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Avgana H, Toledano RS, Akirav I. Examining the Role of Oxytocinergic Signaling and Neuroinflammatory Markers in the Therapeutic Effects of MDMA in a Rat Model for PTSD. Pharmaceuticals (Basel) 2024; 17:846. [PMID: 39065697 PMCID: PMC11279644 DOI: 10.3390/ph17070846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 06/20/2024] [Accepted: 06/25/2024] [Indexed: 07/28/2024] Open
Abstract
MDMA-assisted psychotherapy has shown potential as an effective treatment for post-traumatic stress disorder (PTSD). Preclinical studies involving rodents have demonstrated that MDMA can facilitate the extinction of fear memories. It has been noted that MDMA impacts oxytocin neurons and pro-inflammatory cytokines. Thus, the aim of this study was to explore the role of oxytocinergic signaling and neuroinflammatory markers in the therapeutic effects of MDMA. To achieve this, male rats were subjected to a model of PTSD involving exposure to shock and situational reminders. MDMA was microinjected into the medial prefrontal cortex (mPFC) before extinction training, followed by behavioral tests assessing activity levels, anxiety, and social function. Our findings indicate that MDMA treatment facilitated fear extinction and mitigated the shock-induced increase in freezing, as well as deficits in social behavior. Shock exposure led to altered expression of the gene coding for OXT-R and neuroinflammation in the mPFC and basolateral amygdala (BLA), which were restored by MDMA treatment. Importantly, the OXT-R antagonist L-368,899 prevented MDMA's therapeutic effects on extinction and freezing behavior. In conclusion, MDMA's therapeutic effects in the PTSD model are associated with alterations in OXT-R expression and neuroinflammation, and MDMA's effects on extinction and anxiety may be mediated by oxytocinergic signaling.
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Affiliation(s)
- Haron Avgana
- Department of Psychology, School of Psychological Sciences, University of Haifa, Haifa 3498838, Israel; (H.A.); (R.S.T.)
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa 3498838, Israel
| | - Roni Shira Toledano
- Department of Psychology, School of Psychological Sciences, University of Haifa, Haifa 3498838, Israel; (H.A.); (R.S.T.)
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa 3498838, Israel
| | - Irit Akirav
- Department of Psychology, School of Psychological Sciences, University of Haifa, Haifa 3498838, Israel; (H.A.); (R.S.T.)
- The Integrated Brain and Behavior Research Center (IBBRC), University of Haifa, Haifa 3498838, Israel
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2
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Pantoni MM, Kim JL, Van Alstyne KR, Anagnostaras SG. MDMA and memory, addiction, and depression: dose-effect analysis. Psychopharmacology (Berl) 2022; 239:935-949. [PMID: 35179622 PMCID: PMC8891111 DOI: 10.1007/s00213-022-06086-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/07/2022] [Indexed: 12/17/2022]
Abstract
RATIONALE ±3,4-Methylenedioxymethamphetamine (MDMA) is a recreational drug that shows substantial promise as a psychotherapeutic agent. Still, there is some concern regarding its behavioral toxicity, and its dose-effect relationship is poorly understood. We previously explored the role of dose in the cognitive effects of MDMA in a systematic review of existing literature and found no evidence in animals that MDMA impairs memory at low doses (< 3 mg/kg) but mixed results at high doses (≥ 3 mg/kg). Since this review comprised mostly of single-dose studies and an assortment of methodologies, an empirical dose-ranging study on this topic is warranted. OBJECTIVES The current study aims to evaluate the conclusion from our systematic review that 3 mg/kg may be the threshold for MDMA-induced amnesia, and to further understand the dose-effect relationship of MDMA on behavioral assays of memory, addiction, and depression. METHODS We systematically examined the effects of 0.01 to 10 mg/kg MDMA on Pavlovian fear conditioning; behavioral sensitization, conditioned place preference, and conditioned responding; and the Porsolt forced swim test in mice. RESULTS High doses of MDMA (≥ 3 mg/kg) produced amnesia of fear conditioning memory, some evidence of an addictive potential, and antidepressant effects, while low doses of MDMA (≤ 1 mg/kg) had no effect on these behaviors. CONCLUSIONS The present dose-ranging study provides further evidence that 3 mg/kg is the threshold for MDMA-induced amnesia. These findings, in addition to our systematic review, demonstrate that careful selection of MDMA dose is critical. High doses (≥ 3 mg/kg) should likely be avoided due to evidence that they can produce amnesia and addiction. Conversely, there is little evidence to suggest that low doses, which are usually administered in clinical studies (approximately 1-2 mg/kg), will lead to these same adverse effects. Ultra-low doses (< 1 mg/kg) are likely even safer and should be investigated for therapeutic effects in future studies.
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Affiliation(s)
- Madeline M. Pantoni
- grid.266100.30000 0001 2107 4242Molecular Cognition Laboratory, Department of Psychology, University of California San Diego, La Jolla, CA USA ,grid.266102.10000 0001 2297 6811Translational Psychedelic Research Program, Department of Psychiatry and Behavioral Sciences, University of California San Francisco, CA San Francisco, USA
| | - Jinah L. Kim
- grid.266100.30000 0001 2107 4242Molecular Cognition Laboratory, Department of Psychology, University of California San Diego, La Jolla, CA USA
| | - Kaitlin R. Van Alstyne
- grid.266100.30000 0001 2107 4242Molecular Cognition Laboratory, Department of Psychology, University of California San Diego, La Jolla, CA USA
| | - Stephan G. Anagnostaras
- grid.266100.30000 0001 2107 4242Molecular Cognition Laboratory, Department of Psychology, University of California San Diego, La Jolla, CA USA ,grid.266100.30000 0001 2107 4242Molecular Cognition Laboratory, Program in Neurosciences, University of California San Diego, La Jolla, CA USA
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3
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Chaliha D, Mamo JC, Albrecht M, Lam V, Takechi R, Vaccarezza M. A Systematic Review of the MDMA Model to Address Social Impairment in Autism. Curr Neuropharmacol 2021; 19:1101-1154. [PMID: 33388021 PMCID: PMC8686313 DOI: 10.2174/1570159x19666210101130258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/27/2020] [Accepted: 12/13/2020] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder characterised by repetitive behaviours, cognitive rigidity/inflexibility, and social-affective impairment. Unfortunately, no gold-standard treatments exist to alleviate the core socio-behavioural impairments of ASD. Meanwhile, the prosocial empathogen/entactogen 3,4-methylene-dioxy-methamphetamine (MDMA) is known to enhance sociability and empathy in both humans and animal models of psychological disorders. OBJECTIVE We review the evidence obtained from behavioural tests across the current literature, showing how MDMA can induce prosocial effects in animals and humans, where controlled experiments were able to be performed. METHODS Six electronic databases were consulted. The search strategy was tailored to each database. Only English-language papers were reviewed. Behaviours not screened in this review may have affected the core ASD behaviours studied. Molecular analogues of MDMA have not been investigated. RESULTS We find that the social impairments may potentially be alleviated by postnatal administration of MDMA producing prosocial behaviours in mostly the animal model. CONCLUSION MDMA and/or MDMA-like molecules appear to be an effective pharmacological treatment for the social impairments of autism, at least in animal models. Notably, clinical trials based on MDMA use are now in progress. Nevertheless, larger and more extended clinical studies are warranted to prove the assumption that MDMA and MDMA-like molecules have a role in the management of the social impairments of autism.
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Affiliation(s)
| | | | | | | | | | - Mauro Vaccarezza
- Address correspondence to this author at the Curtin Medical School, Curtin Health Innovation Research Institute, P.O. Box 6845, WA 6102 Perth, Australia; Tel: 08 9266 7671; E-mail:
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Fernández-Teruel A, Tobeña A. Revisiting the role of anxiety in the initial acquisition of two-way active avoidance: pharmacological, behavioural and neuroanatomical convergence. Neurosci Biobehav Rev 2020; 118:739-758. [PMID: 32916193 DOI: 10.1016/j.neubiorev.2020.08.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 07/10/2020] [Accepted: 08/15/2020] [Indexed: 12/19/2022]
Abstract
Two-way active avoidance (TWAA) acquisition constitutes a particular case of approach -avoidance conflict for laboratory rodents. The present article reviews behavioural, psychopharmacological and neuroanatomical evidence accumulated along more than fifty years that provides strong support to the contention that anxiety is critical in the transition from CS (conditioned stimulus)-induced freezing to escape/avoidance responses during the initial stages of TWAA acquisition. Thus, anxiolytic drugs of different types accelerate avoidance acquisition, anxiogenic drugs impair it, and avoidance during these initial acquisition stages is negatively associated with other typical measures of anxiety. In addition behavioural and developmental treatments that reduce or increase anxiety/stress respectively facilitate or impair TWAA acquisition. Finally, evidence for the regulation of TWAA acquisition by septo-hippocampal and amygdala-related mechanisms is discussed. Collectively, the reviewed evidence gives support to the initial acquisition of TWAA as a paradigm with considerable predictive and (in particular) construct validity as an approach-avoidance conflict-based rodent anxiety model.
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Affiliation(s)
- Alberto Fernández-Teruel
- Medical Psychology Unit, Department of Psychiatry and Forensic Medicine, Institute of Neurosciences, School of Medicine, Autonomous University of Barcelona, 08193-Bellaterra, Barcelona, Spain.
| | - Adolf Tobeña
- Medical Psychology Unit, Department of Psychiatry and Forensic Medicine, Institute of Neurosciences, School of Medicine, Autonomous University of Barcelona, 08193-Bellaterra, Barcelona, Spain
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5
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Müller CP. Drug instrumentalization. Behav Brain Res 2020; 390:112672. [PMID: 32442549 DOI: 10.1016/j.bbr.2020.112672] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 12/19/2022]
Abstract
Psychoactive drugs with addiction potential are widely used by people of virtually all cultures in a non-addictive way. In order to understand this behaviour, its population penetrance, and its persistence, drug instrumentalization was suggested as a driving force for this consumption. Drug instrumentalization theory holds that psychoactive drugs are consumed in a very systematic way in order to make other, non-drug-related behaviours more efficient. Here, we review the evolutionary origin of this behaviour and its psychological mechanisms and explore the neurobiological and neuropharmacological mechanisms underlying them. Instrumentalization goals are discussed, for which an environmentally selective and mental state-dependent consumption of psychoactive drugs can be learned and maintained in a non-addictive way. A small percentage of people who regularly instrumentalize psychoactive drugs make a transition to addiction, which often starts with qualitative and quantitative changes in the instrumentalization goals. As such, addiction is proposed to develop from previously established long-term drug instrumentalization. Thus, preventing and treating drug addiction in an individualized medicine approach may essentially require understanding and supporting personal instrumentalization goals.
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Affiliation(s)
- Christian P Müller
- Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander-University Erlangen-Nürnberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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6
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Ahmed SH, Badiani A, Miczek KA, Müller CP. Non-pharmacological factors that determine drug use and addiction. Neurosci Biobehav Rev 2020; 110:3-27. [PMID: 30179633 PMCID: PMC6395570 DOI: 10.1016/j.neubiorev.2018.08.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/26/2018] [Accepted: 08/28/2018] [Indexed: 12/26/2022]
Abstract
Based on their pharmacological properties, psychoactive drugs are supposed to take control of the natural reward system to finally drive compulsory drug seeking and consumption. However, psychoactive drugs are not used in an arbitrary way as pure pharmacological reinforcement would suggest, but rather in a highly specific manner depending on non-pharmacological factors. While pharmacological effects of psychoactive drugs are well studied, neurobiological mechanisms of non-pharmacological factors are less well understood. Here we review the emerging neurobiological mechanisms beyond pharmacological reinforcement which determine drug effects and use frequency. Important progress was made on the understanding of how the character of an environment and social stress determine drug self-administration. This is expanded by new evidence on how behavioral alternatives and opportunities for drug instrumentalization generate different patterns of drug choice. Emerging evidence suggests that the neurobiology of non-pharmacological factors strongly determines pharmacological and behavioral drug action and may, thus, give rise for an expanded system's approach of psychoactive drug use and addiction.
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Affiliation(s)
- Serge H Ahmed
- Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, 146 rue Léo-Saignat, F-33000 Bordeaux, France; CNRS, Institut des Maladies Neurodégénératives, UMR 5293, 146 rue Léo-Saignat, F-33000 Bordeaux, France
| | - Aldo Badiani
- Department of Physiology and Pharmacology, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy; Sussex Addiction Research and Intervention Centre (SARIC), School of Psychology, University of Sussex, BN1 9RH Brighton, UK
| | - Klaus A Miczek
- Psychology Department, Tufts University, Bacon Hall, 530 Boston Avenue, Medford, MA 02155, USA; Department of Neuroscience, Sackler School of Graduate Biomedical Sciences, Boston, MA 02111, USA
| | - Christian P Müller
- Department of Psychiatry and Psychotherapy, University Clinic, Friedrich-Alexander-University Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen, Germany.
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7
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Costa G, De Luca MA, Piras G, Marongiu J, Fattore L, Simola N. Neuronal and peripheral damages induced by synthetic psychoactive substances: an update of recent findings from human and animal studies. Neural Regen Res 2020; 15:802-816. [PMID: 31719240 PMCID: PMC6990793 DOI: 10.4103/1673-5374.268895] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Preclinical and clinical studies indicate that synthetic psychoactive substances, in addition to having abuse potential, may elicit toxic effects of varying severity at the peripheral and central levels. Nowadays, toxicity induced by synthetic psychoactive substances poses a serious harm for health, since recreational use of these substances is on the rise among young and adult people. The present review summarizes recent findings on the peripheral and central toxicity elicited by “old” and “new” synthetic psychoactive substances in humans and experimental animals, focusing on amphetamine derivatives, hallucinogen and dissociative drugs and synthetic cannabinoids.
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Affiliation(s)
- Giulia Costa
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Maria Antonietta De Luca
- Department of Biomedical Sciences; National Institute of Neuroscience (INN), University of Cagliari, Cagliari, Italy
| | - Gessica Piras
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Jacopo Marongiu
- Department of Biomedical Sciences, University of Cagliari, Cagliari, Italy
| | - Liana Fattore
- National Research Council of Italy, Institute of Neuroscience, Cagliari, Italy
| | - Nicola Simola
- Department of Biomedical Sciences; National Institute of Neuroscience (INN), University of Cagliari, Cagliari, Italy
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8
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Dunlap LE, Andrews AM, Olson DE. Dark Classics in Chemical Neuroscience: 3,4-Methylenedioxymethamphetamine. ACS Chem Neurosci 2018; 9:2408-2427. [PMID: 30001118 PMCID: PMC6197894 DOI: 10.1021/acschemneuro.8b00155] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Better known as "ecstasy", 3,4-methylenedioxymethamphetamine (MDMA) is a small molecule that has played a prominent role in defining the ethos of today's teenagers and young adults, much like lysergic acid diethylamide (LSD) did in the 1960s. Though MDMA possesses structural similarities to compounds like amphetamine and mescaline, it produces subjective effects that are unlike any of the classical psychostimulants or hallucinogens and is one of the few compounds capable of reliably producing prosocial behavioral states. As a result, MDMA has captured the attention of recreational users, the media, artists, psychiatrists, and neuropharmacologists alike. Here, we detail the synthesis of MDMA as well as its pharmacology, metabolism, adverse effects, and potential use in medicine. Finally, we discuss its history and why it is perhaps the most important compound for the future of psychedelic science-having the potential to either facilitate new psychedelic research initiatives, or to usher in a second Dark Age for the field.
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Affiliation(s)
- Lee E Dunlap
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
| | - Anne M Andrews
- Departments of Psychiatry and Chemistry & Biochemistry, Semel Institute for Neuroscience and Human Behavior, and Hatos Center for Neuropharmacology , University of California , Los Angeles , California 90095 , United States
| | - David E Olson
- Department of Chemistry , University of California, Davis , One Shields Avenue , Davis , California 95616 , United States
- Department of Biochemistry & Molecular Medicine, School of Medicine , University of California, Davis , 2700 Stockton Blvd, Suite 2102 , Sacramento , California 95817 , United States
- Center for Neuroscience , University of California, Davis , 1544 Newton Ct , Davis , California 95616 , United States
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9
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Alteration of adolescent aversive nicotine response and anxiety-like behavior in nicotine-exposed rats during late lactation period. Behav Brain Res 2017; 337:122-130. [PMID: 28943427 DOI: 10.1016/j.bbr.2017.09.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/15/2017] [Accepted: 09/20/2017] [Indexed: 11/21/2022]
Abstract
Early nicotine exposure is an important cause of further habitual tobacco smoking. Although nicotine has not only rewarding but also aversive properties, the effects of early nicotine exposure on the distinct properties of nicotine are not well known. To reveal the effects of early adolescent nicotine exposure on further persistent tobacco smoking, we demonstrated developmental changes in nicotine-related appetitive and aversive behaviors of rats exposed to nicotine during the late lactation period. Sprague-Dawley rats were injected with saline or nicotine (2, 6 and 12mg/kg). We performed a two bottle free-choice test using escalating doses of nicotine (25, 50 and 100μg/ml), saccharin and quinine and the open field test in both adolescent and adult rats. The rats' aversive response to nicotine was increased according to the increase in nicotine concentration. Adolescent rats showed higher nicotine preference and consumption behaviors than did adult rats at an aversive dose of nicotine. Nicotine-exposed rats increased adolescent nicotine consumption when the nicotine concentration was 12mg/kg. We observed significant increases in anxious behaviors in adolescent nicotine-injected rats compared to saline-injected rats, but there were no alterations in adult rats. In both adolescent and adult rats, saccharin and quinine intake were not significantly different between groups. Taken together, it suggests that repeated nicotine exposure in late lactation period affect changes in aversive nicotine responses and anxious behaviors during adolescence but there is no difference in adults.
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10
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Ponzoni L, Braida D, Bondiolotti G, Sala M. The Non-Peptide Arginine-Vasopressin v 1a Selective Receptor Antagonist, SR49059, Blocks the Rewarding, Prosocial, and Anxiolytic Effects of 3,4-Methylenedioxymethamphetamine and Its Derivatives in Zebra Fish. Front Psychiatry 2017; 8:146. [PMID: 28855876 PMCID: PMC5557732 DOI: 10.3389/fpsyt.2017.00146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/27/2017] [Indexed: 01/23/2023] Open
Abstract
3,4-Methylenedioxymethamphetamine (MDMA) and its derivatives, 2,5-dimethoxy-4-bromo-amphetamine hydrobromide (DOB) and para-methoxyamphetamine (PMA), are recreational drugs whose pharmacological effects have recently been attributed to serotonin 5HT2A/C receptors. However, there is growing evidence that the oxytocin (OT)/vasopressin system can modulate some the effects of MDMA. In this study, MDMA (2.5-10 mg/kg), DOB (0.5 mg/kg), or PMA (0.005, 0.1, or 0.25 mg/kg) were administered intramuscularly to adult zebra fish, alone or in combination with the V1a vasopressin antagonist, SR49059 (0.01-1 ng/kg), before carrying out conditioned place preference (CPP), social preference, novel tank diving, and light-dark tests in order to evaluate subsequent rewarding, social, and emotional-like behavior. The combination of SR49059 and each drug progressively blocked: (1) rewarding behavior as measured by CPP in terms of time spent in drug-paired compartment; (2) prosocial effects measured on the basis of the time spent in the proximity of a nacre fish picture; and (3) anxiolytic effects in terms of the time spent in the upper half of the novel tank and in the white compartment of the tank used for the light-dark test. Antagonism was obtained at SR49059 doses which, when given alone, did not change motor function. In comparison with a control group, receiving vehicle alone, there was a three to five times increase in the brain release of isotocin (the analog of OT in fish) after treatment with the most active doses of MDMA (10 mg/kg), DOB (0.5 mg/kg), and PMA (0.1 mg/kg) as evaluated by means of bioanalytical reversed-phase high-performance liquid chromatography. Taken together, these findings show that the OT/vasopressin system is involved in the rewarding, prosocial, and anxiolytic effects of MDMA, DOB, and PMA in zebra fish and underline the association between this system and the behavioral alterations associated with disorders related to substance abuse.
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Affiliation(s)
| | - Daniela Braida
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Gianpietro Bondiolotti
- Department of Medical Biotechnology and Translational Medicine (BIOMETRA), Università degli Studi di Milano, Milan, Italy
| | - Mariaelvina Sala
- Institute of Neuroscience, Consiglio Nazionale delle Ricerche (CNR), Milan, Italy
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11
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Shortall SE, Green AR, Fone KC, King MV. Caffeine alters the behavioural and body temperature responses to mephedrone without causing long-term neurotoxicity in rats. J Psychopharmacol 2016; 30:698-706. [PMID: 27257032 DOI: 10.1177/0269881116650408] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Administration of caffeine with 3,4-methylenedioxymethamphetamine (MDMA) alters the pharmacological properties of MDMA in rats. The current study examined whether caffeine alters the behavioural and neurochemical effects of mephedrone, which has similar psychoactive effects to MDMA. Rats received either saline, mephedrone (10 mg/kg), caffeine (10 mg/kg) or combined caffeine and mephedrone intraperitoneally twice weekly on consecutive days for three weeks. Locomotor activity (days 1 and 16), novel object discrimination (NOD, day 2), elevated plus maze (EPM) exploration (day 8), rectal temperature changes (day 9) and pre-pulse inhibition (PPI) of acoustic startle response (day 15) were assessed. Seven days after the final injection, brain regions were collected for the measurement of 5-hydroxytryptamine (5-HT), dopamine and their metabolites. Combined caffeine and mephedrone further enhanced the locomotor response observed following either drug administered alone, and converted mephedrone-induced hypothermia to hyperthermia. Co-administration also abolished mephedrone-induced anxiogenic response on the EPM, but had no effect on NOD or PPI. Importantly, no long-term neurotoxicity was detected following repeated mephedrone alone or when co-administered with caffeine. In conclusion, the study suggests a potentially dangerous effect of concomitant caffeine and mephedrone, and highlights the importance of taking polydrug use into consideration when investigating the acute adverse effect profile of popular recreational drugs.
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Affiliation(s)
- Sinead E Shortall
- School of Life Sciences, Medical School, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
| | - A Richard Green
- School of Life Sciences, Medical School, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
| | - Kevin Cf Fone
- School of Life Sciences, Medical School, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
| | - Madeleine V King
- School of Life Sciences, Medical School, Queen's Medical Centre, The University of Nottingham, Nottingham, UK
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12
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Abstract
Most people who are regular consumers of psychoactive drugs are not drug addicts, nor will they ever become addicts. In neurobiological theories, non-addictive drug consumption is acknowledged only as a "necessary" prerequisite for addiction, but not as a stable and widespread behavior in its own right. This target article proposes a new neurobiological framework theory for non-addictive psychoactive drug consumption, introducing the concept of "drug instrumentalization." Psychoactive drugs are consumed for their effects on mental states. Humans are able to learn that mental states can be changed on purpose by drugs, in order to facilitate other, non-drug-related behaviors. We discuss specific "instrumentalization goals" and outline neurobiological mechanisms of how major classes of psychoactive drugs change mental states and serve non-drug-related behaviors. We argue that drug instrumentalization behavior may provide a functional adaptation to modern environments based on a historical selection for learning mechanisms that allow the dynamic modification of consummatory behavior. It is assumed that in order to effectively instrumentalize psychoactive drugs, the establishment of and retrieval from a drug memory is required. Here, we propose a new classification of different drug memory subtypes and discuss how they interact during drug instrumentalization learning and retrieval. Understanding the everyday utility and the learning mechanisms of non-addictive psychotropic drug use may help to prevent abuse and the transition to drug addiction in the future.
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13
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Rao RM, Sadananda M. Influence of State and/or Trait Anxieties of Wistar Rats in an Anxiety Paradigm. Ann Neurosci 2016; 23:44-50. [PMID: 27536021 PMCID: PMC4934415 DOI: 10.1159/000443555] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 11/24/2015] [Indexed: 11/19/2022] Open
Abstract
Systematic individual differences between male Wistar rats can be detected in paradigms such as the elevated plus maze (EPM), which is a widely used behavioral paradigm that measures fear-motivated avoidance behavior. It has been extensively used to assess anxiety profiles with face, construct and predictive validities. During a typical EPM test, animals actively avoid the open arms in favour of the closed arms. We investigated whether individuals carry inherent trait anxiety profiles and whether perturbations of different intensities influence anxiety measures. Inherent anxiety levels and coping strategies following stress have become critical determinants in pre-disposition to other neuropsychiatric disorders and affect biomedical interventions in individuals. One group of rats was screened on EPM and in the activity box. Another set of rats were randomly divided into groups and subjected to perturbations of acute and sub-chronic isolation or restraint and tested in the EPM. Based on open-arm time in the EPM, low or high anxiety profiles were identified with significant differences in all measures. Perturbations of different intensities induced differential anxiety measures as expressed in the EPM. Anxiety levels were significantly reduced in sub-chronic restrained subjects, while isolation did not show marked difference. Anxiety profiles become evident from broad sample sizes and could constitute a critical limiting factor in personalized treatments. Stress-induced anxiety disorders could implicate comorbidity to other neuropsychiatric disorders in individuals. Coping strategies come to the fore in repeated sub-chronic perturbations indicating adaptive responses to the stressor, while acute perturbation enhances expression of anxiety behaviors.
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Affiliation(s)
- Rashmi Madhava Rao
- Brain Research Laboratory, Biotechnology Division, Department of Biosciences, Mangalore University, Mangalagangothri, Mangalore, India
| | - Monika Sadananda
- Brain Research Laboratory, Biotechnology Division, Department of Biosciences, Mangalore University, Mangalagangothri, Mangalore, India
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14
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The novelty-seeking phenotype modulates the long-lasting effects of adolescent MDMA exposure. Physiol Behav 2015; 141:190-8. [PMID: 25619952 DOI: 10.1016/j.physbeh.2015.01.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 01/19/2015] [Accepted: 01/21/2015] [Indexed: 12/18/2022]
Abstract
Exposure to drugs such as ethanol or cocaine during adolescence induces alterations in the central nervous system that are modulated by the novelty-seeking trait. Our aim was to evaluate the influence of this trait on the long-term effects of MDMA administration during adolescence on spontaneous behavior and conditioned rewarding effects in adulthood. Adolescent mice were classified as high or low novelty seekers (HNS or LNS) according to the hole-board test and received either MDMA (0, 10 or 20mg/kg PND 33-42) or saline. Three weeks later, having entered adulthood (PND>68), one set of mice performed the elevated plus maze and social interaction tests, while another set performed the conditioning place preference (CPP) test induced by cocaine-(1mg/kg) or MDMA-(1mg/kg). Only HNS mice treated with MDMA during adolescence acquired CPP in adulthood with a non-effective dose of cocaine or MDMA. Although it did not produce changes in motor activity, exposure to MDMA during adolescence was associated with more aggressive behaviors (threat and attack) and increased social contacts in HNS mice, while an anxiolytic effect was noted in LNS mice pre-treated with the highest dose of MDMA (20mg/kg). Administration of MDMA (10 or 20mg/kg) induced a decrease in DA levels in the striatum in LNS mice only and lower striatal serotonin levels in mice treated with the highest MDMA dose. Our findings show that adolescent MDMA exposure results in higher sensitivity to the conditioned reinforcing properties of MDMA and cocaine in adult HNS mice, which suggests that the relationship between exposure to MDMA in adolescence and a higher probability of substance is a feature of high novelty seekers only.
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Green AR, King MV, Shortall SE, Fone KCF. The preclinical pharmacology of mephedrone; not just MDMA by another name. Br J Pharmacol 2014; 171:2251-68. [PMID: 24654568 DOI: 10.1111/bph.12628] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Revised: 12/05/2013] [Accepted: 12/11/2013] [Indexed: 01/15/2023] Open
Abstract
The substituted β-keto amphetamine mephedrone (4-methylmethcathinone) was banned in the UK in April 2010 but continues to be used recreationally in the UK and elsewhere. Users have compared its psychoactive effects to those of 3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy'). This review critically examines the preclinical data on mephedrone that have appeared over the last 2-3 years and, where relevant, compares the pharmacological effects of mephedrone in experimental animals with those obtained following MDMA administration. Both mephedrone and MDMA enhance locomotor activity and change rectal temperature in rodents. However, both of these responses are of short duration following mephedrone compared with MDMA probably because mephedrone has a short plasma half-life and rapid metabolism. Mephedrone appears to have no pharmacologically active metabolites, unlike MDMA. There is also little evidence that mephedrone induces a neurotoxic decrease in monoamine concentration in rat or mouse brain, again in contrast to MDMA. Mephedrone and MDMA both induce release of dopamine and 5-HT in the brain as shown by in vivo and in vitro studies. The effect on 5-HT release in vivo is more marked with mephedrone even though both drugs have similar affinity for the dopamine and 5-HT transporters in vitro. The profile of action of mephedrone on monoamine receptors and transporters suggests it could have a high abuse liability and several studies have found that mephedrone supports self-administration at a higher rate than MDMA. Overall, current data suggest that mephedrone not only differs from MDMA in its pharmacological profile, behavioural and neurotoxic effects, but also differs from other cathinones.
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Affiliation(s)
- A R Green
- School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
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López-Arnau R, Martínez-Clemente J, Pubill D, Escubedo E, Camarasa J. Serotonergic impairment and memory deficits in adolescent rats after binge exposure of methylone. J Psychopharmacol 2014; 28:1053-63. [PMID: 25237120 DOI: 10.1177/0269881114548439] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Methylone is a cathinone derivative that has recently emerged as a designer drug of abuse in Europe and the USA. Studies on the acute and long-term neurotoxicity of cathinones are starting to be conducted. We investigated the neurochemical/enzymatic changes indicative of neurotoxicity after methylone administration (4 × 20 mg/kg, subcutaneously, per day with 3 h intervals) to adolescent rats, to model human recreational use. In addition, we studied the effect of methylone on spatial learning ad memory using the Morris water maze paradigm. Our experiments were carried out at a high ambient temperature to simulate the hot conditions found in dance clubs where the drug is consumed. We observed a hyperthermic response to methylone that reached a peak 30 min after each dose. We determined a serotonergic impairment in methylone-treated rats, especially in the frontal cortex, where it was accompanied by astrogliosis. Some serotonergic alterations were also present in the hippocampus and striatum. No significant neurotoxic effect on the dopaminergic system was identified. Methylone-treated animals only displayed impairments in the probe trial of the Morris water maze, which concerns reference memory, while the spatial learning process seemed to be preserved.
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Affiliation(s)
- Raúl López-Arnau
- Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section) and Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - José Martínez-Clemente
- Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section) and Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - David Pubill
- Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section) and Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Elena Escubedo
- Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section) and Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
| | - Jorge Camarasa
- Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section) and Institute of Biomedicine (IBUB), Faculty of Pharmacy, University of Barcelona, Barcelona, Spain
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50-kHz calls in rats: Effects of MDMA and the 5-HT1A receptor agonist 8-OH-DPAT. Pharmacol Biochem Behav 2012; 101:258-64. [DOI: 10.1016/j.pbb.2012.01.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 01/10/2012] [Accepted: 01/14/2012] [Indexed: 11/18/2022]
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18
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Pawlak CR, Karrenbauer BD, Schneider P, Ho YJ. The Elevated Plus-Maze Test: Differential Psychopharmacology of Anxiety-Related Behavior. EMOTION REVIEW 2012. [DOI: 10.1177/1754073911421374] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The role of individual factors in behavioral neuroscience is an important, but still neglected, area of research. For example, the Elevated Plus-Maze Test has been one of the most used paradigms to gauge unconditioned aversively motivated behavior in rodents. However, despite a great number of experiments with this test there have been only few efforts to assess systematic individual variations in the elevated plus-maze and related neurobiological functions. The present review aims to give, first, a general overview and introduction about the test, and second, an animal model of anxiety based on natural variance of plus-maze behavior within a given unselected population of rats. Finally, critical aspects of such approaches in animal research are discussed, and suggestions are given as to where to go from here.
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Affiliation(s)
- Cornelius R. Pawlak
- Addictive Behavior and Addiction Medicine, Central Institute of Mental Health, Mannheim, Germany
- Chair of Biological and Clinical Psychology, School of Social Sciences, University of Mannheim, Germany
- Institute of Psychology, University of Frankfurt am Main, Germany
| | - Britta D. Karrenbauer
- Department of Experimental and Physiological Psychology, Philipps-University of Marburg, Germany
| | - Peggy Schneider
- Department of Psychopharmacology, Central Institute of Mental Health, Germany
| | - Ying-Jui Ho
- School of Psychology, Chung Shan Medical University, Taiwan, ROC
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Stewart A, Riehl R, Wong K, Green J, Cosgrove J, Vollmer K, Kyzar E, Hart P, Allain A, Cachat J, Gaikwad S, Hook M, Rhymes K, Newman A, Utterback E, Chang K, Kalueff AV. Behavioral effects of MDMA ('ecstasy') on adult zebrafish. Behav Pharmacol 2011; 22:275-80. [PMID: 21522057 PMCID: PMC3083639 DOI: 10.1097/fbp.0b013e328345f758] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
3,4-methylenedioxymethamphetamine (MDMA, 'ecstasy') is a potent psychedelic drug inducing euphoria and hypersociability in humans, as well as hyperactivity and anxiety in rodents. Adult zebrafish (Danio rerio) have become a widely used species in neurobehavioral research. Here, we explore the effects of a wide range (0.25-120 mg/l) of acute MDMA doses on zebrafish behavior in the novel tank test. Although MDMA was inactive at lower doses (0.25-10 mg/l), higher doses reduced bottom swimming and immobility (40-120 mg/l) and impaired intrasession habituation (10-120 mg/l). MDMA also elevated brain c-fos expression, collectively confirming the usage of zebrafish models for screening of hallucinogenic compounds.
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Affiliation(s)
- Adam Stewart
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Russell Riehl
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Keith Wong
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Jeremy Green
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Jessica Cosgrove
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Karoly Vollmer
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Evan Kyzar
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Peter Hart
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Alexander Allain
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Jonathan Cachat
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Siddharth Gaikwad
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Molly Hook
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Kate Rhymes
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Alan Newman
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Eli Utterback
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Katie Chang
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | - Allan V. Kalueff
- Department of Pharmacology and Neuroscience Program, Zebrafish Neuroscience Research Consortium (ZNRC), Tulane University Medical School, 1430 Tulane Ave., New Orleans, LA 70112, USA
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Nobre M, Cabral A, Brandão M. GABAergic regulation of auditory sensory gating in low- and high-anxiety rats submitted to a fear conditioning procedure. Neuroscience 2010; 171:1152-63. [DOI: 10.1016/j.neuroscience.2010.10.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 09/20/2010] [Accepted: 10/03/2010] [Indexed: 01/22/2023]
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21
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Uddén J, Folia V, Petersson KM. The neuropharmacology of implicit learning. Curr Neuropharmacol 2010; 8:367-81. [PMID: 21629444 PMCID: PMC3080593 DOI: 10.2174/157015910793358178] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Revised: 04/26/2010] [Accepted: 07/21/2010] [Indexed: 12/14/2022] Open
Abstract
Two decades of pharmacologic research on the human capacity to implicitly acquire knowledge as well as cognitive skills and procedures have yielded surprisingly few conclusive insights. We review the empirical literature of the neuropharmacology of implicit learning. We evaluate the findings in the context of relevant computational models related to neurotransmittors such as dopamine, serotonin, acetylcholine and noradrenalin. These include models for reinforcement learning, sequence production, and categorization. We conclude, based on the reviewed literature, that one can predict improved implicit acquisition by moderately elevated dopamine levels and impaired implicit acquisition by moderately decreased dopamine levels. These effects are most prominent in the dorsal striatum. This is supported by a range of behavioral tasks in the empirical literature. Similar predictions can be made for serotonin, although there is yet a lack of support in the literature for serotonin involvement in classical implicit learning tasks. There is currently a lack of evidence for a role of the noradrenergic and cholinergic systems in implicit and related forms of learning. GABA modulators, including benzodiazepines, seem to affect implicit learning in a complex manner and further research is needed. Finally, we identify allosteric AMPA receptors modulators as a potentially interesting target for future investigation of the neuropharmacology of procedural and implicit learning.
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Affiliation(s)
- Julia Uddén
- Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
- Stockholm Brain Institute, Karolinska Institutet, Stockholm, Sweden
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Netherlands
| | - Vasiliki Folia
- Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
- Stockholm Brain Institute, Karolinska Institutet, Stockholm, Sweden
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Netherlands
| | - Karl Magnus Petersson
- Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
- Stockholm Brain Institute, Karolinska Institutet, Stockholm, Sweden
- Donders Institute for Brain, Cognition and Behaviour, Centre for Cognitive Neuroimaging, Radboud University Nijmegen, Netherlands
- Institute of Biotechnology & Bioengineering/CBME, Universidade do Algarve, Faro, Portugal
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22
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Toxicity of ecstasy (MDMA) towards embryonic stem cell-derived cardiac and neural cells. Toxicol In Vitro 2010; 24:1133-8. [DOI: 10.1016/j.tiv.2010.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 11/22/2009] [Accepted: 03/10/2010] [Indexed: 01/29/2023]
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Gouzoulis-Mayfrank E, Daumann J. Neurotoxicity of drugs of abuse--the case of methylenedioxyamphetamines (MDMA, ecstasy), and amphetamines. DIALOGUES IN CLINICAL NEUROSCIENCE 2009. [PMID: 19877498 PMCID: PMC3181923 DOI: 10.31887/dcns.2009.11.3/egmayfrank] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ecstasy (MDMA, 3,4-methylendioxymethamphetamine) and the stimulants methamphetamine (METH, speed) and amphetamine are popular drugs among young people, particularly in the dance scene. When given in high doses both MDMA and the stimulant amphetamines are clearly neurotoxic in laboratory animals. MDMA causes selective and persistent lesions of central serotonergic nerve terminals, whereas amphetamines damage both the serotonergic and dopaminergic systems. In recent years, the question of ecstasy-induced neurotoxicity and possible functional sequelae has been addressed in several studies in drug users. Despite large methodological problems, the bulk of evidence suggests residual alterations of serotonergic transmission in MDMA users, although at least partial recovery may occur after long-term abstinence. However, functional sequelae may persist even after longer periods of abstinence. To date, the most consistent findings associate subtle cognitive impairments with ecstasy use, particularly with memory. In contrast, studies on possible long-term neurotoxic effects of stimulant use have been relatively scarce. Preliminary evidence suggests that alterations of the dopaminergic system may persist even after years of abstinence from METH, and may be associated with deficits in motor and cognitive performance. In this paper, we will review the literature focusing on human studies.
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Umathe SN, Manna SSS, Utturwar KS, Jain NS. Endocannabinoids mediate anxiolytic-like effect of acetaminophen via CB1 receptors. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:1191-9. [PMID: 19580839 DOI: 10.1016/j.pnpbp.2009.06.020] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 06/26/2009] [Accepted: 06/26/2009] [Indexed: 11/16/2022]
Abstract
Acetaminophen (Paracetamol), a most commonly used antipyretic/analgesic agent, is metabolized to AM404 (N-arachidonoylphenolamine) that inhibits uptake and degradation of anandamide which is reported to mediate the analgesic action of acetaminophen via CB1 receptor. AM404 and anandamide are also reported to produce anxiolytic-like behavior. In view of the implication of endocannabinoids in the effect of acetaminophen, we contemplated that acetaminophen may have anxiolytic-like effect. Therefore, this possibility was tested by observing the effects of various doses of acetaminophen in mice on anxiety-related indices of Vogel conflict test and social interaction test. The results from both the tests indicated that acetaminophen (50, 100, or 200 mg/kg, i.p.) or anandamide (10 or 20 microg/mouse, i.c.v.) dose dependently elicited anxiolytic-like effect, that was comparable to diazepam (2 mg/kg, i.p.). Moreover, co-administration of sub-effective dose of acetaminophen (25 mg/kg, i.p.) and anandamide (5 microg/mouse, i.c.v) produced similar anxiolytic effect. Further, pre-treatment with AM251 (a CB1 receptor antagonist; 1 mg/kg, i.p.) antagonized the effects of acetaminophen and anandamide with no per se effect at 1 mg/kg dose, while anxiogenic effect was evident at a higher dose (5 mg/kg, i.p.). None of the treatment/s was found to induce any antinociceptive or locomotor impairment effects. In conclusion, the findings suggested that acetaminophen (50, 100, or 200 mg/kg, i.p.) exhibited dose dependent anxiolytic effect in mice and probably involved endocannabinoid-mediated mechanism in its effect.
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Affiliation(s)
- Sudhir N Umathe
- Department of Pharmaceutical Sciences, Rashtrasant Tukadoji Maharaj Nagpur University, Mahatma Jyotiba Fuley Shaikshanik Parisar, Nagpur, MS-440033, India.
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Atkins K, Burks T, Swann AC, Dafny N. MDMA (ecstasy) modulates locomotor and prefrontal cortex sensory evoked activity. Brain Res 2009; 1302:175-82. [PMID: 19769950 DOI: 10.1016/j.brainres.2009.09.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 09/02/2009] [Accepted: 09/13/2009] [Indexed: 10/20/2022]
Abstract
Ingestion of 3, 4-methylenedioxymethamphetamine (MDMA) leads to heightened response to sensory stimulation; thus, MDMA is referred to as "ecstasy" because it produces pleasurable enhancement of such sensation. There have been no electrophysiological studies that report the consequences of MDMA on sensory input. The present study was initiated to study the effects of acute and chronic MDMA on locomotor activity and sensory evoked field potential from freely behaving rats previously implanted with permanent electrodes in the prefrontal cortex (PFC). The main findings of this study are that: (1) acute MDMA augments locomotor behavior and attenuates the incoming sensory input, (2) chronic treatment of MDMA elicits behavioral sensitization, (3) chronic administration of MDMA results in attenuation of the baseline activity of the sensory evoked field potential, and (4) administration of rechallenge MDMA result in enhancement of the PFC sensory evoked field potential.
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Affiliation(s)
- Kristal Atkins
- Department of Neurobiology and Anatomy, The University of Texas-Medical School at Houston, Houston, TX 77225, USA
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MDMA (Ecstasy) Decreases the Number of Neurons and Stem Cells in Embryonic Cortical Cultures. Cell Mol Neurobiol 2009; 30:13-21. [DOI: 10.1007/s10571-009-9426-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 06/04/2009] [Indexed: 11/26/2022]
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Capela JP, Carmo H, Remião F, Bastos ML, Meisel A, Carvalho F. Molecular and Cellular Mechanisms of Ecstasy-Induced Neurotoxicity: An Overview. Mol Neurobiol 2009; 39:210-71. [DOI: 10.1007/s12035-009-8064-1] [Citation(s) in RCA: 210] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Accepted: 02/27/2009] [Indexed: 11/29/2022]
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Acute behavioural and neurotoxic effects of MDMA plus cocaine in adolescent mice. Neurotoxicol Teratol 2009; 31:49-59. [DOI: 10.1016/j.ntt.2008.07.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 07/23/2008] [Accepted: 07/23/2008] [Indexed: 12/14/2022]
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29
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Abstract
+/-3,4-Methylenedioxymethamphetamine (MDMA) is a chemical derivative of amphetamine that has become a popular drug of abuse and has been shown to deplete serotonin in the brains of users and animals exposed to it. To date, most studies have investigated the effects of MDMA on adult animals. With a majority of users of MDMA being young adults, the chances of the users becoming pregnant and exposing the fetuses to MDMA are also a concern. Evidence to date has shown that developmental exposure to MDMA results in learning and memory impairments in the Morris water maze, a task known to be sensitive to hippocampal disruption, when the animals are tested as adults. Developmental MDMA exposure leads to hypoactivity in the offspring as adults but does not affect outcome on tests of anxiety. MDMA administration decreases pup weight, increases corticosterone and brain-derived neurotrophic factor levels during treatment while decreasing brain levels of serotonin; a decrease that initially dissipates and then reappears in adulthood. Neonatal MDMA exposure increases the sensitivity of the serotonin 1A receptor, a possible mechanism underlying the learning and memory deficits seen. Taken together, the evidence shows that MDMA exposure has adverse effects on the developing brain and behavior. The animal and human data on developmental MDMA exposure are reviewed and their public health implications discussed.
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Behavioural and neurotoxic long-lasting effects of MDMA plus cocaine in adolescent mice. Eur J Pharmacol 2008; 590:204-11. [PMID: 18585379 DOI: 10.1016/j.ejphar.2008.06.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2007] [Revised: 05/23/2008] [Accepted: 06/05/2008] [Indexed: 11/21/2022]
Abstract
The poly-drug pattern is the most common among MDMA users, with cocaine being a frequently associated drug. The aim of the present work was to evaluate the behavioural and neurotoxic long-term effects of exposure during adolescence to MDMA alone or plus cocaine. Mice of 28 to 30 days of age received a treatment of two daily injections of an identical dose of MDMA (5, 10 or 20 mg/kg), alone or plus cocaine (25 mg/kg), for 3 days (6 administrations). Three weeks after receiving MDMA, an increase in the time dedicated by the animals to social contacts with their conspecifics was observed, whilst their behaviour in the elevated plus maze showed no differences from that of non-treated mice. After being exposed to MDMA plus cocaine, mice spent more time in social contacts during the interaction test, as well as exhibiting an anxiolytic profile in the elevated plus maze, with an increase in the time and number of entries in the open arms. The activity of mice treated with cocaine alone or plus MDMA remained constant; the decrease observed among the rest of the animals after the second hour was absent in their case. The level of dopamine in the striatum was diminished in mice treated with 20 mg/kg of MDMA, but this neurotransmitter was not affected in animals exposed to the same dose plus cocaine. The present results highlight pronounced alterations in the behaviour of adult mice after exposure to MDMA and cocaine during adolescence, and demonstrate that these long-term effects can occur without the dopaminergic system becoming affected.
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Piper BJ, Fraiman JB, Owens CB, Ali SF, Meyer JS. Dissociation of the neurochemical and behavioral toxicology of MDMA ('Ecstasy') by citalopram. Neuropsychopharmacology 2008; 33:1192-205. [PMID: 17609680 DOI: 10.1038/sj.npp.1301491] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High or repeated doses of the recreational drug 3,4-methylenedioxymethamphetamine (MDMA, or 'Ecstasy') produce long-lasting deficits in several markers of serotonin (5-HT) system integrity and also alter behavioral function. However, it is not yet clear whether MDMA-induced serotonergic neurotoxicity is responsible for these behavioral changes or whether other mechanisms are involved. The present experiment tested the hypothesis that blocking serotonergic neurotoxicity by pretreatment with the selective 5-HT reuptake inhibitor citalopram will also prevent the behavioral and physiological consequences of an MDMA binge administration. Male, Sprague-Dawley rats (N=67) received MDMA (4 x 10 mg/kg) with or without citalopram (10 mg/kg) pretreatment. Core temperature, ejaculatory response, and body weight were monitored during and immediately following drug treatments. A battery of tests assessing motor, cognitive, exploratory, anxiety, and social behaviors was completed during a 10-week period following MDMA administration. Brain tissue was collected at 1 and 10 weeks after drug treatments for measurement of regional 5-HT transporter binding and (for the 1-week samples) 5-HT and 5-HIAA concentrations. Citalopram pretreatment blocked MDMA-related reductions in aggressive and exploratory behavior measured in the social interaction and hole-board tests respectively. Such pretreatment also had the expected protective effect against MDMA-induced 5-HT neurotoxicity at 1 week following the binge. In contrast, citalopram did not prevent most of the acute effects of MDMA (eg hyperthermia and weight loss), nor did it block the decreased motor activity seen in the binge-treated animals 1 day after dosing. These results suggest that some of the behavioral and physiological consequences of a high-dose MDMA regimen in rats are mediated by mechanisms other than the drug's effects on the serotonergic system. Elucidation of these mechanisms requires further study of the influence of MDMA on other neurotransmitter systems.
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Affiliation(s)
- Brian J Piper
- Neuroscience and Behavior Program, University of Massachusetts, Amherst, MA, USA
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Ludwig V, Mihov Y, Schwarting RKW. Behavioral and neurochemical consequences of multiple MDMA administrations in the rat: role of individual differences in anxiety-related behavior. Behav Brain Res 2007; 189:52-64. [PMID: 18241937 DOI: 10.1016/j.bbr.2007.12.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 12/10/2007] [Indexed: 11/28/2022]
Abstract
Using the elevated plus-maze (EPM), Wistar rats can be distinguished into high (HA) or low anxiety (LA) subjects. These differences seem to reflect traits, since HA and LA rats vary also in other anxiety-dependent tasks, neurochemical mechanisms, and psychopharmacological reactivity, including lasting consequences after single treatment with 3,4-methylenedioxymethamphetamine (MDMA). Here, we tested whether multiple MDMA treatments also have subject-dependent effects. Based on routine EPM screening, male Wistar rats were divided into HA and LA sub-groups, which received five (i.e. multiple) daily injections of MDMA (5 mg/kg) or saline, followed by a test battery, including a challenge test with MDMA, a retest in the EPM, a novel-object test, and a final neurochemical analysis. Acutely, MDMA led to comparable hyperactivity in HA and LA rats. After multiple MDMA, behavioral sensitization was observed, especially in LA rats. Open arm time during the EPM retest (min 0-5) correlated with that of the initial one only in those rats, which had received a single injection of MDMA. Rats with multiple MDMA, especially LA-rats, showed more open-arm time and locomotion during the subsequent 5-10 min of the retest. In a novel-object test, rats with multiple MDMA, again especially LA subjects, showed more exploratory bouts towards the novel object. Neurochemically, multiple MDMA led to moderately lower serotonin in the ventral striatum, and higher dopamine levels in the frontal cortex as compared to single MDMA; these effects were also moderated by subject-dependent factors. Our data show that low-dosed multiple MDMA can lead to behavioral sensitization and outlasting consequences, which affect behavior in the EPM and a novel object task. Detecting such sequels partly requires consideration of individual differences.
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Affiliation(s)
- V Ludwig
- Experimental and Physiological Psychology, Philipps-University of Marburg, Gutenbergstr. 18, 35037 Marburg, Germany
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Schwarting RKW, Jegan N, Wöhr M. Situational factors, conditions and individual variables which can determine ultrasonic vocalizations in male adult Wistar rats. Behav Brain Res 2007; 182:208-22. [PMID: 17367876 DOI: 10.1016/j.bbr.2007.01.029] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 01/23/2007] [Accepted: 01/31/2007] [Indexed: 11/17/2022]
Abstract
The fact that rats emit different types of ultrasonic vocalizations in a variety of contexts has received increasing experimental attention, since such calls might serve as indices of the animal's subjective state, and/or as social signals in various types of interactions with other rats. Here, we present two experiments in adult male Wistar rats where we tested several different situations and conditions with respect to the occurrence of high-frequency (50-kHz) and low-frequency (22-kHz) calls. These experiments showed that rats emitted high-frequency calls when tested singly in a housing cage, which was situated in a room with no other rats present. Calling did not habituate with repeated testing, and occurred in the animal's own home cage, or a fresh housing cage, and irrespective of whether the animal's motivational status was high or low, that is, irrespective of whether they were food-deprived or fed ad libitum. Furthermore, high- and low-frequency calls were observed when applying a standardized new tickling procedure, which provided evidence for effective types of tickling. Most, but not all, young adult rats still accepted this stimulation as play. Therefore, this procedure might be a useful method to elicit high-frequency calls in adult rats. Overall, substantial evidence for inter-individual variability and intra-individual stability in vocalization was provided both, within and between housing cage and tickle tests. This variability seems to depend at least partly on dispositions or traits, which can be gauged by specific screening tests, like measuring risk-assessment in the elevated plus-maze, since animals with more risk-assessment were more likely to emit high-frequency calls during cage and tickle tests. These findings are discussed with respect to the major hypotheses concerning the functional significance of ultrasonic vocalizations, namely the social/communicatory and the motivational/emotional hypothesis.
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Affiliation(s)
- Rainer K W Schwarting
- Experimental and Physiological Psychology, Philipps-University of Marburg, Gutenbergstr. 18, 35032 Marburg, Germany.
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Müller CP, Carey RJ, Huston JP, De Souza Silva MA. Serotonin and psychostimulant addiction: Focus on 5-HT1A-receptors. Prog Neurobiol 2007; 81:133-78. [PMID: 17316955 DOI: 10.1016/j.pneurobio.2007.01.001] [Citation(s) in RCA: 232] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2006] [Revised: 12/04/2006] [Accepted: 01/03/2007] [Indexed: 01/03/2023]
Abstract
Serotonin(1A)-receptors (5-HT(1A)-Rs) are important components of the 5-HT system in the brain. As somatodendritic autoreceptors they control the activity of 5-HT neurons, and, as postsynaptic receptors, the activity in terminal areas. Cocaine (COC), amphetamine (AMPH), methamphetamine (METH) and 3,4-methylenedioxymethamphetamine ("Ecstasy", MDMA) are psychostimulant drugs that can lead to addiction-related behavior in humans and in animals. At the neurochemical level, these psychostimulant drugs interact with monoamine transporters and increase extracellular 5-HT, dopamine and noradrenalin activity in the brain. The increase in 5-HT, which, in addition to dopamine, is a core mechanism of action for drug addiction, hyperactivates 5-HT(1A)-Rs. Here, we first review the role of the various 5-HT(1A)-R populations in spontaneous behavior to provide a background to elucidate the contribution of the 5-HT(1A)-Rs to the organization of psychostimulant-induced addiction behavior. The progress achieved in this field shows the fundamental contribution of brain 5-HT(1A)-Rs to virtually all behaviors associated with psychostimulant addiction. Importantly, the contribution of pre- and postsynaptic 5-HT(1A)-Rs can be dissociated and frequently act in opposite directions. We conclude that 5-HT(1A)-autoreceptors mainly facilitate psychostimulant addiction-related behaviors by a limitation of the 5-HT response in terminal areas. Postsynaptic 5-HT(1A)-Rs, in contrast, predominantly inhibit the expression of various addiction-related behaviors directly. In addition, they may also influence the local 5-HT response by feedback mechanisms. The reviewed findings do not only show a crucial role of 5-HT(1A)-Rs in the control of brain 5-HT activity and spontaneous behavior, but also their complex role in the regulation of the psychostimulant-induced 5-HT response and subsequent addiction-related behaviors.
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Affiliation(s)
- Christian P Müller
- Institute of Physiological Psychology I, University of Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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35
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de Win MML, Reneman L, Jager G, Vlieger EJP, Olabarriaga SD, Lavini C, Bisschops I, Majoie CBLM, Booij J, den Heeten GJ, van den Brink W. A prospective cohort study on sustained effects of low-dose ecstasy use on the brain in new ecstasy users. Neuropsychopharmacology 2007; 32:458-70. [PMID: 17077812 DOI: 10.1038/sj.npp.1301225] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
It is debated whether ecstasy use has neurotoxic effects on the human brain and what the effects are of a low dose of ecstasy use. We prospectively studied sustained effects (>2 weeks abstinence) of a low dose of ecstasy on the brain in ecstasy-naive volunteers using a combination of advanced MR techniques and self-report questionnaires on psychopathology as part of the NeXT (Netherlands XTC Toxicity) study. Outcomes of proton magnetic resonance spectroscopy (1H-MRS), diffusion tensor imaging (DTI), perfusion-weighted imaging (PWI), and questionnaires on depression, impulsivity, and sensation seeking were compared in 30 subjects (12M, 21.8+/-3.1 years) in two sessions before and after first ecstasy use (1.8+/-1.3 tablets). Interval between baseline and follow-up was on average 8.1+/-6.5 months and time between last ecstasy use and follow-up was 7.7+/-4.4 weeks. Using 1H-MRS, no significant changes were observed in metabolite concentrations of N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), and creatine (Cr), nor in ratios of NAA, Cho, and mI relative to Cr. However, ecstasy use was followed by a sustained 0.9% increase in fractional anisotropy (FA) in frontoparietal white matter, a 3.4% decrease in apparent diffusion (ADC) in the thalamus and a sustained decrease in relative regional cerebral blood volume (rrCBV) in the thalamus (-6.2%), dorsolateral frontal cortex (-4.0%), and superior parietal cortex (-3.0%) (all significant at p<0.05, paired t-tests). After correction for multiple comparisons, only the rrCBV decrease in the dorsolateral frontal cortex remained significant. We also observed increased impulsivity (+3.7% on the Barratt Impulsiveness Scale) and decreased depression (-28.0% on the Beck Depression Inventory) in novel ecstasy users, although effect sizes were limited and clinical relevance questionable. As no indications were found for structural neuronal damage with the currently used techniques, our data do not support the concern that incidental ecstasy use leads to extensive axonal damage. However, sustained decreases in rrCBV and ADC values may indicate that even low ecstasy doses can induce prolonged vasoconstriction in some brain areas, although it is not known whether this effect is permanent. Additional studies are needed to replicate these findings.
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Affiliation(s)
- Maartje M L de Win
- Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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36
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Ludwig V, Schwarting RKW. Neurochemical and behavioral consequences of striatal injection of 5,7-dihydroxytryptamine. J Neurosci Methods 2007; 162:108-18. [PMID: 17287026 DOI: 10.1016/j.jneumeth.2006.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2006] [Revised: 12/20/2006] [Accepted: 12/21/2006] [Indexed: 10/23/2022]
Abstract
It is known that central serotonin (5HT) is involved in anxiety, but the behavioral results of many studies have been inconsistent. A prevalent research approach is to destroy 5HT neurotoxically. Such lesions were mostly generated by injecting 5,7-dihydroxytryptamine into ventricles or raphé nuclei, leading to rather global losses of 5HT in the brain. However, there is evidence for differential effects of 5HT in different brain structures regarding anxiety. Therefore, we decided to study the effects of injecting 5,7-dihydroxytryptamine into the forebrain. We chose the ventral striatum as the site of injection, since there is evidence that 5HT may be involved in anxiety there. We administered the neurotoxin bilaterally in adult rats, and analyzed neurochemical and behavioral consequences in three experiments. The first one showed that the toxin dose-dependently (10-50 microg) depleted 5HT in the ventral striatum, neostriatum, frontal cortex, and amygdala. Besides 5HT, dopamine was also partly depleted there. This dopaminergic lesion was prevented in a second experiment, where rats were pre-treated systemically with the dopamine reuptake inhibitor nomifensine. In the final experiment, the functional consequences of such 5HT lesions were tested, which yielded moderate anxiogenic effects in the elevated plus maze and in the open field. Also, there were lesion effects on aversively motivated ultrasonic vocalization during an active avoidance test. In contrast, active avoidance performance itself and general activity in the open field were not affected. Lesion effects became discernible there when challenging rats with MDMA. The psycho-stimulatory effectiveness of this drug, which acts largely via the availability of 5HT in the brain, was reduced to degrees that depended on the size of 5HT lesion. These results are discussed with respect to factors such as severity of lesion, anatomical specificity, and the role of 5HT in anxiety.
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Affiliation(s)
- Verena Ludwig
- Experimental and Physiological Psychology, Philipps-University of Marburg, Gutenbergstrasse 18, 35037 Marburg, Germany.
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37
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Wilson HD, Boyette-Davis J, Fuchs PN. The relationship between basal level of anxiety and the affective response to inflammation. Physiol Behav 2006; 90:506-11. [PMID: 17174362 DOI: 10.1016/j.physbeh.2006.10.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 10/21/2006] [Accepted: 10/25/2006] [Indexed: 01/07/2023]
Abstract
Pain is a multidimensional experience and is modulated by a number of factors. One such factor that plays a critical role in pain modulation is anxiety. However, the influence of individual differences in anxiety on higher order pain processing in rodents remains unclear. Therefore, the purpose of this study was to identify animals that have baseline levels of high and low anxiety using the elevated plus maze and then measure pain threshold and place escape/avoidance responding (a measure of pain affect) in the animals. As expected, there was a range of baseline behavior in the elevated plus maze that was used to separate animals into high and low anxiety groups. Following carrageenan injection, both groups of animals developed a similar degree of mechanical hypersensitivity and both groups showed similar place escape/avoidance behavior. These findings suggest that individual differences in baseline anxiety levels do not significantly contribute to the development of mechanical sensitivity and do not modulate higher order pain processing related to pain affect and motivation.
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Affiliation(s)
- Hilary D Wilson
- University of Texas at Arlington, Department of Psychology, 501 South Nedderman Drive, Arlington, TX 76019, United States
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38
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Piper BJ. A developmental comparison of the neurobehavioral effects of ecstasy (MDMA). Neurotoxicol Teratol 2006; 29:288-300. [PMID: 17174068 PMCID: PMC1896315 DOI: 10.1016/j.ntt.2006.10.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 09/07/2006] [Accepted: 10/06/2006] [Indexed: 11/16/2022]
Abstract
The entactogen +/-3,4-methylenedioxymethamphetamine (MDMA or ecstasy) is a popular recreational drug among college, high school, and, occasionally, middle school students. Preclinical research examining the acute and long-term effects of MDMA has predominately been conducted in reproductively mature subjects but there has been increasing interest in adolescent and in utero exposure. This review examines the acute and long-term responses to MDMA during perinatal, adolescent, and adult periods. The ability of MDMA to alter core body temperature emerges gradually during ontogeny while a reduction in body weight is evident at all ages. Learning and working-memory are also altered independent of the developmental stage of exposure. Current evidence suggests adults are more sensitive to the long-term serotonin depletions following MDMA but younger ages also exhibit substantial and rapid neuroplasticity. Sexually dimorphic MDMA responses have been identified for the acute hyperthermic and motoric effects of MDMA with pubescent males being especially susceptible. Several physiological, behavioral, and neurochemical MDMA issues requiring further study are also outlined.
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Affiliation(s)
- Brian J Piper
- Neuroscience and Behavior Program, University of Massachusetts, Amherst, MA 01003-7710, USA.
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Able JA, Gudelsky GA, Vorhees CV, Williams MT. 3,4-Methylenedioxymethamphetamine in adult rats produces deficits in path integration and spatial reference memory. Biol Psychiatry 2006; 59:1219-26. [PMID: 16324685 PMCID: PMC2888296 DOI: 10.1016/j.biopsych.2005.09.006] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2005] [Revised: 08/26/2005] [Accepted: 09/12/2005] [Indexed: 10/25/2022]
Abstract
BACKGROUND +/-3,4-Methylenedioxymethamphetamine (MDMA) is a recreational drug that causes cognitive deficits in humans. A rat model for learning and memory deficits has not been established, although some cognitive deficits have been reported. METHODS Male Sprague-Dawley rats were treated with MDMA (15 mg/kg x 4 doses) or saline (SAL) (n = 20/treatment group) and tested in different learning paradigms: 1) path integration in the Cincinnati water maze (CWM), 2) spatial learning in the Morris water maze (MWM), and 3) novel object recognition (NOR). One week after drug administration, testing began in the CWM, then four phases of MWM, and finally NOR. Following behavioral testing, monoamine levels were assessed. RESULTS +/-3,4-Methylenedioxymethamphetamine-treated rats committed more CWM errors than did SAL-treated rats. +/-3,4-Methylenedioxymethamphetamine-treated animals were further from the former platform position during each 30-second MWM probe trial but showed no differences during learning trials with the platform present. There were no group differences in NOR. +/-3,4-Methylenedioxymethamphetamine depleted serotonin in all brain regions and dopamine in the striatum. CONCLUSIONS +/-3,4-Methylenedioxymethamphetamine produced MWM reference memory deficits even after complex learning in the CWM, where deficits in path integration learning occurred. Assessment of path integration may provide a sensitive index of MDMA-induced learning deficits.
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Affiliation(s)
- Jessica A Able
- Neuroscience Graduate Program, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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40
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Reinhard C, Wolffgramm J. Long-term voluntary consumption of MDMA and THC in rats is modified by individual and situational factors. Addict Biol 2006; 11:131-44. [PMID: 16800826 DOI: 10.1111/j.1369-1600.2006.00022.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Factors influencing long-term voluntary intake of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) and Delta9-tetrahydrocannabinol (THC; cannabis) were studied in a rat model. Sixty-four male Wistar rats were given free choice for 49 weeks between (1) water and MDMA solution, (2) water and THC solution or (3) water, MDMA solution and THC solution. After the first experiences with the drugs, animals of both monodrug and polydrug group developed an individually stable pattern of MDMA consumption, whereas the individual predictability of THC consumption remained poor. While THC consumption was maintained for the whole experimental period, MDMA consumption decreased with time and was nearly ceased after 3-7 months. Intake of both drugs was adapted to social changes, with THC consumption being more sensitive to social changes than MDMA consumption. In the re-test after 4 months of abstinence, all animals ceased drug consumption when the drug solutions were adulterated with bitter tasting quinine. The results show that the rats had maintained a flexible mode of drug consumption and had not become addicted. Response to novelty of the rats in test trials before the start of drug supply correlated with later MDMA intake. In conclusion, although very low amounts of MDMA and/or THC were consumed, the findings that drug-experienced animals responded differentially to a stressor and that housing conditions influenced drug intake suggests that MDMA and THC can induce psychopharmacological effects in our long-term voluntary consumption paradigm.
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Affiliation(s)
- Carola Reinhard
- Section of Addiction Reseasrch, Department of Psychiatry, University Hospital, Tuebingen, Germany.
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Ando RD, Benko A, Ferrington L, Kirilly E, Kelly PAT, Bagdy G. Partial lesion of the serotonergic system by a single dose of MDMA results in behavioural disinhibition and enhances acute MDMA-induced social behaviour on the social interaction test. Neuropharmacology 2006; 50:884-96. [PMID: 16472832 DOI: 10.1016/j.neuropharm.2005.12.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2005] [Revised: 11/21/2005] [Accepted: 12/16/2005] [Indexed: 10/25/2022]
Abstract
The acute effects of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) on anxiety-related behaviours were studied using indices of social interaction in Dark Agouti (DA) both drug naive rats and those pretreated with MDMA (15 mg/kg i.p.) 3 weeks earlier. The functional neuroanatomy of these MDMA effects was visualised using 2-deoxyglucose imaging of local cerebral glucose use (LCMRglu), whilst MDMA-induced serotonergic neurotoxicity was measured by radioligand binding with [3H]paroxetine. Acute MDMA alone markedly decreased most typical elements of social interaction but increased adjacent lying, a behaviour that also contains social elements. In animals pre-exposed to MDMA, decreased [3H]paroxetine binding indicated serotonergic terminal depletion, and in these animals significant increases in locomotor activity, exploratory behaviour and aggressive behaviour were found. Both behavioural effects and also the metabolic activation induced by acute MDMA were potentiated in rats previously exposed to the drug. In conclusion, a single dose of MDMA caused marked changes in social behaviour acutely that might be interpreted either as a decrease or increase in anxiety. Three weeks after MDMA a behavioural disinhibition similar to psychomotor agitation, a symptom connected to depression or mania, and a sensitization to the acute effects of MDMA are apparent in both the behavioural and brain metabolic effects of the drug.
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Affiliation(s)
- Romeo D Ando
- Department of Vascular Neurology, Semmelweis University, National Institute of Psychiatry and Neurology, Huvosvolgyi ut 116, 1021 Budapest, Hungary
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Easton N, Marsden CA. Ecstasy: are animal data consistent between species and can they translate to humans? J Psychopharmacol 2006; 20:194-210. [PMID: 16510478 DOI: 10.1177/0269881106061153] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The number of 3,4-methylenedioxymethamphetamine (ecstasy or MDMA) animal research articles is rapidly increasing and yet studies which place emphasis on the clinical significance are limited due to a lack of reliable human data. MDMA produces an acute, rapid release of brain serotonin and dopamine in experimental animals and in the rat this is associated with increased locomotor activity and the serotonin behavioural syndrome in rats. MDMA causes dose-dependent hyperthermia, which is potentially fatal, in humans, primates and rodents. Subsequent serotonergic neurotoxicity has been demonstrated by biochemical and histological studies and is reported to last for months in rats and years in non-human primates. Relating human data to findings in animals is complicated by reports that MDMA exposure in mice produces selective long-term dopaminergic impairment with no effect on serotonin. This review compares data obtained from animal and human studies and examines the acute physiological, behavioural and biochemical effects of MDMA as well as the long-term behavioural effects together with serotonergic and dopaminergic impairments. Consideration is also given to the role of neurotoxic metabolites and the influence of age, sex and user groups on the long-term actions of MDMA.
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Affiliation(s)
- Neil Easton
- School of Biomedical Science, University of Nottingham, Queen's Medical Centre, UK.
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Gouzoulis-Mayfrank E, Daumann J. Neurotoxicity of methylenedioxyamphetamines (MDMA; ecstasy) in humans: how strong is the evidence for persistent brain damage? Addiction 2006; 101:348-61. [PMID: 16499508 DOI: 10.1111/j.1360-0443.2006.01314.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The popular dance drug ecstasy (3,4-methylenedioxymethamphetamine: MDMA and some analogues) causes selective and persistent neurotoxic damage of central serotonergic neurones in laboratory animals. Serotonin plays a role in numerous functional systems in the central nervous system (CNS). Consequently, various abnormalities including psychiatric, vegetative, neuroendocrine and cognitive disorders could be expected in humans following MDMA-induced neurotoxic brain damage. AIMS In recent years, the question of ecstasy-induced neurotoxicity and possible functional sequelae has been addressed in several studies with drug users. The aim of this paper was to review this literature and weigh the strength of the evidence for persistent brain damage in ecstasy users. METHODS We used Medline to view all available publications on 'ecstasy' or 'MDMA'. All available studies dealing with ecstasy users entered this analysis. FINDINGS AND CONCLUSIONS Despite large methodological problems the bulk of evidence suggests residual alterations of serotonergic transmission in MDMA users, although at least partial restitution may occur after long-term abstinence. However, functional sequelae may persist even after longer periods of abstinence. To date, the most consistent findings associate subtle cognitive, particularly memory, impairments with heavy ecstasy use. However, the evidence cannot be considered definite and the issues of possible pre-existing traits or the effects of polydrug use are not resolved. RECOMMENDATIONS Questions about the neurotoxic effects of ecstasy on the brain remain highly topical in light of its popularity among young people. More longitudinal and prospective studies are clearly needed in order to obtain a better understanding of the possible long-term sequelae of ecstasy use in humans.
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Moragrega I, Carmen Carrasco M, Redolat R. Effects of housing and nicotine on shuttle-box avoidance in male NMRI mice. Behav Brain Res 2006; 164:178-87. [PMID: 16105696 DOI: 10.1016/j.bbr.2005.06.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 06/10/2005] [Accepted: 06/10/2005] [Indexed: 10/25/2022]
Abstract
The present study aimed to evaluate whether housing condition could interact with nicotine administration in influencing the acquisition of a two-way active avoidance task. Male NMRI mice were either group- or individually housed for 30 days and, after this period, evaluated both in the actimeter and, 24h later, in the elevated plus-maze. On the basis of the percentage of time spent in the open arms of the plus-maze, both group- and individually housed mice were sub-classified into three groups with high, moderate or low anxiety baseline levels. Effects of nicotine on the acquisition of the two-way active avoidance task was assessed in each of these groups of mice using an automated shuttle-box. Mice were treated with nicotine (0.35 mg/kg) or vehicle before each daily training session in the shuttle-box (30 trials) over 5 days. The results showed that motor activity counts were significantly higher in individually housed mice than in group-housed counterparts. The factor "anxiety" in the active avoidance test did not reach statistical significance but the factor "housing" did. The number of avoidances was higher in individually housed than in group-housed mice. Separate analyses performed for individually and group-housed animals indicated that group-housed nicotine-treated mice displayed fewer number of avoidances than saline-treated counterparts. It was concluded that housing condition may be a useful variable in evaluating the effects of nicotine on learning tasks. Indeed, the two-way active avoidance task seems to be sensitive to housing condition.
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Affiliation(s)
- Inés Moragrega
- Departamento de Psicobiología, Facultad de Psicología, Universitat de València, Blasco Ibáñez 21, Valencia 46010, Spain
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Cassel JC, Riegert C, Rutz S, Koenig J, Rothmaier K, Cosquer B, Lazarus C, Birthelmer A, Jeltsch H, Jones BC, Jackisch R. Ethanol, 3,4-methylenedioxymethamphetamine (ecstasy) and their combination: long-term behavioral, neurochemical and neuropharmacological effects in the rat. Neuropsychopharmacology 2005; 30:1870-82. [PMID: 15785779 DOI: 10.1038/sj.npp.1300714] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
This study investigated long-term behavioral, neurochemical, and neuropharmacological effects of ethanol-(+/-)-3,4-methylenedioxymethamphetamine (MDMA, ecstasy) combinations. Over 4 consecutive days, male Long-Evans rats received 1.5 g/kg ethanol and/or 10 mg/kg MDMA, or saline. Rectal temperatures were taken in some rats. Starting 4 days after the last injection, we tested working memory, sensory-motor coordination, and anxiety. Subsequently, we measured cortical, striatal, septal, and hippocampal monoamines (last MDMA injection-euthanasia delay: 20 days), or electrically evoked release of serotonin (5-HT) in cortical and hippocampal slices, and its modulation in the presence of CP 93,129 (3-(1,2,5,6-tetrahydropyrid-4-yl)pyrrollo[3,2-b]pyrid-5-one) or methiotepin (last MDMA injection-euthanasia delays: 3-6 weeks). Ethanol attenuated the MDMA-induced hyperthermia, but only on the first day. In the long-term, MDMA reduced 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) content in most brain regions. The behavioral and neurochemical effects of the ethanol-MDMA combination were comparable to those of MDMA alone; sensory-motor coordination was altered after ethanol and/or MDMA. In hippocampal slices from rats given ethanol and MDMA, the CP 93,129-induced inhibition and methiotepin-induced facilitation of 5-HT release were stronger and weaker, respectively, than in the other groups. This is the first study addressing long-term effects of repeated MDMA and EtOH combined treatments in experimental animals. Whereas the drug combination produced the same behavioral and neurochemical effects as MDMA alone, our neuropharmacological results suggest that MDMA-EtOH interactions may have specific long-term consequences on presynaptic modulation of hippocampal 5-HT release, but not necessarily related to MDMA-induced depletion of 5-HT. Thus, it is likely that the psycho(patho)logical problems reported by ecstasy users drinking alcohol are not solely due to the consumption of MDMA.
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Affiliation(s)
- Jean-Christophe Cassel
- Laboratoire de Neurosciences Comportementales et Cognitives, UMR 7521, CNRS/Université Louis Pasteur, GDR 2905 CNRS, IFR 37 Neurosciences, 12 rue Goethe, F-67000 Strasbourg, France.
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Williams MT, Schaefer TL, Ehrman LA, Able JA, Gudelsky GA, Sah R, Vorhees CV. 3,4-Methylenedioxymethamphetamine administration on postnatal day 11 in rats increases pituitary-adrenal output and reduces striatal and hippocampal serotonin without altering SERT activity. Brain Res 2005; 1039:97-107. [PMID: 15781051 PMCID: PMC2888318 DOI: 10.1016/j.brainres.2005.01.045] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Revised: 01/13/2005] [Accepted: 01/13/2005] [Indexed: 01/13/2023]
Abstract
We have previously shown that +/-3,4-methylenedioxymethamphetamine (MDMA) treatment from P11 to P20 in rats produces deficits in cognitive ability when these animals are tested in adulthood. The purpose of this experiment was to explore the neuroendocrine and neurochemical changes produced by MDMA treatment on P11. We examined monoamines in the hippocampus and striatum and the serotonin transporter in the hippocampus as well as pituitary and adrenal output following administration of MDMA (10 mg/kg, 4 times) on postnatal day 11. Significant depletions in serotonin were evident in the hippocampus 1 h and in the striatum 24 h after the first dose and remained reduced 78 h later. No changes in serotonin transporter were observed following MDMA treatment, although females had lower levels than males. No changes in dopamine were detected. The metabolites of serotonin and dopamine had different profiles than the parent compounds after MDMA administration. Plasmatic ACTH was elevated immediately following MDMA and remained elevated for at least 1 h after the last dose and returned to baseline by 24 h. Corticosterone was increased after the first dose and remained increased for at least 24 h, and returned to baseline by 30 h. The decreases in serotonin in regions important for learning and memory in conjunction with elevated levels of corticosterone during a period of stress hyporesponsiveness suggest that these initial responses to MDMA may contribute to the long-term learning and memory deficits following neonatal MDMA exposure.
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Affiliation(s)
- Michael T Williams
- Division of Child Neurology, Cincinnati Children's Hospital Research Foundation and University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA.
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Schwarting RKW, Borta A. Analysis of behavioral asymmetries in the elevated plus-maze and in the T-maze. J Neurosci Methods 2005; 141:251-60. [PMID: 15661307 DOI: 10.1016/j.jneumeth.2004.06.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Revised: 06/29/2004] [Accepted: 06/30/2004] [Indexed: 10/26/2022]
Abstract
When studying functional asymmetries in normal laboratory rats, several behavioral tests have been applied and proven their utility, including turning in rotometers or open-fields, handedness in paw usage, T-maze alternation, and others. Here, we analyzed male Wistar rats in two tests, namely the elevated plus-maze and the T-maze. In these tests, behavioral asymmetries are rather likely to occur, since the animals have to show several types of turns towards the left or right when ambulating through these environments. In a first study using the plus-maze, we provide detailed data on (A) the types of turns which the animals showed when changing their direction within arms (i.e., 180 degrees turns), and (B) the types of turns when proceeding from one arm to an adjacent one (i.e., 90 degrees turns). With respect to asymmetry, we found moderate biases in favor of the right. On the 1st day of plus-maze testing, there was a trend for more rightward turns within arms. On the 2nd day of testing, there was a trend for turns towards the right when alternating between arms of the plus-maze. In a 2nd study, we asked for asymmetries in the plus-maze in animals, which had been treated acutely with the psychostimulatory amphetamine analogue 3,4-methylene-dioxymethamphetamine (MDMA). Psychostimulants drugs, especially amphetamine, have repeatedly been used before in work on functional asymmetry, since they can enhance or reveal asymmetries in normal rats. MDMA had dose-dependent effects on activity, which affected turns within arms, and turns between arms; however, there was only sparse evidence with respect to asymmetry. Interestingly, and if at all, asymmetry was in favor of the right. Finally, we present data for behavior in the T-maze, where we used a spontaneous test version, that is, the animals could explore the maze but had no task to solve. Asymmetries were measured as turns within the start arm (180 degrees), and as left- or rightward turns between arms (90 degrees ) at the T-point of the maze. In both measures, we again obtained evidence for asymmetries in favor of the right. This work supports previous studies showing that the T-maze is suitable to analyze behavioral asymmetries in rats. In addition, it provides new evidence with respect to the elevated plus-maze, indicating that this standard tool of anxiety research may also be useful in research on behavioral asymmetries and their underlying brain mechanisms. Behavioral biases in favor of the right, as shown here, have often been reported before, especially with Wistar rats. Such biases should be taken into account, since they can serve as an approach to study brain/behavior relationships, and since they may affect the outcome of physiological manipulations or behavioral trainings.
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Affiliation(s)
- Rainer K W Schwarting
- Experimental and Physiological Psychology, Philipps-University of Marburg, Gutenbergstr. 18, 35037 Marburg, Germany.
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Sumnall HR, O'Shea E, Marsden CA, Cole JC. The effects of MDMA pretreatment on the behavioural effects of other drugs of abuse in the rat elevated plus-maze test. Pharmacol Biochem Behav 2004; 77:805-14. [PMID: 15099927 DOI: 10.1016/j.pbb.2004.02.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2003] [Revised: 02/13/2004] [Accepted: 02/13/2004] [Indexed: 10/26/2022]
Abstract
Few preclinical studies have found long-term behavioural consequences of the serotonergic neurotoxicity produced by 3,4-methylenedioxymethamphetamine (MDMA). This study investigated whether pretreatment with MDMA altered the behavioural effects of other drugs of abuse. Adult male Lister hooded rats (n=10/group) were pretreated with 10 mg/kg MDMA or 1 ml/kg saline vehicle intraperitoneally every 2 h for 6 h. Fourteen days later, the behavioural effects of d-amphetamine (2 mg/kg), cocaine (10 mg/kg), ethanol (2.0 g/kg), heroin (0.5 mg/kg), or MDMA (10 mg/kg) were assessed in the elevated plus-maze test. MDMA pretreatment produced approximately 20-25% decrease in hippocampal 5-HT and 5-HIAA concentrations, and [(3)H]paroxetine binding when analysed 2 weeks later. Despite inducing neurotoxicity, this regimen had no effect upon the plus-maze behaviour induced by ethanol, heroin, and MDMA. Acutely, and independent of neurotoxic pretreatment, MDMA produced a clear anxiogenic-like behavioural profile with a reduction of open arm entries and suppression of explorative behaviours. Despite being acutely anxiogenic, pretreatment with a neurotoxic regimen of MDMA has little effect on the anxiety-related effects of other drugs of abuse. It is possible that extended time points would produce significant changes, although the available evidence suggests that the plus-maze may not be a suitable model for detection of behavioural dysfunction after neurotoxic MDMA.
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Affiliation(s)
- H R Sumnall
- Department of Psychology, Eleanor Rathbone Building, University of Liverpool, Liverpool L69 7ZA, UK
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Ho YJ, Chen KH, Tai MY, Tsai YF. MK-801 suppresses muricidal behavior but not locomotion in olfactory bulbectomized rats: involvement of NMDA receptors. Pharmacol Biochem Behav 2004; 77:641-6. [PMID: 15006477 DOI: 10.1016/j.pbb.2004.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2003] [Revised: 01/06/2004] [Accepted: 01/08/2004] [Indexed: 11/23/2022]
Abstract
In rats, olfactory bulbectomy (OBX) causes changes in glutamatergic function in the amygdala (AMG) and induces mouse-killing behavior (MKB). The medial AMG (mAMG) plays an important role in the initiation and maintenance of OBX-induced MKB. In the present study, systemic injection or intra-mAMG perfusion of (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (MK-801) was used to determine the effects of MK-801, a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, on the expression of OBX-induced MKB in male Wistar rats that had undergone OBX 1 month previously. The effects of MK-801 on locomotion in OBX rats were also examined using the open-field test. Intraperitoneal injection of MK-801 at doses of 0.10 and 0.15 mg/kg resulted in reversible suppression of MKB, the effect being maximal within 1 h after drug treatment, then gradually disappearing over 6 h. Locomotor distance in OBX rats was not affected using 0.10 mg/kg of MK-801, but increased after treatment with 0.15 mg/kg of MK-801; both doses, however, caused the rats to spend longer in the central area of the open field. MKB was also reversibly suppressed by local perfusion of 1 mM MK-801 at a rate of 1 microl/min into the mAMG through microdialysis probes. These results suggest that NMDA receptors, at least, in the mAMG, are involved in the expression of OBX-induced MKB.
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Affiliation(s)
- Ying-Jui Ho
- Division of Clinical Psychology, School of Psychology, College of Medicine, Chung Shan Medical University, Taichung 402, Taiwan, ROC
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