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Vaughan RA, Henry LK, Foster JD, Brown CR. Post-translational mechanisms in psychostimulant-induced neurotransmitter efflux. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2024; 99:1-33. [PMID: 38467478 DOI: 10.1016/bs.apha.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The availability of monoamine neurotransmitters in the brain is under the control of dopamine, norepinephrine, and serotonin transporters expressed on the plasma membrane of monoaminergic neurons. By regulating transmitter levels these proteins mediate crucial functions including cognition, attention, and reward, and dysregulation of their activity is linked to mood and psychiatric disorders of these systems. Amphetamine-based transporter substrates stimulate non-exocytotic transmitter efflux that induces psychomotor stimulation, addiction, altered mood, hallucinations, and psychosis, thus constituting a major component of drug neurochemical and behavioral outcomes. Efflux is under the control of transporter post-translational modifications that synergize with other regulatory events, and this review will summarize our knowledge of these processes and their role in drug mechanisms.
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Affiliation(s)
- Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States.
| | - L Keith Henry
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - James D Foster
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Christopher R Brown
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
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2
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Chen R. Cholesterol modulation of interactions between psychostimulants and dopamine transporters. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2023; 99:35-59. [PMID: 38467486 DOI: 10.1016/bs.apha.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The dopamine transporter (DAT) is a key site of action for cocaine and amphetamines. Dysfunctional DAT is associated with aberrant synaptic dopamine transmission and enhanced drug-seeking and taking behavior. Studies in cultured cells and ex vivo suggest that DAT function is sensitive to membrane cholesterol content. Although it is largely unknown whether psychostimulants alter cholesterol metabolism in the brain, emerging evidence indicates that peripheral cholesterol metabolism is altered in patients with psychostimulant use disorder and circulating cholesterol levels are associated with vulnerability to relapse. Cholesterol interacts with sphingolipids forming lipid raft microdomains on the membrane. These cholesterol-rich lipid raft microdomains serve to recruit and assemble other lipids and proteins to initiate signal transduction. There are two spatially and functionally distinct populations of the DAT segregated by cholesterol-rich lipid raft microdomains and cholesterol-scarce non-raft microdomains on the plasma membrane. These two DAT populations are differentially regulated by DAT blockers (e.g. cocaine), substrates (e.g. amphetamine), and protein kinase C providing distinct cholesterol-dependent modulation of dopamine uptake and efflux. In this chapter, we summarize the impact of depletion and addition of membrane cholesterol on DAT conformational changes between the outward-facing and the inward-facing states, lipid raft-associated DAT localization, basal and induced DAT internalization, and DAT function. In particular, we focus on how the interactions of the DAT with cocaine and amphetamine are influenced by membrane cholesterol. Lastly, we discuss the therapeutic potential of cholesterol-modifying drugs as a new avenue to normalize DAT function and dopamine transmission in patients with psychostimulant use disorder.
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Affiliation(s)
- Rong Chen
- Department of Physiology & Pharmacology, Wake Forest University School of Medicine, Winston Salem, NC, United States.
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3
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Davis SE, Cirincione AB, Jimenez-Torres AC, Zhu J. The Impact of Neurotransmitters on the Neurobiology of Neurodegenerative Diseases. Int J Mol Sci 2023; 24:15340. [PMID: 37895020 PMCID: PMC10607327 DOI: 10.3390/ijms242015340] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/16/2023] [Accepted: 10/17/2023] [Indexed: 10/29/2023] Open
Abstract
Neurodegenerative diseases affect millions of people worldwide. Neurodegenerative diseases result from progressive damage to nerve cells in the brain or peripheral nervous system connections that are essential for cognition, coordination, strength, sensation, and mobility. Dysfunction of these brain and nerve functions is associated with Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, and motor neuron disease. In addition to these, 50% of people living with HIV develop a spectrum of cognitive, motor, and/or mood problems collectively referred to as HIV-Associated Neurocognitive Disorders (HAND) despite the widespread use of a combination of antiretroviral therapies. Neuroinflammation and neurotransmitter systems have a pathological correlation and play a critical role in developing neurodegenerative diseases. Each of these diseases has a unique pattern of dysregulation of the neurotransmitter system, which has been attributed to different forms of cell-specific neuronal loss. In this review, we will focus on a discussion of the regulation of dopaminergic and cholinergic systems, which are more commonly disturbed in neurodegenerative disorders. Additionally, we will provide evidence for the hypothesis that disturbances in neurotransmission contribute to the neuronal loss observed in neurodegenerative disorders. Further, we will highlight the critical role of dopamine as a mediator of neuronal injury and loss in the context of NeuroHIV. This review will highlight the need to further investigate neurotransmission systems for their role in the etiology of neurodegenerative disorders.
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Affiliation(s)
| | | | | | - Jun Zhu
- Department of Drug Discovery and Biomedical Sciences, College of Pharmacy, University of South Carolina, 715 Sumter Street, Columbia, SC 29208, USA; (S.E.D.); (A.B.C.); (A.C.J.-T.)
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4
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Shetty M, Bolland DE, Morrell J, Grove BD, Foster JD, Vaughan RA. Dopamine transporter membrane mobility is bidirectionally regulated by phosphorylation and palmitoylation. Curr Res Physiol 2023; 6:100106. [PMID: 38107792 PMCID: PMC10724222 DOI: 10.1016/j.crphys.2023.100106] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 09/20/2023] [Indexed: 12/19/2023] Open
Abstract
The primary regulator of dopamine availability in the brain is the dopamine transporter (DAT), a plasma membrane protein that drives reuptake of released dopamine from the extracellular space into the presynaptic neuron. DAT activity is regulated by post-translational modifications that establish clearance capacity through impacts on transport kinetics, and dysregulation of these events may underlie dopaminergic imbalances in mood and psychiatric disorders. Here, using fluorescence recovery after photobleaching, we show that phosphorylation and palmitoylation induce opposing effects on DAT lateral membrane mobility, which may influence functional outcomes by regulating subcellular localization and binding partner interactions. Membrane mobility was also impacted by amphetamine and in polymorphic variant A559V in directions consistent with enhanced phosphorylation. These findings grow the list of DAT properties controlled by these post-translational modifications and highlight their role in establishment of dopaminergic tone in physiological and pathophysiological states.
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Affiliation(s)
- Madhur Shetty
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | | | - Joshua Morrell
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | - Bryon D. Grove
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | - James D. Foster
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
| | - Roxanne A. Vaughan
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND, 58202, USA
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5
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Small C, Cheng MH, Belay SS, Bulloch SL, Zimmerman B, Sorkin A, Block ER. The Alkylamine Stimulant 1,3-Dimethylamylamine Exhibits Substrate-Like Regulation of Dopamine Transporter Function and Localization. J Pharmacol Exp Ther 2023; 386:266-273. [PMID: 37348963 PMCID: PMC10353075 DOI: 10.1124/jpet.122.001573] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/16/2023] [Accepted: 05/04/2023] [Indexed: 06/24/2023] Open
Abstract
The alkylamine stimulant 1,3-dimethylamylamine (DMAA) is used nonmedically as an appetite suppressant and exercise performance enhancer despite adverse cardiovascular effects that have limited its legal status. There is scant research describing the mechanism of action of DMAA, making it difficult to gauge risks or therapeutic potential. An important molecular target of structurally related phenethylamines, such as amphetamine, for regulating mood, cognition, movement, and the development of substance use disorder is the dopamine transporter, which limits the range and magnitude of dopamine signaling via reuptake from the extracellular space. The present studies were therefore initiated to characterize the effects of DMAA on dopamine transporter function. Specifically, we tested the hypothesis that DMAA exhibits substrate-like effects on dopamine transporter function and trafficking. In transport assays in human embryonic kidney cells, DMAA inhibited dopamine uptake by the human dopamine transporter in a competitive manner. Docking analysis and molecular dynamics simulations supported these findings, revealing that DMAA binds to the S1 substrate binding site and induces a conformational change from outward-facing open to outward-facing closed states, similar to the known substrates. Further supporting substrate-like effects of DMAA, the drug stimulated dopamine transporter endocytosis in a heterologous expression system via cocaine- and protein kinase A-sensitive mechanisms, mirroring findings with amphetamine. Together, these data indicate that DMAA elicits neurologic effects by binding to and regulating function of the dopamine transporter. Furthermore, pharmacologic distinctions from amphetamine reveal structural determinants for regulating transporter conformation and add mechanistic insight for the regulation of dopamine transporter endocytosis. SIGNIFICANCE STATEMENT: The alkylamine stimulant 1,3-dimethylamylamine (DMAA) is used as an appetite suppressant and athletic performance enhancer and is structurally similar to amphetamine, but there is scant research describing its mechanism of action. Characterizing the effects of DMAA on dopamine transporter function supports evaluation of potential risks and therapeutic potential while also revealing mechanistic details of dynamic transporter-substrate interactions.
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Affiliation(s)
- Cassandra Small
- Science Department, Chatham University, Pittsburgh, Pennsylvania (C.S., S.S.B., S.L.B., B.Z., E.R.B.) and Departments of Computational and Systems Biology (M.H.C.) and Cell Biology (A.S.), School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Mary Hongying Cheng
- Science Department, Chatham University, Pittsburgh, Pennsylvania (C.S., S.S.B., S.L.B., B.Z., E.R.B.) and Departments of Computational and Systems Biology (M.H.C.) and Cell Biology (A.S.), School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Saron S Belay
- Science Department, Chatham University, Pittsburgh, Pennsylvania (C.S., S.S.B., S.L.B., B.Z., E.R.B.) and Departments of Computational and Systems Biology (M.H.C.) and Cell Biology (A.S.), School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Sarah L Bulloch
- Science Department, Chatham University, Pittsburgh, Pennsylvania (C.S., S.S.B., S.L.B., B.Z., E.R.B.) and Departments of Computational and Systems Biology (M.H.C.) and Cell Biology (A.S.), School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Brooke Zimmerman
- Science Department, Chatham University, Pittsburgh, Pennsylvania (C.S., S.S.B., S.L.B., B.Z., E.R.B.) and Departments of Computational and Systems Biology (M.H.C.) and Cell Biology (A.S.), School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Alexander Sorkin
- Science Department, Chatham University, Pittsburgh, Pennsylvania (C.S., S.S.B., S.L.B., B.Z., E.R.B.) and Departments of Computational and Systems Biology (M.H.C.) and Cell Biology (A.S.), School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Ethan R Block
- Science Department, Chatham University, Pittsburgh, Pennsylvania (C.S., S.S.B., S.L.B., B.Z., E.R.B.) and Departments of Computational and Systems Biology (M.H.C.) and Cell Biology (A.S.), School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
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6
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Nepal B, Das S, Reith ME, Kortagere S. Overview of the structure and function of the dopamine transporter and its protein interactions. Front Physiol 2023; 14:1150355. [PMID: 36935752 PMCID: PMC10020207 DOI: 10.3389/fphys.2023.1150355] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 02/21/2023] [Indexed: 03/06/2023] Open
Abstract
The dopamine transporter (DAT) plays an integral role in dopamine neurotransmission through the clearance of dopamine from the extracellular space. Dysregulation of DAT is central to the pathophysiology of numerous neuropsychiatric disorders and as such is an attractive therapeutic target. DAT belongs to the solute carrier family 6 (SLC6) class of Na+/Cl- dependent transporters that move various cargo into neurons against their concentration gradient. This review focuses on DAT (SCL6A3 protein) while extending the narrative to the closely related transporters for serotonin and norepinephrine where needed for comparison or functional relevance. Cloning and site-directed mutagenesis experiments provided early structural knowledge of DAT but our contemporary understanding was achieved through a combination of crystallization of the related bacterial transporter LeuT, homology modeling, and subsequently the crystallization of drosophila DAT. These seminal findings enabled a better understanding of the conformational states involved in the transport of substrate, subsequently aiding state-specific drug design. Post-translational modifications to DAT such as phosphorylation, palmitoylation, ubiquitination also influence the plasma membrane localization and kinetics. Substrates and drugs can interact with multiple sites within DAT including the primary S1 and S2 sites involved in dopamine binding and novel allosteric sites. Major research has centered around the question what determines the substrate and inhibitor selectivity of DAT in comparison to serotonin and norepinephrine transporters. DAT has been implicated in many neurological disorders and may play a role in the pathology of HIV and Parkinson's disease via direct physical interaction with HIV-1 Tat and α-synuclein proteins respectively.
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Affiliation(s)
- Binod Nepal
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Sanjay Das
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
| | - Maarten E. Reith
- Department of Psychiatry, New York University School of Medicine, New York City, NY, United States
| | - Sandhya Kortagere
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, United States
- *Correspondence: Sandhya Kortagere,
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Blum K, Han D, Bowirrat A, Downs BW, Bagchi D, Thanos PK, Baron D, Braverman ER, Dennen CA, Gupta A, Elman I, Badgaiyan RD, Llanos-Gomez L, Khalsa J, Barh D, McLaughlin T, Gold MS. Genetic Addiction Risk and Psychological Profiling Analyses for "Preaddiction" Severity Index. J Pers Med 2022; 12:1772. [PMID: 36579510 PMCID: PMC9696872 DOI: 10.3390/jpm12111772] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 10/15/2022] [Accepted: 10/16/2022] [Indexed: 01/01/2023] Open
Abstract
Since 1990, when our laboratory published the association of the DRD2 Taq A1 allele and severe alcoholism in JAMA, there has been an explosion of genetic candidate association studies, including genome-wide association studies (GWAS). To develop an accurate test to help identify those at risk for at least alcohol use disorder (AUD), a subset of reward deficiency syndrome (RDS), Blum's group developed the genetic addiction risk severity (GARS) test, consisting of ten genes and eleven associated risk alleles. In order to statistically validate the selection of these risk alleles measured by GARS, we applied strict analysis to studies that investigated the association of each polymorphism with AUD or AUD-related conditions, including pain and even bariatric surgery, as a predictor of severe vulnerability to unwanted addictive behaviors, published since 1990 until now. This analysis calculated the Hardy-Weinberg Equilibrium of each polymorphism in cases and controls. Pearson's χ2 test or Fisher's exact test was applied to compare the gender, genotype, and allele distribution if available. The statistical analyses found the OR, 95% CI for OR, and the post risk for 8% estimation of the population's alcoholism prevalence revealed a significant detection. Prior to these results, the United States and European patents on a ten gene panel and eleven risk alleles have been issued. In the face of the new construct of the "preaddiction" model, similar to "prediabetes", the genetic addiction risk analysis might provide one solution missing in the treatment and prevention of the neurological disorder known as RDS.
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Affiliation(s)
- Kenneth Blum
- Division of Addiction Research & Education, Center for Sports, Exercise, and Mental Health, Western University of Health Sciences, Pomona, CA 91766, USA
- Division of Nutrigenomics, The Kenneth Blum Behavioral Neurogenetic Institute, LLC, Austin, TX 78701, USA
- Institute of Psychology, ELTE Eötvös Loránd University, 1075 Budapest, Hungary
- Department of Psychiatry, University of Vermont, Burlington, VT 05405, USA
- Department of Psychiatry, Wright University Boonshoft School of Medicine, Dayton, OH 45324, USA
- Division of Nutrigenomics, Victory Nutrition International, Inc., Harleysville, PA 19329, USA
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology, Nonakuri, Purba Medinipur 721172, West Bengal, India
- Department of Molecular Biology, Adelson School of Medicine, Ariel University, Ariel 40700, Israel
| | - David Han
- Department of Management Science and Statistics, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Abdalla Bowirrat
- Department of Molecular Biology, Adelson School of Medicine, Ariel University, Ariel 40700, Israel
| | - Bernard William Downs
- Division of Nutrigenomics, Victory Nutrition International, Inc., Harleysville, PA 19329, USA
| | - Debasis Bagchi
- Division of Nutrigenomics, Victory Nutrition International, Inc., Harleysville, PA 19329, USA
- Department of Pharmaceutical Sciences, College of Pharmacy, Southern University, Houston, TX 77004, USA
| | - Panayotis K. Thanos
- Behavioral Neuropharmacology and Neuroimaging Laboratory on Addictions, Clinical Research Institute on Addictions, Department of Pharmacology and Toxicology, Jacobs School of Medicine and Biosciences, State University of New York at Buffalo, Buffalo, NY 14260, USA
- Department of Psychology, State University of New York at Buffalo, Buffalo, NY 14260, USA
| | - David Baron
- Division of Addiction Research & Education, Center for Sports, Exercise, and Mental Health, Western University of Health Sciences, Pomona, CA 91766, USA
- Division of Nutrigenomics, The Kenneth Blum Behavioral Neurogenetic Institute, LLC, Austin, TX 78701, USA
| | - Eric R. Braverman
- Division of Nutrigenomics, The Kenneth Blum Behavioral Neurogenetic Institute, LLC, Austin, TX 78701, USA
| | - Catherine A. Dennen
- Department of Family Medicine, Jefferson Health Northeast, Philadelphia, PA 19107, USA
| | - Ashim Gupta
- Future Biologics, Lawrenceville, GA 30043, USA
| | - Igor Elman
- Department of Psychiatry, Harvard School of Medicine, Cambridge, MA 02115, USA
| | - Rajendra D. Badgaiyan
- Department of Psychiatry, South Texas Veteran Health Care System, Audie L. Murphy Memorial VA Hospital, Long School of Medicine, University of Texas Health Science Center, San Antonio, TX 78229, USA
- Department of Psychiatry, MT. Sinai School of Medicine, New York, NY 10003, USA
| | - Luis Llanos-Gomez
- Division of Nutrigenomics, The Kenneth Blum Behavioral Neurogenetic Institute, LLC, Austin, TX 78701, USA
| | - Jag Khalsa
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine, George Washington University, Washington, DC 20052, USA
- Medical Consequences of Drug Abuse and Infections Branch, National Institute on Drug Abuse, NIH, Bethesda, MD 20892, USA
| | - Debmalya Barh
- Centre for Genomics and Applied Gene Technology, Institute of Integrative Omics and Applied Biotechnology, Nonakuri, Purba Medinipur 721172, West Bengal, India
- Department of Genetics, Ecology and Evolution, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil
| | - Thomas McLaughlin
- Division of Nutrigenomics, The Kenneth Blum Behavioral Neurogenetic Institute, LLC, Austin, TX 78701, USA
| | - Mark S. Gold
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA
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Miller DR, Bu M, Gopinath A, Martinez LR, Khoshbouei H. Methamphetamine Dysregulation of the Central Nervous System and Peripheral Immunity. J Pharmacol Exp Ther 2021; 379:372-385. [PMID: 34535563 PMCID: PMC9351721 DOI: 10.1124/jpet.121.000767] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 09/16/2021] [Indexed: 11/22/2022] Open
Abstract
Methamphetamine (METH) is a potent psychostimulant that increases extracellular monoamines, such as dopamine and norepinephrine, and affects multiple tissue and cell types in the central nervous system (CNS) and peripheral immune cells. The reinforcing properties of METH underlie its significant abuse potential and dysregulation of peripheral immunity and central nervous system functions. Together, the constellation of METH's effects on cellular targets and regulatory processes has led to immune suppression and neurodegeneration in METH addicts and animal models of METH exposure. Here we extensively review many of the cell types and mechanisms of METH-induced dysregulation of the central nervous and peripheral immune systems. SIGNIFICANCE STATEMENT: Emerging research has begun to show that methamphetamine regulates dopaminergic neuronal activity. In addition, METH affects non-neuronal brain cells, such as microglia and astrocytes, and immunological cells of the periphery. Concurrent disruption of bidirectional communication between dopaminergic neurons and glia in the CNS and peripheral immune cell dysregulation gives rise to a constellation of dysfunctional neuronal, cell, and tissue types. Therefore, understanding the pathophysiology of METH requires consideration of the multiple targets at the interface between basic and clinical neuroscience.
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Affiliation(s)
- Douglas R Miller
- Department of Neuroscience, College of Medicine (D.R.M., M.B., A.G., H.K.), and Department of Oral Biology, College of Dentistry (L.R.M.), University of Florida, Gainesville, Florida
| | - Mengfei Bu
- Department of Neuroscience, College of Medicine (D.R.M., M.B., A.G., H.K.), and Department of Oral Biology, College of Dentistry (L.R.M.), University of Florida, Gainesville, Florida
| | - Adithya Gopinath
- Department of Neuroscience, College of Medicine (D.R.M., M.B., A.G., H.K.), and Department of Oral Biology, College of Dentistry (L.R.M.), University of Florida, Gainesville, Florida
| | - Luis R Martinez
- Department of Neuroscience, College of Medicine (D.R.M., M.B., A.G., H.K.), and Department of Oral Biology, College of Dentistry (L.R.M.), University of Florida, Gainesville, Florida
| | - Habibeh Khoshbouei
- Department of Neuroscience, College of Medicine (D.R.M., M.B., A.G., H.K.), and Department of Oral Biology, College of Dentistry (L.R.M.), University of Florida, Gainesville, Florida
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9
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Lavrova AV, Gretskaya NM, Bezuglov VV. Role of Oxidative Stress in the Etiology of Parkinson’s Disease: Advanced Therapeutic Products. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2021. [DOI: 10.1134/s1068162021050307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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A network of phosphatidylinositol (4,5)-bisphosphate (PIP 2) binding sites on the dopamine transporter regulates amphetamine behavior in Drosophila Melanogaster. Mol Psychiatry 2021; 26:4417-4430. [PMID: 31796894 PMCID: PMC7266731 DOI: 10.1038/s41380-019-0620-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 11/15/2019] [Accepted: 11/21/2019] [Indexed: 12/19/2022]
Abstract
Reward modulates the saliency of a specific drug exposure and is essential for the transition to addiction. Numerous human PET-fMRI studies establish a link between midbrain dopamine (DA) release, DA transporter (DAT) availability, and reward responses. However, how and whether DAT function and regulation directly participate in reward processes remains elusive. Here, we developed a novel experimental paradigm in Drosophila melanogaster to study the mechanisms underlying the psychomotor and rewarding properties of amphetamine (AMPH). AMPH principally mediates its pharmacological and behavioral effects by increasing DA availability through the reversal of DAT function (DA efflux). We have previously shown that the phospholipid, phosphatidylinositol (4, 5)-bisphosphate (PIP2), directly interacts with the DAT N-terminus to support DA efflux in response to AMPH. In this study, we demonstrate that the interaction of PIP2 with the DAT N-terminus is critical for AMPH-induced DAT phosphorylation, a process required for DA efflux. We showed that PIP2 also interacts with intracellular loop 4 at R443. Further, we identified that R443 electrostatically regulates DA efflux as part of a coordinated interaction with the phosphorylated N-terminus. In Drosophila, we determined that a neutralizing substitution at R443 inhibited the psychomotor actions of AMPH. We associated this inhibition with a decrease in AMPH-induced DA efflux in isolated fly brains. Notably, we showed that the electrostatic interactions of R443 specifically regulate the rewarding properties of AMPH without affecting AMPH aversion. We present the first evidence linking PIP2, DAT, DA efflux, and phosphorylation processes with AMPH reward.
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11
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Magee CP, Le BD, Siripathane YH, Wilkins DG, Hanson GR, Fleckenstein AE. Methcathinone decreases dopamine transporter function: Role of protein kinase C. J Neurochem 2021; 159:116-127. [PMID: 34320222 DOI: 10.1111/jnc.15483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 07/19/2021] [Accepted: 07/25/2021] [Indexed: 11/28/2022]
Abstract
Methcathinone (MCAT) is a psychostimulant of abuse that can cause both persistent striatal dopaminergic and serotonergic, as well as hippocampal serotonergic, deficits. Evidence suggests that the rapid effects of stimulants that are structurally and mechanistically similar to MCAT on monoamine transporter function may contribute to the abuse liability and/or persistent monoaminergic deficits caused by these agents. Thus, effects of MCAT on 1) striatal dopamine (DA) transporter (DAT); and 2) striatal and hippocampal serotonin transporter (SERT) function, as determined in tissues from adult male rats, were assessed. As reported previously, a single administration of MCAT rapidly (within 1 hr) decreases striatal [3 H]DA uptake. Similarly, incubation of rat synaptosomes with MCAT at 37℃ (but not 4˚C) decreased striatal [3 H]DA uptake. Incubation with MCAT likewise decreased [3 H]5HT but not vesicular [3 H]DA uptake. MCAT incubation in vitro was without effect on [3 H]DA uptake in striatal synaptosomes prepared from MCAT-treated rats. The decrease in [3 H]DA uptake caused by MCAT incubation: (a) reflected a decrease in Vmax , with minimal change in Km , and (b) was attenuated by co-incubation with the cell-permeable calcium chelator, N,N'-[1,2-ethanediylbis(oxy-2,1-phenylene)]bis[N-[2-[(acetyloxy)methoxy]-2-oxoethyl]-1,1'-bis[(acetyloxy)methyl] ester-glycine (BAPTA-AM), as well as the non-selective protein kinase-C (PKC) inhibitors bisindolylmaleimide-1 (BIM-1) and 2-[1-3(Aminopropyl)indol-3-yl]-3(1-methyl-1H-indol-3-yl)maleimide (or Bisindolylmaleimide VIII; Ro-31-7549). Taken together, these results suggest that in vitro MCAT incubation may model important aspects of MCAT administration in vivo, and that calcium and PKC contribute to the in vitro effects of MCAT on DAT.
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Affiliation(s)
- Charlotte P Magee
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA.,School of Dentistry, University of Utah, Salt Lake City, UT, USA
| | - BaoMinh D Le
- School of Dentistry, University of Utah, Salt Lake City, UT, USA
| | | | - Diana G Wilkins
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - Glen R Hanson
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA.,School of Dentistry, University of Utah, Salt Lake City, UT, USA
| | - Annette E Fleckenstein
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, UT, USA.,School of Dentistry, University of Utah, Salt Lake City, UT, USA
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12
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Ryan RM, Ingram SL, Scimemi A. Regulation of Glutamate, GABA and Dopamine Transporter Uptake, Surface Mobility and Expression. Front Cell Neurosci 2021; 15:670346. [PMID: 33927596 PMCID: PMC8076567 DOI: 10.3389/fncel.2021.670346] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 03/15/2021] [Indexed: 01/31/2023] Open
Abstract
Neurotransmitter transporters limit spillover between synapses and maintain the extracellular neurotransmitter concentration at low yet physiologically meaningful levels. They also exert a key role in providing precursors for neurotransmitter biosynthesis. In many cases, neurons and astrocytes contain a large intracellular pool of transporters that can be redistributed and stabilized in the plasma membrane following activation of different signaling pathways. This means that the uptake capacity of the brain neuropil for different neurotransmitters can be dynamically regulated over the course of minutes, as an indirect consequence of changes in neuronal activity, blood flow, cell-to-cell interactions, etc. Here we discuss recent advances in the mechanisms that control the cell membrane trafficking and biophysical properties of transporters for the excitatory, inhibitory and modulatory neurotransmitters glutamate, GABA, and dopamine.
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Affiliation(s)
- Renae M. Ryan
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Susan L. Ingram
- Department of Neurological Surgery, Oregon Health & Science University, Portland, OR, United States
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13
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New designer phenethylamines 2C-C and 2C-P have abuse potential and induce neurotoxicity in rodents. Arch Toxicol 2021; 95:1413-1429. [PMID: 33515270 DOI: 10.1007/s00204-021-02980-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 01/04/2021] [Indexed: 12/22/2022]
Abstract
2C (2C-x) is the general name for the family of phenethylamines containing two methoxy groups at the 2 and 5 positions of the benzene ring. The abuse of 2C family drugs has grown rapidly, although the abuse potential and neurotoxic properties of 2C drugs have not yet been fully investigated. In this study, we investigated the abuse potential and neurotoxicity of 4-chloro-2,5-dimethoxyphenethylamine (2C-C) and 2,5-dimethoxy-4-propylphenethylamine (2C-P). We found that 2C-C and 2C-P produced conditioned place preference in a dose-dependent manner in mice, and increased self-administration in rats, suggesting that 2C-C and 2C-P have abuse potential. To investigate the neurotoxicity of 2C-C and 2C-P, we examined motor performance and memory impairment after high doses of 2C-C and 2C-P. High doses of 2C-C and 2C-P decreased locomotor activity, rota-rod performance, and lower Y-maze test, novel objective recognition test, and passive avoidance test scores. We also observed that 2C-C and 2C-P affected expression levels of the D1 dopamine receptor, D2 dopamine receptor, dopamine transporter, and phospho-dopamine transporter in the nucleus accumbens and the medial prefrontal cortex, and increased c-Fos immuno-positive cells in the nucleus accumbens. Moreover, high doses of 2C-C and 2C-P induced microglial activation, which is involved in the inflammatory reaction in the striatum. These results suggest that 2C-C and 2C-P have abuse potential by affecting dopaminergic signaling and induce neurotoxicity via initiating neuroinflammation at high doses.
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14
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Ingram SM, Rana T, Manson AM, Yayah FM, Jackson EGB, Anderson C, Davids BO, Goodwin JS. Optogenetically-induced multimerization of the dopamine transporter increases uptake and trafficking to the plasma membrane. J Biol Chem 2021; 296:100787. [PMID: 34015332 PMCID: PMC8203837 DOI: 10.1016/j.jbc.2021.100787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 05/07/2021] [Accepted: 05/13/2021] [Indexed: 11/19/2022] Open
Abstract
The dopamine transporter (DAT) is essential for the reuptake of the released neurotransmitter dopamine (DA) in the brain. Psychostimulants, methamphetamine and cocaine, have been reported to induce the formation of DAT multimeric complexes in vivo and in vitro. The interpretation of DAT multimer function has been primarily in the context of compounds that induce structural and functional modifications of the DAT, complicating the understanding of the significance of DAT multimers. To examine multimerization in the absence of DAT ligands as well as in their presence, we developed a novel, optogenetic fusion chimera of cryptochrome 2 and DAT with an mCherry fluorescent reporter (Cry2-DAT). Using blue light to induce Cry2-DAT multimeric protein complex formation, we were able to simultaneously test the functional contributions of DAT multimerization in the absence or presence of substrates or inhibitors with high spatiotemporal precision. We found that blue light-stimulated Cry2-DAT multimers significantly increased IDT307 uptake and MFZ 9-18 binding in the absence of ligands as well as after methamphetamine and nomifensine treatment. Blue light-induced Cry2-DAT multimerization increased colocalization with recycling endosomal marker Rab11 and had decreased presence in Rab5-positive early endosomes and Rab7-positive late endosomes. Our data suggest that the increased uptake and binding results from induced and rapid trafficking of DAT multimers to the plasma membrane. Our data suggest that DAT multimers may function to help maintain DA homeostasis.
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Affiliation(s)
- Shalonda M Ingram
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA
| | - Tanu Rana
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA
| | - Ashley M Manson
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA
| | - Faisal M Yayah
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA
| | - Evan G B Jackson
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA
| | - Christopher Anderson
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA
| | - Benem-Orom Davids
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA
| | - J Shawn Goodwin
- Department of Biochemistry, Cancer Biology, Neuroscience, and Pharmacology, School of Medicine, Meharry Medical College, Nashville, Tennessee, USA.
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15
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Czarna M, Kuchniak K, Chrapusta SJ, Turzyńska D, Płaźnik A, Taracha E. Diverging changes in rat striatal extracellular dopamine and DOPAC levels and in frequency-modulated 50-kHz ultrasonic vocalizations rate during repeated amphetamine treatment. Behav Brain Res 2020; 393:112745. [DOI: 10.1016/j.bbr.2020.112745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/18/2020] [Accepted: 05/28/2020] [Indexed: 12/27/2022]
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16
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Herland A, Maoz BM, FitzGerald EA, Grevesse T, Vidoudez C, Sheehy SP, Budnik N, Dauth S, Mannix R, Budnik B, Parker KK, Ingber DE. Proteomic and Metabolomic Characterization of Human Neurovascular Unit Cells in Response to Methamphetamine. ACTA ACUST UNITED AC 2020; 4:e1900230. [PMID: 32744807 DOI: 10.1002/adbi.201900230] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 07/02/2020] [Indexed: 01/31/2023]
Abstract
The functional state of the neurovascular unit (NVU), composed of the blood-brain barrier and the perivasculature that forms a dynamic interface between the blood and the central nervous system (CNS), plays a central role in the control of brain homeostasis and is strongly affected by CNS drugs. Human primary brain microvascular endothelium, astrocyte, pericyte, and neural cell cultures are often used to study NVU barrier functions as well as drug transport and efficacy; however, the proteomic and metabolomic responses of these different cell types are not well characterized. Culturing each cell type separately, using deep coverage proteomic analysis and characterization of the secreted metabolome, as well as measurements of mitochondrial activity, the responses of these cells under baseline conditions and when exposed to the NVU-impairing stimulant methamphetamine (Meth) are analyzed. These studies define the previously unknown metabolic and proteomic profiles of human brain pericytes and lead to improved characterization of the phenotype of each of the NVU cell types as well as cell-specific metabolic and proteomic responses to Meth.
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Affiliation(s)
- Anna Herland
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.,Division of Micro and Nanosystems, KTH Royal Institute of Technology, Stockholm, 10044, Sweden.,AIMES, Center for the Advancement of Integrated Engineering and Medical Sciences, Department of Neuroscience, Karolinska Institute, Stockholm, 17177, Sweden
| | - Ben M Maoz
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.,Disease Biophysics Group, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.,Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, 6997801, Israel.,Department of Biomedical Engineering, Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Edward A FitzGerald
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA
| | - Thomas Grevesse
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.,Disease Biophysics Group, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Charles Vidoudez
- Small Molecule Mass Spectrometry Facility, Harvard University, Cambridge, MA, 02138, USA
| | - Sean P Sheehy
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.,Disease Biophysics Group, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Nikita Budnik
- Disease Biophysics Group, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Stephanie Dauth
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.,Disease Biophysics Group, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Robert Mannix
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA
| | - Bogdan Budnik
- Mass Spectrometry and Proteomics Resource Laboratory, Harvard University, Cambridge, MA, 02138, USA
| | - Kevin Kit Parker
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.,Disease Biophysics Group, Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Donald E Ingber
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, MA, 02115, USA.,Vascular Biology Program and Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA, 02115, USA.,Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
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17
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Masuoka T, Tateno A, Sakayori T, Tiger M, Kim W, Moriya H, Ueda S, Arakawa R, Okubo Y. Electroconvulsive therapy decreases striatal dopamine transporter binding in patients with depression: A positron emission tomography study with [ 18F]FE-PE2I. Psychiatry Res Neuroimaging 2020; 301:111086. [PMID: 32464340 DOI: 10.1016/j.pscychresns.2020.111086] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/05/2020] [Accepted: 04/16/2020] [Indexed: 02/06/2023]
Abstract
Electroconvulsive therapy (ECT) is an effective treatment for major depression. Previous studies suggested that dopaminergic neurotransmission plays a crucial role in the mechanism of the action of ECT. Since dopamine transporters (DAT) regulate extracellular dopamine concentration, DAT represents an interesting target for the study of the mechanism of action of ECT. Eight inpatients (7 patients with major depressive disorder and 1 patient with bipolar disorder with a DSM-IV diagnosis) received a series of 7-15(11.3±5.2) bilateral ECT sessions.The severity of symptoms was assessed using the 21-item Hamilton Depression Rating Scale (HDRS) and Clinical Global Impression-Severity (CGI-S). All patients were examined with [18F]FE-PE2I positron emission tomography (PET) at pre-ECT, after the 10th ECT, and at post-ECT. Striatal DAT-binding potential (BPND) of all patients was reduced, with an average change ratio of DAT-BPND of -13.1±5.6%. In the 2 cases with 15 ECT sessions, the ratio change of DAT-BPND after the 15th ECT was larger than that after the 10th ECT. Also, HDRS and CGI-S were reduced. These results indicate that the dopamine nervous system is part of themechanism of action of ECT.
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Affiliation(s)
- Takahiro Masuoka
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan
| | - Amane Tateno
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan
| | - Takeshi Sakayori
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan
| | - Mikael Tiger
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan; Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - WooChan Kim
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan
| | - Hiroki Moriya
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan
| | - Satoshi Ueda
- Faculty of Medical Health, University of Tokyo Health Sciences, 4-11 Ochiai, Tama-shi, Tokyo, Japan
| | - Ryosuke Arakawa
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan; Centre for Psychiatry Research, Department of Clinical Neuroscience, Karolinska Institutet & Stockholm Health Care Services, Stockholm County Council, Stockholm, Sweden
| | - Yoshiro Okubo
- Department of Neuropsychiatry, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-ku, Tokyo, Japan.
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18
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A novel designer drug, 25N-NBOMe, exhibits abuse potential via the dopaminergic system in rodents. Brain Res Bull 2019; 152:19-26. [DOI: 10.1016/j.brainresbull.2019.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/02/2019] [Accepted: 07/02/2019] [Indexed: 12/29/2022]
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19
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Bolland DE, Moritz AE, Stanislowski DJ, Vaughan RA, Foster JD. Palmitoylation by Multiple DHHC Enzymes Enhances Dopamine Transporter Function and Stability. ACS Chem Neurosci 2019; 10:2707-2717. [PMID: 30965003 PMCID: PMC6746250 DOI: 10.1021/acschemneuro.8b00558] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The dopamine transporter (DAT) is a plasma membrane protein that mediates the reuptake of extracellular dopamine (DA) and controls the spatiotemporal dynamics of dopaminergic neurotransmission. The transporter is subject to fine control that tailors clearance of transmitter to physiological demands, and dysregulation of reuptake induced by psychostimulant drugs, transporter polymorphisms, and signaling defects may impact transmitter tone in disease states. We previously demonstrated that DAT undergoes complex regulation by palmitoylation, with acute inhibition of the modification leading to rapid reduction of transport activity and sustained inhibition of the modification leading to transporter degradation and reduced expression. Here, to examine mechanisms and outcomes related to increased modification, we coexpressed DAT with palmitoyl acyltransferases (PATs), also known as DHHC enzymes, which catalyze palmitate addition to proteins. Of 12 PATs tested, DAT palmitoylation was stimulated by DHHC2, DHHC3, DHHC8, DHHC15, and DHHC17, with others having no effect. Increased modification was localized to previously identified palmitoylation site Cys580 and resulted in upregulation of transport kinetics and elevated transporter expression mediated by reduced degradation. These findings confirm palmitoylation as a regulator of multiple DAT properties crucial for appropriate DA homeostasis and identify several potential PAT pathways linked to these effects. Defects in palmitoylation processes thus represent possible mechanisms of transport imbalances in DA disorders.
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Affiliation(s)
| | | | - Daniel J. Stanislowski
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58202
| | - Roxanne A. Vaughan
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58202
| | - James D. Foster
- Department of Biomedical Sciences, University of North Dakota, School of Medicine and Health Sciences, Grand Forks, ND 58202
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20
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Paredes-Zúñiga S, Trost N, De la Paz JF, Alcayaga J, Allende ML. Behavioral effects of triadimefon in zebrafish are associated with alterations of the dopaminergic and serotonergic pathways. Prog Neuropsychopharmacol Biol Psychiatry 2019; 92:118-126. [PMID: 30593828 DOI: 10.1016/j.pnpbp.2018.12.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/14/2018] [Accepted: 12/19/2018] [Indexed: 12/20/2022]
Abstract
Triadimefon (TDF) is a triazole fungicide extensively used in agriculture that has been found as a pollutant in numerous water sources. In mammals, it inhibits monoamine uptake through binding to the dopamine transporter, with a mechanism of action similar to cocaine, resulting in higher levels of dopamine at the synapse. Dopamine is a neurotransmitter involved in a broad spectrum of processes such as locomotion, cognition, reward, and mental disorders. In this work we have studied, for the first time, the effects of TDF on behavior of both larval and adult zebrafish and its connection with changes in the dopaminergic and serotonergic systems. We evaluated the acute exposure of 5 dpf larvae to different concentrations of TDF, ranging from 5 mg/L to 35 mg/L. The lowest concentration does not alter neither locomotor activity nor dopamine levels but produced changes in the expression of two genes, tyrosine hydroxylase 1 (th1) and dopamine transporter (dat). Besides, it induced a reduction in extracellular serotonin and had an anxiolytic-like effect, supported by a decrease in cortisol production. On the other hand, a high concentration of TDF produced a dose-dependent reduction in locomotion, which was reversed or enhanced by D1 (SCH-23390) or D2 (Haloperidol) dopamine receptor antagonists, respectively. Using in vivo electrochemistry, we show that these changes could be associated with higher levels of dopamine in the brain. Thus, in adult zebrafish, though not in larvae, TDF exposure increases locomotor activity, anxiety and aggressiveness, which coincides with the behaviors observed in mammals.
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Affiliation(s)
- Susana Paredes-Zúñiga
- FONDAP Center for Genome Regulation, Faculty of Science, University of Chile, Santiago, Chile
| | - Nils Trost
- FONDAP Center for Genome Regulation, Faculty of Science, University of Chile, Santiago, Chile; Center for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Javiera F De la Paz
- FONDAP Center for Genome Regulation, Faculty of Science, University of Chile, Santiago, Chile
| | - Julio Alcayaga
- Departamento de Biología, Centro de Fisiología Celular, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.
| | - Miguel L Allende
- FONDAP Center for Genome Regulation, Faculty of Science, University of Chile, Santiago, Chile.
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21
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Effects of MDPV on dopamine transporter regulation in male rats. Comparison with cocaine. Psychopharmacology (Berl) 2019; 236:925-938. [PMID: 30284596 DOI: 10.1007/s00213-018-5052-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/24/2018] [Indexed: 10/28/2022]
Abstract
RATIONALE MDPV (3,4-methylenedioxypyrovalerone) is a synthetic cathinone present in bath salts. It is a powerful psychostimulant and blocker of the dopamine transporter (DAT), like cocaine. It is known that acute exposure to psychostimulants induces rapid changes in DAT function. OBJECTIVES To investigate the effects of MDPV on DAT function comparing with cocaine. METHODS Binding of [3H]WIN 35428 was performed on PC 12 cells treated with MDPV and washed. Rat striatal synaptosomes were incubated with MDPV or cocaine (1 μM) for 1 h and [3H]dopamine (DA) uptake was performed. Also, different treatments with MDPV or cocaine were performed in Sprague-Dawley rats to assess locomotor activity and ex vivo [3H]DA uptake. RESULTS MDPV increased surface [3H]WIN 35428 binding on PC 12 cells. In vitro incubation of synaptosomes with MDPV produced significant increases in Vmax and KM for [3H]DA uptake. In synaptosomes from MDPV- (1.5 mg/kg, s.c.) and cocaine- (30 mg/kg, i.p.) treated rats, there was a significantly higher and more persistent increase in [3H]DA uptake in the case of MDPV than cocaine. Repeated doses of MDPV developed tolerance to this DAT upregulation and 24 h after the 5-day treatment with MDPV, [3H]DA uptake was reduced. However, a challenge with the same drugs after withdrawal recovered the DAT upregulation by both drugs and showed an increased response to MDPV vs the first dose. At the same time, animals were sensitized to the stereotypies induced by both psychostimulants. CONCLUSIONS MDPV induces a rapid and reversible functional upregulation of DAT more powerfully and lasting than cocaine.
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22
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Shin EJ, Dang DK, Hwang YG, Tran HQ, Sharma N, Jeong JH, Jang CG, Nah SY, Nabeshima T, Yoneda Y, Cadet JL, Kim HC. Significance of protein kinase C in the neuropsychotoxicity induced by methamphetamine-like psychostimulants. Neurochem Int 2019; 124:162-170. [PMID: 30654115 DOI: 10.1016/j.neuint.2019.01.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 12/27/2018] [Accepted: 01/14/2019] [Indexed: 02/06/2023]
Abstract
The abuse of methamphetamine (MA), an amphetamine (AMPH)-type stimulant, has been demonstrated to be associated with various neuropsychotoxicity, including memory impairment, psychiatric morbidity, and dopaminergic toxicity. Compelling evidence from preclinical studies has indicated that protein kinase C (PKC), a large family of serine/threonine protein kinases, plays an important role in MA-induced neuropsychotoxicity. PKC-mediated N-terminal phosphorylation of dopamine transporter has been identified as one of the prerequisites for MA-induced synaptic dopamine release. Consistently, it has been shown that PKC is involved in MA (or AMPH)-induced memory impairment and mania-like behaviors as well as MA drug dependence. Direct or indirect regulation of factors related to neuronal plasticity seemed to be critical for these actions of PKC. In addition, PKC-mediated mitochondrial dysfunction, oxidative stress or impaired antioxidant defense system has been suggested to play a role in psychiatric and cognitive disturbance induced by MA (or AMPH). In MA-induced dopaminergic toxicity, particularly PKCδ has been shown to trigger oxidative stress, mitochondrial dysfunction, pro-apoptotic changes, and neuroinflammation. Importantly, PKCδ may be a key mediator in the positive feedback loop composed of these detrimental events to potentiate MA-induced dopaminergic toxicity. This review outlines the role of PKC and its individual isozymes in MA-induced neuropsychotoxicity. Better understanding on the molecular mechanism of PKCs might provide a great insight for the development of potential therapeutic or preventive candidates for MA (or AMPH)-associated neuropsychotoxicity.
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Affiliation(s)
- Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 24341, Republic of Korea
| | - Duy-Khanh Dang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 24341, Republic of Korea
| | - Young Gwang Hwang
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 24341, Republic of Korea
| | - Hai-Quyen Tran
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 24341, Republic of Korea
| | - Naveen Sharma
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 24341, Republic of Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Seung-Yeol Nah
- Ginsentology Research Laboratory and Department of Physiology, College of Veterinary Medicine, Konkuk University, Seoul 05029, Republic of Korea
| | - Toshitaka Nabeshima
- Advanced Diagnostic System Research Laboratory, Fujita Health University Graduate School of Health Science, Toyoake 470-1192, Japan
| | - Yukio Yoneda
- Section of Prophylactic Pharmacology, Kanazawa University Venture Business Laboratory, Kanazawa, Ishikawa 920-1192, Japan
| | - Jean Lud Cadet
- NIDA Intramural Program, Molecular Neuropsychiatry Research Branch, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 24341, Republic of Korea.
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23
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Abstract
There is a plethora of amphetamine derivatives exerting stimulant, euphoric, anti-fatigue, and hallucinogenic effects; all structural properties allowing these effects are contained within the amphetamine structure. In the first part of this review, the interaction of amphetamine with the dopamine transporter (DAT), crucially involved in its behavioral effects, is covered, as well as the role of dopamine synthesis, the vesicular monoamine transporter VMAT2, and organic cation 3 transporter (OCT3). The second part deals with requirements in amphetamine's effect on the kinases PKC, CaMKII, and ERK, whereas the third part focuses on where we are in developing anti-amphetamine therapeutics. Thus, treatments are discussed that target DAT, VMAT2, PKC, CaMKII, and OCT3. As is generally true for the development of therapeutics for substance use disorder, there are multiple preclinically promising specific compounds against (meth)amphetamine, for which further development and clinical trials are badly needed.
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Affiliation(s)
- Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, New York, NY, USA.
| | - Margaret E Gnegy
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI, USA
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24
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Tomlinson MJ, Krout D, Pramod AB, Lever JR, Newman AH, Henry LK, Vaughan RA. Identification of the benztropine analog [ 125I]GA II 34 binding site on the human dopamine transporter. Neurochem Int 2018; 123:34-45. [PMID: 30125594 DOI: 10.1016/j.neuint.2018.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/10/2018] [Accepted: 08/14/2018] [Indexed: 12/21/2022]
Abstract
The dopamine transporter (DAT) is a neuronal membrane protein that is responsible for reuptake of dopamine (DA) from the synapse and functions as a major determinant in control of DA neurotransmission. Cocaine and many psychostimulant drugs bind to DAT and block reuptake, inducing DA overflow that forms the neurochemical basis for euphoria and addiction. Paradoxically, however, some ligands such as benztropine (BZT) bind to DAT and inhibit reuptake but do not produce these effects, and it has been hypothesized that differential mechanisms of binding may stabilize specific transporter conformations that affect downstream neurochemical or behavioral outcomes. To investigate the binding mechanisms of BZT on DAT we used the photoaffinity BZT analog [125I]N-[n-butyl-4-(4‴-azido-3‴-iodophenyl)]-4',4″-difluoro-3α-(diphenylmethoxy)tropane ([125I]GA II 34) to identify the site of cross-linking and predict the binding pose relative to that of previously-examined cocaine photoaffinity analogs. Biochemical findings show that adduction of [125I]GA II 34 occurs at residues Asp79 or Leu80 in TM1, with molecular modeling supporting adduction to Leu80 and a pharmacophore pose in the central S1 site similar to that of cocaine and cocaine analogs. Substituted cysteine accessibility method protection analyses verified these findings, but identified some differences in structural stabilization relative to cocaine that may relate to BZT neurochemical outcomes.
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Affiliation(s)
- Michael J Tomlinson
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States
| | - Danielle Krout
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States
| | - Akula Bala Pramod
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States
| | - John R Lever
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO, 65201, United States; Department of Radiology and Radiopharmaceutical Sciences Institute, University of Missouri, Columbia, MO 65211, United States
| | - Amy Hauck Newman
- Medicinal Chemistry Section, National Institute on Drug Abuse - Intramural Research Program, Baltimore, MD 21224, United States
| | - L Keith Henry
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States.
| | - Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, 1301 North Columbia Road, Grand Forks, ND 58202, United States.
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25
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Colon-Perez LM, Pino JA, Saha K, Pompilus M, Kaplitz S, Choudhury N, Jagnarine DA, Geste JR, Levin BA, Wilks I, Setlow B, Bruijnzeel AW, Khoshbouei H, Torres GE, Febo M. Functional connectivity, behavioral and dopaminergic alterations 24 hours following acute exposure to synthetic bath salt drug methylenedioxypyrovalerone. Neuropharmacology 2018; 137:178-193. [PMID: 29729891 DOI: 10.1016/j.neuropharm.2018.04.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 04/26/2018] [Accepted: 04/29/2018] [Indexed: 12/22/2022]
Abstract
Among cathinone drugs known as bath salts, methylenedioxypyrovalerone (MDPV) exerts its potent actions via the dopamine (DA) system, and at intoxicating doses may produce adverse behavioral effects. Previous work by our group suggests that prolonged alterations in correlated neural activity between cortical and striatal areas could underlie, at least in part, the adverse reactions to this bath salt drug. In the present study, we assessed the effect of acute MDPV administration on brain functional connectivity at 1 and 24 h in rats. Using graph theory metrics to assess in vivo brain functional network organization we observed that 24 h after MDPV administration there was an increased clustering coefficient, rich club index, and average path length. Increases in these metrics suggests that MDPV produces a prolonged pattern of correlated activity characterized by greater interactions between subsets of high degree nodes but a reduced interaction with regions outside this core subset. Further analysis revealed that the core set of nodes include prefrontal cortical, amygdala, hypothalamic, somatosensory and striatal areas. At the molecular level, MDPV downregulated the dopamine transporter (DAT) in striatum and produced a shift in its subcellular distribution, an effect likely to involve rapid internalization at the membrane. These new findings suggest that potent binding of MDPV to DAT may trigger internalization and a prolonged alteration in homeostatic regulation of DA and functional brain network reorganization. We propose that the observed MDPV-induced network reorganization and DAergic changes may contribute to previously reported adverse behavioral responses to MDPV.
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Affiliation(s)
- Luis M Colon-Perez
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Center for Addiction Research and Education (CARE), College of Medicine, University of Florida, Gainesville, FL 32610, USA; Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) Facility, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Jose A Pino
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Kaustuv Saha
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Marjory Pompilus
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Sherman Kaplitz
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Nafisa Choudhury
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Darin A Jagnarine
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Jean R Geste
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Brandon A Levin
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Isaac Wilks
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Barry Setlow
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; The McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Center for Addiction Research and Education (CARE), College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Adriaan W Bruijnzeel
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; The McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Center for Addiction Research and Education (CARE), College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Habibeh Khoshbouei
- Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; The McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Center for Addiction Research and Education (CARE), College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Gonzalo E Torres
- Department of Pharmacology and Therapeutics, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Center for Addiction Research and Education (CARE), College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Marcelo Febo
- Department of Psychiatry, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Department of Neuroscience, College of Medicine, University of Florida, Gainesville, FL 32610, USA; The McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; Center for Addiction Research and Education (CARE), College of Medicine, University of Florida, Gainesville, FL 32610, USA; Advanced Magnetic Resonance Imaging and Spectroscopy (AMRIS) Facility, College of Medicine, University of Florida, Gainesville, FL 32610, USA.
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26
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Mackie P, Lebowitz J, Saadatpour L, Nickoloff E, Gaskill P, Khoshbouei H. The dopamine transporter: An unrecognized nexus for dysfunctional peripheral immunity and signaling in Parkinson's Disease. Brain Behav Immun 2018; 70:21-35. [PMID: 29551693 PMCID: PMC5953824 DOI: 10.1016/j.bbi.2018.03.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 02/06/2023] Open
Abstract
The second-most common neurodegenerative disease, Parkinson's Disease (PD) has three hallmarks: dysfunctional dopamine transmission due, at least in part, to dopamine neuron degeneration; intracellular inclusions of α-synuclein aggregates; and neuroinflammation. The origin and interplay of these features remains a puzzle, as does the underlying mechanism of PD pathogenesis and progression. When viewed in the context of neuroimmunology, dopamine also plays a role in regulating peripheral immune cells. Intriguingly, plasma dopamine levels are altered in PD, suggesting collateral dysregulation of peripheral dopamine transmission. The dopamine transporter (DAT), the main regulator of dopaminergic tone in the CNS, is known to exist in lymphocytes and monocytes/macrophages, but little is known about peripheral DAT biology or how DAT regulates the dopaminergic tone, much less how peripheral DAT alters immune function. Our review is guided by the hypothesis that dysfunctional peripheral dopamine signaling might be linked to the dysfunctional immune responses in PD and thereby suggests a potential bidirectional communication between central and peripheral dopamine systems. This review seeks to foster new perspectives concerning PD pathogenesis and progression.
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Affiliation(s)
- Phillip Mackie
- University of Florida College of Medicine, Department of Neuroscience, Gainesville, FL 32611, United States
| | - Joe Lebowitz
- University of Florida College of Medicine, Department of Neuroscience, Gainesville, FL 32611, United States
| | - Leila Saadatpour
- University of Florida College of Medicine, Department of Neuroscience, Gainesville, FL 32611, United States
| | - Emily Nickoloff
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, United States
| | - Peter Gaskill
- Department of Pharmacology and Physiology, Drexel University College of Medicine, Philadelphia, PA 19102, United States
| | - Habibeh Khoshbouei
- University of Florida College of Medicine, Department of Neuroscience, Gainesville, FL 32611, United States.
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Garcia-Olivares J, Baust T, Harris S, Hamilton P, Galli A, Amara SG, Torres GE. Gβγ subunit activation promotes dopamine efflux through the dopamine transporter. Mol Psychiatry 2017; 22:1673-1679. [PMID: 28894302 PMCID: PMC5996372 DOI: 10.1038/mp.2017.176] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/05/2017] [Accepted: 07/28/2017] [Indexed: 01/30/2023]
Abstract
The dopamine transporter (DAT) is an important regulator of brain dopamine (DA) homeostasis, controlling the intensity and duration of DA signaling. DAT is the target for psychostimulants-like cocaine and amphetamine-and plays an important role in neuropsychiatric disorders, including attention-deficit hyperactivity disorder and drug addiction. Thus, a thorough understanding of the mechanisms that regulate DAT function is necessary for the development of clinical interventions to treat DA-related brain disorders. Previous studies have revealed a plethora of protein-protein interactions influencing DAT cellular localization and activity, suggesting that the fine-tuning of DA homeostasis involves multiple mechanisms. We recently reported that G-protein beta-gamma (Gβγ) subunits bind directly to DAT and decrease DA clearance. Here we show that Gβγ induces the release of DA through DAT. Specifically, a Gβγ-binding/activating peptide, mSIRK, increases DA efflux through DAT in heterologous cells and primary dopaminergic neurons in culture. Addition of the Gβγ inhibitor gallein or DAT inhibitors prevents this effect. Residues 582 to 596 in the DAT carboxy terminus were identified as the primary binding site of Gβγ. A TAT peptide containing the Gβγ-interacting domain of DAT blocked the ability of mSIRK to induce DA efflux, consistent with a direct interaction of Gβγ with the transporter. Finally, activation of a G-protein-coupled receptor, the muscarinic M5R, results in DAT-mediated DA efflux through a Gβγ-dependent mechanism. Collectively, our data show that Gβγ interacts with DAT to promote DA efflux. This novel mechanism may have important implications in the regulation of brain DA homeostasis.
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Affiliation(s)
- J Garcia-Olivares
- Laboratory of Cellular and Molecular Neurobiology, National Institute of Mental Health, Bethesda, MD, USA
| | - T Baust
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA
| | - S Harris
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA
| | - P Hamilton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - A Galli
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - SG Amara
- Laboratory of Cellular and Molecular Neurobiology, National Institute of Mental Health, Bethesda, MD, USA
| | - GE Torres
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA
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28
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Amphetamine Reverses Escalated Cocaine Intake via Restoration of Dopamine Transporter Conformation. J Neurosci 2017; 38:484-497. [PMID: 29175958 DOI: 10.1523/jneurosci.2604-17.2017] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/14/2017] [Accepted: 11/17/2017] [Indexed: 12/27/2022] Open
Abstract
Cocaine abuse disrupts dopamine system function, and reduces cocaine inhibition of the dopamine transporter (DAT), which results in tolerance. Although tolerance is a hallmark of cocaine addiction and a DSM-V criterion for substance abuse disorders, the molecular adaptations producing tolerance are unknown, and testing the impact of DAT changes on drug taking behaviors has proven difficult. In regard to treatment, amphetamine has shown efficacy in reducing cocaine intake; however, the mechanisms underlying these effects have not been explored. The goals of this study were twofold; we sought to (1) identify the molecular mechanisms by which cocaine exposure produces tolerance and (2) determine whether amphetamine-induced reductions in cocaine intake are connected to these mechanisms. Using cocaine self-administration and fast-scan cyclic voltammetry in male rats, we show that low-dose, continuous amphetamine treatment, during self-administration or abstinence, completely reversed cocaine tolerance. Amphetamine treatment also reversed escalated cocaine intake and decreased motivation to obtain cocaine as measured in a behavioral economics task, thereby linking tolerance to multiple facets of cocaine use. Finally, using fluorescence resonance energy transfer imaging, we found that cocaine tolerance is associated with the formation of DAT-DAT complexes, and that amphetamine disperses these complexes. In addition to extending our basic understanding of DATs and their role in cocaine reinforcement, we serendipitously identified a novel therapeutic target: DAT oligomer complexes. We show that dispersion of oligomers is concomitant with reduced cocaine intake, and propose that pharmacotherapeutics aimed at these complexes may have potential for cocaine addiction treatment.SIGNIFICANCE STATEMENT Tolerance to cocaine's subjective effects is a cardinal symptom of cocaine addiction and a DSM-V criterion for substance abuse disorders. However, elucidating the molecular adaptions that produce tolerance and determining its behavioral impact have proven difficult. Using cocaine self-administration in rats, we link tolerance to cocaine effects at the dopamine transporter (DAT) with aberrant cocaine-taking behaviors. Further, tolerance was associated with multi-DAT complexes, which formed after cocaine exposure. Treatment with amphetamine deconstructed DAT complexes, reversed tolerance, and decreased cocaine seeking. These data describe the behavioral consequence of cocaine tolerance, provide a putative mechanism for its development, and suggest that compounds that disperse DAT complexes may be efficacious treatments for cocaine addiction.
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29
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Karam CS, Javitch JA. Phosphorylation of the Amino Terminus of the Dopamine Transporter: Regulatory Mechanisms and Implications for Amphetamine Action. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2017; 82:205-234. [PMID: 29413521 DOI: 10.1016/bs.apha.2017.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Amphetamines (AMPHs) are potent psychostimulants that are widely used and abused, with profound medical and societal impact. Their actions at dopaminergic neurons are thought to mediate their therapeutic efficacy as well as their liability for abuse and dependence. AMPHs target the dopamine transporter (DAT), the plasmalemmal membrane protein that mediates the inactivation of released dopamine (DA) through its reuptake. AMPHs act as substrates for DAT and are known to cause mobilization of dopamine (DA) to the cell exterior via DAT-mediated reverse transport (efflux). It has become increasingly evident that the mechanisms that regulate AMPH-induced DA efflux are distinct from those that regulate DA uptake. Central to these mechanisms is the phosphorylation of the DAT amino (N)-terminus, which has been repeatedly demonstrated to facilitate DAT-mediated DA efflux, without impacting other aspects of DAT physiology. This review aims to summarize the current status of knowledge regarding DAT N-terminal phosphorylation and its regulation by protein modulators and the membrane microenvironment. A better understanding of these mechanisms may lead to the identification of novel therapeutic approaches that interfere selectively with the pharmacological effects of AMPHs without altering the physiological function of DAT.
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Affiliation(s)
- Caline S Karam
- College of Physicians & Surgeons, Columbia University, New York, NY, United States; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, United States
| | - Jonathan A Javitch
- College of Physicians & Surgeons, Columbia University, New York, NY, United States; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY, United States.
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30
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Foster JD, Vaughan RA. Phosphorylation mechanisms in dopamine transporter regulation. J Chem Neuroanat 2017; 83-84:10-18. [PMID: 27836487 PMCID: PMC6705611 DOI: 10.1016/j.jchemneu.2016.10.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/26/2016] [Accepted: 10/29/2016] [Indexed: 12/17/2022]
Abstract
The dopamine transporter (DAT) is a plasma membrane phosphoprotein that actively translocates extracellular dopamine (DA) into presynaptic neurons. The transporter is the primary mechanism for control of DA levels and subsequent neurotransmission, and is the target for abused and therapeutic drugs that exert their effects by suppressing reuptake. The transport capacity of DAT is acutely regulated by signaling systems and drug exposure, providing neurons the ability to fine-tune DA clearance in response to specific conditions. Kinase pathways play major roles in these mechanisms, and this review summarizes the current status of DAT phosphorylation characteristics and the evidence linking transporter phosphorylation to control of reuptake and other functions. Greater understanding of these processes may aid in elucidation of their possible contributions to DA disease states and suggest specific phosphorylation sites as targets for therapeutic manipulation of reuptake.
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Affiliation(s)
- James D Foster
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks ND 58202 United States
| | - Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks ND 58202 United States.
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31
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Challasivakanaka S, Zhen J, Smith ME, Reith MEA, Foster JD, Vaughan RA. Dopamine transporter phosphorylation site threonine 53 is stimulated by amphetamines and regulates dopamine transport, efflux, and cocaine analog binding. J Biol Chem 2017; 292:19066-19075. [PMID: 28939767 DOI: 10.1074/jbc.m117.787002] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 08/29/2017] [Indexed: 11/06/2022] Open
Abstract
The dopamine transporter (DAT) controls the spatial and temporal dynamics of dopamine neurotransmission through reuptake of extracellular transmitter and is a target for addictive compounds such as cocaine, amphetamine (AMPH), and methamphetamine (METH). Reuptake is regulated by kinase pathways and drug exposure, allowing for fine-tuning of clearance in response to specific conditions, and here we examine the impact of transporter ligands on DAT residue Thr-53, a proline-directed phosphorylation site previously implicated in AMPH-stimulated efflux mechanisms. Our findings show that Thr-53 phosphorylation is stimulated in a transporter-dependent manner by AMPH and METH in model cells and rat striatal synaptosomes, and in striatum of rats given subcutaneous injection of METH. Rotating disc electrode voltammetry revealed that initial rates of uptake and AMPH-induced efflux were elevated in phosphorylation-null T53A DAT relative to WT and charge-substituted T53D DATs, consistent with functions related to charge or polarity. These effects occurred without alterations of surface transporter levels, and mutants also showed reduced cocaine analog binding affinity that was not rescued by Zn2+ Together these findings support a role for Thr-53 phosphorylation in regulation of transporter kinetic properties that could impact DAT responses to amphetamines and cocaine.
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Affiliation(s)
- Sathya Challasivakanaka
- From the Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58201 and
| | | | - Margaret E Smith
- From the Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58201 and
| | - Maarten E A Reith
- the Departments of Psychiatry and.,Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York 10016
| | - James D Foster
- From the Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58201 and
| | - Roxanne A Vaughan
- From the Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58201 and
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32
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Abramyan AM, Stolzenberg S, Li Z, Loland CJ, Noé F, Shi L. The Isomeric Preference of an Atypical Dopamine Transporter Inhibitor Contributes to Its Selection of the Transporter Conformation. ACS Chem Neurosci 2017; 8:1735-1746. [PMID: 28441487 DOI: 10.1021/acschemneuro.7b00094] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cocaine, a widely abused psychostimulant, inhibits the dopamine transporter (DAT) by trapping the protein in an outward-open conformation, whereas atypical DAT inhibitors such as benztropine have low abuse liability and prefer less outward-open conformations. Here, we use a spectrum of computational modeling and simulation approaches to obtain the underlying molecular mechanism in atomistic detail. Interestingly, our quantum mechanical calculations and molecular dynamics (MD) simulations suggest that a benztropine derivative JHW007 prefers a different stereoisomeric conformation of tropane in binding to DAT compared to that of a cocaine derivative, CFT. To further investigate the different inhibition mechanisms of DAT, we carried out MD simulations in combination with Markov state modeling analysis of wild-type and Y156F DAT in the absence of any ligand or the presence of CFT or JHW007. Our results indicate that the Y156F mutation and CFT shift the conformational equilibrium toward an outward-open conformation, whereas JHW007 prefers an inward-occluded conformation. Our findings reveal the mechanistic details of DAT inhibition by JHW007 at the atomistic level, which provide clues for rational design of atypical inhibitors.
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Affiliation(s)
- Ara M. Abramyan
- Computational
Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications
Discovery Branch, NIH/NIDA/IRP, Baltimore, Maryland 21224, United States
| | - Sebastian Stolzenberg
- Computational
Molecular Biology group, Institute for Mathematics, Freie Universität Berlin, Arnimallee 6, 14195 Berlin, Germany
| | - Zheng Li
- Department
of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York 10065, United States
| | - Claus J. Loland
- Molecular
Neuropharmacology Group, Department of Neuroscience and Pharmacology,
The Faculty of Health Sciences, The Panum Institute, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Frank Noé
- Computational
Molecular Biology group, Institute for Mathematics, Freie Universität Berlin, Arnimallee 6, 14195 Berlin, Germany
| | - Lei Shi
- Computational
Chemistry and Molecular Biophysics Unit, Molecular Targets and Medications
Discovery Branch, NIH/NIDA/IRP, Baltimore, Maryland 21224, United States
- Department
of Physiology and Biophysics, Weill Cornell Medical College of Cornell University, New York, New York 10065, United States
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33
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Karam CS, Sen N, Javitch JA. Phospho-specific antibodies targeting the amino terminus of the human dopamine transporter. J Chem Neuroanat 2017; 83-84:91-98. [PMID: 28571709 DOI: 10.1016/j.jchemneu.2017.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 05/11/2017] [Indexed: 11/29/2022]
Abstract
The dopamine transporter (DAT), which mediates the inactivation of released dopamine through its reuptake, is the primary molecular target for the actions of psychostimulants. An increasing number of studies support an essential role for phosphorylation of serines (Ser) in the distal amino (N) terminus of DAT in regulating its function. Still, the molecular details of the regulation of phosphorylation and its impact on function are not fully understood. To address this, we have developed and characterized two distinct phospho-antibodies that recognize human DAT when it is phosphorylated at Ser7 or Ser12. Our data show that treatment of cells with phorbol 12-myristate 13-acetate (PMA), amphetamine (AMPH) or okadaic acid (OA) leads to an increase in the phosphorylation of DAT at both residues and that these responses are dependent on the activity of protein kinase C. We also show that AMPH-induced and OA-induced phosphorylation of DAT are dependent on Ca2+/calmodulin-dependent protein kinase α. Our data further suggest that the lipid raft localization of DAT is necessary for efficient N-terminal phosphorylation and for the associated behavioral effects of AMPH, demonstrating the potential of these novel antibodies as powerful tools to study DAT regulation and function in vivo.
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Affiliation(s)
- Caline S Karam
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Namita Sen
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Jonathan A Javitch
- Department of Psychiatry, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA; Department of Pharmacology, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA.
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34
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Miller BW, Wroten MG, Sacramento AD, Silva HE, Shin CB, Vieira PA, Ben-Shahar O, Kippin TE, Szumlinski KK. Cocaine craving during protracted withdrawal requires PKCε priming within vmPFC. Addict Biol 2017; 22:629-639. [PMID: 26769453 DOI: 10.1111/adb.12354] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 11/18/2015] [Accepted: 11/26/2015] [Indexed: 12/22/2022]
Abstract
In individuals with a history of drug taking, the capacity of drug-associated cues to elicit indices of drug craving intensifies or incubates with the passage of time during drug abstinence. This incubation of cocaine craving, as well as difficulties with learning to suppress drug-seeking behavior during protracted withdrawal, are associated with a time-dependent deregulation of ventromedial prefrontal cortex (vmPFC) function. As the molecular bases for cocaine-related vmPFC deregulation remain elusive, the present study assayed the consequences of extended access to intravenous cocaine (6 hours/day; 0.25 mg/infusion for 10 day) on the activational state of protein kinase C epsilon (PKCε), an enzyme highly implicated in drug-induced neuroplasticity. The opportunity to engage in cocaine seeking during cocaine abstinence time-dependently altered PKCε phosphorylation within vmPFC, with reduced and increased p-PKCε expression observed in early (3 days) and protracted (30 days) withdrawal, respectively. This effect was more robust within the ventromedial versus dorsomedial PFC, was not observed in comparable cocaine-experienced rats not tested for drug-seeking behavior and was distinct from the rise in phosphorylated extracellular signal-regulated kinase observed in cocaine-seeking rats. Further, the impact of inhibiting PKCε translocation within the vmPFC using TAT infusion proteins upon cue-elicited responding was determined and inhibition coinciding with the period of testing attenuated cocaine-seeking behavior, with an effect also apparent the next day. In contrast, inhibitor pretreatment prior to testing during early withdrawal was without effect. Thus, a history of excessive cocaine taking influences the cue reactivity of important intracellular signaling molecules within the vmPFC, with PKCε playing a critical role in the manifestation of cue-elicited cocaine seeking during protracted drug withdrawal.
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Affiliation(s)
- Bailey W. Miller
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Melissa G. Wroten
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Arianne D. Sacramento
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Hannah E. Silva
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Christina B. Shin
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Philip A. Vieira
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Osnat Ben-Shahar
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Tod E. Kippin
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
| | - Karen K. Szumlinski
- Department of Psychological and Brain Sciences and Neuroscience Research Institute; University of California Santa Barbara; Santa Barbara CA USA
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Current understanding of methamphetamine-associated dopaminergic neurodegeneration and psychotoxic behaviors. Arch Pharm Res 2017; 40:403-428. [DOI: 10.1007/s12272-017-0897-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 12/02/2016] [Indexed: 12/21/2022]
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Bermingham DP, Blakely RD. Kinase-dependent Regulation of Monoamine Neurotransmitter Transporters. Pharmacol Rev 2016; 68:888-953. [PMID: 27591044 PMCID: PMC5050440 DOI: 10.1124/pr.115.012260] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Modulation of neurotransmission by the monoamines dopamine (DA), norepinephrine (NE), and serotonin (5-HT) is critical for normal nervous system function. Precise temporal and spatial control of this signaling in mediated in large part by the actions of monoamine transporters (DAT, NET, and SERT, respectively). These transporters act to recapture their respective neurotransmitters after release, and disruption of clearance and reuptake has significant effects on physiology and behavior and has been linked to a number of neuropsychiatric disorders. To ensure adequate and dynamic control of these transporters, multiple modes of control have evolved to regulate their activity and trafficking. Central to many of these modes of control are the actions of protein kinases, whose actions can be direct or indirectly mediated by kinase-modulated protein interactions. Here, we summarize the current state of our understanding of how protein kinases regulate monoamine transporters through changes in activity, trafficking, phosphorylation state, and interacting partners. We highlight genetic, biochemical, and pharmacological evidence for kinase-linked control of DAT, NET, and SERT and, where applicable, provide evidence for endogenous activators of these pathways. We hope our discussion can lead to a more nuanced and integrated understanding of how neurotransmitter transporters are controlled and may contribute to disorders that feature perturbed monoamine signaling, with an ultimate goal of developing better therapeutic strategies.
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Affiliation(s)
- Daniel P Bermingham
- Department of Pharmacology (D.P.B., R.D.B.) and Psychiatry (R.D.B.), Vanderbilt University Medical Center, Nashville, Tennessee; and Department of Biomedical Sciences, Charles E. Schmidt College of Medicine and Brain Institute, Florida Atlantic University, Jupiter, Florida (R.D.B.)
| | - Randy D Blakely
- Department of Pharmacology (D.P.B., R.D.B.) and Psychiatry (R.D.B.), Vanderbilt University Medical Center, Nashville, Tennessee; and Department of Biomedical Sciences, Charles E. Schmidt College of Medicine and Brain Institute, Florida Atlantic University, Jupiter, Florida (R.D.B.)
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Spence AL, Guerin GF, Goeders NE. The differential effects of alprazolam and oxazepam on methamphetamine self-administration in rats. Drug Alcohol Depend 2016; 166:209-17. [PMID: 27485488 DOI: 10.1016/j.drugalcdep.2016.07.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Methamphetamine is the second most commonly used illicit drug in the world, and despite recent attempts by the Drug Enforcement Administration to combat this epidemic, methamphetamine use is still on the rise. As methamphetamine use increases so does polydrug use, particularly that involving methamphetamine and benzodiazepines. The present study was designed to examine the effects of two benzodiazepines on methamphetamine self-administration. METHODS Five doses of methamphetamine (0.0075, 0.015, 0.03, 0.09, and 0.12mg/kg/infusion) were tested, producing an inverted U-shaped dose-response curve. Rats were then pretreated with oxazepam, alprazolam, or vehicle prior to methamphetamine self-administration. To determine if the effects of these drugs were due to the GABAA receptor and/or translocator protein (TSPO), we also pretreated rats with an antagonist for the benzodiazepine-binding site on the GABAA receptor (i.e., flumazenil) and a TSPO antagonist (i.e., PK11195) prior to alprazolam or oxazepam administration. RESULTS Oxazepam significantly reduced methamphetamine self-administration as demonstrated by a downward shift of the dose-response curve. In contrast, alprazolam significantly enhanced methamphetamine self-administration as evidenced by a leftward shift of the dose-response curve. Flumazenil completely blocked the effects of alprazolam on methamphetamine self-administration. When administered individually, both flumazenil and PK11195 partially reversed the effects of oxazepam on methamphetamine self-administration. However, when these two antagonists were combined, the effects of oxazepam were completely reversed. CONCLUSIONS The GABAA receptor is responsible for the alprazolam-induced enhancement of methamphetamine self-administration, while the activation of both the GABAA receptor and TSPO are responsible for the oxazepam-induced reduction of methamphetamine self-administration.
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Affiliation(s)
- Allyson L Spence
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA 71130, United States.
| | - Glenn F Guerin
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA 71130, United States
| | - Nicholas E Goeders
- Department of Pharmacology, Toxicology, & Neuroscience, Louisiana State University Health Sciences Center - Shreveport, Shreveport, LA 71130, United States
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Sulzer D, Cragg SJ, Rice ME. Striatal dopamine neurotransmission: regulation of release and uptake. ACTA ACUST UNITED AC 2016; 6:123-148. [PMID: 27141430 DOI: 10.1016/j.baga.2016.02.001] [Citation(s) in RCA: 236] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dopamine (DA) transmission is governed by processes that regulate release from axonal boutons in the forebrain and the somatodendritic compartment in midbrain, and by clearance by the DA transporter, diffusion, and extracellular metabolism. We review how axonal DA release is regulated by neuronal activity and by autoreceptors and heteroreceptors, and address how quantal release events are regulated in size and frequency. In brain regions densely innervated by DA axons, DA clearance is due predominantly to uptake by the DA transporter, whereas in cortex, midbrain, and other regions with relatively sparse DA inputs, the norepinephrine transporter and diffusion are involved. We discuss the role of DA uptake in restricting the sphere of influence of DA and in temporal accumulation of extracellular DA levels upon successive action potentials. The tonic discharge activity of DA neurons may be translated into a tonic extracellular DA level, whereas their bursting activity can generate discrete extracellular DA transients.
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Affiliation(s)
- David Sulzer
- Depts of Psychiatry, Neurology, & Pharmacology, NY State Psychiatric Institute, Columbia University, New York, NY, USA
| | - Stephanie J Cragg
- Dept Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Margaret E Rice
- Depts of Neurosurgery & Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
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German CL, Baladi MG, McFadden LM, Hanson GR, Fleckenstein AE. Regulation of the Dopamine and Vesicular Monoamine Transporters: Pharmacological Targets and Implications for Disease. Pharmacol Rev 2016; 67:1005-24. [PMID: 26408528 DOI: 10.1124/pr.114.010397] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Dopamine (DA) plays a well recognized role in a variety of physiologic functions such as movement, cognition, mood, and reward. Consequently, many human disorders are due, in part, to dysfunctional dopaminergic systems, including Parkinson's disease, attention deficit hyperactivity disorder, and substance abuse. Drugs that modify the DA system are clinically effective in treating symptoms of these diseases or are involved in their manifestation, implicating DA in their etiology. DA signaling and distribution are primarily modulated by the DA transporter (DAT) and by vesicular monoamine transporter (VMAT)-2, which transport DA into presynaptic terminals and synaptic vesicles, respectively. These transporters are regulated by complex processes such as phosphorylation, protein-protein interactions, and changes in intracellular localization. This review provides an overview of 1) the current understanding of DAT and VMAT2 neurobiology, including discussion of studies ranging from those conducted in vitro to those involving human subjects; 2) the role of these transporters in disease and how these transporters are affected by disease; and 3) and how selected drugs alter the function and expression of these transporters. Understanding the regulatory processes and the pathologic consequences of DAT and VMAT2 dysfunction underlies the evolution of therapeutic development for the treatment of DA-related disorders.
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Affiliation(s)
- Christopher L German
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Michelle G Baladi
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Lisa M McFadden
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Glen R Hanson
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
| | - Annette E Fleckenstein
- School of Dentistry (C.L.G., M.G.B., G.R.H., A.E.F.) and Department of Pharmacology and Toxicology (L.M.M., G.R.H.), University of Utah, Salt Lake City, Utah
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Spence A, Guerin G, Goeders N. Differential modulation of the discriminative stimulus effects of methamphetamine and cocaine by alprazolam and oxazepam in male and female rats. Neuropharmacology 2016; 102:146-57. [DOI: 10.1016/j.neuropharm.2015.10.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/10/2015] [Accepted: 10/29/2015] [Indexed: 11/17/2022]
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Matthew BJ, Gedzior JS. Drug-induced parkinsonism following chronic methamphetamine use by a patient on haloperidol decanoate. Int J Psychiatry Med 2016; 50:405-11. [PMID: 26526398 DOI: 10.1177/0091217415612736] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This report attempts to highlight that use of an antipsychotic and concurrent chronic use of methamphetamine can cause drug-induced parkinsonism. Methamphetamine is usually not encountered in the list of agents that induce drug-induced parkinsonism and so its consideration particularly during chronic use by a patient who is also on an antipsychotic is worthwhile because of its popularity as an illegal narcotic. This case report describes just such a case of drug-induced parkinsonism which is a subacute syndrome that mimics Parkinson's disease. Although less alarming than dystonia, it is more common, more difficult to treat and can be the cause of significant disability during maintenance treatment especially in the elderly. In most cases, symptoms are reversible in days or weeks, but occasionally, especially in the elderly, or if long-acting injectable antipsychotics are used-as in this case-symptoms may last for weeks or months. The report also illustrates the neuronal workings due to chronic methamphetamine-use and the additive effects of dopamine blockade by antipsychotics such as haloperidol.
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Affiliation(s)
- Binoj J Matthew
- University of California, San Francisco - Fresno Medical Education Program, Fresno, CA, USA
| | - Joanna S Gedzior
- Department of Psychiatry, VA - Central California Health Care System, Fresno, CA, USA
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42
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Fricks-Gleason AN, German CL, Hoonakker AJ, Friend DM, Ganesh KK, Carver AS, Hanson GR, Fleckenstein AE, Keefe KA. An acute, epitope-specific modification in the dopamine transporter associated with methamphetamine-induced neurotoxicity. Synapse 2016; 70:139-46. [PMID: 26799527 DOI: 10.1002/syn.21891] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 12/08/2015] [Accepted: 01/18/2016] [Indexed: 11/12/2022]
Abstract
Preclinical studies demonstrate that repeated, high-dose methamphetamine administrations rapidly decrease plasmalemmal dopamine uptake, which may contribute to aberrant dopamine accumulation, reactive species generation, and long-term dopaminergic deficits. The present study extends these findings by demonstrating a heretofore unreported, epitope-specific modification in the dopamine transporter caused by a methamphetamine regimen that induces these deficits. Specifically, repeated, high-dose methamphetamine injections (4 × 10 mg/kg/injection, 2-h intervals) rapidly decreased immunohistochemical detection of striatal dopamine transporter as assessed 1 h after the final methamphetamine exposure. In contrast, neither a single high dose (1 × 10 mg/kg) nor repeated injections of a lower dose (4 × 2 mg/kg/injection) induced this change. The high-dose regimen-induced alteration was only detected using antibodies directed against the N-terminus. Immunohistochemical staining using antibodies directed against the C-terminus did not reveal any changes. The high-dose regimen also did not alter dopamine transporter expression as assessed using [(125) I]RTI-55 autoradiography. These data suggest that the repeated, high-dose methamphetamine regimen alters the N-terminus of the dopamine transporter. Further, these data may be predictive of persistent dopamine deficits caused by the stimulant. Future studies of the signaling cascades involved should provide novel insight into potential mechanisms underlying the physiological and pathophysiological regulation of the dopamine transporter.
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Affiliation(s)
| | | | | | - Danielle M Friend
- Eating and Addiction Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland, 20892.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, 84112
| | - Kamala K Ganesh
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, 84112
| | - Aaron S Carver
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, 84112
| | - Glen R Hanson
- School of Dentistry, University of Utah, Salt Lake City, Utah, 84108.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, 84112
| | - Annette E Fleckenstein
- School of Dentistry, University of Utah, Salt Lake City, Utah, 84108.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, 84112
| | - Kristen A Keefe
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah, 84112.,Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, 84112
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Moritz AE, Rastedt DE, Stanislowski DJ, Shetty M, Smith MA, Vaughan RA, Foster JD. Reciprocal Phosphorylation and Palmitoylation Control Dopamine Transporter Kinetics. J Biol Chem 2015; 290:29095-105. [PMID: 26424792 DOI: 10.1074/jbc.m115.667055] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Indexed: 11/06/2022] Open
Abstract
The dopamine transporter is a neuronal protein that drives the presynaptic reuptake of dopamine (DA) and is the major determinant of transmitter availability in the brain. Dopamine transporter function is regulated by protein kinase C (PKC) and other signaling pathways through mechanisms that are complex and poorly understood. Here we investigate the role of Ser-7 phosphorylation and Cys-580 palmitoylation in mediating steady-state transport kinetics and PKC-stimulated transport down-regulation. Using both mutational and pharmacological approaches, we demonstrate that these post-translational modifications are reciprocally regulated, leading to transporter populations that display high phosphorylation-low palmitoylation or low phosphorylation-high palmitoylation. The balance between the modifications dictates transport capacity, as conditions that promote high phosphorylation or low palmitoylation reduce transport Vmax and enhance PKC-stimulated down-regulation, whereas conditions that promote low phosphorylation or high palmitoylation increase transport Vmax and suppress PKC-stimulated down-regulation. Transitions between these functional states occur when endocytosis is blocked or undetectable, indicating that the modifications kinetically regulate the velocity of surface transporters. These findings reveal a novel mechanism for control of DA reuptake that may represent a point of dysregulation in DA imbalance disorders.
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Affiliation(s)
- Amy E Moritz
- From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061
| | - Danielle E Rastedt
- From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061
| | - Daniel J Stanislowski
- From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061
| | - Madhur Shetty
- From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061
| | - Margaret A Smith
- From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061
| | - Roxanne A Vaughan
- From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061
| | - James D Foster
- From the Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota 58202-9061
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Korpi ER, den Hollander B, Farooq U, Vashchinkina E, Rajkumar R, Nutt DJ, Hyytiä P, Dawe GS. Mechanisms of Action and Persistent Neuroplasticity by Drugs of Abuse. Pharmacol Rev 2015; 67:872-1004. [DOI: 10.1124/pr.115.010967] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Reith ME, Blough BE, Hong WC, Jones KT, Schmitt KC, Baumann MH, Partilla JS, Rothman RB, Katz JL. Behavioral, biological, and chemical perspectives on atypical agents targeting the dopamine transporter. Drug Alcohol Depend 2015; 147:1-19. [PMID: 25548026 PMCID: PMC4297708 DOI: 10.1016/j.drugalcdep.2014.12.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/04/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Treatment of stimulant-use disorders remains a formidable challenge, and the dopamine transporter (DAT) remains a potential target for antagonist or agonist-like substitution therapies. METHODS This review focuses on DAT ligands, such as benztropine, GBR 12909, modafinil, and DAT substrates derived from phenethylamine or cathinone that have atypical DAT-inhibitor effects, either in vitro or in vivo. The compounds are described from a molecular mechanistic, behavioral, and medicinal-chemical perspective. RESULTS Possible mechanisms for atypicality at the molecular level can be deduced from the conformational cycle for substrate translocation. For each conformation, a crystal structure of a bacterial homolog is available, with a possible role of cholesterol, which is also present in the crystal of Drosophila DAT. Although there is a direct relationship between behavioral potencies of most DAT inhibitors and their DAT affinities, a number of compounds bind to the DAT and inhibit dopamine uptake but do not share cocaine-like effects. Such atypical behavior, depending on the compound, may be related to slow DAT association, combined sigma-receptor actions, or bias for cytosol-facing DAT. Some structures are sterically small enough to serve as DAT substrates but large enough to also inhibit transport. Such compounds may display partial DA releasing effects, and may be combined with release or uptake inhibition at other monoamine transporters. CONCLUSIONS Mechanisms of atypical DAT inhibitors may serve as targets for the development of treatments for stimulant abuse. These mechanisms are novel and their further exploration may produce compounds with unique therapeutic potential as treatments for stimulant abuse.
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Affiliation(s)
- Maarten E.A. Reith
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA,Corresponding author: Maarten E.A. Reith, Department of Psychiatry, Alexandria Center of Life Sciences, New York University School of Medicine, 450 E 29th Street, Room 803, New York, NY 10016. Tel.: 212 - 263 8267; Fax: 212 – 263 8183;
| | - Bruce E. Blough
- Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC 27709, USA
| | - Weimin C. Hong
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Kymry T. Jones
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Kyle C. Schmitt
- Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Michael H. Baumann
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - John S. Partilla
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Richard B. Rothman
- Medicinal Chemistry Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
| | - Jonathan L. Katz
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, USA
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Sitte HH, Freissmuth M. Amphetamines, new psychoactive drugs and the monoamine transporter cycle. Trends Pharmacol Sci 2014; 36:41-50. [PMID: 25542076 PMCID: PMC4502921 DOI: 10.1016/j.tips.2014.11.006] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 11/25/2014] [Accepted: 11/25/2014] [Indexed: 01/05/2023]
Abstract
In monoaminergic neurons, the vesicular transporters and the plasma membrane transporters operate in a relay. Amphetamine and its congeners target this relay to elicit their actions: most amphetamines are substrates, which pervert the relay to elicit efflux of monoamines into the synaptic cleft. However, some amphetamines act as transporter inhibitors. Both compound classes elicit profound psychostimulant effects, which render them liable to recreational abuse. Currently, a surge of new psychoactive substances occurs on a global scale. Chemists bypass drug bans by ingenuous structural variations, resulting in a rich pharmacology. A credible transport model must account for their distinct mode of action and link this to subtle differences in activity and undesired, potentially deleterious effects.
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Affiliation(s)
- Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria; Center for Addiction Research and Science (AddRess), Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
| | - Michael Freissmuth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
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Bayat AH, Haghparast A. Effect of insulin deficiency on the rewarding properties of methamphetamine in streptozotocin-induced diabetic rats. Pharmacol Biochem Behav 2014; 128:8-13. [PMID: 25444864 DOI: 10.1016/j.pbb.2014.11.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 10/29/2014] [Accepted: 11/07/2014] [Indexed: 10/24/2022]
Abstract
The reward is a positive behavioural response to the pleasant stimuli that can be induced by drugs, such as psychostimulants. Furthermore, diabetes mellitus is a chronic disease that many people throughout the world suffer from. Methamphetamine (METH), as a psychostimulant, engages the dopaminergic system in the reward circuitry and the synapses of dopaminergic terminals can be modified by insulin. In this study, in order to assess the effect of insulin deficiency on reward, streptozotocin (STZ)-induced diabetic animals were used as an appropriate model. One hundred and thirty-two adult male rats were divided into nine groups (three non-diabetic and six diabetic groups) to determine the most effective dose of METH (0.25, 0.5, 1 and 2mg/kg ip), and insulin replacement (10U/kg; ip) during the acquisition period in a conditioned place preference (CPP) paradigm. The diabetes model was induced by a single injection of STZ (60mg/kg; ip). The conditioning score was considered to be the difference in time spent in drug- and saline-paired compartments. The results demonstrated that the most effective doses of METH were 1 and 2mg/kg in non-diabetic animals. Although the place preference was not shown in non-diabetic animals at the dose of 0.5mg/kg, this dose significantly induced place preference to METH in STZ-diabetic rats. Additionally, insulin replacement could reverse the METH-induced CPP in diabetic animals. Our findings suggest that the positive effect of insulin deficiency on METH rewarding properties is dependent on insulin level in part, and the replacement of the insulin in diabetic rats as a treatment can improve the rewarding properties of METH.
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Affiliation(s)
- Amir-Hossein Bayat
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, P.O. Box 19615-1178, Tehran, Iran.
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The rare DAT coding variant Val559 perturbs DA neuron function, changes behavior, and alters in vivo responses to psychostimulants. Proc Natl Acad Sci U S A 2014; 111:E4779-88. [PMID: 25331903 DOI: 10.1073/pnas.1417294111] [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] [Indexed: 12/13/2022] Open
Abstract
Despite the critical role of the presynaptic dopamine (DA) transporter (DAT, SLC6A3) in DA clearance and psychostimulant responses, evidence that DAT dysfunction supports risk for mental illness is indirect. Recently, we identified a rare, nonsynonymous Slc6a3 variant that produces the DAT substitution Ala559Val in two male siblings who share a diagnosis of attention-deficit hyperactivity disorder (ADHD), with other studies identifying the variant in subjects with bipolar disorder (BPD) and autism spectrum disorder (ASD). Previously, using transfected cell studies, we observed that although DAT Val559 displays normal total and surface DAT protein levels, and normal DA recognition and uptake, the variant transporter exhibits anomalous DA efflux (ADE) and lacks capacity for amphetamine (AMPH)-stimulated DA release. To pursue the significance of these findings in vivo, we engineered DAT Val559 knock-in mice, and here we demonstrate in this model the presence of elevated extracellular DA levels, altered somatodendritic and presynaptic D2 DA receptor (D2R) function, a blunted ability of DA terminals to support depolarization and AMPH-evoked DA release, and disruptions in basal and psychostimulant-evoked locomotor behavior. Together, our studies demonstrate an in vivo functional impact of the DAT Val559 variant, providing support for the ability of DAT dysfunction to impact risk for mental illness.
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PIP2 regulates psychostimulant behaviors through its interaction with a membrane protein. Nat Chem Biol 2014; 10:582-589. [PMID: 24880859 PMCID: PMC4062427 DOI: 10.1038/nchembio.1545] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Accepted: 04/24/2014] [Indexed: 12/13/2022]
Abstract
Phosphatidylinositol (4,5)-bisphosphate (PIP2) regulates the function of ion channels and transporters. Here, we demonstrate that PIP2 directly binds the human dopamine (DA) transporter (hDAT), a key regulator of DA homeostasis and a target of the psychostimulant amphetamine (AMPH). This binding occurs through electrostatic interactions with positively charged hDAT N-terminal residues and is shown to facilitate AMPH-induced, DAT-mediated DA efflux and the psychomotor properties of AMPH. Substitution of these residues with uncharged amino acids reduces hDAT-PIP2 interactions and AMPH-induced DA efflux, without altering the hDAT physiological function of DA uptake. We evaluated, for the first time, the significance of this interaction in vivo using locomotion as a behavioral assay in Drosophila melanogaster. Expression of mutated hDAT with reduced PIP2 interaction in Drosophila DA neurons impairs AMPH-induced locomotion without altering basal locomotion. We present the first demonstration of how PIP2 interactions with a membrane protein can regulate the behaviors of complex organisms.
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Birbeck JA, Khalid M, Mathews TA. Potentiated striatal dopamine release leads to hyperdopaminergia in female brain-derived neurotrophic factor heterozygous mice. ACS Chem Neurosci 2014; 5:275-81. [PMID: 24517838 DOI: 10.1021/cn400157b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The goal of this study was to determine whether a reduction in brain-derived neurotrophic factor (BDNF) levels in female mice leads to dopaminergic system dysregulation. Through a series of in vivo brain microdialysis and slice voltammetry experiments, we discerned that female BDNF heterozygous (BDNF(+/-)) mice are hyperdopaminergic, similar to their male BDNF(+/-) counterparts. Zero-net flux microdialysis results showed that female BDNF(+/-) mice had increased striatal extracellular dopamine levels, while stimulated regional release by high potassium concentrations potentiated dopamine release through vesicular-mediated depolarization. Using the complementary technique of fast scan cyclic voltammetry, electrical stimulation evoked greater dopamine release in the female BDNF(+/-) mice, whereas dopamine uptake remained unchanged relative to that of female wildtype mice. Following psychostimulant methamphetamine administration, female BDNF(+/-) mice showed potentiated dopamine release compared to their wildtype counterparts. Taken together, these dopamine release impairments in female mice appear to result in a hyperdopaminergic phenotype without concomitant alterations in dopamine uptake.
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Affiliation(s)
- Johnna A. Birbeck
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Madiha Khalid
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - Tiffany A. Mathews
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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