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Glennon RA, Dukat M. 1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane (DOI): From an Obscure to Pivotal Member of the DOX Family of Serotonergic Psychedelic Agents - A Review. ACS Pharmacol Transl Sci 2024; 7:1722-1745. [PMID: 38898956 PMCID: PMC11184610 DOI: 10.1021/acsptsci.4c00157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 04/25/2024] [Accepted: 04/30/2024] [Indexed: 06/21/2024]
Abstract
1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane (DOI, or DOX where X = -I) was first synthesized in 1973 in a structure-activity study to explore the effect of various aryl substituents on the then newly identified, and subsequently controlled, hallucinogenic agent 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM, or DOX where X = -CH3). Over time, DOI was found to be a serotonin (5-HT) receptor agonist using various peripheral 5-HT receptor tissue assays and later, following the identification of multiple families of central 5-HT receptors, an agonist at 5-HT2 serotonin receptors in rat and, then, human brain. Today, classical hallucinogens, currently referred to as serotonergic psychedelic agents, are receiving considerable attention for their potential therapeutic application in various neuropsychiatric disorders including treatment-resistant depression. Here, we review, for the first time, the historical and current developments that led to DOI becoming a unique, perhaps a landmark, agent in 5-HT2 receptor research.
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Affiliation(s)
- Richard A. Glennon
- Department of Medicinal Chemistry
School of Pharmacy, Virginia Commonwealth
University, Richmond, Virginia 23298, United States
| | - Małgorzata Dukat
- Department of Medicinal Chemistry
School of Pharmacy, Virginia Commonwealth
University, Richmond, Virginia 23298, United States
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2
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Mitchell JM, Anderson BT. Psychedelic therapies reconsidered: compounds, clinical indications, and cautious optimism. Neuropsychopharmacology 2024; 49:96-103. [PMID: 37479859 PMCID: PMC10700471 DOI: 10.1038/s41386-023-01656-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/05/2023] [Accepted: 07/06/2023] [Indexed: 07/23/2023]
Abstract
The clinical investigation of psychedelic medicines has blossomed over the last 5 years. Data from a Phase 3 industry trial and a multicenter Phase 2 industry trial, in addition to multiple early phase investigator-initiated and industry trials, have now been published in peer-reviewed journals. This narrative review summarizes both the recent data and the current clinical trials that are being conducted with various classes of "psyche-manifesting" substances, which may prove beneficial in the treatment of a broad range of conditions. Methodological considerations, unique challenges, and next steps for research are discussed in keeping with the uniquely "experiential" nature of these therapies.
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Affiliation(s)
- Jennifer M Mitchell
- Department of Neurology, University of California San Francisco, San Francisco, CA, USA.
- Department of Psychiatry and Behavioral Sciences, University of California San Francisco, San Francisco, CA, USA.
- Department of Veterans Affairs, Research Service, San Francisco VA Medical Center, San Francisco, CA, USA.
- Berkeley Center for the Science of Psychedelics, University of California Berkeley, Berkeley, CA, USA.
| | - Brian T Anderson
- Department of Psychiatry and Behavioral Sciences, University of California San Francisco, San Francisco, CA, USA
- Berkeley Center for the Science of Psychedelics, University of California Berkeley, Berkeley, CA, USA
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3
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Wsół A. Cardiovascular safety of psychedelic medicine: current status and future directions. Pharmacol Rep 2023; 75:1362-1380. [PMID: 37874530 PMCID: PMC10661823 DOI: 10.1007/s43440-023-00539-4] [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: 08/29/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/25/2023]
Abstract
Psychedelics are powerful psychoactive substances that alter perception and mood processes. Their effectiveness in the treatment of psychiatric diseases was known before their prohibition. An increasing number of recent studies, due to the indisputable resurgence of serotonergic hallucinogens, have shown their efficacy in alleviating depression, anxiety, substance abuse therapies, and existential distress treatment in patients facing life-threatening illness. Psychedelics are generally considered to be physiologically safe with low toxicity and low addictive potential. However, their agonism at serotonergic receptors should be considered in the context of possible serotonin-related cardiotoxicity (5-HT2A/2B and 5-HT4 receptors), influence on platelet aggregation (5-HT2A receptor), and their proarrhythmic potential. The use of psychedelics has also been associated with significant sympathomimetic effects in both experimental and clinical studies. Therefore, the present review aims to provide a critical discussion of the cardiovascular safety of psilocybin, d-lysergic acid diethylamide (LSD), N,N-dimethyltryptamine, ayahuasca, and mescaline, based on the results of experimental research and clinical trials in humans. Experimental studies provide inconsistent information on the potential cardiovascular effects and toxicity of psychedelics. Data from clinical trials point to the relative cardiovascular safety of psychedelic-assisted therapies in the population of "healthy" volunteers. However, there is insufficient evidence from therapies carried out with microdoses of psychedelics, and there is still a lack of data on the safety of psychedelics in the population of patients with cardiovascular disease. Therefore, the exact determination of the cardiovascular safety of psychedelic therapies (especially long-term therapies) requires further research.
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Affiliation(s)
- Agnieszka Wsół
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1B, 02-097, Warsaw, Poland.
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4
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Heal DJ, Gosden J, Smith SL, Atterwill CK. Experimental strategies to discover and develop the next generation of psychedelics and entactogens as medicines. Neuropharmacology 2023; 225:109375. [PMID: 36529260 DOI: 10.1016/j.neuropharm.2022.109375] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/18/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022]
Abstract
Research on classical psychedelics (psilocybin, LSD and DMT) and entactogen, MDMA, has produced a renaissance in the search for more effective drugs to treat psychiatric, neurological and various peripheral disorders. Psychedelics and entactogens act though interaction with 5-HT2A and other serotonergic receptors and/or monoamine reuptake transporters. 5-HT, which serves as a neurotransmitter and hormone, is ubiquitously distributed in the brain and peripheral organs, tissues and cells where it has vasoconstrictor, pro-inflammatory and pro-nociceptive actions. Serotonergic psychedelics and entactogens have known safety and toxicity risks. For these drugs, the risks been extensively researched and empirically assessed through human experience. However, novel drug-candidates require thorough non-clinical testing not only to predict clinical efficacy, but also to address the risks they pose during clinical development and later after approval as prescription medicines. We have defined the challenges researchers will encounter when developing novel serotonergic psychedelics and entactogens. We describe screening techniques to predict clinical efficacy and address the safety/toxicity risks emerging from our knowledge of the existing drugs: 1) An early-stage, non-clinical screening cascade to pharmacologically characterise novel drug-candidates. 2) Models to detect hallucinogenic activity. 3) Models to differentiate hallucinogens from entactogens. 4) Non-clinical preclinical lead optimisation technology (PLOT) screening to select drug-candidates. 5) Modified animal models to evaluate the abuse and dependence risks of novel psychedelics in Safety Pharmacology testing. Our intention has been to design non-clinical screening strategies that will reset the balance between benefits and harms to deliver more effective and safer novel psychedelics for clinical use. This article is part of the Special Issue on 'National Institutes of Health Psilocybin Research Speaker Series'.
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Affiliation(s)
- D J Heal
- DevelRx Ltd, BioCity, Nottingham, NG1 1GF, UK; Department of Life Sciences, University of Bath, Bath, BA2 7AY, UK.
| | - J Gosden
- DevelRx Ltd, BioCity, Nottingham, NG1 1GF, UK.
| | - S L Smith
- DevelRx Ltd, BioCity, Nottingham, NG1 1GF, UK.
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5
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Kwan AC, Olson DE, Preller KH, Roth BL. The neural basis of psychedelic action. Nat Neurosci 2022; 25:1407-1419. [PMID: 36280799 PMCID: PMC9641582 DOI: 10.1038/s41593-022-01177-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 09/06/2022] [Indexed: 01/13/2023]
Abstract
Psychedelics are serotonin 2A receptor agonists that can lead to profound changes in perception, cognition and mood. In this review, we focus on the basic neurobiology underlying the action of psychedelic drugs. We first discuss chemistry, highlighting the diversity of psychoactive molecules and the principles that govern their potency and pharmacokinetics. We describe the roles of serotonin receptors and their downstream molecular signaling pathways, emphasizing key elements for drug discovery. We consider the impact of psychedelics on neuronal spiking dynamics in several cortical and subcortical regions, along with transcriptional changes and sustained effects on structural plasticity. Finally, we summarize neuroimaging results that pinpoint effects on association cortices and thalamocortical functional connectivity, which inform current theories of psychedelic action. By synthesizing knowledge across the chemical, molecular, neuronal, and network levels, we hope to provide an integrative perspective on the neural mechanisms responsible for the acute and enduring effects of psychedelics on behavior.
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Affiliation(s)
- Alex C. Kwan
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, USA,Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA,Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA,Correspondence: ; ; ;
| | - David E. Olson
- Department of Chemistry, University of California, Davis, Davis, CA, USA,Department of Biochemistry & Molecular Medicine, School of Medicine, University of California, Davis, Sacramento, CA, USA,Center for Neuroscience, University of California, Davis, Davis, CA, USA,Correspondence: ; ; ;
| | - Katrin H. Preller
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric University Hospital, University of Zurich, Zurich, Switzerland.,Correspondence: ; ; ;
| | - Bryan L. Roth
- Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, NC, USA.,Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, NC, USA.,Psychoactive Drug Screening Program, National Institute of Mental Health, School of Medicine, University of North Carolina, Chapel Hill, NC, USA.,Correspondence: ; ; ;
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6
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Odland AU, Kristensen JL, Andreasen JT. Animal Behavior in Psychedelic Research. Pharmacol Rev 2022; 74:1176-1205. [PMID: 36180111 DOI: 10.1124/pharmrev.122.000590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 06/30/2022] [Indexed: 11/22/2022] Open
Abstract
Psychedelic-assisted psychotherapy holds great promise in the treatment of mental health disorders. Research into 5-hydroxytryptamine 2A receptor (5-HT2AR) agonist psychedelic compounds has increased dramatically over the past two decades. In humans, these compounds produce drastic effects on consciousness, and their therapeutic potential relates to changes in the processing of emotional, social, and self-referential information. The use of animal behavior to study psychedelics is under debate, and this review provides a critical perspective on the translational value of animal behavior studies in psychedelic research. Acute activation of 5-HT2ARs produces head twitches and unique discriminative cues, disrupts sensorimotor gating, and stimulates motor activity while inhibiting exploration in rodents. The acute treatment with psychedelics shows discrepant results in conventional rodent tests of depression-like behaviors but generally induces anxiolytic-like effects and inhibits repetitive behavior in rodents. Psychedelics impair waiting impulsivity but show discrepant effects in other tests of cognitive function. Tests of social interaction also show conflicting results. Effects on measures of time perception depend on the experimental schedule. Lasting or delayed effects of psychedelics in rodent tests related to different behavioral domains appear to be rather sensitive to changes in experimental protocols. Studying the effects of psychedelics on animal behaviors of relevance to effects on psychiatric symptoms in humans, assessing lasting effects, publishing negative findings, and relating behaviors in rodents and humans to other more translatable readouts, such as neuroplastic changes, will improve the translational value of animal behavioral studies in psychedelic research. SIGNIFICANCE STATEMENT: Psychedelics like LSD and psilocybin have received immense interest as potential new treatments of psychiatric disorders. Psychedelics change high-order consciousness in humans, and there is debate about the use of animal behavior studies to investigate these compounds. This review provides an overview of the behavioral effects of 5-HT2AR agonist psychedelics in laboratory animals and discusses the translatability of the effects in animals to effects in humans. Possible ways to improve the utility of animal behavior in psychedelic research are discussed.
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Affiliation(s)
- Anna U Odland
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Jesper L Kristensen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
| | - Jesper T Andreasen
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, 2100, Denmark
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7
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Holze F, Ley L, Müller F, Becker AM, Straumann I, Vizeli P, Kuehne SS, Roder MA, Duthaler U, Kolaczynska KE, Varghese N, Eckert A, Liechti ME. Direct comparison of the acute effects of lysergic acid diethylamide and psilocybin in a double-blind placebo-controlled study in healthy subjects. Neuropsychopharmacology 2022; 47:1180-1187. [PMID: 35217796 PMCID: PMC9018810 DOI: 10.1038/s41386-022-01297-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/31/2022] [Accepted: 02/08/2022] [Indexed: 02/02/2023]
Abstract
Growing interest has been seen in using lysergic acid diethylamide (LSD) and psilocybin in psychiatric research and therapy. However, no modern studies have evaluated differences in subjective and autonomic effects of LSD and psilocybin or their similarities and dose equivalence. We used a double-blind, randomized, placebo-controlled, crossover design in 28 healthy subjects (14 women, 14 men) who underwent five 25 h sessions and received placebo, LSD (100 and 200 µg), and psilocybin (15 and 30 mg). Test days were separated by at least 10 days. Outcome measures included self-rating scales for subjective effects, autonomic effects, adverse effects, effect durations, plasma levels of brain-derived neurotrophic factor (BDNF), prolactin, cortisol, and oxytocin, and pharmacokinetics. The doses of 100 and 200 µg LSD and 30 mg psilocybin produced comparable subjective effects. The 15 mg psilocybin dose produced clearly weaker subjective effects compared with both doses of LSD and 30 mg psilocybin. The 200 µg dose of LSD induced higher ratings of ego-dissolution, impairments in control and cognition, and anxiety than the 100 µg dose. The 200 µg dose of LSD increased only ratings of ineffability significantly more than 30 mg psilocybin. LSD at both doses had clearly longer effect durations than psilocybin. Psilocybin increased blood pressure more than LSD, whereas LSD increased heart rate more than psilocybin. However, both LSD and psilocybin showed comparable cardiostimulant properties, assessed by the rate-pressure product. Both LSD and psilocybin had dose-proportional pharmacokinetics and first-order elimination. Both doses of LSD and the high dose of psilocybin produced qualitatively and quantitatively very similar subjective effects, indicating that alterations of mind that are induced by LSD and psilocybin do not differ beyond the effect duration. Any differences between LSD and psilocybin are dose-dependent rather than substance-dependent. However, LSD and psilocybin differentially increased heart rate and blood pressure. These results may assist with dose finding for future psychedelic research.Trial registration: ClinicalTrials.gov identifier: NCT03604744.
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Affiliation(s)
- Friederike Holze
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Laura Ley
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Felix Müller
- grid.412556.10000 0004 0479 0775Psychiatric University Hospital, University of Basel, Basel, Switzerland
| | - Anna M. Becker
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Isabelle Straumann
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Patrick Vizeli
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Sebastian Silva Kuehne
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Marc A. Roder
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Urs Duthaler
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Karolina E. Kolaczynska
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Nimmy Varghese
- grid.412556.10000 0004 0479 0775Psychiatric University Hospital, University of Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Transfaculty Research Platform Molecular and Cognitive Neuroscience, University of Basel, Basel, Switzerland
| | - Anne Eckert
- grid.412556.10000 0004 0479 0775Psychiatric University Hospital, University of Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Transfaculty Research Platform Molecular and Cognitive Neuroscience, University of Basel, Basel, Switzerland
| | - Matthias E. Liechti
- grid.410567.1Clinical Pharmacology and Toxicology, Department of Biomedicine and Department of Clinical Research, University Hospital Basel, Basel, Switzerland ,grid.6612.30000 0004 1937 0642Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
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De Gregorio D, Inserra A, Enns JP, Markopoulos A, Pileggi M, El Rahimy Y, Lopez-Canul M, Comai S, Gobbi G. Repeated lysergic acid diethylamide (LSD) reverses stress-induced anxiety-like behavior, cortical synaptogenesis deficits and serotonergic neurotransmission decline. Neuropsychopharmacology 2022; 47:1188-1198. [PMID: 35301424 PMCID: PMC9018770 DOI: 10.1038/s41386-022-01301-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 02/02/2023]
Abstract
Lysergic acid diethylamide (LSD) is a serotonergic psychedelic compound receiving increasing interest due to putative anxiolytic and antidepressant properties. However, the potential neurobiological mechanisms mediating these effects remain elusive. Employing in vivo electrophysiology, microionthophoresis, behavioral paradigms and morphology assays, we assessed the impact of acute and chronic LSD administration on anxiety-like behavior, on the cortical dendritic spines and on the activity of serotonin (5-HT) neurons originating in the dorsal raphe nucleus (DRN) in male mice exposed to chronic restraint stress. We found that while the acute intraperitoneal (i.p.) administration of LSD (5, 15 and 30 and 60 μg/kg) did not produce any anxiolytic or antidepressant effects in non-stressed mice, the dose of 30 µg/kg (daily for 7 days) prevented the stress-induced anxiety-like behavior and the stress-induced decrease of cortical spine densitiy. Interestingly, while LSD acutely decreased the firing activity of 5-HT neurons, repeated LSD increased their basal firing rate and restored the low 5-HT firing induced by stress. This effect was accompanied by a decreased inhibitory response of 5-HT neurons to microiontophoretic applications of the 5-HT1A agonist 8-OH-DPAT (8-hydroxy-N,N-dipropyl-2-aminotetralin). In conclusion, repeated LSD prevents the exacerbation of anxiety-like behavior following chronic stress exposure, but has no behavioral effects in non-stressed mice. These effects are paralleled by increased cortical spinogenesis and an enhancement of 5-HT neurotransmission which might be due to 5-HT1A receptors desensitization. Increased cortical spine density and enhancement of serotonergic neurotransmission may thus represent a candidate mechanism which mediate the therapeutic effects of serotonergic psychedelics on stress-induced anxiety.
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Affiliation(s)
- Danilo De Gregorio
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada ,grid.15496.3f0000 0001 0439 0892Present Address: Division of Neuroscience, Vita Salute San Raffaele University, 20132 Milan, Italy
| | - Antonio Inserra
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Justine P. Enns
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Athanasios Markopoulos
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Michael Pileggi
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Youssef El Rahimy
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Martha Lopez-Canul
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada
| | - Stefano Comai
- grid.63984.300000 0000 9064 4811Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1 Montreal, QC Canada ,grid.5608.b0000 0004 1757 3470Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Padua, Italy ,grid.15496.3f0000 0001 0439 0892Present Address: Division of Neuroscience, Vita Salute San Raffaele University, 20132 Milan, Italy
| | - Gabriella Gobbi
- Department of Psychiatry, McGill University and Research Institute of the McGill University Health Center, H3A1A1, Montreal, QC, Canada.
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9
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Vejmola Č, Tylš F, Piorecká V, Koudelka V, Kadeřábek L, Novák T, Páleníček T. Psilocin, LSD, mescaline, and DOB all induce broadband desynchronization of EEG and disconnection in rats with robust translational validity. Transl Psychiatry 2021; 11:506. [PMID: 34601495 PMCID: PMC8487430 DOI: 10.1038/s41398-021-01603-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/16/2021] [Accepted: 08/18/2021] [Indexed: 12/22/2022] Open
Abstract
Serotonergic psychedelics are recently gaining a lot of attention as a potential treatment of several neuropsychiatric disorders. Broadband desynchronization of EEG activity and disconnection in humans have been repeatedly shown; however, translational data from animals are completely lacking. Therefore, the main aim of our study was to assess the effects of tryptamine and phenethylamine psychedelics (psilocin 4 mg/kg, LSD 0.2 mg/kg, mescaline 100 mg/kg, and DOB 5 mg/kg) on EEG in freely moving rats. A system consisting of 14 cortical EEG electrodes, co-registration of behavioral activity of animals with subsequent analysis only in segments corresponding to behavioral inactivity (resting-state-like EEG) was used in order to reach a high level of translational validity. Analyses of the mean power, topographic brain-mapping, and functional connectivity revealed that all of the psychedelics irrespective of the structural family induced overall and time-dependent global decrease/desynchronization of EEG activity and disconnection within 1-40 Hz. Major changes in activity were localized on the large areas of the frontal and sensorimotor cortex showing some subtle spatial patterns characterizing each substance. A rebound of occipital theta (4-8 Hz) activity was detected at later stages after treatment with mescaline and LSD. Connectivity analyses showed an overall decrease in global connectivity for both the components of cross-spectral and phase-lagged coherence. Since our results show almost identical effects to those known from human EEG/MEG studies, we conclude that our method has robust translational validity.
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Affiliation(s)
- Čestmír Vejmola
- National Institute of Mental Health, Klecany, Czechia
- Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Filip Tylš
- National Institute of Mental Health, Klecany, Czechia
- Third Faculty of Medicine, Charles University, Prague, Czechia
| | - Václava Piorecká
- National Institute of Mental Health, Klecany, Czechia
- Department of Biomedical Technology, Faculty of Biomedical Engineering, Czech Technical University in Prague, Prague, Czechia
| | | | | | - Tomáš Novák
- National Institute of Mental Health, Klecany, Czechia
| | - Tomáš Páleníček
- National Institute of Mental Health, Klecany, Czechia.
- Third Faculty of Medicine, Charles University, Prague, Czechia.
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10
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Re-evaluation of the discriminative stimulus effects of lysergic acid diethylamide with male and female Sprague-Dawley rats. Behav Pharmacol 2021; 31:776-786. [PMID: 32960851 DOI: 10.1097/fbp.0000000000000589] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Recent discoveries from clinical trials with psychedelic-assisted therapy have led to a resurgence of interest in the psychopharmacology of lysergic acid diethylamide (LSD). Preclinical drug discrimination is an invaluable tool to investigate the neurochemical mechanisms underlying subjective drug effects. The current study extends previous drug discrimination research by including both sexes. Adult female (n = 8) and male (n = 8) Sprague-Dawley rats were trained to discriminate 0.08 mg/kg LSD from saline under a fixed ratio 20 schedule of food reinforcement. Substitution tests were conducted with several substances, including other serotonergic hallucinogens, psychostimulants, mixed psychedelic-stimulants and synthetic cathinones. Stimulus antagonist tests were conducted with selected serotonin and dopamine antagonists. LSD-substitution with serotonergic hallucinogens was comparable between sexes. Modest but intriguing differences were observed between male and female rats in the extent of partial substitution by 3,4-methylenedioxymethamphetamine and 3,4-methylenedioxyamphetamine enantiomers and the synthetic cathinones, 3,4-methylenedioxypyrovalerone and 4-methylmethcathinone. Dopamine antagonists failed to block the LSD cue in both sexes and exerted stronger rate suppressant effects in male rats. The 5-hydroxytryptamine antagonist, (R)-(+)-a-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl) ethyl]-4-piperidinemethanol (MDL 100 907) blocked LSD discrimination in both sexes, although complete blockade was evident at lower doses in male rats. These results support previous findings regarding the prominent role of serotonergic activities underlying LSDs discriminative stimulus effects in male rats and generalize these findings to female rats. In consideration of the rising popularity in psychedelic-assisted psychotherapy, further research may be warranted to evaluate possible sex differences in the behavioral and subjective effects of LSD.
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Inserra A, De Gregorio D, Gobbi G. Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms. Pharmacol Rev 2020; 73:202-277. [PMID: 33328244 DOI: 10.1124/pharmrev.120.000056] [Citation(s) in RCA: 93] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mounting evidence suggests safety and efficacy of psychedelic compounds as potential novel therapeutics in psychiatry. Ketamine has been approved by the Food and Drug Administration in a new class of antidepressants, and 3,4-methylenedioxymethamphetamine (MDMA) is undergoing phase III clinical trials for post-traumatic stress disorder. Psilocybin and lysergic acid diethylamide (LSD) are being investigated in several phase II and phase I clinical trials. Hence, the concept of psychedelics as therapeutics may be incorporated into modern society. Here, we discuss the main known neurobiological therapeutic mechanisms of psychedelics, which are thought to be mediated by the effects of these compounds on the serotonergic (via 5-HT2A and 5-HT1A receptors) and glutamatergic [via N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors] systems. We focus on 1) neuroplasticity mediated by the modulation of mammalian target of rapamycin-, brain-derived neurotrophic factor-, and early growth response-related pathways; 2) immunomodulation via effects on the hypothalamic-pituitary-adrenal axis, nuclear factor ĸB, and cytokines such as tumor necrosis factor-α and interleukin 1, 6, and 10 production and release; and 3) modulation of serotonergic, dopaminergic, glutamatergic, GABAergic, and norepinephrinergic receptors, transporters, and turnover systems. We discuss arising concerns and ways to assess potential neurobiological changes, dependence, and immunosuppression. Although larger cohorts are required to corroborate preliminary findings, the results obtained so far are promising and represent a critical opportunity for improvement of pharmacotherapies in psychiatry, an area that has seen limited therapeutic advancement in the last 20 years. Studies are underway that are trying to decouple the psychedelic effects from the therapeutic effects of these compounds. SIGNIFICANCE STATEMENT: Psychedelic compounds are emerging as potential novel therapeutics in psychiatry. However, understanding of molecular mechanisms mediating improvement remains limited. This paper reviews the available evidence concerning the effects of psychedelic compounds on pathways that modulate neuroplasticity, immunity, and neurotransmitter systems. This work aims to be a reference for psychiatrists who may soon be faced with the possibility of prescribing psychedelic compounds as medications, helping them assess which compound(s) and regimen could be most useful for decreasing specific psychiatric symptoms.
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Affiliation(s)
- Antonio Inserra
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Danilo De Gregorio
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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12
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Liao IM, Chen JC. Lack of dopamine D4 receptor participation in mouse hyperdopaminergic locomotor response. Behav Brain Res 2020; 396:112925. [PMID: 32971195 DOI: 10.1016/j.bbr.2020.112925] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 08/26/2020] [Accepted: 09/17/2020] [Indexed: 12/21/2022]
Abstract
Chronic methamphetamine (METH) treatment induces behavioral sensitization in rodents. During this process, hyperactivation of the mesolimbic dopamine system plays a central role, and dopamine D2-like receptor-based antipsychotics are known to alleviate the behavioral hyperactivity. The atypical antipsychotic, clozapine (Clz), acts partially as a dopamine D4 receptor (D4R) antagonist and mitigates hyperdopaminergic drug addiction and/or comorbid psychotic symptoms; however, it remains unclear whether D4R blockade contributes to the therapeutic effects of Clz. Here, we evaluated the potential role of D4R in regulating hyperdopaminergia-induced behavioral hyperactivity in METH behavioral sensitization and dopamine transporter (DAT) knockdown (KD) mice. Clz or a D4R-selective antagonist, L-745,870, were co-administered to mice with daily METH in a METH sensitization model, and Clz or L-745,870 were administered alone in a DAT KD hyperactivity model. Locomotor activity and accumbal D4R expression were analyzed. Clz suppressed both the initiation and expression of METH behavioral sensitization, as well as DAT KD hyperactivity. However, repetitive Clz treatment induced tolerance to the suppression effect on METH sensitization initiation. In contrast, D4R inhibition by L-745,870 had no effect on METH sensitization or DAT KD hyperactivity. Accumbal D4R expression was similar between METH-sensitized mice with and without Clz co-treatment. In sum, our results suggest the mesolimbic D4R does not participate in behavioral sensitization encoded by hyperdopaminergia, a finding which likely extends to the therapeutic effects of Clz. Therefore, molecular targets other than D4R should be prioritized in the development of future therapeutics for treatment of hyperdopaminergia-dependent neuropsychiatric disorders.
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Affiliation(s)
- I-Mei Liao
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, 75390-9111, United States
| | - Jin-Chung Chen
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Chang Gung Memorial Hospital, Keelung, Taiwan; Healthy Ageing Research Center, Chang Gung University, Taoyuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan.
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13
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Zamberlan F, Sanz C, Martínez Vivot R, Pallavicini C, Erowid F, Erowid E, Tagliazucchi E. The Varieties of the Psychedelic Experience: A Preliminary Study of the Association Between the Reported Subjective Effects and the Binding Affinity Profiles of Substituted Phenethylamines and Tryptamines. Front Integr Neurosci 2018; 12:54. [PMID: 30467466 PMCID: PMC6235949 DOI: 10.3389/fnint.2018.00054] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/15/2018] [Indexed: 02/05/2023] Open
Abstract
Classic psychedelics are substances of paramount cultural and neuroscientific importance. A distinctive feature of psychedelic drugs is the wide range of potential subjective effects they can elicit, known to be deeply influenced by the internal state of the user ("set") and the surroundings ("setting"). The observation of cross-tolerance and a series of empirical studies in humans and animal models support agonism at the serotonin (5-HT)2A receptor as a common mechanism for the action of psychedelics. The diversity of subjective effects elicited by different compounds has been attributed to the variables of "set" and "setting," to the binding affinities for other 5-HT receptor subtypes, and to the heterogeneity of transduction pathways initiated by conformational receptor states as they interact with different ligands ("functional selectivity"). Here we investigate the complementary (i.e., not mutually exclusive) possibility that such variety is also related to the binding affinity for a range of neurotransmitters and monoamine transporters including (but not limited to) 5-HT receptors. Building on two independent binding affinity datasets (compared to "in silico" estimates) in combination with natural language processing tools applied to a large repository of reports of psychedelic experiences (Erowid's Experience Vaults), we obtained preliminary evidence supporting that the similarity between the binding affinity profiles of psychoactive substituted phenethylamines and tryptamines is correlated with the semantic similarity of the associated reports. We also showed that the highest correlation was achieved by considering the combined binding affinity for the 5-HT, dopamine (DA), glutamate, muscarinic and opioid receptors and for the Ca+ channel. Applying dimensionality reduction techniques to the reports, we linked the compounds, receptors, transporters and the Ca+ channel to distinct fingerprints of the reported subjective effects. To the extent that the existing binding affinity data is based on a low number of displacement curves that requires further replication, our analysis produced preliminary evidence consistent with the involvement of different binding sites in the reported subjective effects elicited by psychedelics. Beyond the study of this particular class of drugs, we provide a methodological framework to explore the relationship between the binding affinity profiles and the reported subjective effects of other psychoactive compounds.
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Affiliation(s)
- Federico Zamberlan
- Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Camila Sanz
- Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Rocío Martínez Vivot
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- Instituto de Investigaciones Biomédicas (BIOMED) and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Carla Pallavicini
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- Fundación Para la Lucha contra las Enfermedades Neurológicas de la Infancia (FLENI), Buenos Aires, Argentina
| | - Fire Erowid
- Erowid Center, Grass Valley, CA, United States
| | | | - Enzo Tagliazucchi
- Departamento de Física, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Física de Buenos Aires (IFIBA) and National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- UMR7225 Institut du Cerveau et de la Moelle épinière (ICM), Paris, France
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Nichols DE. Dark Classics in Chemical Neuroscience: Lysergic Acid Diethylamide (LSD). ACS Chem Neurosci 2018; 9:2331-2343. [PMID: 29461039 DOI: 10.1021/acschemneuro.8b00043] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lysergic acid diethylamide (LSD) is one of the most potent psychoactive agents known, producing dramatic alterations of consciousness after submilligram (≥20 μg) oral doses. Following the accidental discovery of its potent psychoactive effects in 1943, it was supplied by Sandoz Laboratories as an experimental drug that might be useful as an adjunct for psychotherapy, or to give psychiatrists insight into the mental processes in their patients. The finding of serotonin in the mammalian brain in 1953, and its structural resemblance to LSD, quickly led to ideas that serotonin in the brain might be involved in mental disorders, initiating rapid research interest in the neurochemistry of serotonin. LSD proved to be physiologically very safe and nonaddictive, with a very low incidence of adverse events when used in controlled experiments. Widely hailed by psychiatry as a breakthrough in the 1950s and early 1960s, clinical research with LSD ended by about 1970, when it was formally placed into Schedule 1 of the Controlled Substances Act of 1970 following its growing popularity as a recreational drug. Within the past 5 years, clinical research with LSD has begun in Europe, but there has been none in the United States. LSD is proving to be a powerful tool to help understand brain dynamics when combined with modern brain imaging methods. It remains to be seen whether therapeutic value for LSD can be confirmed in controlled clinical trials, but promising results have been obtained in small pilot trials of depression, anxiety, and addictions using psilocybin, a related psychedelic molecule.
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Affiliation(s)
- David E. Nichols
- Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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d-Lysergic acid diethylamide, psilocybin, and other classic hallucinogens: Mechanism of action and potential therapeutic applications in mood disorders. PROGRESS IN BRAIN RESEARCH 2018; 242:69-96. [PMID: 30471683 DOI: 10.1016/bs.pbr.2018.07.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Depression and anxiety are psychiatric diagnoses commonly associated with low quality of life and low percentage of responsiveness by patients treated with currently available drugs. Thus, research into alternative compounds to treat these disorders is essential to guarantee a patient's remission. The last decade has witnessed a revamped interest for the application of psychedelic medicine for the treatment of mental disorders due to anecdotal reports and clinical studies which show that low doses of d-lysergic acid diethylamide (LSD) and psilocybin may have antidepressant effects. LSD and psilocybin have demonstrated mood-modulating properties likely due to their capacity to modulate serotonergic (5-HT), dopaminergic (DA) and glutamatergic systems. LSD, belonging to the category of "classic halluginogens," interacts with the 5-HT system through 5HT1A, and 5HT2A receptors, with the DA system through D2 receptors, and indirectly also the glutamatergic neurotransmission thought the recruitment of N-methyl-d-aspartate (NMDA) receptors. Randomized clinical studies have confirmed its antidepressant and anxiolytic effects in humans. Thus, in this chapter, we will review the pharmacology of psychedelic drugs, report the most striking clinical evidence which substantiate the therapeutic potentials of these fascinating compounds in mood disorders, and look into the horizon of where psychedelic medicine is heading.
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16
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De Gregorio D, Comai S, Posa L, Gobbi G. d-Lysergic Acid Diethylamide (LSD) as a Model of Psychosis: Mechanism of Action and Pharmacology. Int J Mol Sci 2016; 17:E1953. [PMID: 27886063 PMCID: PMC5133947 DOI: 10.3390/ijms17111953] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/25/2016] [Accepted: 11/14/2016] [Indexed: 12/15/2022] Open
Abstract
d-Lysergic Acid Diethylamide (LSD) is known for its hallucinogenic properties and psychotic-like symptoms, especially at high doses. It is indeed used as a pharmacological model of psychosis in preclinical research. The goal of this review was to understand the mechanism of action of psychotic-like effects of LSD. We searched Pubmed, Web of Science, Scopus, Google Scholar and articles' reference lists for preclinical studies regarding the mechanism of action involved in the psychotic-like effects induced by LSD. LSD's mechanism of action is pleiotropic, primarily mediated by the serotonergic system in the Dorsal Raphe, binding the 5-HT2A receptor as a partial agonist and 5-HT1A as an agonist. LSD also modulates the Ventral Tegmental Area, at higher doses, by stimulating dopamine D₂, Trace Amine Associate receptor 1 (TAAR₁) and 5-HT2A. More studies clarifying the mechanism of action of the psychotic-like symptoms or psychosis induced by LSD in humans are needed. LSD's effects are mediated by a pleiotropic mechanism involving serotonergic, dopaminergic, and glutamatergic neurotransmission. Thus, the LSD-induced psychosis is a useful model to test the therapeutic efficacy of potential novel antipsychotic drugs, particularly drugs with dual serotonergic and dopaminergic (DA) mechanism or acting on TAAR₁ receptors.
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MESH Headings
- Animals
- Antipsychotic Agents/pharmacology
- Behavior, Animal/drug effects
- Disease Models, Animal
- Dopamine/metabolism
- Dopamine/pharmacology
- Dorsal Raphe Nucleus/drug effects
- Dorsal Raphe Nucleus/metabolism
- Dorsal Raphe Nucleus/physiopathology
- Drug Evaluation, Preclinical
- Hallucinogens/metabolism
- Hallucinogens/pharmacology
- Humans
- Lysergic Acid Diethylamide/metabolism
- Lysergic Acid Diethylamide/pharmacology
- Psychotic Disorders/drug therapy
- Psychotic Disorders/metabolism
- Psychotic Disorders/physiopathology
- Rats
- Receptor, Serotonin, 5-HT1A/metabolism
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptors, Dopamine/metabolism
- Receptors, G-Protein-Coupled/metabolism
- Receptors, Glutamate/metabolism
- Serotonin Receptor Agonists/metabolism
- Serotonin Receptor Agonists/pharmacology
- Synaptic Transmission/drug effects
- Ventral Tegmental Area/drug effects
- Ventral Tegmental Area/metabolism
- Ventral Tegmental Area/physiopathology
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Affiliation(s)
- Danilo De Gregorio
- Neurobiological Psychiatry Unit, McGill University, Montreal, QC H3A 1A1, Canada.
| | - Stefano Comai
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, 20132 Milan, Italy.
| | - Luca Posa
- Neurobiological Psychiatry Unit, McGill University, Montreal, QC H3A 1A1, Canada.
| | - Gabriella Gobbi
- Neurobiological Psychiatry Unit, McGill University, Montreal, QC H3A 1A1, Canada.
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17
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Halberstadt AL. Behavioral and pharmacokinetic interactions between monoamine oxidase inhibitors and the hallucinogen 5-methoxy-N,N-dimethyltryptamine. Pharmacol Biochem Behav 2016; 143:1-10. [PMID: 26780349 PMCID: PMC5403252 DOI: 10.1016/j.pbb.2016.01.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 11/08/2015] [Accepted: 01/14/2016] [Indexed: 01/13/2023]
Abstract
Monoamine oxidase inhibitors (MAOIs) are often ingested together with tryptamine hallucinogens, but relatively little is known about the consequences of their combined use. We have shown previously that monoamine oxidase-A (MAO-A) inhibitors alter the locomotor profile of the hallucinogen 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) in rats, and enhance its interaction with 5-HT2A receptors. The goal of the present studies was to investigate the mechanism for the interaction between 5-MeO-DMT and MAOIs, and to determine whether other behavioral responses to 5-MeO-DMT are similarly affected. Hallucinogens disrupt prepulse inhibition (PPI) in rats, an effect typically mediated by 5-HT2A activation. 5-MeO-DMT also disrupts PPI but the effect is primarily attributable to 5-HT1A activation. The present studies examined whether an MAOI can alter the respective contributions of 5-HT1A and 5-HT2A receptors to the effects of 5-MeO-DMT on PPI. A series of interaction studies using the 5-HT1A antagonist WAY-100,635 and the 5-HT2A antagonist MDL 11,939 were performed to assess the respective contributions of these receptors to the behavioral effects of 5-MeO-DMT in rats pretreated with an MAOI. The effects of MAO-A inhibition on the pharmacokinetics of 5-MeO-DMT and its metabolism to bufotenine were assessed using liquid chromatography-electrospray ionization-selective reaction monitoring-tandem mass spectrometry (LC-ESI-SRM-MS/MS). 5-MeO-DMT (1mg/kg) had no effect on PPI when tested 45-min post-injection but disrupted PPI in animals pretreated with the MAO-A inhibitor clorgyline or the MAO-A/B inhibitor pargyline. The combined effect of 5-MeO-DMT and pargyline on PPI was antagonized by pretreatment with either WAY-100,635 or MDL 11,939. Inhibition of MAO-A increased the level of 5-MeO-DMT in plasma and whole brain, but had no effect on the conversion of 5-MeO-DMT to bufotenine, which was found to be negligible. The present results confirm that 5-MeO-DMT can disrupt PPI by activating 5-HT2A, and indicate that MAOIs alter 5-MeO-DMT pharmacodynamics by increasing its accumulation in the central nervous system.
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Affiliation(s)
- Adam L Halberstadt
- Department of Psychiatry, University of California San Diego, La Jolla, CA, United States; Research Service, VA San Diego Healthcare System, San Diego, CA, United States.
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18
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Abstract
Psychedelics (serotonergic hallucinogens) are powerful psychoactive substances that alter perception and mood and affect numerous cognitive processes. They are generally considered physiologically safe and do not lead to dependence or addiction. Their origin predates written history, and they were employed by early cultures in many sociocultural and ritual contexts. After the virtually contemporaneous discovery of (5R,8R)-(+)-lysergic acid-N,N-diethylamide (LSD)-25 and the identification of serotonin in the brain, early research focused intensively on the possibility that LSD and other psychedelics had a serotonergic basis for their action. Today there is a consensus that psychedelics are agonists or partial agonists at brain serotonin 5-hydroxytryptamine 2A receptors, with particular importance on those expressed on apical dendrites of neocortical pyramidal cells in layer V. Several useful rodent models have been developed over the years to help unravel the neurochemical correlates of serotonin 5-hydroxytryptamine 2A receptor activation in the brain, and a variety of imaging techniques have been employed to identify key brain areas that are directly affected by psychedelics. Recent and exciting developments in the field have occurred in clinical research, where several double-blind placebo-controlled phase 2 studies of psilocybin-assisted psychotherapy in patients with cancer-related psychosocial distress have demonstrated unprecedented positive relief of anxiety and depression. Two small pilot studies of psilocybin-assisted psychotherapy also have shown positive benefit in treating both alcohol and nicotine addiction. Recently, blood oxygen level-dependent functional magnetic resonance imaging and magnetoencephalography have been employed for in vivo brain imaging in humans after administration of a psychedelic, and results indicate that intravenously administered psilocybin and LSD produce decreases in oscillatory power in areas of the brain's default mode network.
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Affiliation(s)
- David E Nichols
- Eschelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina
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19
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Kyzar EJ, Kalueff AV. Exploring Hallucinogen Pharmacology and Psychedelic Medicine with Zebrafish Models. Zebrafish 2016; 13:379-90. [PMID: 27002655 DOI: 10.1089/zeb.2016.1251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
After decades of sociopolitical obstacles, the field of psychiatry is experiencing a revived interest in the use of hallucinogenic agents to treat brain disorders. Along with the use of ketamine for depression, recent pilot studies have highlighted the efficacy of classic serotonergic hallucinogens, such as lysergic acid diethylamide and psilocybin, in treating addiction, post-traumatic stress disorder, and anxiety. However, many basic pharmacological and toxicological questions remain unanswered with regard to these compounds. In this study, we discuss psychedelic medicine as well as the behavioral and toxicological effects of hallucinogenic drugs in zebrafish. We emphasize this aquatic organism as a model ideally suited to assess both the potential toxic and therapeutic effects of major known classes of hallucinogenic compounds. In addition, novel drugs with hallucinogenic properties can be efficiently screened using zebrafish models. Well-designed preclinical studies utilizing zebrafish can contribute to the reemerging treatment paradigm of psychedelic medicine, leading to new avenues of clinical exploration for psychiatric disorders.
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Affiliation(s)
- Evan J Kyzar
- 1 Department of Psychiatry, College of Medicine, University of Illinois at Chicago , Chicago, Illinois
| | - Allan V Kalueff
- 2 Research Institute for Marine Drugs and Nutrition, College of Food Science and Technology, Guangdong Ocean University (GDOU) , Zhanjiang, China .,3 ZENEREI Institute , Slidell, Louisiana.,4 Institute of Translational Biomedicine, St. Petersburg State University , St. Petersburg, Russia .,5 Institutes of Chemical Technology and Natural Sciences, Ural Federal University , Ekaterinburg, Russia .,6 The International Zebrafish Neuroscience Research Consortium (ZNRC) , Slidell, Louisiana
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20
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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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21
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Blough BE, Landavazo A, Decker AM, Partilla JS, Baumann MH, Rothman RB. Interaction of psychoactive tryptamines with biogenic amine transporters and serotonin receptor subtypes. Psychopharmacology (Berl) 2014; 231:4135-44. [PMID: 24800892 PMCID: PMC4194234 DOI: 10.1007/s00213-014-3557-7] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Accepted: 03/19/2014] [Indexed: 01/10/2023]
Abstract
RATIONALE Synthetic hallucinogenic tryptamines, especially those originally described by Alexander Shulgin, continue to be abused in the USA. The range of subjective experiences produced by different tryptamines suggests that multiple neurochemical mechanisms are involved in their actions, in addition to the established role of agonist activity at serotonin 2A (5-HT₂A) receptors. OBJECTIVES This study evaluated the interaction of a series of synthetic tryptamines with biogenic amine neurotransmitter transporters and with serotonin (5-HT) receptor subtypes implicated in psychedelic effects. METHODS Neurotransmitter transporter activity was determined in rat brain synaptosomes. Receptor activity was determined using calcium mobilization and DiscoveRx PathHunter assays in HEK293, Gα16-CHO, and CHOk1 cells transfected with human receptors. RESULTS Twenty-one tryptamines were analyzed in transporter uptake and release assays, and 5-HT₂A, serotonin 1A (5-HT₁A), and 5-HT₂A β-arrestin functional assays. Eight of the compounds were found to have 5-HT-releasing activity. Thirteen compounds were found to be 5-HT uptake inhibitors or were inactive. All tryptamines were 5-HT₂A agonists with a range of potencies and efficacies, but only a few compounds were 5-HT1A agonists. Most tryptamines recruited β-arrestin through 5-HT₂A activation. CONCLUSIONS All psychoactive tryptamines are 5-HT₂A agonists, but 5-HT transporter (SERT) activity may contribute significantly to the pharmacology of certain compounds. The in vitro transporter data confirm structure-activity trends for releasers and uptake inhibitors whereby releasers tend to be structurally smaller compounds. Interestingly, two tertiary amines were found to be selective substrates at SERT, which dispels the notion that 5-HT-releasing activity is limited only to primary or secondary amines.
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Affiliation(s)
- Bruce E. Blough
- Discovery Science Technology, RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA,Corresponding author. Tel.: 919-541-1244; fax: 919-541-6499;
| | - Antonio Landavazo
- Discovery Science Technology, RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA
| | - Ann M. Decker
- Discovery Science Technology, RTI International, 3040 Cornwallis Road, Research Triangle Park, NC 27709, USA
| | - John S. Partilla
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Michael H. Baumann
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Richard B. Rothman
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
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22
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Donahue TJ, Hillhouse TM, Webster KA, Young R, De Oliveira EO, Porter JH. (S)-amisulpride as a discriminative stimulus in C57BL/6 mice and its comparison to the stimulus effects of typical and atypical antipsychotics. Eur J Pharmacol 2014; 734:15-22. [DOI: 10.1016/j.ejphar.2014.03.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 03/10/2014] [Accepted: 03/20/2014] [Indexed: 11/28/2022]
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23
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Buchborn T, Schröder H, Höllt V, Grecksch G. Repeated lysergic acid diethylamide in an animal model of depression: Normalisation of learning behaviour and hippocampal serotonin 5-HT2 signalling. J Psychopharmacol 2014; 28:545-52. [PMID: 24785760 DOI: 10.1177/0269881114531666] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A re-balance of postsynaptic serotonin (5-HT) receptor signalling, with an increase in 5-HT1A and a decrease in 5-HT2A signalling, is a final common pathway multiple antidepressants share. Given that the 5-HT1A/2A agonist lysergic acid diethylamide (LSD), when repeatedly applied, selectively downregulates 5-HT2A, but not 5-HT1A receptors, one might expect LSD to similarly re-balance the postsynaptic 5-HT signalling. Challenging this idea, we use an animal model of depression specifically responding to repeated antidepressant treatment (olfactory bulbectomy), and test the antidepressant-like properties of repeated LSD treatment (0.13 mg/kg/d, 11 d). In line with former findings, we observe that bulbectomised rats show marked deficits in active avoidance learning. These deficits, similarly as we earlier noted with imipramine, are largely reversed by repeated LSD administration. Additionally, bulbectomised rats exhibit distinct anomalies of monoamine receptor signalling in hippocampus and/or frontal cortex; from these, only the hippocampal decrease in 5-HT2 related [(35)S]-GTP-gamma-S binding is normalised by LSD. Importantly, the sham-operated rats do not profit from LSD, and exhibit reduced hippocampal 5-HT2 signalling. As behavioural deficits after bulbectomy respond to agents classified as antidepressants only, we conclude that the effect of LSD in this model can be considered antidepressant-like, and discuss it in terms of a re-balance of hippocampal 5-HT2/5-HT1A signalling.
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Affiliation(s)
- Tobias Buchborn
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany
| | - Helmut Schröder
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany
| | - Volker Höllt
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany
| | - Gisela Grecksch
- Institute of Pharmacology and Toxicology, Otto-von-Guericke University, Magdeburg, Germany
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Juncosa JI, Hansen M, Bonner LA, Cueva JP, Maglathlin R, McCorvy JD, Marona-Lewicka D, Lill MA, Nichols DE. Extensive rigid analogue design maps the binding conformation of potent N-benzylphenethylamine 5-HT2A serotonin receptor agonist ligands. ACS Chem Neurosci 2013; 4:96-109. [PMID: 23336049 DOI: 10.1021/cn3000668] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 07/17/2012] [Indexed: 11/28/2022] Open
Abstract
Based on the structure of the superpotent 5-HT(2A) agonist 2-(4-bromo-2,5-dimethoxyphenyl)-N-[(2-methoxyphenyl)methyl]ethanamine, which consists of a ring-substituted phenethylamine skeleton modified with an N-benzyl group, we designed and synthesized a small library of constrained analogues to identify the optimal arrangement of the pharmacophoric elements of the ligand. Structures consisted of diversely substituted tetrahydroisoquinolines, piperidines, and one benzazepine. Based on the structure of (S,S)-9b, which showed the highest affinity of the series, we propose an optimal binding conformation. (S,S)-9b also displayed 124-fold selectivity for the 5-HT(2A) over the 5-HT(2C) receptor, making it the most selective 5-HT(2A) receptor agonist ligand currently known.
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Affiliation(s)
- Jose I. Juncosa
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - Martin Hansen
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - Lisa A. Bonner
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - Juan Pablo Cueva
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - Rebecca Maglathlin
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - John D. McCorvy
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - Danuta Marona-Lewicka
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - Markus A. Lill
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
| | - David E. Nichols
- Department of Medicinal Chemistry and Molecular Pharmacology,
College of Pharmacy, Purdue University,
West Lafayette, Indiana 47907, United States
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25
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Serotonergic hallucinogens differentially modify gamma and high frequency oscillations in the rat nucleus accumbens. Psychopharmacology (Berl) 2013; 228:271-82. [PMID: 23525524 PMCID: PMC3693439 DOI: 10.1007/s00213-013-3057-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Accepted: 02/11/2013] [Indexed: 12/15/2022]
Abstract
RATIONALE The nucleus accumbens (NAc) is a site critical for the actions of many drugs of abuse. Psychoactive compounds, such as N-methyl-D-aspartate receptor (NMDAR) antagonists, modify gamma (40-90) and high frequency oscillations (HFO, 130-180 Hz) in local field potentials (LFPs) recorded in the NAc. Lysergic acid diethylamide (LSD) and 2,5-dimethoxy-4-iodoamphetamine (DOI) are serotonergic hallucinogens and activation of 5HT2A receptors likely underlies their hallucinogenic effects. Whether these compounds can also modulate LFP oscillations in the NAc is unclear. OBJECTIVE This study aims to examine the effect of serotonergic hallucinogens on gamma and HFO recorded in the NAc and to test whether 5HT2A receptors mediate the effects observed. METHODS LFPs were recorded from the NAc of freely moving rats. Drugs were administered intraperitoneally. RESULTS LSD (0.03-0.3 mg/kg) and DOI (0.5-2.0 mg/kg) increased the power and reduced the frequency of HFO. In contrast, the hallucinogens produced a robust reduction in the power of low (40-60 Hz), but not high gamma oscillations (70-90 Hz). MDL 11939 (1.0 mg/kg), a 5HT2A receptor antagonist, fully reversed the changes induced by DOI on HFO but only partially for the low gamma band. Equivalent increases in HFO power were observed after TCB-2 (5HT2A receptor agonist, 0.1-1.5 mg/kg), but not CP 809101 (5H2C receptor agonist, 0.1-3 mg/kg). Notably, hallucinogen-induced increases in HFO power were smaller than those produced by ketamine (25 mg/kg). CONCLUSIONS Serotonergic hallucinogen-induced changes in HFO and gamma are mediated, at least in part, by stimulation of 5HT2A receptors. Comparison of the oscillatory changes produced by serotonergic hallucinogens and NMDAR antagonists are also discussed.
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26
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Self-administration of agonists selective for dopamine D2, D3, and D4 receptors by rhesus monkeys. Behav Pharmacol 2012; 23:331-8. [PMID: 22785383 DOI: 10.1097/fbp.0b013e3283564dbb] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Dopamine receptor mechanisms are believed to play a role in the reinforcing effects of cocaine and other drugs of abuse. The lack of receptor-selective agonists has made it difficult to determine the role of the individual dopamine receptors in mediating these reinforcing effects. In this study, rhesus monkeys with a history of intravenous cocaine self-administration were tested for the reinforcing effects of several D(3)-preferring agonists, a D(2)-preferring agonist, and a D(4) agonist. The D(2)-preferring agonist did not maintain responding in any monkeys, and the D(4) agonist was self-administered at low rates, just above those maintained by saline, in one monkey. The D(3)-preferring agonists were self-administered by approximately half of the animals, although at lower rates than cocaine. These results indicate that the apparent limited reinforcing effectiveness of D(2)-like agonists requires activity at D(3) receptors. Previous data from this laboratory and others also suggest that these drugs may not serve as reinforcers directly; the behavior may be maintained by response-contingent delivery of stimuli previously paired with cocaine. The ability of drug-related stimuli to maintain responding apparently differs among monkeys and other organisms, and may be related to individual differences in drug-taking behavior in humans.
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Potential serotonin 5-HT(1A) and dopamine D(4) receptor modulation of the discriminative stimulus effects of amphetamine in rats. Behav Pharmacol 2011; 22:508-15. [PMID: 21814134 DOI: 10.1097/fbp.0b013e328349fc31] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Activation of the dopaminergic system underlies the behavioral effects of (+)-amphetamine, and plays a major role in its discriminative stimulus properties. Although serotonin receptors modulate dopamine levels in the brain, and 5-HT(1A) and 5-HT(2) receptor agonists do not mimic (+)-amphetamine, pretreatment with 5-HT(2A/2C) agonists significantly potentiates the (+)-amphetamine cue. Further, 5-HT(2) antagonists do not modify the discriminative stimulus effect of (+)-amphetamine, but 5-HT(1A) antagonists have never been tested in (+)-amphetamine-trained rats. This study sought to characterize the effects of the 5-HT(1A) antagonist WAY 100635 on (+)-amphetamine-induced discriminative stimulus effects. Male Sprague-Dawley rats were trained in a two-lever, fixed ratio 50, food-reinforced task with (+)-amphetamine sulfate (1.0 mg/kg, i.p., 30 min pretreatment time) as the discriminative stimulus. Substitution and combination tests with WAY 100635 were then performed. WAY 100635 did not produce substitution in amphetamine-trained rats, but significantly increased behavioral disruption. In combination tests 0.4 and 5.4 mg/kg doses of WAY 100635 potentiated the amphetamine cue. We suggest that low doses of WAY 100635 potentiated the (+)-amphetamine cue by blockade of 5-HT(1A) receptors, but stimulation of the dopamine D(4) receptor by higher doses of WAY 100635 may be responsible for potentiation of amphetamine-induced behavioral sensitization. The high percentage of behavioral disruption in substitution tests might suggest that rats trained to discriminate (+)-amphetamine from saline show behavioral sensitization that is not detectable by the drug discrimination assay but may be expressed as hyperactivity and stereotypic behavior that disrupts operant behavior.
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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: 233] [Impact Index Per Article: 17.9] [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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Marona-Lewicka D, Nichols CD, Nichols DE. An animal model of schizophrenia based on chronic LSD administration: old idea, new results. Neuropharmacology 2011; 61:503-12. [PMID: 21352832 DOI: 10.1016/j.neuropharm.2011.02.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Revised: 01/12/2011] [Accepted: 02/02/2011] [Indexed: 11/18/2022]
Abstract
Many people who take LSD experience a second temporal phase of LSD intoxication that is qualitatively different, and was described by Daniel Freedman as "clearly a paranoid state." We have previously shown that the discriminative stimulus effects of LSD in rats also occur in two temporal phases, with initial effects mediated by activation of 5-HT(2A) receptors (LSD30), and the later temporal phase mediated by dopamine D2-like receptors (LSD90). Surprisingly, we have now found that non-competitive NMDA antagonists produced full substitution in LSD90 rats, but only in older animals, whereas in LSD30, or in younger animals, these drugs did not mimic LSD. Chronic administration of low doses of LSD (>3 months, 0.16 mg/kg every other day) induces a behavioral state characterized by hyperactivity and hyperirritability, increased locomotor activity, anhedonia, and impairment in social interaction that persists at the same magnitude for at least three months after cessation of LSD treatment. These behaviors, which closely resemble those associated with psychosis in humans, are not induced by withdrawal from LSD; rather, they are the result of neuroadaptive changes occurring in the brain during the chronic administration of LSD. These persistent behaviors are transiently reversed by haloperidol and olanzapine, but are insensitive to MDL-100907. Gene expression analysis data show that chronic LSD treatment produced significant changes in multiple neurotransmitter system-related genes, including those for serotonin and dopamine. Thus, we propose that chronic treatment of rats with low doses of LSD can serve as a new animal model of psychosis that may mimic the development and progression of schizophrenia, as well as model the established disease better than current acute drug administration models utilizing amphetamine or NMDA antagonists such as PCP.
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MESH Headings
- Akathisia, Drug-Induced/etiology
- Animals
- Antipsychotic Agents/therapeutic use
- Behavior, Animal/drug effects
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Disease Models, Animal
- Dopamine Agonists/administration & dosage
- Dopamine Agonists/toxicity
- Gene Expression Regulation/drug effects
- Lysergic Acid Diethylamide/administration & dosage
- Lysergic Acid Diethylamide/toxicity
- Male
- Motor Activity/drug effects
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Psychotic Disorders/drug therapy
- Psychotic Disorders/metabolism
- Psychotic Disorders/physiopathology
- RNA, Messenger/metabolism
- Random Allocation
- Rats
- Rats, Sprague-Dawley
- Receptor, Serotonin, 5-HT2A/chemistry
- Receptor, Serotonin, 5-HT2C/genetics
- Receptor, Serotonin, 5-HT2C/metabolism
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, Steroid/genetics
- Receptors, Steroid/metabolism
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/metabolism
- Schizophrenia/drug therapy
- Schizophrenia/metabolism
- Schizophrenia/physiopathology
- Serotonin 5-HT2 Receptor Agonists/administration & dosage
- Serotonin 5-HT2 Receptor Agonists/toxicity
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Affiliation(s)
- Danuta Marona-Lewicka
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, 575 Stadium Mall Dr., Purdue University, West Lafayette, IN 47906-2091, USA
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30
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Characterization of behavioral and endocrine effects of LSD on zebrafish. Behav Brain Res 2010; 214:277-84. [DOI: 10.1016/j.bbr.2010.05.039] [Citation(s) in RCA: 190] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Accepted: 05/23/2010] [Indexed: 11/22/2022]
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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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32
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Winter JC. Hallucinogens as discriminative stimuli in animals: LSD, phenethylamines, and tryptamines. Psychopharmacology (Berl) 2009; 203:251-63. [PMID: 18979087 DOI: 10.1007/s00213-008-1356-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Accepted: 09/24/2008] [Indexed: 12/24/2022]
Abstract
BACKGROUND Although man's first encounters with hallucinogens predate written history, it was not until the rise of the sister disciplines of organic chemistry and pharmacology in the nineteenth century that scientific studies became possible. Mescaline was the first to be isolated and its chemical structure determined. Since then, additional drugs have been recovered from their natural sources and synthetic chemists have contributed many more. Given their profound effects upon human behavior and the need for verbal communication to access many of these effects, some see humans as ideal subjects for study of hallucinogens. However, if we are to determine the mechanisms of action of these agents, establish hypotheses testable in human subjects, and explore the mechanistic links between hallucinogens and such apparently disparate topics as idiopathic psychosis, transcendental states, drug abuse, stress disorders, and cognitive dysfunction, studies in animals are essential. Stimulus control by hallucinogens has provided an intuitively attractive approach to the study of these agents in nonverbal species. OBJECTIVE The intent of this review is to provide a brief account of events from the time of the first demonstration of hallucinogen-induced stimulus control to the present. In general, the review is limited to lysergic acid diethylamide (LSD) and the hallucinogenic derivatives of phenethylamine and tryptamine. RESULTS The pharmacological basis for stimulus control by LSD and hallucinogenic phenethylamines and tryptamines is serotonergic in nature. The 5-HT(2A) receptor appears to be the primary site of action with significant modulation by other serotonergic sites including 5-HT(2C) and 5-HT(1A) receptors. Interactions with other neurotransmitters, especially glutamate and dopamine, are under active investigation. Most studies to date have been conducted in the rat but transgenic mice offer interesting possibilities. CONCLUSIONS Hallucinogen-induced stimulus control provides a unique behavioral tool for the prediction of subjective effects in man and for the elucidation of the pharmacological mechanisms of the action of these agents.
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Affiliation(s)
- J C Winter
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, 102 Farber Hall, Buffalo, NY 14214-3000, USA.
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