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Kundu D, Zhu A, Kim E, Paudel S, Jang CG, Lee YS, Kim KM. Potential Functional Role of Phenethylamine Derivatives in Inhibiting Dopamine Reuptake: Structure-Activity Relationship. Biomol Ther (Seoul) 2023; 31:108-115. [PMID: 36098044 PMCID: PMC9810443 DOI: 10.4062/biomolther.2022.047] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 07/25/2022] [Accepted: 08/03/2022] [Indexed: 01/13/2023] Open
Abstract
Numerous psychotropic and addictive substances possess structural features similar to those of β-phenethylamine (β-PEA). In this study, we selected 29 β-PEA derivatives and determined their structure-activity relationship (SAR) to their ability to inhibit dopamine (DA) reuptake; conducted docking simulation for two selected compounds; and identified their potential functionals. The compounds were subdivided into arylethylamines, 2-(alkyl amino)-1-arylalkan-1-one derivatives and alkyl 2-phenyl-2-(piperidin-2-yl)acetate derivatives. An aromatic group, alkyl group, and alkylamine derivative were attached to the arylethylamine and 2-(alkyl amino)-1-arylalkan-1-one derivatives. The inhibitory effect of the compounds on dopamine reuptake increased in the order of the compounds substituted with phenyl, thiophenyl, and substituted phenyl groups in the aromatic position; compounds with longer alkyl groups and smaller ring-sized compounds at the alkylamine position showed stronger inhibitory activities. Docking simulation conducted for two compounds, 9 and 28, showed that the (S)-form of compound 9 was more stable than the (R)-form, with a good fit into the binding site covered by helices 1, 3, and 6 of human dopamine transporter (hDAT). In contrast, the (R, S)-configuration of compound 28 was more stable than that of other isomers and was firmly placed in the binding pocket of DAT bound to DA. DA-induced endocytosis of dopamine D2 receptors was inhibited when they were co-expressed with DAT, which lowered extracellular DA levels, and uninhibited when they were pretreated with compound 9 or 28. In summary, this study revealed critical structural features responsible for the inhibition of DA reuptake and the functional role of DA reuptake inhibitors in regulating D2 receptor function.
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Affiliation(s)
- Dooti Kundu
- College of Pharmacy, Chonnam National University, Gwangju 61146, Republic of Korea
| | - Anlin Zhu
- College of Pharmacy, Chonnam National University, Gwangju 61146, Republic of Korea
| | - Eunae Kim
- College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea
| | - Suresh Paudel
- College of Pharmacy, Chonnam National University, Gwangju 61146, Republic of Korea
| | - Choon-Gon Jang
- College of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yong Sup Lee
- College of Pharmacy, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Kyeong-Man Kim
- College of Pharmacy, Chonnam National University, Gwangju 61146, Republic of Korea,Corresponding Author E-mail: , Tel: +82-62-530-2936, Fax: +82-62-530-2949
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2
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Liu C, Liu Z, Fang Y, Du Z, Yan Z, Yuan X, Dai L, Yu T, Xiong M, Tian Y, Li H, Li F, Zhang J, Meng L, Wang Z, Jiang H, Zhang Z. Exposure to the environmentally toxic pesticide maneb induces Parkinson's disease-like neurotoxicity in mice: A combined proteomic and metabolomic analysis. CHEMOSPHERE 2022; 308:136344. [PMID: 36087732 DOI: 10.1016/j.chemosphere.2022.136344] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 08/03/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Maneb is a typical dithiocarbamate fungicide that has been extensively used worldwide. Epidemiological evidence shows that exposure to maneb is an environmental risk factor for Parkinson's disease (PD). However, the mechanisms underlying maneb-induced neurotoxicity have yet to be elucidated. In this study, we exposed SH-SY5Y cells to maneb at environmentally relevant concentrations (0, 0.1, 5, 10 mg/L) and found that maneb dose-dependently decreased the cell viability. Furthermore, maneb (60 mg/kg) induced PD-like motor impairment in α-synuclein A53T transgenic mice. The results of tandem mass tag (TMT) proteomics and metabolomics studies of mouse brain and serum revealed significant changes in proteins and metabolites in the pathways involved in the neurotransmitter system. The omics results were verified by targeted metabolomics and Western blot analysis, which demonstrated that maneb induced disturbance of the PD-related pathways, including the phenylalanine and tryptophan metabolism pathways, dopaminergic synapse, synaptic vesicle cycle, mitochondrial dysfunction, and oxidative stress. In addition, the PD-like phenotype induced by maneb was attenuated by the asparagine endopeptidase (AEP) inhibitor compound #11 (CP11) (10 mg/kg), indicating that AEP may play a role in maneb-induced neurotoxicity. To the best of our knowledge, this is the first study to investigate the molecular mechanisms underlying maneb-induced PD-like phenotypes using multiomics analysis, which identified novel therapeutic targets for PD associated with pesticides and other environmental pollutants.
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Affiliation(s)
- Chaoyang Liu
- Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan, 430073, China; Department of Environmental Engineering, Zhongnan University of Economics and Law, Wuhan, 430073, China; Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zehua Liu
- Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan, 430073, China; Department of Environmental Engineering, Zhongnan University of Economics and Law, Wuhan, 430073, China
| | - Yanyan Fang
- Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan, 430073, China; Department of Environmental Engineering, Zhongnan University of Economics and Law, Wuhan, 430073, China
| | - Zhen Du
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250355, China
| | - Zhi Yan
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250355, China
| | - Xin Yuan
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Lijun Dai
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Ting Yu
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Min Xiong
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Ye Tian
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Honghu Li
- Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan, 430073, China; Department of Environmental Engineering, Zhongnan University of Economics and Law, Wuhan, 430073, China
| | - Fei Li
- Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan, 430073, China; Department of Environmental Engineering, Zhongnan University of Economics and Law, Wuhan, 430073, China
| | - Jingdong Zhang
- Research Center for Environment and Health, Zhongnan University of Economics and Law, Wuhan, 430073, China; Department of Environmental Engineering, Zhongnan University of Economics and Law, Wuhan, 430073, China
| | - Lanxia Meng
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Zhihao Wang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China
| | - Haiqiang Jiang
- Innovative Institute of Chinese Medicine and Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan, Shandong, 250355, China
| | - Zhentao Zhang
- Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, 430060, China.
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3
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Vecchio LM, Sullivan P, Dunn AR, Bermejo MK, Fu R, Masoud ST, Gregersen E, Urs NM, Nazari R, Jensen PH, Ramsey A, Goldstein DS, Miller GW, Salahpour A. Enhanced tyrosine hydroxylase activity induces oxidative stress, causes accumulation of autotoxic catecholamine metabolites, and augments amphetamine effects in vivo. J Neurochem 2021; 158:960-979. [PMID: 33991113 PMCID: PMC8376767 DOI: 10.1111/jnc.15432] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/10/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022]
Abstract
In Parkinson's disease, dopamine‐containing nigrostriatal neurons undergo profound degeneration. Tyrosine hydroxylase (TH) is the rate‐limiting enzyme in dopamine biosynthesis. TH increases in vitro formation of reactive oxygen species, and previous animal studies have reported links between cytosolic dopamine build‐up and oxidative stress. To examine effects of increased TH activity in catecholaminergic neurons in vivo, we generated TH‐over‐expressing mice (TH‐HI) using a BAC‐transgenic approach that results in over‐expression of TH with endogenous patterns of expression. The transgenic mice were characterized by western blot, qPCR, and immunohistochemistry. Tissue contents of dopamine, its metabolites, and markers of oxidative stress were evaluated. TH‐HI mice had a 3‐fold increase in total and phosphorylated TH levels and an increased rate of dopamine synthesis. Coincident with elevated dopamine turnover, TH‐HI mice showed increased striatal production of H2O2 and reduced glutathione levels. In addition, TH‐HI mice had elevated striatal levels of the neurotoxic dopamine metabolites 3,4‐dihydroxyphenylacetaldehyde and 5‐S‐cysteinyl‐dopamine and were more susceptible than wild‐type mice to the effects of amphetamine and methamphetamine. These results demonstrate that increased TH alone is sufficient to produce oxidative stress in vivo, build up autotoxic dopamine metabolites, and augment toxicity.
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Affiliation(s)
- Laura M Vecchio
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Patricia Sullivan
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological, Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Amy R Dunn
- The Jackson Laboratory. Bar Harbor, Maine, USA
| | - Marie Kristel Bermejo
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Rong Fu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Shababa T Masoud
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Emil Gregersen
- Danish Research Institute of Translational Neuroscience - DANDRITE, Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus C., Denmark
| | - Nikhil M Urs
- Department of Pharmacology and Therapeutics, University of Florida, Gainsville, FL, USA
| | - Reza Nazari
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Poul Henning Jensen
- Danish Research Institute of Translational Neuroscience - DANDRITE, Department of Biomedicine, Faculty of Health, Aarhus University, Aarhus C., Denmark
| | - Amy Ramsey
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - David S Goldstein
- Autonomic Medicine Section, Clinical Neurosciences Program, Division of Intramural Research, National Institute of Neurological, Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Gary W Miller
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University Medical Centre, New York, NY, USA
| | - Ali Salahpour
- Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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Kreisler AD, Terranova MJ, Somkuwar SS, Purohit DC, Wang S, Head BP, Mandyam CD. In vivo reduction of striatal D1R by RNA interference alters expression of D1R signaling-related proteins and enhances methamphetamine addiction in male rats. Brain Struct Funct 2020; 225:1073-1088. [PMID: 32246242 DOI: 10.1007/s00429-020-02059-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 03/18/2020] [Indexed: 01/06/2023]
Abstract
This study sought to determine if reducing dopamine D1 receptor (D1R) expression in the dorsal striatum (DS) via RNA-interference alters methamphetamine self-administration. A lentiviral construct containing a short hairpin RNA (shRNA) was used to knock down D1R expression (D1RshRNA). D1RshRNA in male rats increased responding for methamphetamine (i.v.) under a fixed-ratio schedule in an extended access paradigm, compared to D1R-intact rats. D1RshRNA also produced a vertical shift in a dose-response paradigm and enhanced responding for methamphetamine in a progressive-ratio schedule, generating a drug-vulnerable phenotype. D1RshRNA did not alter responding for sucrose (oral) under a fixed-ratio schedule compared to D1R-intact rats. Western blotting confirmed reduced D1R expression in methamphetamine and sucrose D1RshRNA rats. D1RshRNA reduced the expression of PSD-95 and MAPK-1 and increased the expression of dopamine transporter (DAT) in the DS from methamphetamine, but not sucrose rats. Sucrose density gradient fractionation was performed in behavior-naïve controls, D1RshRNA- and D1R-intact rats to determine the subcellular localization of D1Rs, DAT and D1R signaling proteins. D1Rs, DAT, MAPK-1 and PSD-95 predominantly localized to heavy fractions, and the membrane/lipid raft protein caveolin-1 (Cav-1) and flotillin-1 were distributed equally between buoyant and heavy fractions in controls. Methamphetamine increased localization of PSD-95, Cav-1, and flotillin-1 in D1RshRNA and D1R-intact rats to buoyant fractions. Our studies indicate that reduced D1R expression in the DS increases vulnerability to methamphetamine addiction-like behavior, and this is accompanied by striatal alterations in the expression of DAT and D1R signaling proteins and is independent of the subcellular localization of these proteins.
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Affiliation(s)
| | | | | | | | - Shanshan Wang
- VA San Diego Healthcare System, San Diego, CA, 92161, USA
- Department of Anesthesiology, University of California San Diego, San Diego, CA, 92161, USA
| | - Brian P Head
- VA San Diego Healthcare System, San Diego, CA, 92161, USA
- Department of Anesthesiology, University of California San Diego, San Diego, CA, 92161, USA
| | - Chitra D Mandyam
- VA San Diego Healthcare System, San Diego, CA, 92161, USA.
- Department of Anesthesiology, University of California San Diego, San Diego, CA, 92161, USA.
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5
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Koch ET, Raymond LA. Dysfunctional striatal dopamine signaling in Huntington's disease. J Neurosci Res 2019; 97:1636-1654. [PMID: 31304622 DOI: 10.1002/jnr.24495] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 06/06/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022]
Abstract
Dopamine signaling in the striatum is critical for a variety of behaviors including movement, behavioral flexibility, response to reward and many forms of learning. Alterations to dopamine transmission contribute to pathological features of many neurological diseases, including Huntington's disease (HD). HD is an autosomal dominant genetic disorder caused by a CAG repeat expansion in the Huntingtin gene. The striatum is preferentially degenerated in HD, and this region receives dopaminergic input from the substantia nigra. Studies of HD patients and genetic rodent models have shown changes to levels of dopamine and its receptors in the striatum, and alterations in dopamine receptor signaling and modulation of other neurotransmitters, notably glutamate. Throughout his career, Dr. Michael Levine's research has furthered our understanding of dopamine signaling in the striatum of healthy rodents and HD mouse models. This review will focus on the work of his group and others in elucidating alterations to striatal dopamine signaling that contribute to pathophysiology in HD mouse models, and how these findings relate to human HD studies. We will also discuss current and potential therapeutic interventions for HD that target the dopamine system, and future research directions for this field.
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Affiliation(s)
- Ellen T Koch
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada
| | - Lynn A Raymond
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.,Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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6
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Solinas M, Belujon P, Fernagut PO, Jaber M, Thiriet N. Dopamine and addiction: what have we learned from 40 years of research. J Neural Transm (Vienna) 2018; 126:481-516. [PMID: 30569209 DOI: 10.1007/s00702-018-1957-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 11/17/2018] [Indexed: 12/22/2022]
Abstract
Among the neurotransmitters involved in addiction, dopamine (DA) is clearly the best known. The critical role of DA in addiction is supported by converging evidence that has been accumulated in the last 40 years. In the present review, first we describe the dopaminergic system in terms of connectivity, functioning and involvement in reward processes. Second, we describe the functional, structural, and molecular changes induced by drugs within the DA system in terms of neuronal activity, synaptic plasticity and transcriptional and molecular adaptations. Third, we describe how genetic mouse models have helped characterizing the role of DA in addiction. Fourth, we describe the involvement of the DA system in the vulnerability to addiction and the interesting case of addiction DA replacement therapy in Parkinson's disease. Finally, we describe how the DA system has been targeted to treat patients suffering from addiction and the result obtained in clinical settings and we discuss how these different lines of evidence have been instrumental in shaping our understanding of the physiopathology of drug addiction.
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Affiliation(s)
- Marcello Solinas
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France.
| | - Pauline Belujon
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
| | - Pierre Olivier Fernagut
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
| | - Mohamed Jaber
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
- CHU de Poitiers, Poitiers, France
| | - Nathalie Thiriet
- Université de Poitiers, INSERM, U-1084, Laboratoire de Neurosciences Expérimentales et Cliniques, Poitiers, France
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7
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Efimova EV, Gainetdinov RR, Budygin EA, Sotnikova TD. Dopamine transporter mutant animals: a translational perspective. J Neurogenet 2017; 30:5-15. [PMID: 27276191 DOI: 10.3109/01677063.2016.1144751] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The dopamine transporter (DAT) plays an important homeostatic role in the control of both the extracellular and intraneuronal concentrations of dopamine, thereby providing effective control over activity of dopaminergic transmission. Since brain dopamine is known to be involved in numerous neuropsychiatric disorders, investigations using mice with genetically altered DAT function and thus intensity of dopamine-mediated signaling have provided numerous insights into the pathology of these disorders and novel pathological mechanisms that could be targeted to provide new therapeutic approaches for these disorders. In this brief overview, we discuss recent investigations involving animals with genetically altered DAT function, particularly focusing on translational studies providing new insights into pathology and pharmacology of dopamine-related disorders. Perspective applications of these and newly developed models of DAT dysfunction are also discussed.
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Affiliation(s)
- Evgeniya V Efimova
- a Institute of Translational Biomedicine, St. Petersburg State University , St. Petersburg , Russia ;,b Skolkovo Institute of Science and Technology , Skolkovo , Moscow Region , Russia
| | - Raul R Gainetdinov
- a Institute of Translational Biomedicine, St. Petersburg State University , St. Petersburg , Russia ;,b Skolkovo Institute of Science and Technology , Skolkovo , Moscow Region , Russia
| | - Evgeny A Budygin
- a Institute of Translational Biomedicine, St. Petersburg State University , St. Petersburg , Russia ;,c Department of Neurobiology and Anatomy , Wake Forest School of Medicine , Winston-Salem , NC , USA
| | - Tatyana D Sotnikova
- a Institute of Translational Biomedicine, St. Petersburg State University , St. Petersburg , Russia
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8
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Lohr KM, Masoud ST, Salahpour A, Miller GW. Membrane transporters as mediators of synaptic dopamine dynamics: implications for disease. Eur J Neurosci 2017; 45:20-33. [PMID: 27520881 PMCID: PMC5209277 DOI: 10.1111/ejn.13357] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 07/12/2016] [Accepted: 08/02/2016] [Indexed: 12/14/2022]
Abstract
Dopamine was first identified as a neurotransmitter localized to the midbrain over 50 years ago. The dopamine transporter (DAT; SLC6A3) and the vesicular monoamine transporter 2 (VMAT2; SLC18A2) are regulators of dopamine homeostasis in the presynaptic neuron. DAT transports dopamine from the extracellular space into the cytosol of the presynaptic terminal. VMAT2 then packages this cytosolic dopamine into vesicular compartments for subsequent release upon neurotransmission. Thus, DAT and VMAT2 act in concert to move the transmitter efficiently throughout the neuron. Accumulation of dopamine in the neuronal cytosol can trigger oxidative stress and neurotoxicity, suggesting that the proper compartmentalization of dopamine is critical for neuron function and risk of disease. For decades, studies have examined the effects of reduced transporter function in mice (e.g. DAT-KO, VMAT2-KO, VMAT2-deficient). However, we have only recently been able to assess the effects of elevated transporter expression using BAC transgenic methods (DAT-tg, VMAT2-HI mice). Complemented with in vitro work and neurochemical techniques to assess dopamine compartmentalization, a new focus on the importance of transporter proteins as both models of human disease and potential drug targets has emerged. Here, we review the importance of DAT and VMAT2 function in the delicate balance of neuronal dopamine.
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Affiliation(s)
- Kelly M Lohr
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA, 30322, USA
| | - Shababa T Masoud
- Department of Pharmacology and Toxicology, University of Toronto, ON, Canada
| | - Ali Salahpour
- Department of Pharmacology and Toxicology, University of Toronto, ON, Canada
| | - Gary W Miller
- Department of Environmental Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA, 30322, USA
- Center for Neurodegenerative Diseases, Emory University, Atlanta, GA, USA
- Department of Pharmacology, Emory University, Atlanta, GA, USA
- Department of Neurology, Emory University, Atlanta, GA, USA
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9
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Khoja S, Shah V, Garcia D, Asatryan L, Jakowec MW, Davies DL. Role of purinergic P2X4 receptors in regulating striatal dopamine homeostasis and dependent behaviors. J Neurochem 2016; 139:134-48. [PMID: 27402173 DOI: 10.1111/jnc.13734] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 06/26/2016] [Accepted: 06/28/2016] [Indexed: 11/27/2022]
Abstract
Purinergic P2X4 receptors (P2X4Rs) belong to the P2X superfamily of ion channels regulated by ATP. We recently demonstrated that P2X4R knockout (KO) mice exhibited deficits in sensorimotor gating, social interaction, and ethanol drinking behavior. Dopamine (DA) dysfunction may underlie these behavioral changes, but there is no direct evidence for P2X4Rs' role in DA neurotransmission. To test this hypothesis, we measured markers of DA function and dependent behaviors in P2X4R KO mice. P2X4R KO mice exhibited altered density of pre-synaptic markers including tyrosine hydroxylase, dopamine transporter; post-synaptic markers including dopamine receptors and phosphorylation of downstream targets including dopamine and cyclic-AMP regulated phosphoprotein of 32 kDa and cyclic-AMP-response element binding protein in different parts of the striatum. Ivermectin, an allosteric modulator of P2X4Rs, significantly affected dopamine and cyclic AMP regulated phosphoprotein of 32 kDa and extracellular regulated kinase1/2 phosphorylation in the striatum. Sensorimotor gating deficits in P2X4R KO mice were rescued by DA antagonists. Using the 6-hydroxydopamine model of DA depletion, P2X4R KO mice exhibited an attenuated levodopa (L-DOPA)-induced motor behavior, whereas ivermectin enhanced this behavior. Collectively, these findings identified an important role for P2X4Rs in maintaining DA homeostasis and illustrate how this association is important for CNS functions including motor control and sensorimotor gating. We propose that P2X4 receptors (P2X4Rs) regulate dopamine (DA) homeostasis and associated behaviors. Pre-synaptic and post-synaptic DA markers were significantly altered in the dorsal and ventral striatum of P2X4R KO mice, implicating altered DA neurotransmission. Sensorimotor gating deficits in P2X4R KO mice were rescued by DA antagonists. Ivermectin (IVM), a positive modulator of P2X4Rs, enhanced levodopa (L-DOPA)-induced motor behavior. These studies highlight potential interactions between P2X4Rs and DA system.
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Affiliation(s)
- Sheraz Khoja
- Department of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Southern California, Los Angeles, California, USA
| | - Vivek Shah
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Damaris Garcia
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Liana Asatryan
- Titus Family Department of Clinical Pharmacy, School of Pharmacy, University of Southern California, Los Angeles, California, USA
| | - Michael W Jakowec
- Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Daryl L Davies
- Titus Family Department of Clinical Pharmacy, School of Pharmacy, University of Southern California, Los Angeles, California, USA.
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10
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Hong SI, Kim MJ, You IJ, Kwon SH, Ma SX, Hwang JY, Seo JY, Ko YH, Lee BR, Lee SY, Jang CG. Phentermine induces conditioned rewarding effects via activation of the PI3K/Akt signaling pathway in the nucleus accumbens. Psychopharmacology (Berl) 2016; 233:1405-13. [PMID: 26887589 DOI: 10.1007/s00213-016-4231-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 02/02/2016] [Indexed: 01/18/2023]
Abstract
RATIONALE Phentermine is structurally similar to methamphetamine and is widely used as an anti-obesity drug in the USA and many other countries. The potential for reward of phentermine has been noted; however, the mechanisms of phentermine dependence have not been established. OBJECTIVES Here, we investigated the rewarding and dopaminergic behavioral responses to phentermine in mice and found that phentermine produced conditioned rewarding effects through the phosphoinositide 3-kinase (PI3K)/Akt signaling pathway in the nucleus accumbens (NAc). METHODS The impact of phentermine was assessed using conditioned place preference (CPP) test, climbing behavior test, and western blot analysis. RESULTS Phentermine 1 and 3 mg/kg (i.p.) significantly increased CPP. Phentermine, a known dopamine releaser, boosted apomorphine-induced climbing behavior in mice, and methamphetamine (i.p.) also increased apomorphine-induced dopaminergic behavior. Phentermine and methamphetamine increased the level of expression of the dopamine transporter (DAT) and phospho-Akt proteins to a similar degree in the NAc of CPP mice. To determine whether the conditioned rewarding effects of phentermine were mediated through the PI3K/Akt pathway, we assessed the effects of the Akt inhibitor LY294002 on phentermine-induced place preference and climbing behavior. LY294002 (1 and 3 μg/site, i.c.v.) reduced phentermine-induced CPP and phentermine-increased climbing behavior. However, LY294002 did not change CPP and climbing behavior itself and also did not decrease apomorphine-induced climbing behavior in mice. Further, LY294002 decreased the phentermine-increased levels of DAT protein and phosphorylation of Akt in the NAc of CPP mice. CONCLUSIONS Thus, these findings suggest that phentermine induces conditioned rewarding effects via activation of the PI3K/Akt signaling pathway in the NAc.
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Affiliation(s)
- Sa-Ik Hong
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Min-Jung Kim
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - In-Jee You
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Seung-Hwan Kwon
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Shi-Xun Ma
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Ji-Young Hwang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Jee-Yeon Seo
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Yong-Hyun Ko
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Bo Ram Lee
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Seok-Yong Lee
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, 440-746, Republic of Korea.
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11
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Postsynaptic D2 dopamine receptor supersensitivity in the striatum of mice lacking TAAR1. Neuropharmacology 2015; 93:308-13. [DOI: 10.1016/j.neuropharm.2015.02.010] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/13/2015] [Accepted: 02/16/2015] [Indexed: 01/11/2023]
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12
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John WS, Newman AH, Nader MA. Differential effects of the dopamine D3 receptor antagonist PG01037 on cocaine and methamphetamine self-administration in rhesus monkeys. Neuropharmacology 2015; 92:34-43. [PMID: 25576373 PMCID: PMC4346463 DOI: 10.1016/j.neuropharm.2014.12.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/17/2014] [Accepted: 12/22/2014] [Indexed: 12/17/2022]
Abstract
The dopamine D3 receptor (D3R) has been shown to mediate many of the behavioral effects of psychostimulants associated with high abuse potential. This study extended the assessment of the highly selective D3R antagonist PG01037 on cocaine and methamphetamine (MA) self-administration to include a food-drug choice procedure. Eight male rhesus monkeys (n=4/group) served as subjects in which complete cocaine and MA dose-response curves were determined daily in each session. When choice was stable, monkeys received acute and five-day treatment of PG01037 (1.0-5.6 mg/kg, i.v.). Acute administration of PG01037 was effective in reallocating choice from cocaine to food and decreasing cocaine intake, however, tolerance developed by day 5 of treatment. Up to doses that disrupted responding, MA choice and intake were not affected by PG01037 treatment. PG01037 decreased total reinforcers earned per session and the behavioral potency was significantly greater on MA-food choice compared to cocaine-food choice. Furthermore, the acute efficacy of PG01037 was correlated with the sensitivity of the D3/D2R agonist quinpirole to elicit yawning. These data suggest (1) that efficacy of D3R compounds in decreasing drug choice is greater in subjects with lower D3R, perhaps suggesting that it is percent occupancy that is the critical variable in determining efficacy and (2) differences in D3R activity in chronic cocaine vs. MA users. Although tolerance developed to the effects of PG01037 treatment on cocaine choice, tolerance did not develop to the disruptive effects on food-maintained responding. These findings suggest that combination treatments that decrease cocaine-induced elevations in DA may enhance the efficacy of D3R antagonists on cocaine self-administration.
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Affiliation(s)
- William S John
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD, USA.
| | - Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
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13
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Masoud ST, Vecchio LM, Bergeron Y, Hossain MM, Nguyen LT, Bermejo MK, Kile B, Sotnikova TD, Siesser WB, Gainetdinov RR, Wightman RM, Caron MG, Richardson JR, Miller GW, Ramsey AJ, Cyr M, Salahpour A. Increased expression of the dopamine transporter leads to loss of dopamine neurons, oxidative stress and l-DOPA reversible motor deficits. Neurobiol Dis 2014; 74:66-75. [PMID: 25447236 DOI: 10.1016/j.nbd.2014.10.016] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/07/2014] [Accepted: 10/22/2014] [Indexed: 01/17/2023] Open
Abstract
The dopamine transporter is a key protein responsible for regulating dopamine homeostasis. Its function is to transport dopamine from the extracellular space into the presynaptic neuron. Studies have suggested that accumulation of dopamine in the cytosol can trigger oxidative stress and neurotoxicity. Previously, ectopic expression of the dopamine transporter was shown to cause damage in non-dopaminergic neurons due to their inability to handle cytosolic dopamine. However, it is unknown whether increasing dopamine transporter activity will be detrimental to dopamine neurons that are inherently capable of storing and degrading dopamine. To address this issue, we characterized transgenic mice that over-express the dopamine transporter selectively in dopamine neurons. We report that dopamine transporter over-expressing (DAT-tg) mice display spontaneous loss of midbrain dopamine neurons that is accompanied by increases in oxidative stress markers, 5-S-cysteinyl-dopamine and 5-S-cysteinyl-DOPAC. In addition, metabolite-to-dopamine ratios are increased and VMAT2 protein expression is decreased in the striatum of these animals. Furthermore, DAT-tg mice also show fine motor deficits on challenging beam traversal that are reversed with l-DOPA treatment. Collectively, our findings demonstrate that even in neurons that routinely handle dopamine, increased uptake of this neurotransmitter through the dopamine transporter results in oxidative damage, neuronal loss and l-DOPA reversible motor deficits. In addition, DAT over-expressing animals are highly sensitive to MPTP-induced neurotoxicity. The effects of increased dopamine uptake in these transgenic mice could shed light on the unique vulnerability of dopamine neurons in Parkinson's disease.
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Affiliation(s)
- S T Masoud
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle - Rm 4302, Toronto, ON M5S 1A8, Canada.
| | - L M Vecchio
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle - Rm 4302, Toronto, ON M5S 1A8, Canada.
| | - Y Bergeron
- Department of Medical Biology, Université du Québec à Trois-Rivières, QC G9A 5H7 Canada.
| | - M M Hossain
- Environmental and Occupational Health Sciences Institute, Rutgers, 170 Frelinghuysen Road, EOHSI 340, Piscataway, NJ 08854, USA.
| | - L T Nguyen
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle - Rm 4302, Toronto, ON M5S 1A8, Canada.
| | - M K Bermejo
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle - Rm 4302, Toronto, ON M5S 1A8, Canada.
| | - B Kile
- Department of Chemistry, University of North Carolina at Chapel Hill, NC 27599, USA.
| | - T D Sotnikova
- Neuroscience and Brain Technologies, Italian Institute of Technology, Via Morego 30, Genova 16163, Italy; Faculty of Biology and Soil Science, St. Petersburg State University, St. Petersburg 199034, Russia.
| | - W B Siesser
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | - R R Gainetdinov
- Neuroscience and Brain Technologies, Italian Institute of Technology, Via Morego 30, Genova 16163, Italy; Faculty of Biology and Soil Science, St. Petersburg State University, St. Petersburg 199034, Russia; Skolkovo Institute of Science and Technology, Skolkovo, 143025 Moscow Region, Russia.
| | - R M Wightman
- Department of Chemistry, University of North Carolina at Chapel Hill, NC 27599, USA.
| | - M G Caron
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
| | - J R Richardson
- Environmental and Occupational Health Sciences Institute, Rutgers, 170 Frelinghuysen Road, EOHSI 340, Piscataway, NJ 08854, USA.
| | - G W Miller
- Department of Environmental Health, Emory University, Atlanta, GA 30322, USA; Department of Pharmacology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA.
| | - A J Ramsey
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle - Rm 4302, Toronto, ON M5S 1A8, Canada.
| | - M Cyr
- Department of Medical Biology, Université du Québec à Trois-Rivières, QC G9A 5H7 Canada.
| | - A Salahpour
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle - Rm 4302, Toronto, ON M5S 1A8, Canada.
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14
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Steinkellner T, Mus L, Eisenrauch B, Constantinescu A, Leo D, Konrad L, Rickhag M, Sørensen G, Efimova EV, Kong E, Willeit M, Sotnikova TD, Kudlacek O, Gether U, Freissmuth M, Pollak DD, Gainetdinov RR, Sitte HH. In vivo amphetamine action is contingent on αCaMKII. Neuropsychopharmacology 2014; 39:2681-93. [PMID: 24871545 PMCID: PMC4207348 DOI: 10.1038/npp.2014.124] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 05/01/2014] [Accepted: 05/05/2014] [Indexed: 11/09/2022]
Abstract
Addiction to psychostimulants (ie, amphetamines and cocaine) imposes a major socioeconomic burden. Prevention and treatment represent unmet medical needs, which may be addressed, if the mechanisms underlying psychostimulant action are understood. Cocaine acts as a blocker at the transporters for dopamine (DAT), serotonin (SERT), and norepinephrine (NET), but amphetamines are substrates that do not only block the uptake of monoamines but also induce substrate efflux by promoting reverse transport. Reverse transport has been a focus of research for decades but its mechanistic basis still remains enigmatic. Recently, transporter-interacting proteins were found to regulate amphetamine-triggered reverse transport: calmodulin kinase IIα (αCaMKII) is a prominent example, because it binds the carboxyl terminus of DAT, phosphorylates its amino terminus, and supports amphetamine-induced substrate efflux in vitro. Here, we investigated whether, in vivo, the action of amphetamine was contingent on the presence of αCaMKII by recording the behavioral and neurochemical effects of amphetamine. Measurement of dopamine efflux in the dorsal striatum by microdialysis revealed that amphetamine induced less dopamine efflux in mice lacking αCaMKII. Consistent with this observation, the acute locomotor responses to amphetamine were also significantly blunted in αCaMKII-deficient mice. In addition, while the rewarding properties of amphetamine were preserved in αCaMKII-deficient mice, their behavioral sensitization to amphetamine was markedly reduced. Our findings demonstrate that amphetamine requires the presence of αCaMKII to elicit a full-fledged effect on DAT in vivo: αCaMKII does not only support acute amphetamine-induced dopamine efflux but is also important in shaping the chronic response to amphetamine.
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Affiliation(s)
- Thomas Steinkellner
- Institute of Pharmacology, Center for
Physiology and Pharmacology, Medical University Vienna, Waehringer Strasse,
Vienna, Austria
| | - Liudmilla Mus
- Department of Neuroscience and Brain
Technologies, Istituto Italiano di Tecnologia (IIT), Via Morego,
Genova, Italy,Department of Psychopharmacology,
Institute of Pharmacology, Pavlov Medical University, St
Petersburg, Russia
| | - Birgit Eisenrauch
- Institute of Pharmacology, Center for
Physiology and Pharmacology, Medical University Vienna, Waehringer Strasse,
Vienna, Austria
| | - Andreea Constantinescu
- Institute of Pharmacology, Center for
Physiology and Pharmacology, Medical University Vienna, Waehringer Strasse,
Vienna, Austria
| | - Damiana Leo
- Department of Neuroscience and Brain
Technologies, Istituto Italiano di Tecnologia (IIT), Via Morego,
Genova, Italy
| | - Lisa Konrad
- Institute of Pharmacology, Center for
Physiology and Pharmacology, Medical University Vienna, Waehringer Strasse,
Vienna, Austria
| | - Mattias Rickhag
- Molecular Neuropharmacology and Genetics
Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and
Medical Sciences, The Panum Institute, University of Copenhagen,
Copenhagen, Denmark
| | - Gunnar Sørensen
- Molecular Neuropharmacology and Genetics
Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and
Medical Sciences, The Panum Institute, University of Copenhagen,
Copenhagen, Denmark
| | - Evgenia V Efimova
- Skolkovo Institute of Science and
Technology (Skoltech), Skolkovo, Moscow,
Russia
| | - Eryan Kong
- Department of Neurophysiology and
Neuropharmacology, Center for Physiology and Pharmacology, Medical University
Vienna, Waehringer Strasse, Vienna, Austria
| | - Matthäus Willeit
- Department of Psychiatry and
Psychotherapy, Medical University of Vienna, Waehringer Guertel,
Vienna, Austria
| | - Tatyana D Sotnikova
- Department of Neuroscience and Brain
Technologies, Istituto Italiano di Tecnologia (IIT), Via Morego,
Genova, Italy
| | - Oliver Kudlacek
- Institute of Pharmacology, Center for
Physiology and Pharmacology, Medical University Vienna, Waehringer Strasse,
Vienna, Austria
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics
Laboratory, Department of Neuroscience and Pharmacology, Faculty of Health and
Medical Sciences, The Panum Institute, University of Copenhagen,
Copenhagen, Denmark
| | - Michael Freissmuth
- Institute of Pharmacology, Center for
Physiology and Pharmacology, Medical University Vienna, Waehringer Strasse,
Vienna, Austria
| | - Daniela D Pollak
- Department of Neurophysiology and
Neuropharmacology, Center for Physiology and Pharmacology, Medical University
Vienna, Waehringer Strasse, Vienna, Austria
| | - Raul R Gainetdinov
- Department of Neuroscience and Brain
Technologies, Istituto Italiano di Tecnologia (IIT), Via Morego,
Genova, Italy,Skolkovo Institute of Science and
Technology (Skoltech), Skolkovo, Moscow,
Russia,Faculty of Biology and Soil Science, St
Petersburg State University, St Petersburg,
Russia
| | - Harald H Sitte
- Institute of Pharmacology, Center for
Physiology and Pharmacology, Medical University Vienna, Waehringer Strasse,
Vienna, Austria,Institute of Pharmacology, Center for Physiology and
Pharmacology, Medical University Vienna, Waehringer Strasse 13A,
Vienna
1090, Austria, Tel: +43 1 40160 31323, Fax: +43 1
40160 931300, E-mail:
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15
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Abstract
Several studies have reported the coupling of dopamine signaling to phospholipase C β (PLCβ) both in vitro and in vivo. However, the precise physiological relevance of this signaling pathway in mediating dopamine behaviors is still unclear. Here we report that stimulation of dopamine receptor signaling in vivo with systemic administration of apomorphine, amphetamine, and cocaine leads to increased production of inositol triphosphate (IP3) in the mouse striatum. Using selective antagonists and dopamine D1 and D2 receptor knock-out animals, we show that the production of IP3 is mediated by the D1 receptor, but not the D2 receptor. A selective blocker of PLCβ, U73122, was used to assess the physiological relevance of D1-mediated IP3 production. We show that U73122 inhibits the locomotor-stimulating effects of apomorphine, amphetamine, cocaine, and SKF81297. Furthermore, U73122 also suppresses the spontaneous hyperactivity exhibited by dopamine transporter knock-out mice. Importantly, the effects of U73122 are selective to dopamine-mediated hyperactivity, as this compound does not affect hyperactivity induced by the glutamate NMDA receptor antagonist MK801. Finally, we present evidence showing that an imbalance of D1- and D2-mediated signaling following U73122 treatment modifies the locomotor output of animals from horizontal locomotor activity to vertical activity, further highlighting the importance of the PLCβ pathway in the regulation of forward locomotion via dopamine receptors.
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16
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Arapulisamy O, Mannangatti P, Jayanthi LD. Regulated norepinephrine transporter interaction with the neurokinin-1 receptor establishes transporter subcellular localization. J Biol Chem 2013; 288:28599-610. [PMID: 23979140 DOI: 10.1074/jbc.m113.472878] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neurokinin-1 receptor (NK1R) mediates down-regulation of human norepinephrine (NE) transporter (hNET) via protein kinase C (PKC). However, native NET regulation by NK1R and the mechanism by which NK1R targets NET among other potential effectors are unknown. Effect of NK1R activation on native NET regulation and NET/NK1R interaction were studied using rat brain synaptosomes expressing native NET and NK1R as well as human placental trophoblast (HTR) cells coexpressing WT-hNET or NK1R/PKC-resistant hNET-T258A,S259A double mutant (NET-DM) and hNK1R. The selective NK1R agonist, GR73632, and Substance-P (SP) inhibited NE transport and reduced plasma membrane expression of NET and NK1R. Pretreatment with the NK1R antagonist, EMEND (aprepitant) prevented these NK1R-mediated effects. Immunoprecipitation experiments showed that NET forms stable complexes with NK1R. In HTR cells, combined biotinylation and immunoprecipitation studies revealed plasma membrane localization of NET·NK1R complexes. Receptor activation resulted in the internalization of NET·NK1R complexes. Lipid raft and immunoprecipitation analyses revealed the presence of NET·NK1R complexes exclusively in non-raft membrane fractions under basal/unstimulated conditions. However, NK1R activation led to translocation of NET·NK1R complexes to raft-rich membrane fractions. Importantly, PKCα was found in association with raft-localized NET following SP treatment. Similar to WT-NET, PKC-resistant NET-DM was found in association with NK1R exclusively in non-raft fractions. However, SP treatment failed to translocate NET-DM·NK1R complexes from non-raft fractions to raft fractions. Collectively, these results suggest that NK1R forms physical complexes with NET and that the receptor-mediated Thr(258) + Ser(259) motif-dependent translocation of NET·NK1R complexes into raft-rich microdomains facilitates NET/NK1R interaction with PKCα to coordinate spatially restricted NET regulation.
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Affiliation(s)
- Obulakshmi Arapulisamy
- From the Department of Neurosciences, Division of Neuroscience Research, Medical University of South Carolina, Charleston, South Carolina 29425 and
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17
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Jaaro-Peled H, Niwa M, Foss CA, Murai R, de Los Reyes S, Kamiya A, Mateo Y, O'Donnell P, Cascella NG, Nabeshima T, Guilarte TR, Pomper MG, Sawa A. Subcortical dopaminergic deficits in a DISC1 mutant model: a study in direct reference to human molecular brain imaging. Hum Mol Genet 2013; 22:1574-80. [PMID: 23314019 DOI: 10.1093/hmg/ddt007] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Imaging of the human brain has been an invaluable aid in understanding neuropsychopharmacology and, in particular, the role of dopamine in the striatum in mental illness. Here, we report a study in a genetic mouse model for major mental illness guided by results from human brain imaging: a systematic study using small animal positron emission tomography (PET), autoradiography, microdialysis and molecular biology in a putative dominant-negative mutant DISC1 transgenic model. This mouse model showed augmented binding of radioligands to the dopamine D2 receptor (D2R) in the striatum as well as neurochemical and behavioral changes to methamphetamine administration. Previously we reported that this model displayed deficits in the forced swim test, a representative indicator of antidepressant efficacy. By combining the results of our two studies, we propose a working hypothesis for future studies that this model might represent a mixed condition of depression and psychosis. We hope that this study will also help bridge a major gap in translational psychiatry between basic characterization of animal models and clinico-pharmacological assessment of patients mainly through PET imaging.
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Affiliation(s)
- Hanna Jaaro-Peled
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
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18
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Zheng W, Wang H, Zeng Z, Lin J, Little PJ, Srivastava LK, Quirion R. The possible role of the Akt signaling pathway in schizophrenia. Brain Res 2012; 1470:145-58. [PMID: 22771711 DOI: 10.1016/j.brainres.2012.06.032] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 06/19/2012] [Accepted: 06/25/2012] [Indexed: 02/07/2023]
Abstract
Serine/threonine protein kinase v-akt murine thymoma viral oncogene homolog (Akt) is one of the survival kinases with multiple biological functions in the brain and throughout the body. Schizophrenia is one of the most devastating psychiatric disorders. Accumulating evidence has indicated the involvement of the Akt signaling pathway in the pathogenesis of this disorder. Genetic linkage and association studies have identified Akt-1 as a candidate susceptibility gene related for schizophrenia. The level of Akt-1 protein and its kinase activity decreased significantly both in white blood cells from schizophrenic patients and in postmortem brain tissue of schizophrenic patients. Consistent with these findings, alterations in the upstream and downstream pathways of Akt have also been found in many psychiatric disorders. Furthermore, both typical and atypical antipsychotic drugs modify the Akt signaling pathway in a variety of conditions relative to schizophrenia. In addition as a survival kinase, Akt participates in neurodevelopment, synaptic plasticity, protein synthesis and neurotransmission in the central nervous system. It is thought that reduced activity of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway could at least partially explain the cognitive impairment, synaptic morphologic abnormality, neuronal atrophy and dysfunction of neurotransmitter signaling in schizophrenia. In addition, reduced levels of Akt may increase the effects of risk factors on neurodevelopment, attenuate the effects of growth factors on neurodevelopment and reduce the response of patients to antipsychotic agents. More recently, the role of Akt signaling in the functions of schizophrenia susceptibility genes such as disrupted-in-schizophrenia 1 (DISC-1), neuregulin-1 (NRG-1) and dysbindin-1 has been reported. Thus, Akt deficiency may create a context permissive for the expression of risk-gene effects in neuronal morphology and function. This paper reviews the role of Akt in the pathophysiology of schizophrenia and as a potential therapeutic strategy targeting Akt.
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Affiliation(s)
- Wenhua Zheng
- Neuropharmacology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
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19
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Jacobsen JPR, Siesser WB, Sachs BD, Peterson S, Cools MJ, Setola V, Folgering JHA, Flik G, Caron MG. Deficient serotonin neurotransmission and depression-like serotonin biomarker alterations in tryptophan hydroxylase 2 (Tph2) loss-of-function mice. Mol Psychiatry 2012; 17:694-704. [PMID: 21537332 PMCID: PMC3536482 DOI: 10.1038/mp.2011.50] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Probably the foremost hypothesis of depression is the 5-hydroxytryptamine (5-HT, serotonin) deficiency hypothesis. Accordingly, anomalies in putative 5-HT biomarkers have repeatedly been reported in depression patients. However, whether such anomalies in fact reflect deficient central 5-HT neurotransmission remains unresolved. We employed a naturalistic model of 5-HT deficiency, the tryptophan hydroxylase 2 (Tph2) R439H knockin mouse, to address this question. We report that Tph2 knockin mice have reduced basal and stimulated levels of extracellular 5-HT (5-HT(Ext)). Interestingly, cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) and fenfluramine-induced plasma prolactin levels are markedly diminished in the Tph2 knockin mice. These data seemingly confirm that low CSF 5-HIAA and fenfluramine-induced plasma prolactin reflects chronic, endogenous central nervous system (CNS) 5-HT deficiency. Moreover, 5-HT(1A) receptor agonist-induced hypothermia is blunted and frontal cortex 5-HT(2A) receptors are increased in the Tph2 knockin mice. These data likewise parallel core findings in depression, but are usually attributed to anomalies in the respective receptors rather than resulting from CNS 5-HT deficiency. Further, 5-HT(2A) receptor function is enhanced in the Tph2 knockin mice. In contrast, 5-HT(1A) receptor levels and G-protein coupling is normal in Tph2 knockin mice, indicating that the blunted hypothermic response relates directly to the low 5-HT(Ext). Thus, we show that not only low CSF 5-HIAA and a blunted fenfluramine-induced prolactin response, but also blunted 5-HT(1A) agonist-induced hypothermia and increased 5-HT(2A) receptor levels are bona fide biomarkers of chronic, endogenous 5-HT deficiency. Potentially, some of these biomarkers could identify patients likely to have 5-HT deficiency. This could have clinical research utility or even guide pharmacotherapy.
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Affiliation(s)
- JPR Jacobsen
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - WB Siesser
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - BD Sachs
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - S Peterson
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - MJ Cools
- Department of Cell Biology, Duke University, Durham, NC, USA
| | - V Setola
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC, USA
| | | | - G Flik
- BrainsOnline, Groningen, The Netherlands
| | - MG Caron
- Department of Cell Biology, Duke University, Durham, NC, USA,Department of Neurobiology, Duke University Medical Center, Durham, NC, USA
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20
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Managò F, Espinoza S, Salahpour A, Sotnikova TD, Caron MG, Premont RT, Gainetdinov RR. The role of GRK6 in animal models of Parkinson's disease and L-DOPA treatment. Sci Rep 2012; 2:301. [PMID: 22393477 PMCID: PMC3293148 DOI: 10.1038/srep00301] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Accepted: 02/14/2012] [Indexed: 01/11/2023] Open
Abstract
G protein-coupled Receptor Kinase 6 (GRK6) belongs to a family of kinases that phosphorylate GPCRs. GRK6 levels were found to be altered in Parkinson's Disease (PD) and D2 dopamine receptors are supersensitive in mice lacking GRK6 (GRK6-KO mice). To understand how GRK6 modulates the behavioral manifestations of dopamine deficiency and responses to L-DOPA, we used three approaches to model PD in GRK6-KO mice: 1) the cataleptic response to haloperidol; 2) introducing GRK6 mutation to an acute model of absolute dopamine deficiency, DDD mice; 3) hemiparkinsonian 6-OHDA model. Furthermore, dopamine-related striatal signaling was analyzed by assessing the phosphorylation of AKT/GSK3β and ERK1/2. GRK6 deficiency reduced cataleptic behavior, potentiated the acute effect of L-DOPA in DDD mice, reduced rotational behavior in hemi-parkinsonian mice, and reduced abnormal involuntary movements induced by chronic L-DOPA. These data indicate that approaches to regulate GRK6 activity could be useful in modulating both therapeutic and side-effects of L-DOPA.
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Affiliation(s)
- Francesca Managò
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa, Italy
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21
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Beaulieu JM, Del'guidice T, Sotnikova TD, Lemasson M, Gainetdinov RR. Beyond cAMP: The Regulation of Akt and GSK3 by Dopamine Receptors. Front Mol Neurosci 2011; 4:38. [PMID: 22065948 PMCID: PMC3206544 DOI: 10.3389/fnmol.2011.00038] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 10/13/2011] [Indexed: 01/11/2023] Open
Abstract
Brain dopamine receptors have been preferred targets for numerous pharmacological compounds developed for the treatment of various neuropsychiatric disorders. Recent discovery that D2 dopamine receptors, in addition to cAMP pathways, can engage also in Akt/GSK3 signaling cascade provided a new framework to understand intracellular signaling mechanisms involved in dopamine-related behaviors and pathologies. Here we review a recent progress in understanding the role of Akt, GSK3, and related signaling molecules in dopamine receptor signaling and functions. Particularly, we focus on the molecular mechanisms involved, interacting partners, role of these signaling events in the action of antipsychotics, psychostimulants, and antidepressants as well as involvement in pathophysiology of schizophrenia, bipolar disorder, and Parkinson’s disease. Further understanding of the role of Akt/GSK3 signaling in dopamine receptor functions could provide novel targets for pharmacological interventions in dopamine-related disorders.
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Affiliation(s)
- Jean-Martin Beaulieu
- Department of Psychiatry and Neuroscience, Université Laval-CRULRG Québec, QC, Canada
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Abstract
Bipolar disorder (BP) is a debilitating psychiatric disorder, affecting ∼2% of the worldwide population, for which the etiological basis, pathogenesis, and neurocircuitry remain poorly understood. Individuals with BP suffer from recurrent episodes of mania and depression, which are commonly treated with the mood stabilizer lithium. However, nearly half of BP patients do not respond adequately to lithium therapy and the clinically relevant mechanisms of lithium for mood stabilization remain elusive. Here, we modeled lithium responsiveness using cellular assays of glycogen synthase kinase 3 (GSK-3) signaling and mood-related behavioral assays in inbred strains of mice that differ in their response to lithium. We found that activating AKT through phosphosrylation of a key regulatory site (Thr308) was associated with lithium response-activation of signaling pathways downstream of GSK-3 in cells and attenuation of mood-related behaviors in mice-and this response was attenuated by selective and direct inhibition of AKT kinase activity. Conversely, the expression of constitutively active AKT1 in both the cellular and behavioral assays conferred lithium sensitivity. In contrast, selective and direct GSK-3 inhibition by the ATP-competitive inhibitor CHIR99021 bypassed the requirement for AKT activation and modulated behavior in both lithium-responsive and non-responsive mouse strains. These results distinguish the mechanism of action of lithium from direct GSK-3 inhibition both in vivo and in vitro, and highlight the therapeutic potential for selective GSK-3 inhibitors in BP treatment.
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Marazziti D, Di Pietro C, Mandillo S, Golini E, Matteoni R, Tocchini‐Valentini GP. Absence of the GPR37/PAEL receptor impairs striatal Akt and ERK2 phosphorylation, ΔFosB expression, and conditioned place preference to amphetamine and cocaine. FASEB J 2011; 25:2071-81. [DOI: 10.1096/fj.10-175737] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Daniela Marazziti
- Istituto di Biologia Cellulare‐Consiglio Nazionale delle RicercheCampus A. Buzzati‐TraversoMonterotondo ScaloRomeItaly
| | - Chiara Di Pietro
- Istituto di Biologia Cellulare‐Consiglio Nazionale delle RicercheCampus A. Buzzati‐TraversoMonterotondo ScaloRomeItaly
| | - Silvia Mandillo
- Istituto di Biologia Cellulare‐Consiglio Nazionale delle RicercheCampus A. Buzzati‐TraversoMonterotondo ScaloRomeItaly
| | - Elisabetta Golini
- Istituto di Biologia Cellulare‐Consiglio Nazionale delle RicercheCampus A. Buzzati‐TraversoMonterotondo ScaloRomeItaly
| | - Rafaele Matteoni
- Istituto di Biologia Cellulare‐Consiglio Nazionale delle RicercheCampus A. Buzzati‐TraversoMonterotondo ScaloRomeItaly
| | - Glauco P. Tocchini‐Valentini
- Istituto di Biologia Cellulare‐Consiglio Nazionale delle RicercheCampus A. Buzzati‐TraversoMonterotondo ScaloRomeItaly
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McDougall SA, Der-Ghazarian T, Britt CE, Varela FA, Crawford CA. Postnatal manganese exposure alters the expression of D2L and D2S receptor isoforms: relationship to PKA activity and Akt levels. Synapse 2010; 65:583-91. [PMID: 21484877 DOI: 10.1002/syn.20877] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2010] [Accepted: 09/27/2010] [Indexed: 01/04/2023]
Abstract
Postnatal manganese chloride (Mn) exposure causes persistent changes in presynaptic dopamine (DA) functioning (e.g., Mn reduces DA transporter levels and DA uptake), but evidence that Mn affects postsynaptic DA receptors and their associated second messenger systems is equivocal. Therefore, a goal of the present study was to determine whether exposing rats to Mn on postnatal days (PD) 1-21 would cause long-term alterations in D2 long (D2L) and D2 short (D2S) receptors that were detectible in adulthood (i.e., on PD 90). Signaling systems associated with D2 receptors were also assessed. Specifically, we measured protein kinase A (PKA) activity in the dorsal striatum and prefrontal cortex (PFC), whereas immunoblotting was used to quantify phosphorylated Akt (p-Akt) and phosphorylated ERK. Results showed that early Mn exposure caused a persistent elevation of D2L and D2S protein expression in the dorsal striatum, as well as an increase in the number of D2 binding sites. Conversely, Mn reduced D2 specific binding in the PFC on PD 90. PKA activity of Mn-treated rats was enhanced in both the dorsal striatum and PFC, whereas p-Akt levels were elevated in the dorsal striatum. When considered together, these results suggest that postnatal Mn exposure either directly or indirectly alters the functioning of postsynaptic DA receptors. One possibility is that early Mn exposure depresses presynaptic dopaminergic functioning and reduces DA levels, thereby causing an up-regulation of D2 receptors and a dysregulation of DA-associated signaling pathways. An alternative explanation is that early Mn exposure affects D2 receptors and PKA/p-Akt levels via independent mechanisms.
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Affiliation(s)
- Sanders A McDougall
- Department of Psychology, California State University, San Bernardino, California 92407, USA.
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Ramamoorthy S, Shippenberg TS, Jayanthi LD. Regulation of monoamine transporters: Role of transporter phosphorylation. Pharmacol Ther 2010; 129:220-38. [PMID: 20951731 DOI: 10.1016/j.pharmthera.2010.09.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 09/24/2010] [Indexed: 10/18/2022]
Abstract
Presynaptic biogenic amine transporters mediate reuptake of released amines from the synapse, thus regulating serotonin, dopamine and norepinephrine neurotransmission. Medications utilized in the treatment of depression, attention deficit-hyperactivity disorder and other psychiatric disorders possess high affinity for amine transporters. In addition, amine transporters are targets for psychostimulants. Altered expression of biogenic amine transporters has long been implicated in several psychiatric and degenerative disorders. Therefore, appropriate regulation and maintenance of biogenic amine transporter activity is critical for the maintenance of normal amine homoeostasis. Accumulating evidence suggests that cellular protein kinases and phosphatases regulate amine transporter expression, activity, trafficking and degradation. Amine transporters are phosphoproteins that undergo dynamic control under the influence of various kinase and phosphatase activities. This review presents a brief overview of the role of amine transporter phosphorylation in the regulation of amine transport in the normal and diseased brain. Understanding the molecular mechanisms by which phosphorylation events affect amine transporter activity is essential for understanding the contribution of transporter phosphorylation to the regulation of monoamine neurotransmission and for identifying potential new targets for the treatment of various brain diseases.
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Affiliation(s)
- Sammanda Ramamoorthy
- Department of Neurosciences, Division of Neuroscience Research, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Deslauriers J, Lefrançois M, Larouche A, Sarret P, Grignon S. Antipsychotic-induced DRD2 upregulation and its prevention by α-lipoic acid in SH-SY5Y Neuroblastoma cells. Synapse 2010; 65:321-31. [DOI: 10.1002/syn.20851] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 07/27/2010] [Indexed: 11/11/2022]
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Hahn T, Heinzel S, Dresler T, Plichta MM, Renner TJ, Markulin F, Jakob PM, Lesch KP, Fallgatter AJ. Association between reward-related activation in the ventral striatum and trait reward sensitivity is moderated by dopamine transporter genotype. Hum Brain Mapp 2010; 32:1557-65. [PMID: 20845394 DOI: 10.1002/hbm.21127] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2009] [Revised: 05/14/2010] [Accepted: 06/21/2010] [Indexed: 12/31/2022] Open
Abstract
The impact of individual differences on human reward processing has been a focus of research in recent years, particularly, as they are associated with a variety of neuropsychiatric diseases including addiction and attention-deficit/hyperactivity disorder. Studies exploring the neural basis of individual differences in reward sensitivity have consistently implicated the ventral striatum (VS) as a core component of the human reward system. However, the mechanisms of dopaminergic neurotransmission underlying ventral striatal activation as well as trait reward sensitivity remain speculative. We addressed this issue by investigating the triadic interplay between VS reactivity during reward anticipation using functional magnetic resonance imaging, trait reward sensitivity, and dopamine (DA) transporter genotype (40-bp 3'VNTR of DAT, SLC6A3) affecting synaptic DA neurotransmission. Our results show that DAT variation moderates the association between VS-reactivity and trait reward sensitivity. Specifically, homozygote carriers of the DAT 10-repeat allele exhibit a strong positive correlation between reward sensitivity and reward-related VS activity whereas this relationship is absent in the DAT 9-repeat allele carriers. We discuss the possibility that this moderation of VS-trait relation might arise from DAT-dependent differences in DA availability affecting synaptic plasticity within the VS. Generally, studying the impact of dopaminergic gene variations on the relation between reward-related brain activity and trait reward sensitivity might facilitate the investigation of complex mechanisms underlying disorders linked to dysregulation of DA neurotransmission.
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Affiliation(s)
- Tim Hahn
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Würzburg, 97080 Würzburg, Germany.
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Strengths and limitations of genetic models of ADHD. ACTA ACUST UNITED AC 2010; 2:21-30. [DOI: 10.1007/s12402-010-0021-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 02/09/2010] [Indexed: 12/15/2022]
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Developmental vitamin D deficiency alters dopamine-mediated behaviors and dopamine transporter function in adult female rats. Psychopharmacology (Berl) 2010; 208:159-68. [PMID: 19921153 DOI: 10.1007/s00213-009-1717-y] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 10/26/2009] [Indexed: 02/05/2023]
Abstract
RATIONALE Developmental vitamin D (DVD) deficiency has been proposed as a risk factor for schizophrenia. DVD deficiency in neonatal rats is associated with alterations in cellular development, dopamine metabolism, and brain morphology. DVD-deficient adult rats show novelty-induced hyperlocomotion and an enhanced locomotor response to MK-801, which can be ameliorated by pretreatment with the antipsychotic drug haloperidol. OBJECTIVES In this study, we examined locomotor responses of male and female juvenile and adult rats to a dose range of amphetamine. We also measured dopamine receptor and monoamine transporter densities in adult brain. RESULTS Female DVD-deficient adult rats displayed an enhanced sensitivity to amphetamine-induced locomotion, an increased dopamine transporter density in the caudate-putamen and increased affinity in the nucleus accumbens compared with control females. By contrast, there were no differences between control and DVD-deficient male rats. DISCUSSION Taken together, this suggests an alteration in the development of the dopamine system and on dopamine-mediated behaviors in female DVD-deficient rats, and this may be relevant to the underlying neurobiology of schizophrenia.
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Bédard AC, Schulz KP, Cook EH, Fan J, Clerkin SM, Ivanov I, Halperin JM, Newcorn JH. Dopamine transporter gene variation modulates activation of striatum in youth with ADHD. Neuroimage 2009; 53:935-42. [PMID: 20026227 DOI: 10.1016/j.neuroimage.2009.12.041] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Revised: 12/07/2009] [Accepted: 12/09/2009] [Indexed: 10/20/2022] Open
Abstract
Polymorphisms in the 3'UTR variable number tandem repeat (VNTR) of exon 15 of the dopamine transporter gene (DAT1) have been linked to attention-deficit hyperactivity disorder (ADHD); moreover, variability in DAT1 3'UTR genotype may contribute to both heterogeneity of the ADHD phenotype and differences in response to stimulant medications. The impact of this VNTR on neuronal function in individuals with ADHD remains unclear despite evidence that the polymorphisms influence dopamine transporter expression. Thus, we used event-related functional magnetic resonance imaging to examine the impact of DAT1 3'UTR genotype on brain activation during response inhibition in unmedicated children and adolescents with ADHD. Twenty-one youth with ADHD who were homozygous for the 10-repeat (10R) allele of the DAT1 3'UTR and 12 youth who were carriers of the 9-repeat (9R) allele were scanned while they performed a Go/No-Go task. Response inhibition was modeled by contrasting activation during correct No-Go trials versus correct Go trials. Participants who were homozygous for the DAT1 3'UTR 10R allele and those who had a single 9R allele did not differ on percent of trials with successful inhibition, which was the primary measure of inhibitory control. Yet, youth with the DAT1 3'UTR 10R/10R genotype had significantly greater inhibitory control-related activation than those with one 9R allele in the left striatum, right dorsal premotor cortex, and bilaterally in the temporoparietal cortical junction. These findings provide preliminary evidence that neural activity related to inhibitory control may differ as a function of DAT1 3'UTR genotype in youth with ADHD.
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Affiliation(s)
- Anne-Claude Bédard
- Department of Psychiatry, Mount Sinai School of Medicine, Box 1230, One Gustave L. Levy Place, New York, NY 10029, USA
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