry
- Methoxydimethyltryptamines/pharmacology
- Monoamine Oxidase Inhibitors/pharmacology
- Motor Activity/drug effects
- Pattern Recognition, Automated
- Pharmaceutical Vehicles/administration & dosage
- Pharmaceutical Vehicles/chemistry
- Piperazines/pharmacology
- Piperidines/pharmacology
- Psychotropic Drugs/chemistry
- Psychotropic Drugs/pharmacology
- Pyridines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT2A/drug effects
- Receptor, Serotonin, 5-HT2A/physiology
- Serotonin 5-HT1 Receptor Antagonists
- Time Factors
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093-0804, USA
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Affiliation(s)
- David E Nichols
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Purdue University, West Lafayette, Indiana 47906-2091, USA.
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Hallucinogen-like effects of N,N-dipropyltryptamine (DPT): possible mediation by serotonin 5-HT1A and 5-HT2A receptors in rodents. Pharmacol Biochem Behav 2007; 88:358-65. [PMID: 17905422 DOI: 10.1016/j.pbb.2007.09.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Revised: 09/06/2007] [Accepted: 09/07/2007] [Indexed: 11/28/2022]
Abstract
N,N-dipropyltryptamine (DPT) is a synthetic tryptamine hallucinogen which has been used psychotherapeutically in humans, but has been studied preclinically only rarely. In the present studies, DPT was tested in a drug-elicited head-twitch assay in mice, and in rats trained to discriminate lysergic acid diethylamide (LSD), N,N-dimethyl-4-phosphoryloxytryptamine (psilocybin), or 3,4-methylenedioxymethamphetamine (MDMA). A separate group of rats was also trained to recognize DPT itself as a discriminative stimulus, and in all cases, the behavioral effects of DPT were challenged with the selective serotonin (5-HT)2A antagonist M100907, the 5-HT1A selective antagonist WAY-100635, or their combination. In the head-twitch assay, DPT elicited dose-dependent effects, producing a biphasic dose-effect curve. WAY-100635 produced a parallel rightward shift in the dose-effect curve for head twitches, indicative of surmountable antagonism, but the antagonist effects of M100907 were functionally insurmountable. DPT produced partial to full substitution when tested in rats trained to discriminate LSD, psilocybin or MDMA, and served as a discriminative stimulus. In all cases, the antagonist effects of M100907 were more profound than were those of WAY-100635. DPT is thus active in two rodent models relevant to 5-HT2 agonist activity. The effectiveness with which M100907 antagonizes the behavioral actions of this compound strongly suggest that the 5-HT2A receptor is an important site of action for DPT, but the modulatory actions of WAY-100635 also imply a 5-HT1A-mediated component to the actions of this compound.
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