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Dafny N, Claussen C, Frazier E, Liu Y. Differential Roles of Key Brain Regions: Ventral Tegmental Area, Locus Coeruleus, Dorsal Raphe, Nucleus Accumbens, Caudate Nucleus, and Prefrontal Cortex in Regulating Response to Methylphenidate: Insights from Neuronal and Behavioral Studies in Freely Behaving Rats. Int J Mol Sci 2024; 25:5938. [PMID: 38892125 PMCID: PMC11173053 DOI: 10.3390/ijms25115938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 05/20/2024] [Accepted: 05/21/2024] [Indexed: 06/21/2024] Open
Abstract
A total of 3102 neurons were recorded before and following acute and chronic methylphenidate (MPD) administration. Acute MPD exposure elicits mainly increases in neuronal and behavioral activity in dose-response characteristics. The response to chronic MPD exposure, as compared to acute 0.6, 2.5, or 10.0 mg/kg MPD administration, elicits electrophysiological and behavioral sensitization in some animals and electrophysiological and behavioral tolerance in others when the neuronal recording evaluations were performed based on the animals' behavioral responses, or amount of locomotor activity, to chronic MPD exposure. The majority of neurons recorded from those expressing behavioral sensitization responded to chronic MPD with further increases in firing rate as compared to the initial MPD responses. The majority of neurons recorded from animals expressing behavioral tolerance responded to chronic MPD with decreases in their firing rate as compared to the initial MPD exposures. Each of the six brain areas studied-the ventral tegmental area, locus coeruleus, dorsal raphe, nucleus accumbens, prefrontal cortex, and caudate nucleus (VTA, LC, DR, NAc, PFC, and CN)-responds significantly (p < 0.001) differently to MPD, suggesting that each one of the above brain areas exhibits different roles in the response to MPD. Moreover, this study demonstrates that it is essential to evaluate neuronal activity responses to psychostimulants based on the animals' behavioral responses to acute and chronic effects of the drug from several brain areas simultaneously to obtain accurate information on each area's role in response to the drug.
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Affiliation(s)
- Nachum Dafny
- Department of Neurobiology and Anatomy, McGovern Medical School, University of Texas Health Science Center, 6431 Fannin Street, Houston, TX 77030, USA; (C.C.); (Y.L.)
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Reyes-Vasquez C, Jones Z, Tang B, Dafny N. Dopamine, Norepinephrine and Serotonin Participate Differently in Methylphenidate Action in Concomitant Behavioral and Ventral Tegmental Area, Locus Coeruleus and Dorsal Raphe Neuronal Study in Young Rats. Int J Mol Sci 2023; 24:16628. [PMID: 38068951 PMCID: PMC10705956 DOI: 10.3390/ijms242316628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/03/2023] [Accepted: 11/03/2023] [Indexed: 12/18/2023] Open
Abstract
Methylphenidate (MPD), known as Ritalin, is a psychostimulant used to treat children, adults, and the elderly. MPD exerts its effects through increasing concentrations of dopamine (DA), norepinephrine (NE), and serotonin (5-HT) in the synaptic cleft. Concomitant behavioral and neuronal recording from the ventral tegmental area (VTA), locus coeruleus (LC), and from the dorsal raphe (DR) nucleus, which are the sources of DA, NE, and 5-HT to the mesocorticolimbic circuit, were investigated following acute and repetitive (chronic) saline, 0.6, 2.5, or 10.0 mg/kg MPD. Animals received daily saline or MPD administration on experimental days 1 to 6 (ED1-6), followed by a 3-day washout period and MPD rechallenge on ED10. Each chronic MPD dose elicits behavioral sensitization in some animals while inducing behavioral tolerance in others. The uniqueness of this study is in the evaluation of neuronal activity based on the behavioral response to chronic MPD. Neuronal excitation was observed mainly in brain areas of animals exhibiting behavioral sensitization, while neuronal attenuation following chronic MPD was observed in animals expressing behavioral tolerance. Different ratios of excitatory/inhibitory neuronal responses were obtained from the VTA, LC, or DR following chronic MPD. Thus, each brain area responds differently to each MPD dose used, suggesting that DA, NE, and 5-HT in the VTA, LC, and DR exert different effects.
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Affiliation(s)
- Cruz Reyes-Vasquez
- Physiology Department, Medical School, National Autonomous University of Mexico, Mexico City 04510, Mexico
| | - Zachary Jones
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center, 6431 Fannin Street, Houston, TX 77030, USA
| | - Bin Tang
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center, 6431 Fannin Street, Houston, TX 77030, USA
| | - Nachum Dafny
- Department of Neurobiology and Anatomy, McGovern Medical School, The University of Texas Health Science Center, 6431 Fannin Street, Houston, TX 77030, USA
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Keshen A, Bartel S, Frank GKW, Svedlund NE, Nunes A, Dixon L, Ali SI, Kaplan AS, Hay P, Touyz S, Romo-Nava F, McElroy SL. The potential role of stimulants in treating eating disorders. Int J Eat Disord 2022; 55:318-331. [PMID: 34846763 DOI: 10.1002/eat.23650] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 11/22/2021] [Accepted: 11/22/2021] [Indexed: 01/26/2023]
Abstract
BACKGROUND Many individuals with eating disorders remain symptomatic after a course of psychotherapy and pharmacotherapy; therefore, the development of innovative treatments is essential. METHOD To learn more about the current evidence for treating eating disorders with stimulants, we searched for original articles and reviews published up to April 29, 2021 in PubMed and MEDLINE using the following search terms: eating disorders, anorexia, bulimia, binge eating, stimulants, amphetamine, lisdexamfetamine, methylphenidate, and phentermine. RESULTS We propose that stimulant medications represent a novel avenue for future research based on the following: (a) the relationship between eating disorders and attention deficit/hyperactivity disorder (ADHD); (b) a neurobiological rationale; and (c) the current (but limited) evidence for stimulants as treatments for some eating disorders. Despite the possible benefits of such medications, there are also risks to consider such as medication misuse, adverse cardiovascular events, and reduction of appetite and pathological weight loss. With those risks in mind, we propose several directions for future research including: (a) randomized controlled trials to study stimulant treatment in those with bulimia nervosa (with guidance on strategies to mitigate risk); (b) examining stimulant treatment in conjunction with psychotherapy; (c) investigating the impact of stimulants on "loss of control" eating in youth with ADHD; and (d) exploring relevant neurobiological mechanisms. We also propose specific directions for exploring mediators and moderators in future clinical trials. DISCUSSION Although this line of investigation may be viewed as controversial by some in the field, we believe that the topic warrants careful consideration for future research.
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Affiliation(s)
- Aaron Keshen
- Eating Disorder Program, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada.,Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Sara Bartel
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Guido K W Frank
- Department of Psychiatry, University of California at San Diego, San Diego, California, USA.,Rady Children's Hospital San Diego, San Diego, California, USA
| | - Nils Erik Svedlund
- Department of Clinical Neuroscience, Centre for Psychiatry Research, Karolinska Institutet-Stockholm Health Care Services, Stockholm, Sweden
| | - Abraham Nunes
- Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.,Faculty of Computer Science, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Laura Dixon
- Eating Disorder Program, Nova Scotia Health Authority, Halifax, Nova Scotia, Canada
| | - Sarrah I Ali
- Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Allan S Kaplan
- Centre for Addiction and Mental Health, Department of Psychiatry, Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Phillipa Hay
- Translational Health Research Institute, Western Sydney University, Campbelltown, New South Wales, Australia
| | - Stephan Touyz
- School of Psychology and Inside Out Institute, University of Sydney, Sydney, New South Wales, Australia
| | - Francisco Romo-Nava
- Lindner Center of HOPE, Mason, Ohio, USA.,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Susan L McElroy
- Lindner Center of HOPE, Mason, Ohio, USA.,Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Lages YV, Maisonnette SS, Rosseti FP, Galvão BO, Landeira-Fernandez J. Haloperidol and methylphenidate alter motor behavior and responses to conditioned fear of Carioca Low-conditioned Freezing rats. Pharmacol Biochem Behav 2021; 211:173296. [PMID: 34752797 DOI: 10.1016/j.pbb.2021.173296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 11/29/2022]
Abstract
Animal models are important tools for studying neuropsychological disorders. Considering their limitations, a more extensive translational research must encompass data that are generated from several models. Therefore, a comprehensive characterization of these models is needed in terms of behavior and neurophysiology. The present study evaluated the behavioral responses of Carioca Low-conditioned Freezing (CLF) rats to haloperidol and methylphenidate. The CLF breeding line is characterized by low freezing defensive responses to contextual cues that are associated with aversive stimuli. CLF rats exhibited a delayed response to haloperidol at lower doses, needing higher doses to reach similar levels of catatonia as control randomly bred animals. Methylphenidate increased freezing responses to conditioned fear and induced motor effects in the open field. Thus, CLF rats differ from controls in their responses to both haloperidol and methylphenidate. Because of the dopamine-related molecular targets of these drugs, we hypothesize that dopaminergic alterations related to those of animal models of hyperactivity and attention disorders might underlie the observed phenotypes of the CLF line of rats.
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Affiliation(s)
- Yury V Lages
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Silvia S Maisonnette
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Flávia P Rosseti
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Bruno O Galvão
- Department of Psychology, Santa Úrsula University, Rio de Janeiro, Brazil
| | - J Landeira-Fernandez
- Department of Psychology, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro, Brazil.
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