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Wolfgang AS, Fonzo GA, Gray JC, Krystal JH, Grzenda A, Widge AS, Kraguljac NV, McDonald WM, Rodriguez CI, Nemeroff CB. MDMA and MDMA-Assisted Therapy. Am J Psychiatry 2025; 182:79-103. [PMID: 39741438 DOI: 10.1176/appi.ajp.20230681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2025]
Abstract
MDMA (i.e., 3,4-methylenedixoymethamphetamine), commonly known as "Ecstasy" or "Molly," has been used since the 1970s both in recreational and therapeutic settings. The Food and Drug Administration (FDA) designated MDMA-Assisted Therapy (MDMA-AT) as a Breakthrough Therapy for posttraumatic stress disorder (PTSD) in 2017, and the FDA is requiring an additional phase 3 trial after rejecting the initial New Drug Application in 2024. Unlike other psychedelics, MDMA uniquely induces prosocial subjective effects of heightened trust and self-compassion while maintaining ego functioning as well as cognitive and perceptual lucidity. While recreational use in nonmedical settings may still cause harm, especially due to adulterants or when used without proper precautions, conclusions that can be drawn from studies of recreational use are limited by many confounds. This especially limits the extent to which evidence related to recreational use can be extrapolated to therapeutic use. A considerable body of preliminary evidence suggests that MDMA-AT delivered in a controlled clinical setting is a safe and efficacious treatment for PTSD. After a course of MDMA-AT involving three MDMA administrations supported by psychotherapy, 67%-71% of individuals with PTSD no longer meet diagnostic criteria after MDMA-AT versus 32%-48% with placebo-assisted therapy, and effects endure at long-term follow-up. This review primarily aims to distinguish evidence of recreational use in nonclinical settings versus MDMA-AT using pharmaceutical-grade MDMA in controlled clinical settings. This review further describes the putative neurobiological mechanisms of MDMA underlying its therapeutic effects, the clinical evidence of MDMA-AT, considerations at the level of public health and policy, and future research directions.
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Affiliation(s)
- Aaron S Wolfgang
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - Gregory A Fonzo
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - Joshua C Gray
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - John H Krystal
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - Adrienne Grzenda
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - Alik S Widge
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - Nina V Kraguljac
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - William M McDonald
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - Carolyn I Rodriguez
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
| | - Charles B Nemeroff
- Directorate of Behavioral Health, Walter Reed National Military Medical Center, Bethesda, MD (Wolfgang); Departments of Psychiatry (Wolfgang) and Medical and Clinical Psychology (Gray), Uniformed Services University, Bethesda, MD; Departments of Psychiatry (Wolfgang, Krystal), Neuroscience (Krystal), and Psychology (Krystal), Yale University School of Medicine, New Haven, CT; Center for Psychedelic Research and Therapy, Department of Psychiatry and Behavioral Sciences, The University of Texas at Austin Dell Medical School (Fonzo, Nemeroff); Department of Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, UCLA (Grzenda); Department of Psychiatry & Behavioral Sciences, University of Minnesota, Minneapolis (Widge); Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham (Kraguljac); Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta (McDonald); Department of Psychiatry and Behavioral Sciences, Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, CA (Rodriguez)
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Inserra A, De Gregorio D, Gobbi G. Psychedelics in Psychiatry: Neuroplastic, Immunomodulatory, and Neurotransmitter Mechanisms. Pharmacol Rev 2021; 73:202-277. [PMID: 33328244 DOI: 10.1124/pharmrev.120.000056] [Citation(s) in RCA: 118] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [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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Lee J, Thwaites S, Gogos A, van den Buuse M. Pharmacological Mechanisms Involved in Sensory Gating Disruption Induced by (±)-3,4-Methylene- Dioxymethamphetamine (MDMA): Relevance to Schizophrenia. Brain Sci 2020; 10:brainsci10010044. [PMID: 31941052 PMCID: PMC7016806 DOI: 10.3390/brainsci10010044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/26/2019] [Accepted: 01/10/2020] [Indexed: 11/25/2022] Open
Abstract
Sensory gating deficits have been demonstrated in schizophrenia, but the mechanisms involved remain unclear. In the present study, we used disruption of paired-pulse gating of evoked potentials in rats by the administration of (±)-3,4-methylene-dioxymethamphetamine (MDMA) to study serotonergic and dopaminergic mechanisms involved in auditory sensory gating deficits. Male Sprague-Dawley rats were instrumented with cortical surface electrodes to record evoked potential changes in response to pairs of 85dB tones (S1 and S2), 500msec apart. Administration of MDMA eliminated the normal reduction in the amplitude of S2 compared to S1, representing disruption of auditory sensory gating. Pretreatment of the animals with the dopamine D1 receptor antagonist, SCH23390, the dopamine D2 receptor antagonist, haloperidol, the serotonin (5-HT)1A receptor antagonist, WAY100635, or the 5-HT2A receptor antagonist, ketanserin, all blocked the effect of MDMA, although the drugs differentially affected the individual S1 and S2 amplitudes. These data show involvement of both dopaminergic and serotonergic mechanisms in disruption of auditory sensory gating by MDMA. These and previous results suggest that MDMA targets serotonergic pathways, involving both 5-HT1A and 5-HT2A receptors, leading to dopaminergic activation, involving both D1 and D2 receptors, and ultimately sensory gating deficits. It is speculated that similar interactive mechanisms are affected in schizophrenia.
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Affiliation(s)
- Jaime Lee
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne 3010, Australia
| | - Shane Thwaites
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne 3010, Australia
| | - Andrea Gogos
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne 3010, Australia
| | - Maarten van den Buuse
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne 3010, Australia
- School of Psychology and Public Health, La Trobe University, Melbourne 3086, Australia
- Correspondence: ; Tel.: +61-394-795-257
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Schiavone S, Neri M, Maffione AB, Frisoni P, Morgese MG, Trabace L, Turillazzi E. Increased iNOS and Nitrosative Stress in Dopaminergic Neurons of MDMA-Exposed Rats. Int J Mol Sci 2019; 20:E1242. [PMID: 30871034 PMCID: PMC6429174 DOI: 10.3390/ijms20051242] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/28/2019] [Accepted: 03/05/2019] [Indexed: 12/29/2022] Open
Abstract
Several mechanisms underlying 3,4-Methylenedioxy-N-methylamphetamine (MDMA) neurotoxicity have been proposed, including neurochemical alterations and excitotoxicity mediated by reactive oxygen species (ROS), nitric oxide (NO), and reactive nitrogen species (RNS). However, ROS, NO, and RNS sources in the brain are not fully known. We aimed to investigate possible alterations in the expression of the ROS producer NOX enzymes (NOX2, NOX1, and NOX4), NO generators (iNOS, eNOS, and nNOS), markers of oxidative (8-hydroxy-2'-deoxyguanosine, 8OHdG), and nitrosative (3-nitrotyrosine, NT) stress, as well as the colocalization between cells positive for the dopamine transporter (DT1) and cells expressing the neuronal nuclei (NeuN) marker, in the frontal cortex of rats receiving saline or MDMA, sacrificed 6 h, 16 h, or 24 h after its administration. MDMA did not affect NOX2, NOX1, and NOX4 immunoreactivity, whereas iNOS expression was enhanced. The number of NT-positive cells was increased in MDMA-exposed animals, whereas no differences were detected in 8OHdG expression among experimental groups. MDMA and NT markers colocalized with DT1 positive cells. DT1 immunostaining was found in NeuN-positive stained cells. Virtually no colocalization was observed with microglia and astrocytes. Moreover, MDMA immunostaining was not found in NOX2-positive cells. Our results suggest that iNOS-derived nitrosative stress, but not NOX enzymes, may have a crucial role in the pathogenesis of MDMA-induced neurotoxicity, highlighting the specificity of different enzymatic systems in the development of neuropathological alterations induced by the abuse of this psychoactive compound.
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Affiliation(s)
- Stefania Schiavone
- Department of Clinical and Experimental Medicine, University of Foggia, Via Napoli, 20, 71122 Foggia, Italy.
| | - Margherita Neri
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Fossato di Mortara, 70, 44100 Ferrara, Italy.
| | - Angela Bruna Maffione
- Department of Clinical and Experimental Medicine, University of Foggia, Via Napoli, 20, 71122 Foggia, Italy.
| | - Paolo Frisoni
- Department of Morphology, Surgery and Experimental Medicine, University of Ferrara, Via Fossato di Mortara, 70, 44100 Ferrara, Italy.
| | - Maria Grazia Morgese
- Department of Clinical and Experimental Medicine, University of Foggia, Via Napoli, 20, 71122 Foggia, Italy.
| | - Luigia Trabace
- Department of Clinical and Experimental Medicine, University of Foggia, Via Napoli, 20, 71122 Foggia, Italy.
| | - Emanuela Turillazzi
- Section of Legal Medicine, Department of Surgical, Medical, Molecular and Critical Pathology, University of Pisa, Via Roma 55, 56126 Pisa, Italy.
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Saber I, Milewski A, Reitz AB, Rawls SM, Walker EA. Effects of dopaminergic and serotonergic compounds in rats trained to discriminate a high and a low training dose of the synthetic cathinone mephedrone. Psychopharmacology (Berl) 2019; 236:1015-1029. [PMID: 30980094 PMCID: PMC6589396 DOI: 10.1007/s00213-019-05241-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 03/24/2019] [Indexed: 12/29/2022]
Abstract
RATIONALE The underlying pharmacological mechanisms of mephedrone, especially as related to interactions with different neurotransmitter systems, are a critical area of study as mephedrone continues to be abused. OBJECTIVE Direct-acting 5-HT2A/2C receptor agonists and antagonists and D1-3 receptor antagonists were examined in two groups of rats trained to discriminate mephedrone. A high dose of mephedrone was trained to extend previous results with traditional monoamine transporter inhibitors and substrate releasers. A very low dose of mephedrone was trained to preferentially capture serotonergic activity and to minimize the influence of rate-decreasing effects on substitution patterns. Selective 5-HT2A/2C and D1-3 receptor antagonists were examined in both groups. METHODS Male Sprague-Dawley rats were trained to discriminate either a low dose of 0.5 mg/kg mephedrone (N = 24) or a high dose of 3.2 mg/kg mephedrone (N = 11) from saline. RESULTS In the low training-dose group, mephedrone, MDMA, methamphetamine, d-amphetamine, cocaine, and enantiomers of mephedrone substituted for mephedrone; mCPP partially substituted overall for mephedrone; and DOI, WAY163909, and morphine failed to substitute for mephedrone. In the high training-dose group, only mephedrone and MDMA substituted for mephedrone. Sulpiride produced a small antagonism of the low training dose of mephedrone while SCH23390, SB242084, and ketanserin altered response rates. CONCLUSIONS A lower training dose of mephedrone produces a discriminative stimulus fully mimicked by MDMA, methamphetamine, cocaine, and d-amphetamine, whereas a higher training dose of mephedrone requires a discriminative stimulus that was only mimicked by MDMA. Dopaminergic or serotoninergic antagonists failed to produce significant blockade of mephedrone at either training dose.
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Affiliation(s)
- Iman Saber
- Department of Pharmaceutical Sciences, School of Pharmacy, Temple University, Philadelphia, Pennsylvania, USA
| | - Andrew Milewski
- Department of Pharmaceutical Sciences, School of Pharmacy, Temple University, Philadelphia, Pennsylvania, USA
| | | | - Scott M. Rawls
- Center for Substance Abuse Research, and Temple University, Philadelphia, Pennsylvania, USA,Department of Pharmacology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
| | - Ellen A. Walker
- Department of Pharmaceutical Sciences, School of Pharmacy, Temple University, Philadelphia, Pennsylvania, USA,Center for Substance Abuse Research, and Temple University, Philadelphia, Pennsylvania, USA
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