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Tao Y, Jin M, Zhang H, Ran M, Xu H, Zou S, Deng F, Huang L, Zhang H, Wang X, Wang Y, Hou H, Liang S, Ma X, Yin L. PRKCB methylation: a potential biomarker of MDD with childhood chronic stress, a cross-sectional study in drug-naive, first-episode adolescent MDD. Epigenetics 2024; 19:2408159. [PMID: 39342638 DOI: 10.1080/15592294.2024.2408159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 08/29/2024] [Accepted: 09/17/2024] [Indexed: 10/01/2024] Open
Abstract
The purpose of this study was to investigate the relationship between childhood chronic stress(CCS), Protein kinase C beta (PRKCB) methylation and adolescent major depressive disorder (MDD). After recruiting 100 adolescents with MDD and 50 healthy controls (HCs), we evaluated the severity of CCS. PRKCB methylation was assessed by pyrosequencing using whole blood-derived DNA. To explore the relationship between CCS, PRKCB and adolescent MDD, we conducted correlation analysis and regression analysis, and constructed multiplicative interaction models and generalized linear models. PRKCB methylation and CCS were both found to be associated with MDD, and CCS was associated with PRKCB methylation. No significant CCS-PRKCB methylation interactions were observed. However, we found the interaction of CCS and MDD on PRKCB methylation. Our results found that PRKCB methylation was influenced by CCS and the disease itself, and PRKCB methylation was significantly positively associated with MDD severity, suggesting that PRKCB methylation may be a potential biomarker for adolescent MDD. This study is a cross-sectional observational study, which cannot draw the conclusion of causality. Prospective cohort studies are needed to further examine the relationship between CCS, adolescent MDD, and PRKCB methylation.
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Affiliation(s)
- Yuanmei Tao
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, Sichuan Clinical Medical Research Center for Mental Disorder, Chengdu, Sichuan, China
| | - Meijiang Jin
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, Sichuan Clinical Medical Research Center for Mental Disorder, Chengdu, Sichuan, China
| | - Hang Zhang
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, Sichuan Clinical Medical Research Center for Mental Disorder, Chengdu, Sichuan, China
| | - Maojia Ran
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, Sichuan Clinical Medical Research Center for Mental Disorder, Chengdu, Sichuan, China
| | - Hanmei Xu
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Shoukang Zou
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, The Fourth People's Hospital of Chengdu, Chengdu, Sichuan, China
| | - Fang Deng
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, The Fourth People's Hospital of Chengdu, Chengdu, Sichuan, China
| | - Lijuan Huang
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Hong Zhang
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Xiaolan Wang
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Yanping Wang
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Huijin Hou
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Shufang Liang
- Department of Biotherapy, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Xiaohong Ma
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, Sichuan Clinical Medical Research Center for Mental Disorder, Chengdu, Sichuan, China
| | - Li Yin
- Department of Psychiatry, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Department of Psychiatry, Sichuan Clinical Medical Research Center for Mental Disorder, Chengdu, Sichuan, China
- Institute for Systematic Genetics, Frontiers Science Center for Disease-Related Molecular Network, Chengdu, Sichuan, China
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Kim YJ, Choi SJ, Hong SI, Park JC, Lee Y, Ma SX, Hur KH, Lee Y, Kim KM, Kim HK, Kim HY, Lee SY, Choi SY, Jang CG. The ion channel TRPA1 is a modulator of the cocaine reward circuit in the nucleus accumbens. Mol Psychiatry 2024:10.1038/s41380-024-02623-4. [PMID: 38822069 DOI: 10.1038/s41380-024-02623-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 05/03/2024] [Accepted: 05/21/2024] [Indexed: 06/02/2024]
Abstract
Drug addiction therapies commonly fail because continued drug use promotes the release of excessive and pleasurable dopamine levels. Because the connection between pleasure and drug use becomes hard-wired in the nucleus accumbens (NAc), which interfaces motivation, effective therapies need to modulate this mesolimbic reward system. Here, we report that mice with knockdown of the cation channel TRPA1 (transient receptor potential ankyrin 1) were resistant to the drug-seeking behavior and reward effects of cocaine compared to their wildtype litter mates. In our study, we demonstrate that TRPA1 inhibition in the NAc reduces cocaine activity and dopamine release, and conversely, that TRPA1 is critical for cocaine-induced synaptic strength in dopamine receptor 1-expressing medium spiny neurons. Taken together, our data support that cocaine-induced reward-related behavior and synaptic release of dopamine in the NAc are controlled by TRPA1 and suggest that TRPA1 has therapeutic potential as a target for drug misuse therapies.
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Affiliation(s)
- Young-Jung Kim
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Su Jeong Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080, Republic of Korea
| | - Sa-Ik Hong
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Jung-Cheol Park
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080, Republic of Korea
| | - Youyoung Lee
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Shi-Xun Ma
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Kwang-Hyun Hur
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Young Lee
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080, Republic of Korea
| | - Kyeong-Man Kim
- Pharmacology Laboratory, College of Pharmacy, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Hyung Kyu Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Hee Young Kim
- Department of Physiology, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Seok-Yong Lee
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea
| | - Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, 03080, Republic of Korea.
| | - Choon-Gon Jang
- Department of Pharmacology, School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
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3
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Roy PK, Rajesh Y, Mandal M. Therapeutic targeting of membrane-associated proteins in central nervous system tumors. Exp Cell Res 2021; 406:112760. [PMID: 34339674 DOI: 10.1016/j.yexcr.2021.112760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/28/2021] [Accepted: 07/28/2021] [Indexed: 12/09/2022]
Abstract
The activity of the most complex system, the central nervous system (CNS) is profoundly regulated by a huge number of membrane-associated proteins (MAP). A minor change stimulates immense chemical changes and the elicited response is organized by MAP, which acts as a receptor of that chemical or channel enabling the flow of ions. Slight changes in the activity or expression of these MAPs lead to severe consequences such as cognitive disorders, memory loss, or cancer. CNS tumors are heterogeneous in nature and hard-to-treat due to random mutations in MAPs; like as overexpression of EGFRvIII/TGFβR/VEGFR, change in adhesion molecules α5β3 integrin/SEMA3A, imbalance in ion channel proteins, etc. Extensive research is under process for developing new therapeutic approaches using these proteins such as targeted cytotoxic radiotherapy, drug-delivery, and prodrug activation, blocking of receptors like GluA1, developing viral vector against cell surface receptor. The combinatorial approach of these strategies along with the conventional one might be more potential. Henceforth, our review focuses on in-depth analysis regarding MAPs aiming for a better understanding for developing an efficient therapeutic approach for targeting CNS tumors.
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Affiliation(s)
- Pritam Kumar Roy
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, India
| | - Yetirajam Rajesh
- Department of Human and Molecular Genetics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
| | - Mahitosh Mandal
- School of Medical Science and Technology, Indian Institute of Technology Kharagpur, India.
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Rakovska A, Javitt D, Petkova-Kirova P, Balla A, Ang R, Kalfin R. Neurochemical evidence that cysteamine modulates amphetamine-induced dopaminergic neuronal activity in striatum by decreasing dopamine release: an in vivo microdialysis study in freely moving rats. Brain Res Bull 2019; 153:39-46. [DOI: 10.1016/j.brainresbull.2019.08.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/18/2019] [Accepted: 08/06/2019] [Indexed: 01/01/2023]
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Altshuler RD, Carpenter CA, Franke TJ, Gnegy ME, Jutkiewicz EM. The protein kinase Cβ-selective inhibitor, enzastaurin, attenuates amphetamine-stimulated locomotor activity and self-administration behaviors in rats. Psychopharmacology (Berl) 2019; 236:3231-3242. [PMID: 31134292 PMCID: PMC6832797 DOI: 10.1007/s00213-019-05278-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/14/2019] [Indexed: 12/31/2022]
Abstract
RATIONALE Pathological amphetamine (AMPH) use is a serious public health concern with no pharmacological treatment options. Protein kinase Cβ (PKCβ) has been implicated in the mechanism of action of AMPH, such that inhibition of PKCβ attenuates AMPH-stimulated dopamine efflux in vivo. With this in mind, inhibition of PKCβ may be a viable therapeutic target for AMPH use disorder. OBJECTIVE The purpose of this study is to demonstrate that selective pharmacological inhibition of PKCβ alters AMPH-stimulated behaviors in rats. METHODS Rats were administered intracerebroventricular (i.c.v.) injections of the PKCβ-selective inhibitor enzastaurin 0.5, 3, 6, or 18 h before evaluating AMPH-stimulated locomotion (0.32-3.2 mg/kg). Rats were trained to make responses for different doses of AMPH infusions or sucrose under a fixed ratio 5 schedule of reinforcement, and the effects of enzastaurin pretreatment 3 or 18 h prior to a self-administration session were determined. Also, the effect of enzastaurin on AMPH-stimulated PKC activity in the ventral striatum was evaluated. RESULTS A large dose of enzastaurin (1 nmol) decreased AMPH-stimulated locomotor activity 0.5 h following enzastaurin administration. Small doses of enzastaurin (10-30 pmol) attenuated AMPH-stimulated locomotor activity and shifted the AMPH dose-effect curve to the right following an 18-h pretreatment. Rats pretreated with enzastaurin 18 h, but not 3, prior to a self-administration session showed a decrease in the number of responses for AMPH, shifted the ascending limb of the amphetamine dose effect curve, and produced no change in responses for sucrose. AMPH-stimulated PKC activity was decreased following a 0.5- or 18-h pretreatment, but not a 3-h pretreatment of enzastaurin. CONCLUSIONS These results demonstrate that inhibition of PKCβ will decrease AMPH-stimulated behaviors and neurobiological changes and suggest that PKCβ is potentially a viable target for AMPH use disorder.
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Affiliation(s)
- Rachel D Altshuler
- Department of Pharmacology, University of Michigan, 1150 W. Medical Center Dr, Ann Arbor, MI, 48109, USA
| | - Colleen A Carpenter
- Department of Pharmacology, University of Michigan, 1150 W. Medical Center Dr, Ann Arbor, MI, 48109, USA
| | - Timothy J Franke
- Department of Pharmacology, University of Michigan, 1150 W. Medical Center Dr, Ann Arbor, MI, 48109, USA
| | - Margaret E Gnegy
- Department of Pharmacology, University of Michigan, 1150 W. Medical Center Dr, Ann Arbor, MI, 48109, USA
| | - Emily M Jutkiewicz
- Department of Pharmacology, University of Michigan, 1150 W. Medical Center Dr, Ann Arbor, MI, 48109, USA.
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6
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Dal-Pont GC, Resende WR, Bianchini G, Gava FF, Peterle BR, Trajano KS, Varela RB, Quevedo J, Valvassori SS. Tamoxifen has an anti-manic effect but not protect the brain against oxidative stress in an animal model of mania induced by ouabain. J Psychiatr Res 2019; 113:181-189. [PMID: 30981159 DOI: 10.1016/j.jpsychires.2019.03.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/15/2019] [Accepted: 03/21/2019] [Indexed: 11/18/2022]
Abstract
Studies have suggested the involvement of oxidative stress in the physiopathology of bipolar disorder. Preclinical data have shown that PKC inhibitors may act as mood-stabilizing agents and protect the brain in animal models of mania. The present study aimed to evaluate the effects of Lithium (Li) or tamoxifen (TMX) on behavioral changes and oxidative stress parameters in an animal model of mania induced by ouabain (OUA). Wistar rats received a single intracerebroventricular (ICV) injection of OUA or artificial cerebrospinal fluid (ACSF). From the day following ICV injection, the rats were treated for seven days with intraperitoneal injections of saline, Li or TMX twice a day. On the 7th day after OUA injection, locomotor activity was measured using the open-field test, and the oxidative stress parameters were evaluated in the hippocampus and frontal cortex of rats. The results showed that OUA induced hyperactivity in rats, which is considered a manic-like behavior. Also, OUA increased lipid peroxidation and oxidative damage to proteins, as well as causing alterations to antioxidant enzymes in the frontal cortex and hippocampus of rats. The Li or TMX treatment reversed the manic-like behavior induced by OUA. Besides, Li, but not TMX, reversed the oxidative damage caused by OUA. These results suggest that the manic-like effects induced by OUA and the antimanic effects of TMX seem not to be related to the oxidative stress.
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Affiliation(s)
- Gustavo C Dal-Pont
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Wilson R Resende
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Guilherme Bianchini
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Fernanda F Gava
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Bruna R Peterle
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Kerolen S Trajano
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - Roger B Varela
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil
| | - João Quevedo
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil; Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA; Neuroscience Graduate Program, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, USA; Translational Psychiatry Program, Department of Psychiatry and Behavioral Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston (UTHealth), Houston, TX, USA
| | - Samira S Valvassori
- Translational Psychiatry Laboratory, Graduate Program in Health Sciences, University of Southern Santa Catarina (UNESC), Criciúma, SC, Brazil.
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Zestos AG, Carpenter C, Kim Y, Low MJ, Kennedy RT, Gnegy ME. Ruboxistaurin Reduces Cocaine-Stimulated Increases in Extracellular Dopamine by Modifying Dopamine-Autoreceptor Activity. ACS Chem Neurosci 2019; 10:1960-1969. [PMID: 30384585 DOI: 10.1021/acschemneuro.8b00259] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Cocaine is a highly abused drug, and cocaine addiction affects millions of individuals worldwide. Cocaine blocks normal uptake function at the dopamine transporter (DAT), thus increasing extracellular dopamine. Currently, no chemical therapies are available to treat cocaine abuse. Previous works showed that the selective inhibitors of protein kinase Cβ (PKCβ), enzastaurin and ruboxistaurin, attenuate dopamine overflow and locomotion stimulated by another psychostimulant drug, amphetamine. We now test if ruboxistaurin similarly affects cocaine action. Perfusion of 1 μM ruboxistaurin directly into the core of the nucleus accumbens via retrodialysis reduced cocaine-stimulated increases in dopamine overflow, measured using microdialysis sampling, with simultaneous reductions in locomotor behavior. Because cocaine activity is highly regulated by dopamine autoreceptors, we examined whether ruboxistaurin was acting at the level of the D2 autoreceptor. Perfusion of 5 μM raclopride, a selective D2-like receptor antagonist, before addition of ruboxistaurin, abrogated the effect of ruboxistaurin on cocaine-stimulated dopamine overflow and hyperlocomotion. Further, ruboxistaurin was inactive against cocaine-stimulated locomotor activity in mice with a genetic deletion in D2 receptors as compared to wild-type mice. In contrast, blockade or deletion of dopamine D2 receptors did not abolish the attenuating effect of ruboxistaurin on amphetamine-stimulated activities. Therefore, the inhibition of PKCβ reduces dopamine overflow and locomotor activity stimulated by both cocaine and amphetamine, but the mechanism of action differs for each stimulant. These data suggest that inhibition of PKCβ would serve as a target to reduce the abuse of either amphetamine or cocaine.
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Affiliation(s)
- Alexander G. Zestos
- Department of Chemistry and Center for Behavioral Neuroscience, American University, Washington, D.C. 20016, United States
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8
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Benleulmi-Chaachoua A, Hegron A, Le Boulch M, Karamitri A, Wierzbicka M, Wong V, Stagljar I, Delagrange P, Ahmad R, Jockers R. Melatonin receptors limit dopamine reuptake by regulating dopamine transporter cell-surface exposure. Cell Mol Life Sci 2018; 75:4357-4370. [PMID: 30043140 PMCID: PMC11105639 DOI: 10.1007/s00018-018-2876-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 06/26/2018] [Accepted: 07/16/2018] [Indexed: 12/11/2022]
Abstract
Melatonin, a neuro-hormone released by the pineal gland, has multiple effects in the central nervous system including the regulation of dopamine (DA) levels, but how melatonin accomplishes this task is not clear. Here, we show that melatonin MT1 and MT2 receptors co-immunoprecipitate with the DA transporter (DAT) in mouse striatal synaptosomes. Increased DA re-uptake and decreased amphetamine-induced locomotor activity were observed in the striatum of mice with targeted deletion of MT1 or MT2 receptors. In vitro experiments confirmed the interactions and recapitulated the inhibitory effect of melatonin receptors on DA re-uptake. Melatonin receptors retained DAT in the endoplasmic reticulum in its immature non-glycosylated form. In conclusion, we reveal one of the first molecular complexes between G protein-coupled receptors (MT1 and MT2) and transporters (DAT) in which melatonin receptors regulate the availability of DAT at the plasma membrane, thus limiting the striatal DA re-uptake capacity in mice.
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MESH Headings
- Animals
- Cell Membrane/metabolism
- Corpus Striatum/metabolism
- Dopamine/metabolism
- Dopamine Plasma Membrane Transport Proteins/genetics
- Dopamine Plasma Membrane Transport Proteins/metabolism
- HEK293 Cells
- Humans
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Motor Activity/genetics
- Protein Binding
- Receptor, Melatonin, MT1/genetics
- Receptor, Melatonin, MT1/metabolism
- Receptor, Melatonin, MT2/genetics
- Receptor, Melatonin, MT2/metabolism
- Synaptosomes/metabolism
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Affiliation(s)
- Abla Benleulmi-Chaachoua
- Inserm, U1016, Institut Cochin, 22 Rue Mechain, 75014, Paris, France
- CNRS, UMR 8104, 22 Rue Mechain, 75014, Paris, France
- University of Paris Descartes, Sorbonne Paris Cité, 12 Rue de l'École de Médecine, 75006, Paris, France
| | - Alan Hegron
- Inserm, U1016, Institut Cochin, 22 Rue Mechain, 75014, Paris, France
- CNRS, UMR 8104, 22 Rue Mechain, 75014, Paris, France
- University of Paris Descartes, Sorbonne Paris Cité, 12 Rue de l'École de Médecine, 75006, Paris, France
| | - Marine Le Boulch
- Inserm, U1016, Institut Cochin, 22 Rue Mechain, 75014, Paris, France
- CNRS, UMR 8104, 22 Rue Mechain, 75014, Paris, France
- University of Paris Descartes, Sorbonne Paris Cité, 12 Rue de l'École de Médecine, 75006, Paris, France
| | - Angeliki Karamitri
- Inserm, U1016, Institut Cochin, 22 Rue Mechain, 75014, Paris, France
- CNRS, UMR 8104, 22 Rue Mechain, 75014, Paris, France
- University of Paris Descartes, Sorbonne Paris Cité, 12 Rue de l'École de Médecine, 75006, Paris, France
| | - Marta Wierzbicka
- Donnelly Centre, Department of Biochemistry, Faculty of Medicine, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada
| | - Victoria Wong
- Donnelly Centre, Department of Biochemistry, Faculty of Medicine, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada
| | - Igor Stagljar
- Donnelly Centre, Department of Biochemistry, Faculty of Medicine, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada
- Department of Molecular Genetics, Faculty of Medicine, University of Toronto, 160 College Street, Toronto, ON, M5S 3E1, Canada
| | - Philippe Delagrange
- Pôle d'Innovation Thérapeutique Neuropsychiatrie, Institut de Recherches Servier, 125 Chemin de Ronde, 78290, Croissy, France
| | - Raise Ahmad
- Inserm, U1016, Institut Cochin, 22 Rue Mechain, 75014, Paris, France
- CNRS, UMR 8104, 22 Rue Mechain, 75014, Paris, France
- University of Paris Descartes, Sorbonne Paris Cité, 12 Rue de l'École de Médecine, 75006, Paris, France
| | - Ralf Jockers
- Inserm, U1016, Institut Cochin, 22 Rue Mechain, 75014, Paris, France.
- CNRS, UMR 8104, 22 Rue Mechain, 75014, Paris, France.
- University of Paris Descartes, Sorbonne Paris Cité, 12 Rue de l'École de Médecine, 75006, Paris, France.
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Sambo DO, Lebowitz JJ, Khoshbouei H. The sigma-1 receptor as a regulator of dopamine neurotransmission: A potential therapeutic target for methamphetamine addiction. Pharmacol Ther 2018; 186:152-167. [PMID: 29360540 PMCID: PMC5962385 DOI: 10.1016/j.pharmthera.2018.01.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Methamphetamine (METH) abuse is a major public health issue around the world, yet there are currently no effective pharmacotherapies for the treatment of METH addiction. METH is a potent psychostimulant that increases extracellular dopamine levels by targeting the dopamine transporter (DAT) and alters neuronal activity in the reward centers of the brain. One promising therapeutic target for the treatment of METH addiction is the sigma-1 receptor (σ1R). The σ1R is an endoplasmic reticulum-localized chaperone protein that is activated by cellular stress, and, unique to this chaperone, its function can also be induced or inhibited by different ligands. Upon activation of this unique "chaperone receptor", the σ1R regulates a variety of cellular functions and possesses neuroprotective activity in the brain. Interestingly, a variety of σ1R ligands modulate dopamine neurotransmission and reduce the behavioral effects of METH in animal models of addictive behavior, suggesting that the σ1R may be a viable therapeutic target for the treatment of METH addiction. In this review, we provide background on METH and the σ1R as well as a literature review regarding the role of σ1Rs in modulating both dopamine neurotransmission and the effects of METH. We aim to highlight the complexities of σ1R pharmacology and function as well as the therapeutic potential of the σ1R as a target for the treatment of METH addiction.
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Affiliation(s)
- Danielle O Sambo
- University of Florida, College of Medicine, Department of Neuroscience, Gainesville, FL 32611, United States
| | - Joseph J Lebowitz
- University of Florida, College of Medicine, Department of Neuroscience, Gainesville, FL 32611, United States
| | - Habibeh Khoshbouei
- University of Florida, College of Medicine, Department of Neuroscience, Gainesville, FL 32611, United States.
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10
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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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11
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Interaction Between the Trace Amine-Associated Receptor 1 and the Dopamine D 2 Receptor Controls Cocaine's Neurochemical Actions. Sci Rep 2017; 7:13901. [PMID: 29066851 PMCID: PMC5655641 DOI: 10.1038/s41598-017-14472-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 10/11/2017] [Indexed: 02/07/2023] Open
Abstract
Recent evidence suggests that the trace amine-associated receptor 1 (TAAR1) plays a pivotal role in the regulation of dopamine (DA) transmission and cocaine’s actions. However, the underlying mechanisms through which TAAR1 activation mediates these effects have not yet been elucidated. Here, we used fast-scan cyclic voltammetry to measure DA dynamics and explore such mechanisms. We show, first, that the full TAAR1 agonist, RO5256390, dose-dependently blocked cocaine-induced inhibition of DA clearance in slices of the nucleus accumbens. Second, subthreshold inhibition of PKA or PKC phosphorylation did not prevent TAAR1 suppression of cocaine effects whereas subeffective doses of the DA D2 receptor antagonist, L-741,626, rescued cocaine’s ability to produce changes in DA uptake in the presence of full TAAR1 activation, thus indicating that TAAR1 modulation of cocaine effects requires simultaneous DA D2 receptor activation. Predictably, inhibition of glycogen synthase kinase-3 (GSK-3), which results from activation of D2/TAAR1 heterodimers, fully reproduced the inhibitory effects of TAAR1 activation on cocaine-induced changes in DA transmission. Collectively, the present observations reveal that the ability of TAAR1 to regulate cocaine effects is linked to cooperative interactions with D2 autoreceptors and associated downstream molecular targets converging on GSK-3 and suggest a new mechanism to disrupt cocaine neurochemical actions.
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12
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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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13
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Carpenter C, Zestos AG, Altshuler R, Sorenson RJ, Guptaroy B, Showalter HD, Kennedy RT, Jutkiewicz E, Gnegy ME. Direct and Systemic Administration of a CNS-Permeant Tamoxifen Analog Reduces Amphetamine-Induced Dopamine Release and Reinforcing Effects. Neuropsychopharmacology 2017; 42:1940-1949. [PMID: 28492278 PMCID: PMC5561350 DOI: 10.1038/npp.2017.95] [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: 03/08/2017] [Revised: 04/29/2017] [Accepted: 05/03/2017] [Indexed: 01/09/2023]
Abstract
Amphetamines (AMPHs) are globally abused. With no effective treatment for AMPH addiction to date, there is urgent need for the identification of druggable targets that mediate the reinforcing action of this stimulant class. AMPH-stimulated dopamine efflux is modulated by protein kinase C (PKC) activation. Inhibition of PKC reduces AMPH-stimulated dopamine efflux and locomotor activity. The only known CNS-permeant PKC inhibitor is the selective estrogen receptor modulator tamoxifen. In this study, we demonstrate that a tamoxifen analog, 6c, which more potently inhibits PKC than tamoxifen but lacks affinity for the estrogen receptor, reduces AMPH-stimulated increases in extracellular dopamine and reinforcement-related behavior. In rat striatal synaptosomes, 6c was almost fivefold more potent at inhibiting AMPH-stimulated dopamine efflux than [3H]dopamine uptake through the dopamine transporter (DAT). The compound did not compete with [3H]WIN 35,428 binding or affect surface DAT levels. Using microdialysis, direct accumbal administration of 1 μM 6c reduced dopamine overflow in freely moving rats. Using LC-MS, we demonstrate that 6c is CNS-permeant. Systemic treatment of rats with 6 mg/kg 6c either simultaneously or 18 h prior to systemic AMPH administration reduced both AMPH-stimulated dopamine overflow and AMPH-induced locomotor effects. Finally, 18 h pretreatment of rats with 6 mg/kg 6c s.c. reduces AMPH-self administration but not food self-administration. These results demonstrate the utility of tamoxifen analogs in reducing AMPH effects on dopamine and reinforcement-related behaviors and suggest a new avenue of development for therapeutics to reduce AMPH abuse.
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Affiliation(s)
- Colleen Carpenter
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Alexander G Zestos
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Rachel Altshuler
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Roderick J Sorenson
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
- Vahlteich Medicinal Chemistry Core, University of Michigan, Ann Arbor, MI, USA
| | - Bipasha Guptaroy
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Hollis D Showalter
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI, USA
- Vahlteich Medicinal Chemistry Core, University of Michigan, Ann Arbor, MI, USA
| | - Robert T Kennedy
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Emily Jutkiewicz
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
| | - Margaret E Gnegy
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, USA
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14
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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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15
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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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16
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Yang S, Ben-Shalom R, Ahn M, Liptak AT, van Rijn RM, Whistler JL, Bender KJ. β-Arrestin-Dependent Dopaminergic Regulation of Calcium Channel Activity in the Axon Initial Segment. Cell Rep 2016; 16:1518-1526. [PMID: 27452469 DOI: 10.1016/j.celrep.2016.06.098] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 05/27/2016] [Accepted: 06/29/2016] [Indexed: 11/26/2022] Open
Abstract
G-protein-coupled receptors (GPCRs) initiate a variety of signaling cascades, depending on effector coupling. β-arrestins, which were initially characterized by their ability to "arrest" GPCR signaling by uncoupling receptor and G protein, have recently emerged as important signaling effectors for GPCRs. β-arrestins engage signaling pathways that are distinct from those mediated by G protein. As such, arrestin-dependent signaling can play a unique role in regulating cell function, but whether neuromodulatory GPCRs utilize β-arrestin-dependent signaling to regulate neuronal excitability remains unclear. Here, we find that D3 dopamine receptors (D3R) regulate axon initial segment (AIS) excitability through β-arrestin-dependent signaling, modifying CaV3 voltage dependence to suppress high-frequency action potential generation. This non-canonical D3R signaling thereby gates AIS excitability via pathways distinct from classical GPCR signaling pathways.
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Affiliation(s)
- Sungchil Yang
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Roy Ben-Shalom
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Misol Ahn
- Department of Pathology and Institute for Neurodegenerative Diseases, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Alayna T Liptak
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Richard M van Rijn
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Jennifer L Whistler
- Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kevin J Bender
- Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Alcohol and Addiction Research Group, Department of Neurology, University of California, San Francisco, San Francisco, CA 94158, USA.
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17
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Zestos AG, Mikelman SR, Kennedy RT, Gnegy ME. PKCβ Inhibitors Attenuate Amphetamine-Stimulated Dopamine Efflux. ACS Chem Neurosci 2016; 7:757-66. [PMID: 26996926 DOI: 10.1021/acschemneuro.6b00028] [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] [Indexed: 12/16/2022] Open
Abstract
Amphetamine abuse afflicts over 13 million people, and there is currently no universally accepted treatment for amphetamine addiction. Amphetamine serves as a substrate for the dopamine transporter and reverses the transporter to cause an increase in extracellular dopamine. Activation of the beta subunit of protein kinase C (PKCβ) enhances extracellular dopamine in the presence of amphetamine by facilitating the reverse transport of dopamine and internalizing the D2 autoreceptor. We previously demonstrated that PKCβ inhibitors block amphetamine-stimulated dopamine efflux in synaptosomes from rat striatum in vitro. In this study, we utilized in vivo microdialysis in live, behaving rats to assess the effect of the PKCβ inhibitors, enzastaurin and ruboxistaurin, on amphetamine-stimulated locomotion and increases in monoamines and their metabolites. A 30 min perfusion of the nucleus accumbens core with 1 μM enzastaurin or 1 μM ruboxistaurin reduced efflux of dopamine and its metabolite 3-methoxytyramine induced by amphetamine by approximately 50%. The inhibitors also significantly reduced amphetamine-stimulated extracellular levels of norepinephrine. The stimulation of locomotor behavior by amphetamine, measured simultaneously with the analytes, was comparably reduced by the PKCβ inhibitors. Using a stable isotope label retrodialysis procedure, we determined that ruboxistaurin had no effect on basal levels of dopamine, norepinephrine, glutamate, or GABA. In addition, normal uptake function through the dopamine transporter was unaltered by the PKCβ inhibitors, as measured in rat synaptosomes. Our results support the utility of using PKCβ inhibitors to reduce the effects of amphetamine.
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Affiliation(s)
- Alexander G. Zestos
- Department
of Pharmacology, University of Michigan, 2301 MSRB III, 1150 W. Medical Center
Drive, Ann Arbor, Michigan 48109-5632, United States
- Department
of Chemistry, University of Michigan, 9300 North University Avenue, Ann Arbor, Michigan 48105, United States
| | - Sarah R. Mikelman
- Department
of Pharmacology, University of Michigan, 2301 MSRB III, 1150 W. Medical Center
Drive, Ann Arbor, Michigan 48109-5632, United States
| | - Robert T. Kennedy
- Department
of Pharmacology, University of Michigan, 2301 MSRB III, 1150 W. Medical Center
Drive, Ann Arbor, Michigan 48109-5632, United States
- Department
of Chemistry, University of Michigan, 9300 North University Avenue, Ann Arbor, Michigan 48105, United States
| | - Margaret E. Gnegy
- Department
of Pharmacology, University of Michigan, 2301 MSRB III, 1150 W. Medical Center
Drive, Ann Arbor, Michigan 48109-5632, United States
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18
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Verma V. Classic Studies on the Interaction of Cocaine and the Dopamine Transporter. CLINICAL PSYCHOPHARMACOLOGY AND NEUROSCIENCE 2015; 13:227-38. [PMID: 26598579 PMCID: PMC4662164 DOI: 10.9758/cpn.2015.13.3.227] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/29/2015] [Accepted: 06/05/2015] [Indexed: 11/18/2022]
Abstract
The dopamine transporter is responsible for recycling dopamine after release. Inhibitors of the dopamine transporter, such as cocaine, will stop the reuptake of dopamine and allow it to stay extracellularly, causing prominent changes at the molecular, cellular, and behavioral levels. There is much left to be known about the mechanism and site(s) of binding, as well as the effect that cocaine administration does to dopamine transporter-cocaine binding sites and gene expression which also plays a strong role in cocaine abusers and their behavioral characteristics. Thus, if more light is shed on the dopamine transporter-cocaine interaction, treatments for addiction and even other diseases of the dopaminergic system may not be too far ahead. As today's ongoing research expands on the shoulders of classic research done in the 1990s and 2000s, the foundation of core research done in that time period will be reviewed, which forms the basis of today's work and tomorrow's therapies.
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Affiliation(s)
- Vivek Verma
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
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19
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The role of Pak-interacting exchange factor-β phosphorylation at serines 340 and 583 by PKCγ in dopamine release. J Neurosci 2014; 34:9268-80. [PMID: 25009260 DOI: 10.1523/jneurosci.4278-13.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Protein kinase C (PKC) has been implicated in the control of neurotransmitter release. The AS/AGU rat, which has a nonsense mutation in PKCγ, shows symptoms of parkinsonian syndrome, including dopamine release impairments in the striatum. Here, we found that the AS/AGU rat is PKCγ-knock-out (KO) and that PKCγ-KO mice showed parkinsonian syndrome. However, the PKCγ substrates responsible for the regulated exocytosis of dopamine in vivo have not yet been elucidated. To identify the PKCγ substrates involved in dopamine release, we used PKCγ-KO mice and a phosphoproteome analysis. We found 10 candidate phosphoproteins that had decreased phosphorylation levels in the striatum of PKCγ-KO mice. We focused on Pak-interacting exchange factor-β (βPIX), a Cdc42/Rac1 guanine nucleotide exchange factor, and found that PKCγ directly phosphorylates βPIX at Ser583 and indirectly at Ser340 in cells. Furthermore, we found that PKC phosphorylated βPIX in vivo. Classical PKC inhibitors and βPIX knock-down (KD) significantly suppressed Ca(2+)-evoked dopamine release in PC12 cells. Wild-type βPIX, and not the βPIX mutants Ser340 Ala or Ser583 Ala, fully rescued the decreased dopamine release by βPIX KD. Double KD of Cdc42 and Rac1 decreased dopamine release from PC12 cells. These findings indicate that the phosphorylation of βPIX at Ser340 and Ser583 has pivotal roles in Ca(2+)-evoked dopamine release in the striatum. Therefore, we propose that PKCγ positively modulates dopamine release through β2PIX phosphorylation. The PKCγ-βPIX-Cdc42/Rac1 phosphorylation axis may provide a new therapeutic target for the treatment of parkinsonian syndrome.
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20
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Pereira M, Andreatini R, Schwarting RKW, Brenes JC. Amphetamine-induced appetitive 50-kHz calls in rats: a marker of affect in mania? Psychopharmacology (Berl) 2014; 231:2567-77. [PMID: 24414610 DOI: 10.1007/s00213-013-3413-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 12/18/2013] [Indexed: 11/30/2022]
Abstract
RATIONALE Animal models aimed to mimic mania have in common the lack of genuine affective parameters. Although rodent amphetamine-induced hyperlocomotion is a frequently used behavioral model of mania, locomotor activity is a rather unspecific target for developing new pharmacological therapies, and does not necessarily constitute a cardinal symptom in bipolar disorder (BD). Hence, alternative behavioral markers sensitive to stimulants are required. OBJECTIVES Since D-amphetamine induces appetitive 50-kHz ultrasonic vocalizations (USV) in rats, we asked whether established or potential antimanic drugs would inhibit this effect, thereby possibly complementing traditional analysis of locomotor activity. METHODS Amphetamine-treated rats (2.5 mg/kg) were systemically administered with the antimanic drugs lithium (100 mg/kg) and tamoxifen (1 mg/kg). Since protein kinase C (PKC) activity has been implicated in the pathophysiology of bipolar disorder and the biochemical effects of mood stabilizers, the new PKC inhibitor myricitrin (10, 30 mg/kg) was also evaluated. RESULTS We demonstrate for the first time that drugs with known or potential antimanic activity were effective in reversing amphetamine-induced appetitive 50-kHz calls. Treatments particularly normalized amphetamine-induced increases of frequency-modulated calls, a subtype presumably indicative of positive affect in the rat. CONCLUSIONS Our findings suggest that amphetamine-induced 50-kHz calls might constitute a marker for communicating affect that provides a useful model of exaggerated euphoric mood and pressured speech. The antimanic-like effects of the PKC inhibitors tamoxifen and myricitrin support the predictive and etiological validity of both drugs in this model and highlight the role of PKC signaling as a promising target to treat mania and psychosis-related disorders.
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Affiliation(s)
- Marcela Pereira
- Department of Pharmacology, Federal University of Paraná (UFPR), Curitiba, PR 81540-990, Brazil
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21
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Protein phosphatases but not reactive oxygen species play functional role in acute amphetamine-mediated dopamine release. Cell Biochem Biophys 2014; 66:831-41. [PMID: 23625176 DOI: 10.1007/s12013-013-9608-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Drug abuse-induced neurodegeneration can be triggered by elevated production of reactive oxygen species (ROS). Involvement of oxidative stress in acute amphetamine (AMPH)-mediated dopamine (DA) release, however, has not been completely understood yet. In order to elucidate the dopaminergic response of PC12 cells to a single dose of 10 μM AMPH, ROS production was measured as related to the extracellular DA level. Due to the spontaneous oxidation of peroxide-sensitive fluorophore 2',7'-dichlorofluorescin diacetate (DCFH-DA) to 2',7'-dichlorofluorescein (DCF), the increase in fluorescence could not be unambiguously attributed to AMPH-triggered ROS production. Based on Amplex Red fluorescence, no ROS production was detected after acute AMPH application. Our data strongly suggest that ROS development was not the main triggering factor for immediate DA release after acute AMPH treatment. On the other hand, AMPH-induced elevation of DA levels in rat brain striatal slices was quenched by the water soluble antioxidant, N-acetylcysteine (NAC) at 10 mM. In this study, we also investigated the contribution of protein phosphatases to the AMPH-induced rat brain striatal dopaminergic response. The experimental protocol, double AMPH challenge was applied for screening the effect of NAC and cantharidin on AMPH-mediated DA release. Here we show that AMPH-mediated DA release increased nearly twofold in striatal rat brain slices pretreated for 30 min with 1000 μM cantharidin, a selective PP1 and PP2A inhibitor. These findings prove the lack of ROS inhibitory action on protein phosphatase activity in acute AMPH-mediated DA efflux.
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22
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Vaughan RA, Foster JD. Mechanisms of dopamine transporter regulation in normal and disease states. Trends Pharmacol Sci 2013; 34:489-96. [PMID: 23968642 DOI: 10.1016/j.tips.2013.07.005] [Citation(s) in RCA: 283] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 11/17/2022]
Abstract
The dopamine (DA) transporter (DAT) controls the spatial and temporal dynamics of DA neurotransmission by driving reuptake of extracellular transmitter into presynaptic neurons. Many diseases such as depression, bipolar disorder, Parkinson's disease (PD), and attention deficit hyperactivity disorder (ADHD) are associated with abnormal DA levels, implicating DAT as a factor in their etiology. Medications used to treat these disorders and many addictive drugs target DAT and enhance dopaminergic signaling by suppressing transmitter reuptake. We now understand that the transport and binding properties of DAT are regulated by complex and overlapping mechanisms that provide neurons with the ability to modulate DA clearance in response to physiological demands. These processes are controlled by endogenous signaling pathways and affected by exogenous transporter ligands, demonstrating their importance for normal neurotransmission, drug abuse, and disease treatments. Increasing evidence supports the disruption of these mechanisms in DA disorders, implicating dysregulation of transport in disease etiologies and suggesting these processes as potential points for therapeutic manipulation of DA availability.
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Affiliation(s)
- Roxanne A Vaughan
- Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58202, USA.
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23
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Rickhag M, Owens WA, Winkler MT, Strandfelt KN, Rathje M, Sørensen G, Andresen B, Madsen KL, Jørgensen TN, Wörtwein G, Woldbye DPD, Sitte H, Daws LC, Gether U. Membrane-permeable C-terminal dopamine transporter peptides attenuate amphetamine-evoked dopamine release. J Biol Chem 2013; 288:27534-27544. [PMID: 23884410 DOI: 10.1074/jbc.m112.441295] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The dopamine transporter (DAT) is responsible for sequestration of extracellular dopamine (DA). The psychostimulant amphetamine (AMPH) is a DAT substrate, which is actively transported into the nerve terminal, eliciting vesicular depletion and reversal of DA transport via DAT. Here, we investigate the role of the DAT C terminus in AMPH-evoked DA efflux using cell-permeant dominant-negative peptides. A peptide, which corresponded to the last 24 C-terminal residues of DAT (TAT-C24 DAT) and thereby contained the Ca(2+)-calmodulin-dependent protein kinase IIα (CaMKIIα) binding domain and the PSD-95/Discs-large/ZO-1 (PDZ)-binding sequence of DAT, was made membrane-permeable by fusing it to the cell membrane transduction domain of the HIV-1 Tat protein (TAT-C24WT). The ability of TAT-C24WT but not a scrambled peptide (TAT-C24Scr) to block the CaMKIIα-DAT interaction was supported by co-immunoprecipitation experiments in heterologous cells. In heterologous cells, we also found that TAT-C24WT, but not TAT-C24Scr, decreased AMPH-evoked 1-methyl-4-phenylpyridinium efflux. Moreover, chronoamperometric recordings in striatum revealed diminished AMPH-evoked DA efflux in mice preinjected with TAT-C24WT. Both in heterologous cells and in striatum, the peptide did not further inhibit efflux upon KN-93-mediated inhibition of CaMKIIα activity, consistent with a dominant-negative action preventing binding of CaMKIIα to the DAT C terminus. This was further supported by the ability of a peptide with perturbed PDZ-binding sequence, but preserved CaMKIIα binding (TAT-C24AAA), to diminish AMPH-evoked DA efflux in vivo to the same extent as TAT-C24WT. Finally, AMPH-induced locomotor hyperactivity was attenuated following systemic administration of TAT-C24WT but not TAT-C24Scr. Summarized, our findings substantiate that DAT C-terminal protein-protein interactions are critical for AMPH-evoked DA efflux and suggest that it may be possible to target protein-protein interactions to modulate transporter function and interfere with psychostimulant effects.
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Affiliation(s)
- Mattias Rickhag
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - William A Owens
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Marie-Therese Winkler
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, A-1090 Vienna, Austria
| | - Kristine Nørgaard Strandfelt
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Mette Rathje
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Gunnar Sørensen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark; Laboratory of Neuropsychiatry, Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Bjørn Andresen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Kenneth L Madsen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Trine Nygaard Jørgensen
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Gitta Wörtwein
- Laboratory of Neuropsychiatry, Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - David P D Woldbye
- Laboratory of Neuropsychiatry, Faculty of Health and Medical Sciences, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Harald Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, A-1090 Vienna, Austria
| | - Lynette C Daws
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Ulrik Gether
- Molecular Neuropharmacology Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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HIV-1 Tat protein decreases dopamine transporter cell surface expression and vesicular monoamine transporter-2 function in rat striatal synaptosomes. J Neuroimmune Pharmacol 2012; 7:629-39. [PMID: 22570010 DOI: 10.1007/s11481-012-9369-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 04/16/2012] [Indexed: 12/13/2022]
Abstract
The dopamine (DA) transporter (DAT) and vesicular monoamine transporter (VMAT2) proteins interact as a biochemical complex to regulate dopaminergic neurotransmission. We have reported that HIV-1Tat(1-86) decreases the specific [(3)H]DA uptake and [(3)H]WIN 35,428 binding sites without a change in total DAT immunoreactivity in rat striatum (Zhu et al., 2009b). The present study determined the effects of Tat on DAT phosphorylation and trafficking, and vesicular [(3)H]DA uptake. Pre-incubation of rat striatal synaptosomes with the protein kinase C (PKC) inhibitor bisindolylmaleimide I (1 μM) completely blocked Tat(1-86)-induced reduction of [(3)H]DA uptake, indicating that Tat regulates DAT function through a PKC-dependent mechanism. After exposure of synaptosomes to Tat(1-86) (1 μM), DAT immunoreactivity was decreased in plasma membrane enriched fractions (P3) and increased in vesicle-enriched fractions (P4) relative to controls without change in total synaptosomal fractions (P2), suggesting that Tat-induced inhibition of DA uptake is attributable to DAT internalization. Although both DAT and VMAT2 proteins are essential for the regulation of DA disposition in synapse and cytosol, Tat inhibited the specific [(3)H]DA uptake into vesicles (P4) and synaptosomes (P2) by 35 % and 26 %, respectively, inferring that the inhibitory effect of Tat was more profound in VMAT2 protein than in DAT protein. Taken together, the current study reveals that Tat inhibits DAT function through a PKC and trafficking-dependent mechanism and that Tat impacts the dopaminergic tone by regulating both DAT and VMAT2 proteins. These findings provide new insight into understanding the pharmacological mechanisms of HIV-1 viral protein-induced dysfunction of DA neurotransmission in HIV-infected patients.
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Shin EJ, Duong CX, Nguyen XKT, Li Z, Bing G, Bach JH, Park DH, Nakayama K, Ali SF, Kanthasamy AG, Cadet JL, Nabeshima T, Kim HC. Role of oxidative stress in methamphetamine-induced dopaminergic toxicity mediated by protein kinase Cδ. Behav Brain Res 2012; 232:98-113. [PMID: 22512859 DOI: 10.1016/j.bbr.2012.04.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 03/28/2012] [Accepted: 04/02/2012] [Indexed: 12/13/2022]
Abstract
This study examined the role of protein kinase C (PKC) isozymes in methamphetamine (MA)-induced dopaminergic toxicity. Multiple-dose administration of MA did not significantly alter PKCα, PKCβI, PKCβII, or PKCζ expression in the striatum, but did significantly increase PKCδ expression. Gö6976 (a co-inhibitor of PKCα and -β), hispidin (PKCβ inhibitor), and PKCζ pseudosubstrate inhibitor (PKCζ inhibitor) did not significantly alter MA-induced behavioral impairments. However, rottlerin (PKCδ inhibitor) significantly attenuated behavioral impairments in a dose-dependent manner. In addition, MA-induced behavioral impairments were not apparent in PKCδ knockout (-/-) mice. MA-induced oxidative stress (i.e., lipid peroxidation and protein oxidation) was significantly attenuated in rottlerin-treated mice and was not apparent in PKCδ (-/-) mice. Consistent with this, MA-induced apoptosis (i.e., terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic cells) was significantly attenuated in rottlerin-treated mice. Furthermore, MA-induced increases in the dopamine (DA) turnover rate and decreases in tyrosine hydroxylase (TH) activity and the expression of TH, dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2) were not significantly observed in rottlerin-treated or PKCδ (-/-) mice. Our results suggest that PKCδ gene expression is a key mediator of oxidative stress and dopaminergic damage induced by MA. Thus, inhibition of PKCδ may be a useful target for protection against MA-induced neurotoxicity.
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Affiliation(s)
- Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Chu Xuan Duong
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Xuan-Khanh Thi Nguyen
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Zhengyi Li
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Guoying Bing
- Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky, Lexington, KY 40536, USA
| | - Jae-Hyung Bach
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Dae Hun Park
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Keiichi Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | - Syed F Ali
- Division of Neurotoxicology, National Center of Toxicological Research, FDA, Jefferson, Arkansas 72079, USA
| | - Anumantha G Kanthasamy
- Parkinson's Disorder Research Laboratory, Iowa Center for Advanced Neurotoxicology, Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
| | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch, DHHS/NIH/NIDA Intramural Research Program, Baltimore, MD 21224, USA
| | - Toshitaka Nabeshima
- Department of Regional Pharmaceutical Care and Sciences and Department of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, Meijo University, Nagoya 468-8503, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
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Vargas-Medrano J, Castrejon-Tellez V, Plenge F, Ramirez I, Miranda M. PKCβ-dependent phosphorylation of the glycine transporter 1. Neurochem Int 2011; 59:1123-32. [PMID: 21864610 DOI: 10.1016/j.neuint.2011.08.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 08/01/2011] [Accepted: 08/05/2011] [Indexed: 10/17/2022]
Abstract
The extracellular levels of the neurotransmitter glycine in the brain are tightly regulated by the glycine transporter 1 (GlyT1) and the clearance rate for glycine depends on its rate of transport and the levels of cell surface GlyT1. Over the years, it has been shown that PKC tightly regulates the activity of several neurotransmitter transporters. In the present work, by stably expressing three N-terminus GlyT1 isoforms in porcine aortic endothelial cells and assaying for [(32)P]-orthophosphate metabolic labeling, we demonstrated that the isoforms GlyT1a, GlyT1b, and GlyT1c were constitutively phosphorylated, and that phosphorylation was dramatically enhanced, in a time dependent fashion, after PKC activation by phorbol ester. The phosphorylation was PKC-dependent, since pre-incubation of the cells with bisindolylmaleimide I, a selective PKC inhibitor, abolished the phorbol ester-induced phosphorylation. Blotting with specific anti-phospho-tyrosine antibodies did not yield any signal that could correspond to GlyT1 tyrosine phosphorylation, suggesting that the phosphorylation occurs at serine and/or threonine residues. In addition, a 23-40%-inhibition on V(max) was obtained by incubation with phorbol ester without a significant change on the apparent Km value. Furthermore, pre-incubation of the cells with the selective PKCα/β inhibitor Gö6976 abolished the downregulation effect of phorbol ester on uptake and phosphorylation, whereas the selective PKCβ inhibitors (PKCβ inhibitor or LY333531) prevented the phosphorylation without affecting glycine uptake, defining a specific role of classical PKC on GlyT1 uptake and phosphorylation. Taken together, these data suggest that conventional PKCα/β regulates the uptake of glycine, whereas PKCβ is responsible for GlyT1 phosphorylation.
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Affiliation(s)
- Javier Vargas-Medrano
- Department of Biological Sciences and Border Biomedical Research Center, University of Texas at El Paso, El Paso, TX 79968, USA
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Kristensen AS, Andersen J, Jørgensen TN, Sørensen L, Eriksen J, Loland CJ, Strømgaard K, Gether U. SLC6 neurotransmitter transporters: structure, function, and regulation. Pharmacol Rev 2011; 63:585-640. [PMID: 21752877 DOI: 10.1124/pr.108.000869] [Citation(s) in RCA: 601] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The neurotransmitter transporters (NTTs) belonging to the solute carrier 6 (SLC6) gene family (also referred to as the neurotransmitter-sodium-symporter family or Na(+)/Cl(-)-dependent transporters) comprise a group of nine sodium- and chloride-dependent plasma membrane transporters for the monoamine neurotransmitters serotonin (5-hydroxytryptamine), dopamine, and norepinephrine, and the amino acid neurotransmitters GABA and glycine. The SLC6 NTTs are widely expressed in the mammalian brain and play an essential role in regulating neurotransmitter signaling and homeostasis by mediating uptake of released neurotransmitters from the extracellular space into neurons and glial cells. The transporters are targets for a wide range of therapeutic drugs used in treatment of psychiatric diseases, including major depression, anxiety disorders, attention deficit hyperactivity disorder and epilepsy. Furthermore, psychostimulants such as cocaine and amphetamines have the SLC6 NTTs as primary targets. Beginning with the determination of a high-resolution structure of a prokaryotic homolog of the mammalian SLC6 transporters in 2005, the understanding of the molecular structure, function, and pharmacology of these proteins has advanced rapidly. Furthermore, intensive efforts have been directed toward understanding the molecular and cellular mechanisms involved in regulation of the activity of this important class of transporters, leading to new methodological developments and important insights. This review provides an update of these advances and their implications for the current understanding of the SLC6 NTTs.
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Affiliation(s)
- Anders S Kristensen
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Abstract
Spontaneous and/or stimulated neural activity of the nigrostriatal dopamine (DA) pathway makes amines run out from the neurons. This DA dynamic follows a rather complex path, running in or out the terminals, and flushing or diffusing into the extracellular space. The location of this leakage is not limited to the axon terminals; it also occurs from the cell bodies and dendrites. This molecular release mechanism was, for a long time, considered as being produced, in part, by the exocytosis of previously stored vesicles. The DA carrier protein (DAT, DA transporter) embedded in the DA cell membrane is known to clear previously released amines through an inward DA influx. The DAT also appears to be an active vector of amine release. Particular local conditions and the presence of numerous psychostimulant substances are able to trigger an outward efflux of DA through the DAT. This process, delivering slowly large amounts of amine could play a major regulatory role in extracellular DA homeostasis.
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Affiliation(s)
- Vincent Leviel
- INSERM U846, Stem Cell and Brain Research Institute, Bron, France.
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29
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Tamoxifen effects on respiratory chain complexes and creatine kinase activities in an animal model of mania. Pharmacol Biochem Behav 2011; 98:304-10. [DOI: 10.1016/j.pbb.2011.01.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2010] [Revised: 12/27/2010] [Accepted: 01/23/2011] [Indexed: 12/27/2022]
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Abstract
The dopamine transporter (DAT) is a critical regulator of dopaminergic neurotransmission. Research in both rat striatum and heterologous cells suggests that protein kinase C beta (PKCbeta) is important for proper trafficking of DAT. However, a critical gap that is missing from the literature is the localization of PKCbeta to mesencephalic dopaminergic neurons. In this study we examined the co-localization of DAT, which serves to identify dopaminergic neurons, and PKCbeta in mesencephalic dopaminergic cells. Using immunofluorescence and confocal microscopy, we demonstrated co-localization of DAT and PKCbeta in primary cultures of mesencephalic neurons and in dopamine neurons in rat substantia nigra and ventral tegmental area. PKCbetawas not specific for dopamine neurons in the two brain regions. This is the first demonstration of co-localization of PKCbeta and DAT in mesencephalic neurons. The co-localization of PKCbeta with DAT in mesencephalic neurons corroborates our previous studies demonstrating a role for PKCbeta in DAT function.
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Opazo F, Schulz JB, Falkenburger BH. PKC links Gq-coupled receptors to DAT-mediated dopamine release. J Neurochem 2010; 114:587-96. [DOI: 10.1111/j.1471-4159.2010.06788.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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32
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Wang Y, Moquin KF, Michael AC. Evidence for coupling between steady-state and dynamic extracellular dopamine concentrations in the rat striatum. J Neurochem 2010; 114:150-9. [PMID: 20403079 DOI: 10.1111/j.1471-4159.2010.06740.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A previous study from our laboratory demonstrated the presence within the rat striatum of dopaminergic terminals in different dynamical states, determined at least in part by the extent to which terminals are subject to autoinhibition. The present study is designed to test the hypothesis that heterogeneity in the basal tonic extracellular dopamine concentration contributes to the variable extent of autoinhibition. We probed basal extracellular dopamine concentrations using a previously demonstrated strategy that utilizes intrastriatal microinfusion of kynurenate, a substance that according to voltammetric measurements decreases extracellular dopamine from its basal concentration. In the striatum, however, we find that the response to kynurenate infusion is itself heterogeneous, allowing a broad classification of sites within the striatum as kynurenate-insensitive and kynurenate-sensitive, respectively. These newly identified kynurenate-insensitive and sensitive sites yield substantially and significantly different evoked dopamine release as measured by voltammetry during electrical stimulation of the medial forebrain bundle. Our findings confirm the hypothesis that heterogeneity in the local basal concentration of dopamine is responsible for the variable extent of autoinhibition within the striatum and support the conclusion that the steady state and dynamical components of extracellular dopamine in this brain region are coupled.
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Affiliation(s)
- Yuexiang Wang
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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33
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Eriksen J, Jørgensen TN, Gether U. Regulation of dopamine transporter function by protein-protein interactions: new discoveries and methodological challenges. J Neurochem 2010; 113:27-41. [PMID: 20085610 DOI: 10.1111/j.1471-4159.2010.06599.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The dopamine transporter (DAT) plays a key role in regulating dopaminergic signalling in the brain by mediating rapid clearance of dopamine from the synaptic clefts. The psychostimulatory actions of cocaine and amphetamine are primarily the result of a direct interaction of these compounds with DAT leading to attenuated dopamine clearance and for amphetamine even increased dopamine release. In the last decade, intensive efforts have been directed towards understanding the molecular and cellular mechanisms governing the activity and availability of DAT in the plasma membrane of the pre-synaptic neurons. This has led to the identification of a plethora of different kinases, receptors and scaffolding proteins that interact with DAT and hereby either modulate the catalytic activity of the transporter or regulate its trafficking and degradation. Several new tools for studying DAT regulation in live cells have also recently become available such as fluorescently tagged cocaine analogues and fluorescent substrates. Here we review the current knowledge about the role of protein-protein interactions in DAT regulation as well as we describe the most recent methodological developments that have been established to overcome the challenges associated with the study of DAT in endogenous systems.
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Affiliation(s)
- Jacob Eriksen
- Molecular Neuropharmacology Group and Center for Pharmacogenomics, Department of Neuroscience and Pharmacology, The Panum Institute, University of Copenhagen, Copenhagen N, Denmark
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34
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Dopamine and amphetamine rapidly increase dopamine transporter trafficking to the surface: live-cell imaging using total internal reflection fluorescence microscopy. J Neurosci 2009; 29:3328-36. [PMID: 19279270 DOI: 10.1523/jneurosci.5386-08.2009] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Rapid treatment (1 min) of rat striatal synaptosomes with low-dose amphetamine increases surface expression of the dopamine transporter (DAT). Using mouse neuroblastoma N2A cells, stably transfected with green fluorescent protein-DAT, we demonstrate the real-time substrate-induced rapid trafficking of DAT to the plasma membrane using total internal reflection fluorescence microscopy (TIRFM). Both the physiological substrate, dopamine, and amphetamine began to increase surface DAT within 10 s of drug addition and steadily increased surface DAT until removal 2 min later. The substrate-induced rise in surface DAT was dose-dependent, was blocked by cocaine, and abated after drug removal. Although individual vesicle fusion was not visually detectable, exocytosis of DAT was blocked using both tetanus neurotoxin and botulinum neurotoxin C to cleave soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. Notably, the dopamine-induced increase in surface DAT was cocaine-sensitive but D(2)-receptor independent. TIRFM data were confirmed in human DAT-N2A cells using biotinylation, and similar effects were detected in rat striatal synaptosomes. A specific inhibitor of protein kinase C-beta blocked the substrate-mediated increase in surface DAT in both DAT-N2A cells and rat striatal synaptosomes. These data demonstrate that the physiological substrate, dopamine, and amphetamine rapidly increase the trafficking of DAT to the surface by a mechanism dependent on SNARE proteins and protein kinase C-beta but independent of dopamine D(2) receptor activation. Importantly, this study suggests that the reuptake system is poised to rapidly increase its function during dopamine secretion to tightly regulate dopaminergic neurotransmission.
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35
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Robertson SD, Matthies HJG, Galli A. A closer look at amphetamine-induced reverse transport and trafficking of the dopamine and norepinephrine transporters. Mol Neurobiol 2009; 39:73-80. [PMID: 19199083 PMCID: PMC2729543 DOI: 10.1007/s12035-009-8053-4] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 01/12/2009] [Indexed: 10/21/2022]
Abstract
Amphetamine (AMPH) and its derivatives are regularly used in the treatment of a wide array of disorders such as attention-deficit hyperactivity disorder (ADHD), obesity, traumatic brain injury, and narcolepsy (Prog Neurobiol 75:406-433, 2005; J Am Med Assoc 105:2051-2054, 1935; J Am Acad Child Adolesc Psychiatry 41:514-521, 2002; Neuron 43:261-269, 2004; Annu Rev Pharmacol Toxicol 47:681-698, 2007; Drugs Aging 21:67-79, 2004). Despite the important medicinal role for AMPH, it is more widely known for its psychostimulant and addictive properties as a drug of abuse. The primary molecular targets of AMPH are both the vesicular monoamine transporters (VMATs) and plasma membrane monoamine-dopamine (DA), norepinephrine (NE), and serotonin (5-HT)-transporters. The rewarding and addicting properties of AMPH rely on its ability to act as a substrate for these transporters and ultimately increase extracellular levels of monoamines. AMPH achieves this elevation in extracellular levels of neurotransmitter by inducing synaptic vesicle depletion, which increases intracellular monoamine levels, and also by promoting reverse transport (efflux) through plasma membrane monoamine transporters (J Biol Chem 237:2311-2317, 1962; Med Exp Int J Exp Med 6:47-53, 1962; Neuron 19:1271-1283, 1997; J Physiol 144:314-336, 1958; J Neurosci 18:1979-1986, 1998; Science 237:1219-1223, 1987; J Neurosc 15:4102-4108, 1995). This review will focus on two important aspects of AMPH-induced regulation of the plasma membrane monoamine transporters-transporter mediated monoamine efflux and transporter trafficking.
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Affiliation(s)
- S D Robertson
- Neuroscience Graduate Program, Vanderbilt University, Nashville, TN, USA
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Loweth JA, Svoboda R, Austin JD, Guillory AM, Vezina P. The PKC inhibitor Ro31-8220 blocks acute amphetamine-induced dopamine overflow in the nucleus accumbens. Neurosci Lett 2009; 455:88-92. [PMID: 19368852 DOI: 10.1016/j.neulet.2009.03.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 03/03/2009] [Accepted: 03/03/2009] [Indexed: 10/21/2022]
Abstract
Acute administration of the psychostimulant amphetamine increases extracellular levels of dopamine (DA) by reversing the DA transporter on ascending midbrain DA neurons. In vitro studies using striatal synaptosomal, slice and nucleus accumbens (NAcc) tissue preparations have implicated protein kinase C (PKC) in this effect. The present study further examined this effect in vivo by assessing the ability of the PKC inhibitor, Ro31-8220 (10 microM), to inhibit acute amphetamine-induced DA overflow when applied with this drug to the NAcc via reverse dialysis. Amphetamine was applied at a concentration of 30 microM, and the core and shell subregions of the NAcc were assayed separately in freely moving rats. These brain regions play a role in the acute locomotor-activating and motivational effects of amphetamine. Consistent with the findings of previous in vitro experiments, reverse dialysis of Ro31-8220 with amphetamine robustly attenuated the ability of this drug to increase extracellular levels of dopamine in both the core and shell subregions of the NAcc. These results confirm that amphetamine stimulates dopamine overflow via a PKC-dependent mechanism.
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Affiliation(s)
- Jessica A Loweth
- Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA.
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37
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Zhu J, Reith MEA. Role of the dopamine transporter in the action of psychostimulants, nicotine, and other drugs of abuse. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2009; 7:393-409. [PMID: 19128199 DOI: 10.2174/187152708786927877] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A number of studies over the last two decades have demonstrated the critical importance of dopamine (DA) in the behavioral pharmacology and addictive properties of abused drugs. The DA transporter (DAT) is a major target for drugs of abuse in the category of psychostimulants, and for methylphenidate (MPH), a drug used for treating attention deficit hyperactivity disorder (ADHD), which can also be a psychostimulant drug of abuse. Other drugs of abuse such as nicotine, ethanol, heroin and morphine interact with the DAT in more indirect ways. Despite the different ways in which drugs of abuse can affect DAT function, one evolving theme in all cases is regulation of the DAT at the level of surface expression. DAT function is dynamically regulated by multiple intracellular and extracellular signaling pathways and several protein-protein interactions. In addition, DAT expression is regulated through the removal (internalization) and recycling of the protein from the cell surface. Furthermore, recent studies have demonstrated that individual differences in response to novel environments and psychostimulants can be predicted based on individual basal functional DAT expression. Although current knowledge of multiple factors regulating DAT activity has greatly expanded, many aspects of this regulation remain to be elucidated; these data will enable efforts to identify drugs that might be used therapeutically for drug dependence therapeutics.
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Affiliation(s)
- J Zhu
- Department of Psychology, University of South Carolina, Columbia, SC 29208, USA.
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38
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Chen R, Furman CA, Zhang M, Kim MN, Gereau RW, Leitges M, Gnegy ME. Protein kinase Cbeta is a critical regulator of dopamine transporter trafficking and regulates the behavioral response to amphetamine in mice. J Pharmacol Exp Ther 2008; 328:912-20. [PMID: 19098163 DOI: 10.1124/jpet.108.147959] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The dopamine transporter (DAT) is a key mediator of dopaminergic neurotransmission and a major target for amphetamine. We found previously that protein kinase C (PKC) beta regulates amphetamine-mediated dopamine efflux. Here, using PKCbeta wild-type (WT) and knockout (KO) mice, we report a novel role for PKCbeta in amphetamine-induced regulation of DAT trafficking and activity. PKCbeta KO mice have less striatal surface DAT, [3H]dopamine uptake, and amphetamine-stimulated dopamine efflux, yet higher novelty-induced locomotor activity than WT mice. Although a short exposure (< or =90 s) to amphetamine rapidly increases striatal surface DAT and [3H]dopamine uptake in WT mice, this treatment decreases surface DAT and [3H]dopamine uptake in KO mice. Increases in surface DAT and [3H]dopamine uptake are not evident in KO mice until a longer exposure (60 min) to amphetamine, by which time WT mice exhibit decreased surface DAT and dopamine uptake. The slowness of amphetamine-induced striatal DAT trafficking in PKCbeta KO mice was mimicked by the use of a specific PKCbeta inhibitor, LY379196, in WT mice. Furthermore, PKCbeta KO mice exhibit reduced locomotor responsiveness to amphetamine compared with WT, which could be explained by reduced surface DAT and delayed amphetamine-induced DAT trafficking in KO mice. Our results indicate that PKCbeta is crucial for proper trafficking of DAT to the surface and for functioning of DAT and amphetamine signaling, providing new insight into the role of PKCbeta as an important regulator of dopaminergic homeostasis.
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Affiliation(s)
- Rong Chen
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
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Mallinger AG, Thase ME, Haskett R, Buttenfield J, Luckenbaugh DA, Frank E, Kupfer DJ, Manji HK. Verapamil augmentation of lithium treatment improves outcome in mania unresponsive to lithium alone: preliminary findings and a discussion of therapeutic mechanisms. Bipolar Disord 2008; 10:856-66. [PMID: 19594501 PMCID: PMC3387673 DOI: 10.1111/j.1399-5618.2008.00636.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Attenuation of protein kinase C (PKC) is a mechanism common to both established (lithium, valproate) and some novel (tamoxifen) antimanic agents. Verapamil, although primarily known as a calcium channel blocker, also has PKC inhibitory activity. Verapamil has shown antimanic activity in some but not all studies. Therefore, we investigated verapamil, used alone or as an adjunctive treatment, in manic patients who did not respond to an initial adequate trial of lithium. METHODS Each study phase lasted three weeks. Subjects were treated openly with lithium in Phase 1 (n = 45). Those who failed to respond were randomly assigned to double-blind treatment in Phase 2 with either verapamil (n = 10) or continued-lithium (n = 8). Phase 2 nonresponders (n = 10) were assigned to combined verapamil/lithium in Phase 3. RESULTS Response in Phase 2 did not differ significantly between verapamil and continued-lithium. During Phase 3, response to combined treatment was significantly better than overall response to monotherapy in Phase 2 (Fisher's Exact test, p = 0.043). Mania ratings improved during combined treatment in Phase 3 by 88.2% (linear mixed model analysis, F = 4.34, p = 0.013), compared with 10.5% improvement during Phase 2. CONCLUSIONS In this preliminary investigation, verapamil monotherapy did not demonstrate antimanic efficacy. By contrast, the combination of verapamil plus lithium was highly efficacious. Our findings thus suggest that verapamil may have potential utility as an adjunct to lithium. This effect may be mediated by additive actions on PKC inhibition, which may be an important mechanism for antimanic agents in general.
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Affiliation(s)
- Alan G Mallinger
- Mood and Anxiety Disorders Program, National Institutes of Health Intramural Research Program, Building 10, Room 3N210, MSC 1290, Bethesda, MD 20892, USA.
| | - Michael E Thase
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh,Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Roger Haskett
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh
| | - Joan Buttenfield
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh
| | - David A Luckenbaugh
- Mood and Anxiety Disorders Program, National Institutes of Health Intramural Research Program, Bethesda, MD
| | - Ellen Frank
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh
| | - David J Kupfer
- Department of Psychiatry, University of Pittsburgh School of Medicine, Pittsburgh
| | - Husseini K Manji
- Mood and Anxiety Disorders Program, National Institutes of Health Intramural Research Program, Bethesda, MD
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Mitala CM, Wang Y, Borland LM, Jung M, Shand S, Watkins S, Weber SG, Michael AC. Impact of microdialysis probes on vasculature and dopamine in the rat striatum: a combined fluorescence and voltammetric study. J Neurosci Methods 2008; 174:177-85. [PMID: 18674561 DOI: 10.1016/j.jneumeth.2008.06.034] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 06/25/2008] [Accepted: 06/26/2008] [Indexed: 11/25/2022]
Abstract
Measuring extracellular dopamine in the brain of living animals by means of microdialysis and/or voltammetry is a route towards understanding both normal brain function and pathology. Previous reports, however, suggest that the tissue response to implantation of devices may affect the outcome of the measurements. To address the source of the tissue response and its impact on striatal dopamine systems microdialysis probes were placed in the striatum of anesthetized rats. Images obtained by dual-label fluorescence microscopy show signs of ischemia and opening of the blood-brain barrier near the probe tracks. Opening of the blood-brain barrier was further examined by determining dialysate concentrations of carbi-DOPA, a drug that normally does not penetrate the brain. Although carbi-DOPA was recovered in brain dialysate, it did not alter dialysate dopamine levels or evoked dopamine release as measured by voltammetry near the probes. Microdialysis probes also significantly diminished the effect of intrastriatal infusion of kynurenate on extracellular dopamine levels as measured by voltammetry near the probes.
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Affiliation(s)
- Christina M Mitala
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA 15260, United States
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Ferris MJ, Mactutus CF, Booze RM. Neurotoxic profiles of HIV, psychostimulant drugs of abuse, and their concerted effect on the brain: current status of dopamine system vulnerability in NeuroAIDS. Neurosci Biobehav Rev 2008; 32:883-909. [PMID: 18430470 PMCID: PMC2527205 DOI: 10.1016/j.neubiorev.2008.01.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 01/09/2008] [Accepted: 01/13/2008] [Indexed: 12/21/2022]
Abstract
There are roughly 30-40 million HIV-infected individuals in the world as of December 2007, and drug abuse directly contributes to one-third of all HIV infections in the United States. Antiretroviral therapy has increased the lifespan of HIV-seropositives, but CNS function often remains diminished, effectively decreasing quality of life. A modest proportion may develop HIV-associated dementia, the severity and progression of which is increased with drug abuse. HIV and drugs of abuse in the CNS target subcortical brain structures and DA systems in particular. This toxicity is mediated by a number of neurotoxic mechanisms, including but not limited to, aberrant immune response and oxidative stress. Therefore, novel therapeutic strategies must be developed that can address a wide variety of disparate neurotoxic mechanisms and apoptotic cascades. This paper reviews the research pertaining to the where, what, and how of HIV and cocaine/methamphetamine toxicity in the CNS. Specifically, where these toxins most affect the brain, what aspects of the virus are neurotoxic, and how these toxins mediate neurotoxicity.
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Affiliation(s)
- Mark J Ferris
- University of South Carolina, Program in Behavioral Neuroscience, Columbia, SC 29208, United States.
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Szobot CM, Shih MC, Schaefer T, Júnior N, Hoexter MQ, Fu YK, Pechansky F, Bressan RA, Rohde LA. Methylphenidate DAT binding in adolescents with Attention-Deficit/ Hyperactivity Disorder comorbid with Substance Use Disorder - a single Photon Emission Computed Tomography with [Tc99m]TRODAT-1 study. Neuroimage 2008; 40:1195-201. [DOI: 10.1016/j.neuroimage.2007.12.050] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 12/12/2007] [Accepted: 12/18/2007] [Indexed: 11/26/2022] Open
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Einat H, Yuan P, Szabo ST, Dogra S, Manji HK. Protein kinase C inhibition by tamoxifen antagonizes manic-like behavior in rats: implications for the development of novel therapeutics for bipolar disorder. Neuropsychobiology 2007; 55:123-31. [PMID: 17641532 DOI: 10.1159/000106054] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Accepted: 03/24/2007] [Indexed: 11/19/2022]
Abstract
RATIONALE In the context of bipolar disorder (BPD) research it was demonstrated that administration of the structurally dissimilar mood stabilizers lithium and valproate produced a striking reduction in protein kinase C (PKC) in rat brain. In a small clinical study, tamoxifen (a PKC inhibitor) had antimanic efficacy. However, both lithium and valproate exert many biochemical changes and attribution of therapeutic relevance to any molecular findings needs to be based on linking them to behavioral effects. OBJECTIVES The present study was designed to explore such relationship by studying the effects of PKC inhibition in amphetamine-induced behavioral animal models of mania and changes in GAP-43. METHODS The effects of two daily tamoxifen (1 mg/kg) i.p. injections on acute or chronic (7 injections) amphetamine (0.5 mg/kg) -induced behaviors and GAP-43 phosphorylation were tested. RESULTS The study demonstrates that tamoxifen significantly reduced amphetamine-induced hyperactivity in a large open field without affecting spontaneous activity levels and normalized amphetamine-induced increase in visits to the center of an open field (representing risk-taking behavior). Tamoxifen also attenuated amphetamine-induced phosphorylation of GAP-43, a result that is consistent with the behavioral findings. CONCLUSIONS These results support the possibility that PKC signaling may play an important role in the pathophysiology and treatment of BPD. These findings may have direct clinical implications as they offer a new avenue for attempts to develop more specific drugs for the disorder.
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Affiliation(s)
- Haim Einat
- University of Minnesota, College of Pharmacy, Duluth, MN 55812, USA.
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Boudanova E, Navaroli DM, Melikian HE. Amphetamine-induced decreases in dopamine transporter surface expression are protein kinase C-independent. Neuropharmacology 2007; 54:605-12. [PMID: 18164041 DOI: 10.1016/j.neuropharm.2007.11.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Revised: 11/07/2007] [Accepted: 11/12/2007] [Indexed: 11/26/2022]
Abstract
Amphetamine (AMPH) is a potent dopamine (DA) transporter (DAT) inhibitor that markedly increases extracellular DA levels. In addition to its actions as a DAT antagonist, acute AMPH exposure induces DAT losses from the plasma membrane, implicating transporter-specific membrane trafficking in amphetamine's actions. Despite reports that AMPH modulates DAT surface expression, the trafficking mechanisms leading to this effect are currently not defined. We recently reported that DAT residues 587-596 play an integral role in constitutive and protein kinase C (PKC)-accelerated DAT internalization. In the current study, we tested whether the structural determinants required for PKC-stimulated DAT internalization are necessary for AMPH-induced DAT sequestration. Acute amphetamine exposure increased DAT endocytic rates, but DAT carboxy terminal residues 587-590, which are required for PKC-stimulated internalization, were not required for AMPH-accelerated DAT endocytosis. AMPH decreased DAT endocytic recycling, but did not modulate transferrin receptor recycling, suggesting that AMPH does not globally diminish endocytic recycling. Finally, treatment with a PKC inhibitor demonstrated that AMPH-induced DAT losses from the plasma membrane were not dependent upon PKC activity. These results suggest that the mechanisms responsible for AMPH-mediated DAT internalization are independent from those governing PKC-sensitive DAT endocytosis.
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Affiliation(s)
- Ekaterina Boudanova
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, 303 Belmont Street, Worcester, MA 01604, USA
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Thwar PK, Guptaroy B, Zhang M, Gnegy ME, Burns MA, Linderman JJ. Simple transporter trafficking model for amphetamine-induced dopamine efflux. Synapse 2007; 61:500-14. [PMID: 17415796 DOI: 10.1002/syn.20390] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Amphetamine and its derivatives are important drugs of abuse causing both short-term excitatory and long-term addictive effects. The short-term excitatory effects are linked to amphetamine's ability to maintain high levels of dopamine (DA) outside the cell both by inhibiting DA reuptake after synaptic transmission and by enhancing the efflux of DA from the dopaminergic cells. The molecular mechanisms by which amphetamine elicits the efflux of DA and similar monoamines are still unclear. Recent literature data suggest that trafficking of the monoamine transporters is a phenomenon that underlies observed changes in amphetamine-induced monoamine reuptake and efflux. We develop an ordinary differential equation model incorporating the diverse mechanistic details behind amphetamine-induced DA efflux and demonstrate its utility in describing our experimental data. We also demonstrate an experimental method to track the time-varying concentration of membrane-bound transporter molecules from the DA efflux data. The good fit between our model and the experimental data supports the hypothesis that amphetamine-induced transporter trafficking is necessary to produce extended efflux of DA. This model can explain the relative significance of different processes associated with DA efflux at different times and at different concentration ranges of amphetamine and DA.
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Affiliation(s)
- Prasanna K Thwar
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA
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Chen R, Zhang M, Park S, Gnegy ME. C57BL/6J mice show greater amphetamine-induced locomotor activation and dopamine efflux in the striatum than 129S2/SvHsd mice. Pharmacol Biochem Behav 2007; 87:158-63. [PMID: 17524461 PMCID: PMC2104492 DOI: 10.1016/j.pbb.2007.04.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 04/19/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
Inbred strains of mice have served as valuable models for studying genetic susceptibility to drug addiction, an alternative to genetically modified mouse models. This is the first study comparing amphetamine (AMPH) effects on locomotor stimulation and dopamine efflux between two inbred strains of mice C57BL/6J and 129S2/SvHsd, frequently used as background strains for production of genetically engineered mice. There were no significant differences in basal locomotor activity and basal dopamine levels between the two strains. However, C57BL/6J mice showed greater AMPH-stimulated locomotor activity and AMPH-induced striatal dopamine efflux than 129S2/SvHsd mice. The differential AMPH effects could not be explained by differences in presynaptic dopamine components such as surface and total dopamine transporter (DAT) expression levels, striatal dopamine contents, and DAT activity. C57BL/6J and 129S2/SvHsd mice are excellent models for future identification of genetic, molecular, and behavioral components related to individual vulnerability to AMPH addiction. This study emphasizes the importance of mouse strain selections in the production of genetically modified mice for investigating phenotypes and mechanisms of psychostimulants.
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Affiliation(s)
- Rong Chen
- Department of Pharmacology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA
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Fleckenstein AE, Volz TJ, Riddle EL, Gibb JW, Hanson GR. New insights into the mechanism of action of amphetamines. Annu Rev Pharmacol Toxicol 2007; 47:681-98. [PMID: 17209801 DOI: 10.1146/annurev.pharmtox.47.120505.105140] [Citation(s) in RCA: 482] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Amphetamine is a psychostimulant commonly used to treat several disorders, including attention deficit, narcolepsy, and obesity. Plasmalemmal and vesicular monoamine transporters, such as the neuronal dopamine transporter and the vesicular monoamine transporter-2, are two of its principal targets. This review focuses on new insights, obtained from both in vivo and in vitro studies, into the molecular mechanisms whereby amphetamine, and the closely related compounds methamphetamine and methylenedioxymethamphetamine, cause monoamine, and particularly dopamine, release. These mechanisms include amphetamine-induced exchange diffusion, reverse transport, and channel-like transport phenomena as well as the weak base properties of amphetamine. Additionally, amphetamine analogs may affect monoamine transporters through phosphorylation, transporter trafficking, and the production of reactive oxygen and nitrogen species. All of these mechanisms have potential implications for both amphetamine- and methamphetamine-induced neurotoxicity, as well as dopaminergic neurodegenerative diseases.
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Affiliation(s)
- Annette E Fleckenstein
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA.
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Narita M, Nagumo Y, Miyatake M, Ikegami D, Kurahashi K, Suzuki T. Implication of protein kinase C in the orexin-induced elevation of extracellular dopamine levels and its rewarding effect. Eur J Neurosci 2007; 25:1537-45. [PMID: 17425580 DOI: 10.1111/j.1460-9568.2007.05403.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the present study, we investigated the role of orexinergic systems in the activation of midbrain dopamine neurons. In an in vitro study, exposure to either orexin A or orexin B under superfusion conditions produced a transient increase in the intracellular Ca(2+) concentration through the phospholipase C (PLC)/protein kinase C (PKC) pathway via G(q11)alpha or Gbetagamma subunits in midbrain cultured neurons, which were shown to be tyrosine hydroxylase (TH)-positive cells, but not in purified midbrain astrocytes. Here we show that in vivo injection with a selective PKC inhibitor chelerythrine chloride or 2-{8-[(dimethylamino)methyl]-6,7,8,9-tetrahydropyrido[1,2-a]indol-3-yl}-3-1-methyl-1H-indol-3-ylmaleimide HCl (Ro-32-0432) into the ventral tegmental area (VTA) significantly suppressed the place preference and increased levels of dopamine in the nucleus accumbens (NAcc) induced by intra-VTA injection of orexins. These results strongly support the idea that activation of the orexin-containing neuron in the VTA leads to the direct activation of mesolimbic dopamine neurons through the activation of the PLC/PKC pathway via G(q11)alpha or Gbetagamma-subunit activation, which could be associated with the development of its rewarding effect.
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Affiliation(s)
- Minoru Narita
- Department of Toxicology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, 2-4-41 Ebara, Shinagawa-ku, Tokyo 142-8501, Japan.
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Foster JD, Cervinski MA, Gorentla BK, Vaughan RA. Regulation of the dopamine transporter by phosphorylation. Handb Exp Pharmacol 2006:197-214. [PMID: 16722237 DOI: 10.1007/3-540-29784-7_10] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The dopamine transporter (DAT) is a neuronal phosphoprotein and target for psychoactive drugs that plays a critical role in terminating dopaminergic transmission by reuptake of dopamine from the synaptic space. Control of DAT activity and plasma membrane expression are therefore central to drug actions and the spatial and temporal regulation of synaptic dopamine levels. DATs rapidly traffic between the plasma membrane and endosomal compartments in both constitutive and protein kinase C-dependent manners. Kinase activators, phosphatase inhibitors, and transported substrates modulate DAT phosphorylation and activity, but the underlying mechanisms and role of phosphorylation in these processes are poorly understood. Complex adaptive changes in DAT function potentially related to these processes are also induced by psychostimulant and therapeutic transport blockers such as cocaine and methylphenidate. This chapter provides an overview of the current state of knowledge regarding DAT phosphorylation and its relationship to transporter activity and trafficking. A better understanding of how dopaminergic neurons regulate DAT function and the role of phosphorylation may lead to the identification of novel therapeutic targets for the treatment and prevention of dopaminergic disorders.
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Affiliation(s)
- J D Foster
- Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine and Health Sciences, 501 North Columbia Road, Grand Forks, ND 58203, USA
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Mazei-Robinson MS, Blakely RD. ADHD and the dopamine transporter: are there reasons to pay attention? Handb Exp Pharmacol 2006:373-415. [PMID: 16722244 DOI: 10.1007/3-540-29784-7_17] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The catecholamine dopamine (DA) plays an important role as a neurotransmitter in the brain in circuits linked to motor function, reward, and cognition. The presynaptic DA transporter (DAT) inactivates DA following release and provides a route for non-exocytotic DA release (efflux) triggered by amphetamines. The synaptic role of DATs first established through antagonist studies and more recently validated through mouse gene-knockout experiments, raises questions as to whether altered DAT structure or regulation support clinical disorders linked to compromised DA signaling, including drug abuse, schizophrenia, and attention deficit hyperactivity disorder (ADHD). As ADHD appears to have highly heritable components and the most commonly prescribed therapeutics for ADHD target DAT, studies ranging from brain imaging to genomic and genetic analyses have begun to probe the DAT gene and its protein for possible contributions to the disorder and/or its treatment. In this review, after a brief overview of ADHD prevalence and diagnostic criteria, we examine the rationale and experimental findings surrounding a role for human DAT in ADHD. Based on the available evidence from our lab and labs of workers in the field, we suggest that although a common variant within the human DAT (hDAT) gene (SLC6A3) is unlikely to play a major role in the ADHD, contributions of hDAT to risk maybe most evident in phenotypic subgroups. The in vitro and in vivo validation of functional variants, pursued for contributions to endophenotypes in a within family approach, may help elucidate DAT and DA contributions to ADHD and its treatment.
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Affiliation(s)
- M S Mazei-Robinson
- Vanderbilt School of Medicine, Suite 7140, MRB III, Nashville, TN 37232-8548, USA
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