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Devoght J, Comhair J, Morelli G, Rigo JM, D'Hooge R, Touma C, Palme R, Dewachter I, vandeVen M, Harvey RJ, Schiffmann SN, Piccart E, Brône B. Dopamine-mediated striatal activity and function is enhanced in GlyRα2 knockout animals. iScience 2023; 26:107400. [PMID: 37554441 PMCID: PMC10404725 DOI: 10.1016/j.isci.2023.107400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/27/2023] [Accepted: 07/12/2023] [Indexed: 08/10/2023] Open
Abstract
The glycine receptor alpha 2 (GlyRα2) is a ligand-gated ion channel which upon activation induces a chloride conductance. Here, we investigated the role of GlyRα2 in dopamine-stimulated striatal cell activity and behavior. We show that depletion of GlyRα2 enhances dopamine-induced increases in the activity of putative dopamine D1 receptor-expressing striatal projection neurons, but does not alter midbrain dopamine neuron activity. We next show that the locomotor response to d-amphetamine is enhanced in GlyRα2 knockout animals, and that this increase correlates with c-fos expression in the dorsal striatum. 3-D modeling revealed an increase in the neuronal ensemble size in the striatum in response to D-amphetamine in GlyRα2 KO mice. Finally, we show enhanced appetitive conditioning in GlyRα2 KO animals that is likely due to increased motivation, but not changes in associative learning or hedonic response. Taken together, we show that GlyRα2 is an important regulator of dopamine-stimulated striatal activity and function.
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Affiliation(s)
- Jens Devoght
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | - Joris Comhair
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | - Giovanni Morelli
- Brain Development and Disease Laboratory, Instituto Italiano di Tecnologia, 16163 Genova, Italy
| | | | - Rudi D'Hooge
- Laboratory for Biological Psychology, University of Leuven, 3000 Leuven, Belgium
| | - Chadi Touma
- Department of Behavioural Biology, University of Osnabrück, 49076 Osnabrück, Germany
| | - Rupert Palme
- Institute of Biochemistry, University of Veterinary Medicine Vienna, Vienna A-1210, Austria
| | - Ilse Dewachter
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
| | | | - Robert J. Harvey
- School of Health, University of the Sunshine Coast, Sippy Downs, QLD, Australia
- Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Serge N. Schiffmann
- Laboratory of Neurophysiology, Université libre de Bruxelles, 1070 Brussels, Belgium
| | | | - Bert Brône
- Department of Neuroscience, UHasselt, 3500 Hasselt, Belgium
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2
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Nolan SO, Zachry JE, Johnson AR, Brady LJ, Siciliano CA, Calipari ES. Direct dopamine terminal regulation by local striatal microcircuitry. J Neurochem 2020; 155:475-493. [PMID: 32356315 DOI: 10.1111/jnc.15034] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 02/06/2023]
Abstract
Regulation of axonal dopamine release by local microcircuitry is at the hub of several biological processes that govern the timing and magnitude of signaling events in reward-related brain regions. An important characteristic of dopamine release from axon terminals in the striatum is that it is rapidly modulated by local regulatory mechanisms. These processes can occur via homosynaptic mechanisms-such as presynaptic dopamine autoreceptors and dopamine transporters - as well heterosynaptic mechanisms such as retrograde signaling from postsynaptic cholinergic and dynorphin systems, among others. Additionally, modulation of dopamine release via diffusible messengers, such as nitric oxide and hydrogen peroxide, allows for various metabolic factors to quickly and efficiently regulate dopamine release and subsequent signaling. Here we review how these mechanisms work in concert to influence the timing and magnitude of striatal dopamine signaling, independent of action potential activity at the level of dopaminergic cell bodies in the midbrain, thereby providing a parallel pathway by which dopamine can be modulated. Understanding the complexities of local regulation of dopamine signaling is required for building comprehensive frameworks of how activity throughout the dopamine system is integrated to drive signaling and control behavior.
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Affiliation(s)
- Suzanne O Nolan
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Jennifer E Zachry
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Amy R Johnson
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Lillian J Brady
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Cody A Siciliano
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN TN, USA
| | - Erin S Calipari
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.,Vanderbilt Center for Addiction Research, Vanderbilt University, Nashville, TN TN, USA.,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.,Department of Psychiatry and Behavioral Sciences, Vanderbilt University, Nashville, TN, USA
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3
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Keighron JD, Giancola JB, Shaffer RJ, DeMarco EM, Coggiano MA, Slack RD, Hauck Newman A, Tanda G. Distinct effects of (R)-modafinil and its (R)- and (S)-fluoro-analogs on mesolimbic extracellular dopamine assessed by voltammetry and microdialysis in rats. Eur J Neurosci 2019; 50:2045-2053. [PMID: 30402972 PMCID: PMC8294075 DOI: 10.1111/ejn.14256] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 10/29/2018] [Accepted: 10/31/2018] [Indexed: 02/06/2023]
Abstract
Psychostimulant use disorders remain an unabated public health concern worldwide, but no FDA approved medications are currently available for treatment. Modafinil (MOD), like cocaine, is a dopamine reuptake inhibitor and one of the few drugs evaluated in clinical trials that has shown promise for the treatment of cocaine or methamphetamine use disorders in some patient subpopulations. Recent structure-activity relationship and preclinical studies on a series of MOD analogs have provided insight into modifications of its chemical structure that may lead to advancements in clinical efficacy. Here, we have tested the effects of the clinically available (R)-enantiomer of MOD on extracellular dopamine levels in the nucleus accumbens shell, a mesolimbic dopaminergic projection field that plays significant roles in various aspects of psychostimulant use disorders, measured in vivo by fast-scan cyclic voltammetry and by microdialysis in Sprague-Dawley rats. We have compared these results with those obtained under identical experimental conditions with two novel and enantiopure bis(F) analogs of MOD, JBG1-048 and JBG1-049. The results show that (R)-modafinil (R-MOD), JBG1-048, and JBG1-049, when administered intravenously with cumulative drug-doses, will block the dopamine transporter and reduce the clearance rate of dopamine, increasing its extracellular levels. Differences among the compounds in their maximum stimulation of dopamine levels, and in their time course of effects were also observed. These data highlight the mechanistic underpinnings of R-MOD and its bis(F) analogs as pharmacological tools to guide the discovery of novel medications to treat psychostimulant use disorders.
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Affiliation(s)
- Jacqueline D. Keighron
- Medication Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
| | - JoLynn B. Giancola
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
| | - Rachel J. Shaffer
- Medication Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
| | - Emily M. DeMarco
- Medication Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
| | - Mark A. Coggiano
- Medication Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
| | - Rachel D. Slack
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
| | - Amy Hauck Newman
- Medication Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
| | - Gianluigi Tanda
- Medication Development Program, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Department of Health and Human Services; 333 Cassell Drive, TRIAD Bldg., Baltimore, MD, USA, 21224
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4
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Newman AH, Cao J, Keighron JD, Jordan CJ, Bi GH, Liang Y, Abramyan AM, Avelar AJ, Tschumi CW, Beckstead MJ, Shi L, Tanda G, Xi ZX. Translating the atypical dopamine uptake inhibitor hypothesis toward therapeutics for treatment of psychostimulant use disorders. Neuropsychopharmacology 2019; 44:1435-1444. [PMID: 30858517 PMCID: PMC6785152 DOI: 10.1038/s41386-019-0366-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/27/2019] [Accepted: 02/27/2019] [Indexed: 11/10/2022]
Abstract
Medication-assisted treatments are unavailable to patients with cocaine use disorders. Efforts to develop potential pharmacotherapies have led to the identification of a promising lead molecule, JJC8-091, that demonstrates a novel binding mode at the dopamine transporter (DAT). Here, JJC8-091 and a structural analogue, JJC8-088, were extensively and comparatively assessed to elucidate neurochemical correlates to their divergent behavioral profiles. Despite sharing significant structural similarity, JJC8-088 was more cocaine-like, increasing extracellular DA concentrations in the nucleus accumbens shell (NAS) efficaciously and more potently than JJC8-091. In contrast, JJC8-091 was not self-administered and was effective in blocking cocaine-induced reinstatement to drug seeking. Electrophysiology experiments confirmed that JJC8-091 was more effective than JJC8-088 at inhibiting cocaine-mediated enhancement of DA neurotransmission. Further, when VTA DA neurons in DAT-cre mice were optically stimulated, JJC8-088 produced a significant leftward shift in the stimulation-response curve, similar to cocaine, while JJC8-091 shifted the curve downward, suggesting attenuation of DA-mediated brain reward. Computational models predicted that JJC8-088 binds in an outward facing conformation of DAT, similar to cocaine. Conversely, JJC8-091 steers DAT towards a more occluded conformation. Collectively, these data reveal the underlying molecular mechanism at DAT that may be leveraged to rationally optimize leads for the treatment of cocaine use disorders, with JJC8-091 representing a compelling candidate for development.
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Affiliation(s)
- Amy Hauck Newman
- Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD, 21224, USA.
| | - Jianjing Cao
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Jacqueline D. Keighron
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Chloe J. Jordan
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Guo-Hua Bi
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Ying Liang
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Ara M. Abramyan
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Alicia J. Avelar
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX USA
| | - Christopher W. Tschumi
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX USA ,0000 0000 8527 6890grid.274264.1Aging & Metabolism Research Group, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Michael J. Beckstead
- 0000 0001 0629 5880grid.267309.9Department of Cellular and Integrative Physiology, UT Health Science Center, San Antonio, TX USA ,0000 0000 8527 6890grid.274264.1Aging & Metabolism Research Group, Oklahoma Medical Research Foundation, Oklahoma City, OK USA
| | - Lei Shi
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Gianluigi Tanda
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
| | - Zheng-Xiong Xi
- 0000 0004 1936 8075grid.48336.3aMolecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, MD 21224 USA
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5
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G protein-coupled receptor signaling in VTA dopaminergic neurons bidirectionally regulates the acute locomotor response to amphetamine but does not affect behavioral sensitization. Neuropharmacology 2019; 161:107663. [PMID: 31173760 DOI: 10.1016/j.neuropharm.2019.06.002] [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: 02/18/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 11/20/2022]
Abstract
Amphetamine (AMPH) acts as a substrate of the dopamine transporter (DAT) and causes a dramatic increase in extracellular dopamine (DA). Upon entering DA neurons, AMPH promotes DA efflux via DAT through a mechanism implicating depletion of DA from vesicular stores, activation of kinase pathways and transporter phosphorylation. Despite the role of intracellular signaling for AMPH action, it remains elusive how the response to AMPH is affected in vivo by metabotropic regulation via G protein coupled receptor signaling pathways. Here, we show by employment of Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) that the acute hyperlocomotor response to AMPH is bidirectionally regulated by metabotropic input to VTA DA neurons with a markedly enhanced response upon activation of a Gs-coupled pathway and a markedly decreased locomotor response upon activation of a Gi-coupled pathway. The unique mechanism of action for AMPH was underlined by the absence of an effect of Gs activation on the locomotor response to the DAT inhibitor cocaine. Regardless of the profound effect on the acute AMPH response, repeated Gs activation or Gi activation did not affect development of AMPH sensitization. Furthermore, activation of a Gs-pathway or activation of a Gi-pathway in DA neurons did not have any effect on the AMPH-induced locomotor response in the AMPH sensitized mice. This suggests induction of alterations in DA neuronal functions that overrule the stimulatory or inhibitory effect of metabotropic input seen in drug-naïve mice. The data thereby underline the remarkable strength of maladaptive changes that occur upon intake of strong psychostimulants. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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6
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Yu Y, de Campos RPS, Hong S, Krastev DL, Sadanand S, Leung Y, Wheeler AR. A microfluidic platform for continuous monitoring of dopamine homeostasis in dopaminergic cells. MICROSYSTEMS & NANOENGINEERING 2019; 5:10. [PMID: 31057937 PMCID: PMC6409360 DOI: 10.1038/s41378-019-0049-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 05/24/2023]
Abstract
Homeostasis of dopamine, a classical neurotransmitter, is a key indicator of neuronal health. Dysfunction in the regulation of dopamine is implicated in a long list of neurological disorders, including addiction, depression, and neurodegeneration. The existing methods used to evaluate dopamine homeostasis in vitro are inconvenient and do not allow for continuous non-destructive measurement. In response to this challenge, we introduce an integrated microfluidic system that combines dopaminergic cell culture and differentiation with electroanalytical measurements of extracellular dopamine in real-time at any point during an assay. We used the system to examine the behavior of differentiated SH-SY5Y cells upon exposure to four dopamine transporter ant/agonists (cocaine, ketamine, epigallocatechin gallate, and amphetamine) and study their pharmacokinetics. The IC50 values of cocaine, ketamine, and epigallocatechin gallate were determined to be (average ± standard deviation) 3.7 ± 1.1 µM, 51.4 ± 17.9 µM, and 2.6 ± 0.8 µM, respectively. Furthermore, we used the new system to study amphetamine-mediated dopamine release to probe the related phenomena of dopamine transporter-mediated reverse-transport and dopamine release from vesicles. We propose that this platform, which is the first platform to simultaneously evaluate uptake and release, could be useful to screen for drugs and other agents that target dopaminergic neurons and the function of the dopamine transporter. More broadly, this platform should be adaptable for any application that could benefit from high-temporal resolution electroanalysis combined with multi-day cell culture using small numbers of cells.
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Affiliation(s)
- Yue Yu
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5s 3G9 Canada
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1 Canada
| | - Richard P. S. de Campos
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1 Canada
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6 Canada
| | - Seolim Hong
- Department of Human Biology, University of Toronto, 300 Huron Street, Toronto, ON M5S 3J6 Canada
| | - Dimitar L. Krastev
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1 Canada
- Department of Human Biology, University of Toronto, 300 Huron Street, Toronto, ON M5S 3J6 Canada
| | - Siddharth Sadanand
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1 Canada
| | - Yen Leung
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1 Canada
| | - Aaron R. Wheeler
- Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5s 3G9 Canada
- Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1 Canada
- Department of Chemistry, University of Toronto, 80 St George St., Toronto, ON M5S 3H6 Canada
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7
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Mumtaz F, Khan MI, Zubair M, Dehpour AR. Neurobiology and consequences of social isolation stress in animal model-A comprehensive review. Biomed Pharmacother 2018; 105:1205-1222. [PMID: 30021357 DOI: 10.1016/j.biopha.2018.05.086] [Citation(s) in RCA: 200] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 05/10/2018] [Accepted: 05/18/2018] [Indexed: 12/09/2022] Open
Abstract
The brain is a vital organ, susceptible to alterations under genetic influences and environmental experiences. Social isolation (SI) acts as a stressor which results in alterations in reactivity to stress, social behavior, function of neurochemical and neuroendocrine system, physiological, anatomical and behavioral changes in both animal and humans. During early stages of life, acute or chronic SIS has been proposed to show signs and symptoms of psychiatric and neurological disorders such as anxiety, depression, schizophrenia, epilepsy and memory loss. Exposure to social isolation stress induces a variety of endocrinological changes including the activation of hypothalamic-pituitary-adrenal (HPA) axis, culminating in the release of glucocorticoids (GCs), release of catecholamines, activation of the sympatho-adrenomedullary system, release of Oxytocin and vasopressin. In several regions of the central nervous system (CNS), SIS alters the level of neurotransmitter such as dopamine, serotonin, gamma aminobutyric acid (GABA), glutamate, nitrergic system and adrenaline as well as leads to alteration in receptor sensitivity of N-methyl-D-aspartate (NMDA) and opioid system. A change in the function of oxidative and nitrosative stress (O&NS) mediated mitochondrial dysfunction, inflammatory factors, neurotrophins and neurotrophicfactors (NTFs), early growth response transcription factor genes (Egr) and C-Fos expression are also involved as a pathophysiological consequences of SIS which induce neurological and psychiatric disorders.
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Affiliation(s)
- Faiza Mumtaz
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Muhammad Imran Khan
- Department of Pharmacy, Kohat University of Science and Technology, 26000 Kohat, KPK, Pakistan; Drug Detoxification Health Welfare Research Center, Bannu, KPK, Pakistan
| | - Muhammad Zubair
- Key Laboratory of Integrated Management of Crop Diseases and Pests, College of Plant Protection, Nanjing Agriculture University, Nanjing, 210095, PR China
| | - Ahmad Reza Dehpour
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran.
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Schuweiler D, Athens J, Thompson J, Vazhayil S, Garris P. Effects of an acute therapeutic or rewarding dose of amphetamine on acquisition of Pavlovian autoshaping and ventral striatal dopamine signaling. Behav Brain Res 2018; 336:191-203. [DOI: 10.1016/j.bbr.2017.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 07/28/2017] [Accepted: 09/01/2017] [Indexed: 12/16/2022]
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9
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A pipette-based calibration system for fast-scan cyclic voltammetry with fast response times. Biotechniques 2016; 61:269-271. [PMID: 27839513 DOI: 10.2144/000114476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 09/20/2016] [Indexed: 11/23/2022] Open
Abstract
Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique that utilizes the oxidation and/or reduction of an analyte of interest to infer rapid changes in concentrations. In order to calibrate the resulting oxidative or reductive current, known concentrations of an analyte must be introduced under controlled settings. Here, I describe a simple and cost-effective method, using a Petri dish and pipettes, for the calibration of carbon fiber microelectrodes (CFMs) using FSCV.
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Bobak MJ, Weber MW, Doellman MA, Schuweiler DR, Athens JM, Juliano SA, Garris PA. Modafinil Activates Phasic Dopamine Signaling in Dorsal and Ventral Striata. J Pharmacol Exp Ther 2016; 359:460-470. [PMID: 27733628 DOI: 10.1124/jpet.116.236000] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/11/2016] [Indexed: 11/22/2022] Open
Abstract
Modafinil (MOD) exhibits therapeutic efficacy for treating sleep and psychiatric disorders; however, its mechanism is not completely understood. Compared with other psychostimulants inhibiting dopamine (DA) uptake, MOD weakly interacts with the dopamine transporter (DAT) and modestly elevates striatal dialysate DA, suggesting additional targets besides DAT. However, the ability of MOD to induce wakefulness is abolished with DAT knockout, conversely suggesting that DAT is necessary for MOD action. Another psychostimulant target, but one not established for MOD, is activation of phasic DA signaling. This communication mode during which burst firing of DA neurons generates rapid changes in extracellular DA, the so-called DA transients, is critically implicated in reward learning. Here, we investigate MOD effects on phasic DA signaling in the striatum of urethane-anesthetized rats with fast-scan cyclic voltammetry. We found that MOD (30-300 mg/kg i.p.) robustly increases the amplitude of electrically evoked phasic-like DA signals in a time- and dose-dependent fashion, with greater effects in dorsal versus ventral striata. MOD-induced enhancement of these electrically evoked amplitudes was mediated preferentially by increased DA release compared with decreased DA uptake. Principal component regression of nonelectrically evoked recordings revealed negligible changes in basal DA with high-dose MOD (300 mg/kg i.p.). Finally, in the presence of the D2 DA antagonist, raclopride, low-dose MOD (30 mg/kg i.p.) robustly elicited DA transients in dorsal and ventral striata. Taken together, these results suggest that activation of phasic DA signaling is an important mechanism underlying the clinical efficacy of MOD.
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Affiliation(s)
- Martin J Bobak
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Matthew W Weber
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Melissa A Doellman
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | | | - Jeana M Athens
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Steven A Juliano
- School of Biological Sciences, Illinois State University, Normal, Illinois
| | - Paul A Garris
- School of Biological Sciences, Illinois State University, Normal, Illinois
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11
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Covey DP, Bunner KD, Schuweiler DR, Cheer JF, Garris PA. Amphetamine elevates nucleus accumbens dopamine via an action potential-dependent mechanism that is modulated by endocannabinoids. Eur J Neurosci 2016; 43:1661-73. [PMID: 27038339 PMCID: PMC5819353 DOI: 10.1111/ejn.13248] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/29/2016] [Indexed: 02/04/2023]
Abstract
The reinforcing effects of abused drugs are mediated by their ability to elevate nucleus accumbens dopamine. Amphetamine (AMPH) was historically thought to increase dopamine by an action potential-independent, non-exocytotic type of release called efflux, involving reversal of dopamine transporter function and driven by vesicular dopamine depletion. Growing evidence suggests that AMPH also acts by an action potential-dependent mechanism. Indeed, fast-scan cyclic voltammetry demonstrates that AMPH activates dopamine transients, reward-related phasic signals generated by burst firing of dopamine neurons and dependent on intact vesicular dopamine. Not established for AMPH but indicating a shared mechanism, endocannabinoids facilitate this activation of dopamine transients by broad classes of abused drugs. Here, using fast-scan cyclic voltammetry coupled to pharmacological manipulations in awake rats, we investigated the action potential and endocannabinoid dependence of AMPH-induced elevations in nucleus accumbens dopamine. AMPH increased the frequency, amplitude and duration of transients, which were observed riding on top of slower dopamine increases. Surprisingly, silencing dopamine neuron firing abolished all AMPH-induced dopamine elevations, identifying an action potential-dependent origin. Blocking cannabinoid type 1 receptors prevented AMPH from increasing transient frequency, similar to reported effects on other abused drugs, but not from increasing transient duration and inhibiting dopamine uptake. Thus, AMPH elevates nucleus accumbens dopamine by eliciting transients via cannabinoid type 1 receptors and promoting the summation of temporally coincident transients, made more numerous, larger and wider by AMPH. Collectively, these findings are inconsistent with AMPH eliciting action potential-independent dopamine efflux and vesicular dopamine depletion, and support endocannabinoids facilitating phasic dopamine signalling as a common action in drug reinforcement.
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Affiliation(s)
- Dan P. Covey
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kendra D. Bunner
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Douglas R. Schuweiler
- School of Biological Sciences, Illinois State University, 210 Julian Hall, Normal, IL 61790-4120, USA
| | - Joseph F. Cheer
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Psychiatry, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Paul A. Garris
- School of Biological Sciences, Illinois State University, 210 Julian Hall, Normal, IL 61790-4120, USA
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Singer BF, Guptaroy B, Austin CJ, Wohl I, Lovic V, Seiler JL, Vaughan RA, Gnegy ME, Robinson TE, Aragona BJ. Individual variation in incentive salience attribution and accumbens dopamine transporter expression and function. Eur J Neurosci 2016; 43:662-70. [PMID: 26613374 DOI: 10.1111/ejn.13134] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 11/19/2015] [Accepted: 11/23/2015] [Indexed: 01/23/2023]
Abstract
Cues (conditioned stimuli; CSs) associated with rewards can come to motivate behavior, but there is considerable individual variation in their ability to do so. For example, a lever-CS that predicts food reward becomes attractive and wanted, and elicits reward-seeking behavior, to a greater extent in some rats ('sign-trackers'; STs) than others ('goal-trackers'; GTs). Variation in dopamine (DA) neurotransmission in the nucleus accumbens (NAc) core is thought to contribute to such individual variation. Given that the DA transporter (DAT) exerts powerful regulation over DA signaling, we characterized the expression and function of the DAT in the accumbens of STs and GTs. STs showed greater DAT surface expression in ventral striatal synaptosomes than GTs, and ex vivo fast-scan cyclic voltammetry recordings of electrically evoked DA release confirmed enhanced DAT function in STs, as indicated by faster DA uptake, specifically in the NAc core. Consistent with this, systemic amphetamine (AMPH) produced greater inhibition of DA uptake in STs than in GTs. Furthermore, injection of AMPH directly into the NAc core enhanced lever-directed approach in STs, presumably by amplifying the incentive value of the CS, but had no effect on goal-tracking behavior. On the other hand, there were no differences between STs and GTs in electrically-evoked DA release in slices, or in total ventral striatal DA content. We conclude that greater DAT surface expression may facilitate the attribution of incentive salience to discrete reward cues. Investigating this variability in animal sub-populations may help explain why some people abuse drugs while others do not.
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Affiliation(s)
- Bryan F Singer
- Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Bipasha Guptaroy
- Department of Pharmacology, University of Michigan School of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Curtis J Austin
- Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Isabella Wohl
- Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Vedran Lovic
- Department of Psychology, Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
| | - Jillian L Seiler
- Psychology Department, University of Illinois at Chicago, Chicago, IL, USA
| | - Roxanne A Vaughan
- Department of Basic Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, USA
| | - Margaret E Gnegy
- Department of Pharmacology, University of Michigan School of Medicine, University of Michigan, Ann Arbor, MI, USA
| | - Terry E Robinson
- Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Brandon J Aragona
- Biopsychology Area, Department of Psychology, University of Michigan, Ann Arbor, MI, 48109, USA
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13
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Ramsson ES, Cholger D, Dionise A, Poirier N, Andrus A, Curtiss R. Characterization of Fast-Scan Cyclic Voltammetric Electrodes Using Paraffin as an Effective Sealant with In Vitro and In Vivo Applications. PLoS One 2015; 10:e0141340. [PMID: 26505195 PMCID: PMC4623982 DOI: 10.1371/journal.pone.0141340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/07/2015] [Indexed: 12/21/2022] Open
Abstract
Fast-scan cyclic voltammetry (FSCV) is a powerful technique for measuring sub-second changes in neurotransmitter levels. A great time-limiting factor in the use of FSCV is the production of high-quality recording electrodes; common recording electrodes consist of cylindrical carbon fiber encased in borosilicate glass. When the borosilicate is heated and pulled, the molten glass ideally forms a tight seal around the carbon fiber cylinder. It is often difficult, however, to guarantee a perfect seal between the glass and carbon. Indeed, much of the time spent creating electrodes is in an effort to find a good seal. Even though epoxy resins can be useful in this regard, they are irreversible (seals are permanent), wasteful (epoxy cannot be reused once hardener is added), hazardous (hardeners are often caustic), and require curing. Herein we characterize paraffin as an electrode sealant for FSCV microelectrodes. Paraffin boasts the advantages of near-immediate curing times, simplicity in use, long shelf-life and stable waterproof seals capable of withstanding extended cycling. Borosilicate electrode tips were left intact or broken and dipped in paraffin embedding wax. Excess wax was removed from the carbon surface with xyelenes or by repeated cycling at an extended waveform (-0.4 to 1.4V, 400 V/s, 60 Hz). Then, the waveform was switched to a standard waveform (-0.4 to 1.3V, 400 V/s, 10 Hz) and cycled until stable. Wax-sealing does not inhibit electrode sensitivity, as electrodes detected linear changes in dopamine before and after wax (then xylenes) exposure. Paraffin seals are intact after 11 days of implantation in the mouse, and still capable of measuring transient changes in in vivo dopamine. From this it is clear that paraffin wax is an effective sealant for FSCV electrodes that provides a convenient substitute to epoxy sealants.
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Affiliation(s)
- Eric S. Ramsson
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Daniel Cholger
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Albert Dionise
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Nicholas Poirier
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Avery Andrus
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Randi Curtiss
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
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Yorgason JT, Calipari ES, Ferris MJ, Karkhanis AN, Fordahl SC, Weiner JL, Jones SR. Social isolation rearing increases dopamine uptake and psychostimulant potency in the striatum. Neuropharmacology 2015; 101:471-9. [PMID: 26525189 DOI: 10.1016/j.neuropharm.2015.10.025] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 10/02/2015] [Accepted: 10/20/2015] [Indexed: 12/12/2022]
Abstract
Social isolation rearing (SI) is a model of early life stress that results in neurobiological alterations leading to increased anxiety-like behaviors. These animals also exhibit an increased propensity to administer psychostimulants, such as cocaine; however, the mechanisms governing this increased addiction vulnerability remain to be elucidated. Long-term stressors have been shown to produce important alterations in nucleus accumbens core (NAc) function. The NAc regulates motivated and goal-directed behaviors, and individual differences in NAc function have been shown to be predictive of addiction vulnerability. Rats were reared in group (GH; 4/cage) or SI (1/cage) conditions from weaning (PD 28) into early adulthood (PD 77) and dopamine release was assessed using voltammetry in brain slices containing the NAc and dorsomedial striatum. SI rats exhibited enhanced dopamine release and uptake in both regions compared to GH rats. In regard to psychostimulant effects directly at the dopamine transporter (DAT), methylphenidate and amphetamine, but not cocaine, inhibited uptake more in SI than GH rats. The increased potencies were positively correlated with uptake rates, suggesting that increased potencies of amphetamine-like compounds are due to changes in DAT function. Cocaine's effects on uptake were similar between rearing conditions, however, cocaine enhanced evoked dopamine release greater in SI than GH rats, suggesting that the enhanced cocaine reinforcement in SI animals involves a DAT independent mechanism. Together, the results provide the first evidence that greater psychostimulant effects in SI compared to GH rats are due to effects on dopamine terminals related to uptake dependent and independent mechanisms.
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Affiliation(s)
- Jordan T Yorgason
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
| | - Erin S Calipari
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
| | - Mark J Ferris
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
| | - Anushree N Karkhanis
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
| | - Steven C Fordahl
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
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Siciliano CA, Calipari ES, Jones SR. Amphetamine potency varies with dopamine uptake rate across striatal subregions. J Neurochem 2014; 131:348-55. [PMID: 24988947 DOI: 10.1111/jnc.12808] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/27/2014] [Accepted: 07/01/2014] [Indexed: 02/01/2023]
Abstract
Amphetamine is a central nervous system psychostimulant with a high potential for abuse. Recent literature has shown that genetic and drug-induced elevations in dopamine transporter (DAT) expression augment the neurochemical and behavioral potency of psychostimulant releasers. However, it remains to be determined if the well-documented differences in DAT levels across striatal regions drive regionally distinct amphetamine effects within individuals. DAT levels and dopamine uptake rates have been shown to follow a gradient in the striatum, with the highest levels in the dorsal regions and lowest levels in the nucleus accumbens shell; thus, we hypothesized that amphetamine potency would follow this gradient. Using fast scan cyclic voltammetry in mouse brain slices, we examined DAT inhibition and changes in exocytotic dopamine release by amphetamine across four striatal regions (dorsal and ventral caudate-putamen, nucleus accumbens core and shell). Consistent with our hypothesis, amphetamine effects at the DAT and on release decreased across regions from dorsal to ventral, and both measures of potency were highly correlated with dopamine uptake rates. Separate striatal subregions are involved in different aspects of motivated behaviors, such as goal-directed and habitual behaviors, that become dysregulated by drug abuse, making it critically important to understand regional differences in drug potencies.
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Affiliation(s)
- Cody A Siciliano
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
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16
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Covey DP, Roitman MF, Garris PA. Illicit dopamine transients: reconciling actions of abused drugs. Trends Neurosci 2014; 37:200-10. [PMID: 24656971 DOI: 10.1016/j.tins.2014.02.002] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 01/27/2014] [Accepted: 02/05/2014] [Indexed: 01/03/2023]
Abstract
Phasic increases in brain dopamine are required for cue-directed reward seeking. Although compelling within the framework of appetitive behavior, the view that illicit drugs hijack reward circuits by hyperactivating these dopamine transients is inconsistent with established psychostimulant pharmacology. However, recent work reclassifying amphetamine (AMPH), cocaine, and other addictive dopamine-transporter inhibitors (DAT-Is) supports transient hyperactivation as a unifying hypothesis of abused drugs. We argue here that reclassification also identifies generating burst firing by dopamine neurons as a keystone action. Unlike natural rewards, which are processed by sensory systems, drugs act directly on the brain. Consequently, to mimic natural rewards and exploit reward circuits, dopamine transients must be elicited de novo. Of available drug targets, only burst firing achieves this essential outcome.
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Affiliation(s)
- Dan P Covey
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA
| | - Mitchell F Roitman
- Department of Psychology, University of Illinois at Chicago, Chicago, IL 60607-7137, USA
| | - Paul A Garris
- School of Biological Sciences, Illinois State University, Normal, IL 61790-4120, USA.
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Synthetic cathinones: chemical phylogeny, physiology, and neuropharmacology. Life Sci 2013; 97:20-6. [PMID: 24231923 DOI: 10.1016/j.lfs.2013.10.029] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 10/22/2013] [Accepted: 10/25/2013] [Indexed: 11/21/2022]
Abstract
This mini-review summarizes the history of cathinone and its synthesized derivatives from early records to the present day, including the appearance of synthetic cathinones in the drug combination known as bath salts. Bath salts may consist of one compound (MDPV) or combinations of MDPV and one or more other synthetic cathinones, which may also appear alone without MDPV. We briefly review recent in vitro studies of bath salts components alone or in combination, focusing on pharmacological and biophysical studies. Finally we summarize new data from in vivo procedures that characterize the abuse-related neurochemical and behavioral effects of synthetic cathinones in rats.
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Marquez P, Hamid A, Lutfy K. The role of NOP receptors in psychomotor stimulation and locomotor sensitization induced by cocaine and amphetamine in mice. Eur J Pharmacol 2013; 707:41-5. [PMID: 23524092 PMCID: PMC3652801 DOI: 10.1016/j.ejphar.2013.03.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Revised: 03/12/2013] [Accepted: 03/13/2013] [Indexed: 01/22/2023]
Abstract
We have previously shown that orphanin FQ (also known as nociceptin; OFQ/N) attenuates the motor stimulatory effect of cocaine and blocks locomotor sensitization induced by cocaine. Furthermore, we have shown that cocaine treatment altered the level of endogenous OFQ/N, raising the possibility that endogenous OFQ/N and its receptor (NOP) may be crucial in these actions of cocaine. Accordingly, in the present study, we sought to determine the role of NOP receptors in psychomotor stimulation and locomotor sensitization induced by cocaine or amphetamine. Mice lacking the NOP receptor and their wild-type littermates were habituated to motor activity chambers for 1h, injected with cocaine (0, 15 or 30 mg/kg) or amphetamine (0, 1 or 3mg/kg), and motor activity was recorded for 1h. For sensitization induced by these drugs, mice were treated with saline or the highest dose of each drug once daily for three consecutive days and tested on day 8. On this day, mice were habituated to the chambers for 1h, then received a challenge dose of cocaine (15 mg/kg) or amphetamine (1mg/kg), and motor activity was recorded for 1h. Cocaine and amphetamine each induced hyperlocomotion but the extent of this response was not different between NOP receptor null mice and their controls. Sensitization developed to the motor stimulatory action of each drug, but the magnitude of cocaine-induced sensitization was only higher in null mice compared to their controls. Together, the present results suggest that the endogenous OFQ/N/NOP receptor system may modulate the development of cocaine-induced locomotor sensitization.
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Affiliation(s)
- Paul Marquez
- Dept. of Pharm. Sci., Coll of Pharmacy, Western Univ. of Health Sci., Pomona, CA 91766
- Dept. of Endocrinology/Medicine, Charles Drew University, Los Angeles, CA 90059
| | - Abdul Hamid
- Dept. of Endocrinology/Medicine, Charles Drew University, Los Angeles, CA 90059
| | - Kabirullah Lutfy
- Dept. of Pharm. Sci., Coll of Pharmacy, Western Univ. of Health Sci., Pomona, CA 91766
- Dept. of Endocrinology/Medicine, Charles Drew University, Los Angeles, CA 90059
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19
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Covey DP, Juliano SA, Garris PA. Amphetamine elicits opposing actions on readily releasable and reserve pools for dopamine. PLoS One 2013; 8:e60763. [PMID: 23671560 PMCID: PMC3643976 DOI: 10.1371/journal.pone.0060763] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 03/02/2013] [Indexed: 11/18/2022] Open
Abstract
Amphetamine, a highly addictive drug with therapeutic efficacy, exerts paradoxical effects on the fundamental communication modes employed by dopamine neurons in modulating behavior. While amphetamine elevates tonic dopamine signaling by depleting vesicular stores and driving non-exocytotic release through reverse transport, this psychostimulant also activates phasic dopamine signaling by up-regulating vesicular dopamine release. We hypothesized that these seemingly incongruent effects arise from amphetamine depleting the reserve pool and enhancing the readily releasable pool. This novel hypothesis was tested using in vivo voltammetry and stimulus trains of varying duration to access different vesicular stores. We show that amphetamine actions are stimulus dependent in the dorsal striatum. Specifically, amphetamine up-regulated vesicular dopamine release elicited by a short-duration train, which interrogates the readily releasable pool, but depleted release elicited by a long-duration train, which interrogates the reserve pool. These opposing actions of vesicular dopamine release were associated with concurrent increases in tonic and phasic dopamine responses. A link between vesicular depletion and tonic signaling was supported by results obtained for amphetamine in the ventral striatum and cocaine in both striatal sub-regions, which demonstrated augmented vesicular release and phasic signals only. We submit that amphetamine differentially targeting dopamine stores reconciles the paradoxical activation of tonic and phasic dopamine signaling. Overall, these results further highlight the unique and region-distinct cellular mechanisms of amphetamine and may have important implications for its addictive and therapeutic properties.
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Affiliation(s)
- Dan P. Covey
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Steven A. Juliano
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Paul A. Garris
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
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20
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Avelar AJ, Juliano SA, Garris PA. Amphetamine augments vesicular dopamine release in the dorsal and ventral striatum through different mechanisms. J Neurochem 2013; 125:373-85. [PMID: 23406303 PMCID: PMC3633730 DOI: 10.1111/jnc.12197] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 02/05/2013] [Accepted: 02/12/2013] [Indexed: 11/30/2022]
Abstract
Amphetamine has well-established actions on pre-synaptic dopamine signaling, such as inhibiting uptake and degradation, activating synthesis, depleting vesicular stores, and promoting dopamine-transporter reversal and non-exocytotic release. Recent in vivo studies have identified an additional mechanism: augmenting vesicular release. In this study, we investigated how amphetamine elicits this effect. Our hypothesis was that amphetamine enhances vesicular dopamine release in dorsal and ventral striata by differentially targeting dopamine synthesis and degradation. In urethane-anesthetized rats, we employed voltammetry to monitor dopamine, electrical stimulation to deplete stores or assess vesicular release and uptake, and pharmacology to isolate degradation and synthesis. While amphetamine increased electrically evoked dopamine levels, inhibited uptake, and up-regulated vesicular release in both striatal sub-regions in controls, this psychostimulant elicited region-specific effects on evoked levels and vesicular release but not uptake in drug treatments. Evoked levels better correlated with vesicular release compared with uptake, supporting enhanced vesicular release as an important amphetamine mechanism. Taken together, these results suggested that amphetamine enhances vesicular release in the dorsal striatum by activating dopamine synthesis and inhibiting dopamine degradation, but targeting an alternative mechanism in the ventral striatum. Region-distinct activation of vesicular dopamine release highlights complex cellular actions of amphetamine and may have implications for its behavioral effects.
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Affiliation(s)
- Alicia J. Avelar
- Cell Biology, Physiology & Development Section, School of Biological Sciences, Illinois State University, Normal, IL 61790 USA
| | - Steven A. Juliano
- Behavior, Ecology, Evolution, & Systematics Section, School of Biological Sciences, Illinois State University, Normal, IL 61790 USA
| | - Paul A. Garris
- Cell Biology, Physiology & Development Section, School of Biological Sciences, Illinois State University, Normal, IL 61790 USA
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21
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Scardochio T, Clarke PBS. Inhibition of 50-kHz ultrasonic vocalizations by dopamine receptor subtype-selective agonists and antagonists in adult rats. Psychopharmacology (Berl) 2013. [PMID: 23192317 DOI: 10.1007/s00213-012-2931-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
RATIONALE Adult rats emit ultrasonic calls at around 22 and 50 kHz, which are often elicited by aversive and rewarding stimuli, respectively. Dopamine (DA) plays a role in aspects of both reward and aversion. OBJECTIVE The purpose of this study is to investigate the effects of DA receptor subtype-selective agonists on 22- and 50-kHz call rates. METHODS Ultrasonic calls were recorded in adult male rats that were initially screened with amphetamine to eliminate low 50-kHz callers. The remaining subjects were tested after acute intraperitoneal or subcutaneous injection of the following DA receptor-selective agonists and antagonists: A68930 (D1-like agonist), quinpirole (D2-like agonist), PD 128907 (D3 agonist), PD 168077 (D4 agonist), SCH 39166 (D1-like antagonist), L-741,626 (D2 antagonist), NGB 2904 (D3 antagonist), and L-745,870 (D4 antagonist). The indirect DA/noradrenaline agonist amphetamine served as a positive control. RESULTS As expected, amphetamine strongly increased 50-kHz call rates. In contrast, D1-, D2-, and D3-selective DA receptor agonists, when given alone, inhibited calling; combinations of D1- and D2-like agonists also decreased call rate. Given alone, the D1-like and D3 antagonists significantly decreased call rate, with a similar trend for the D2 antagonist. Agonist-antagonist combinations also decreased calling. The D4 agonist and antagonist did not significantly affect 50-kHz call rates. Twenty-two-kilohertz calls occurred infrequently under all drug conditions. CONCLUSION Following systemic drug administration, tonic pharmacological activation of D1-like or D2-like DA receptors, either alone or in combination, does not appear sufficient to induce 50-kHz calls. Dopaminergic transmission through D1, D2, and D3 receptors appears necessary for spontaneous calling.
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Affiliation(s)
- Tina Scardochio
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building Rm. 1320, 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
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22
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Howard CD, Pastuzyn ED, Barker-Haliski ML, Garris PA, Keefe KA. Phasic-like stimulation of the medial forebrain bundle augments striatal gene expression despite methamphetamine-induced partial dopamine denervation. J Neurochem 2013; 125:555-65. [PMID: 23480199 DOI: 10.1111/jnc.12234] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 02/20/2013] [Accepted: 03/04/2013] [Indexed: 11/30/2022]
Abstract
Methamphetamine-induced partial dopamine depletions are associated with impaired basal ganglia function, including decreased preprotachykinin mRNA expression and impaired transcriptional activation of activity-regulated, cytoskeleton-associated (Arc) gene in striatum. Recent work implicates deficits in phasic dopamine signaling as a potential mechanism linking methamphetamine-induced dopamine loss to impaired basal ganglia function. This study thus sought to establish a causal link between phasic dopamine transmission and altered basal ganglia function by determining whether the deficits in striatal neuron gene expression could be restored by increasing phasic dopamine release. Three weeks after pretreatment with saline or a neurotoxic regimen of methamphetamine, rats underwent phasic- or tonic-like stimulation of ascending dopamine neurons. Striatal gene expression was examined using in situ hybridization histochemistry. Phasic-like, but not tonic-like, stimulation induced immediate-early genes Arc and zif268 in both groups, despite the partial striatal dopamine denervation in methamphetamine-pretreated rats, with the Arc expression occurring in presumed striatonigral efferent neurons. Phasic-like stimulation also restored preprotachykinin mRNA expression. These results suggest that disruption of phasic dopamine signaling likely underlies methamphetamine-induced impairments in basal ganglia function, and that restoring phasic dopamine signaling may be a viable approach to manage long-term consequences of methamphetamine-induced dopamine loss on basal ganglia functions.
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23
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Wright JM, Dobosiewicz MRS, Clarke PBS. The role of dopaminergic transmission through D1-like and D2-like receptors in amphetamine-induced rat ultrasonic vocalizations. Psychopharmacology (Berl) 2013; 225:853-68. [PMID: 23052567 DOI: 10.1007/s00213-012-2871-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Accepted: 09/02/2012] [Indexed: 12/23/2022]
Abstract
RATIONALE Systemic amphetamine (AMPH) administration increases the rate of 50-kHz ultrasonic vocalizations (USVs) in adult rats and preferentially enhances the 'trill' subtype; these effects of AMPH critically depend on noradrenergic transmission, but the possible contributions of dopamine are unclear. OBJECTIVE To assess the role of dopamine in 50-kHz USVs emitted drug-free and following systemic AMPH administration. METHODS Adult male Long-Evans rats pre-selected for high AMPH-induced calling rates were tested with AMPH (1 mg/kg, intraperitoneal (IP)) and saline following pretreatment with the following dopamine receptor antagonists: SCH 23390 (0.005-0.02 mg/kg, subcutaneous (SC)), SCH 39166 (0.03-0.3 mg/kg, SC), haloperidol (0.1, 0.2 mg/kg, IP), sulpiride (20-80 mg/kg, SC), raclopride (0.1-0.5 mg/kg, SC), clozapine (4 mg/kg, SC), risperidone (0.5 mg/kg, SC), and pimozide (1 mg/kg, IP). The dopamine and noradrenaline reuptake inhibitors (GBR 12909 and nisoxetine, respectively) were also tested, alone and in combination. RESULTS SCH 23390, SCH 39166, haloperidol, and raclopride dose-dependently inhibited vocalizations under AMPH and suppressed the proportion of trill calls. Sulpiride, however, had no discernable effect on call rate or profile, even at a high dose that reduced locomotor activity. Single doses of clozapine, risperidone, and pimozide all markedly decreased calling under saline and AMPH. Finally, GBR 12909 and nisoxetine failed to promote 50-kHz USVs detectably or alter the subtype profile, when tested alone or in combination. CONCLUSIONS The rate of 50-kHz USVs and the call subtype profile following systemic AMPH administration depends on dopaminergic neurotransmission through D1-like and D2-like receptors. However, inhibiting dopamine and/or noradrenaline reuptake appears insufficient to induce calling.
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Affiliation(s)
- Jennifer M Wright
- Department of Pharmacology and Therapeutics, McGill University, McIntyre Medical Building Rm. 1320 3655 Promenade Sir William Osler, Montreal, QC, H3G 1Y6, Canada
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24
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Daberkow DP, Brown HD, Bunner KD, Kraniotis SA, Doellman MA, Ragozzino ME, Garris PA, Roitman MF. Amphetamine paradoxically augments exocytotic dopamine release and phasic dopamine signals. J Neurosci 2013; 33:452-63. [PMID: 23303926 PMCID: PMC3711765 DOI: 10.1523/jneurosci.2136-12.2013] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 10/29/2012] [Accepted: 11/08/2012] [Indexed: 11/21/2022] Open
Abstract
Drugs of abuse hijack brain-reward circuitry during the addiction process by augmenting action potential-dependent phasic dopamine release events associated with learning and goal-directed behavior. One prominent exception to this notion would appear to be amphetamine (AMPH) and related analogs, which are proposed instead to disrupt normal patterns of dopamine neurotransmission by depleting vesicular stores and promoting nonexocytotic dopamine efflux via reverse transport. This mechanism of AMPH action, though, is inconsistent with its therapeutic effects and addictive properties, which are thought to be reliant on phasic dopamine signaling. Here we used fast-scan cyclic voltammetry in freely moving rats to interrogate principal neurochemical responses to AMPH in the striatum and relate these changes to behavior. First, we showed that AMPH dose-dependently enhanced evoked dopamine responses to phasic-like current pulse trains for up to 2 h. Modeling the data revealed that AMPH inhibited dopamine uptake but also unexpectedly potentiated vesicular dopamine release. Second, we found that AMPH increased the amplitude, duration, and frequency of spontaneous dopamine transients, the naturally occurring, nonelectrically evoked, phasic increases in extracellular dopamine. Finally, using an operant sugar reward paradigm, we showed that low-dose AMPH augmented dopamine transients elicited by sugar-predictive cues. However, operant behavior failed at high-dose AMPH, which was due to phasic dopamine hyperactivity and the decoupling of dopamine transients from the reward predictive cue. These findings identify upregulation of exocytotic dopamine release as a key AMPH action in behaving animals and support a unified mechanism of abused drugs to activate phasic dopamine signaling.
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Affiliation(s)
- D P Daberkow
- School of Biological Sciences, Cell Biology, Physiology and Development Section, Illinois State University, Normal, Illinois 61790, USA
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Espana RA, Jones SR. Presynaptic dopamine modulation by stimulant self-administration. Front Biosci (Schol Ed) 2013; 5:261-76. [PMID: 23277050 DOI: 10.2741/s371] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mesolimbic dopamine system is an essential participant in the initiation and modulation of various forms of goal-directed behavior, including drug reinforcement and addiction processes. Dopamine neurotransmission is increased by acute administration of all drugs of abuse, including the stimulants cocaine and amphetamine. Chronic exposure to these drugs via voluntary self-administration provides a model of stimulant abuse that is useful in evaluating potential behavioral and neurochemical adaptations that occur during addiction. This review describes commonly used methodologies to measure dopamine and baseline parameters of presynaptic dopamine regulation, including exocytotic release and reuptake through the dopamine transporter in the nucleus accumbens core, as well as dramatic adaptations in dopamine neurotransmission and drug sensitivity that occur with acute non-contingent and chronic, contingent self-administration of cocaine and amphetamine.
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Affiliation(s)
- Rodrigo A Espana
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
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