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Vaughan RA, Henry LK, Foster JD, Brown CR. Post-translational mechanisms in psychostimulant-induced neurotransmitter efflux. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2024; 99:1-33. [PMID: 38467478 DOI: 10.1016/bs.apha.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
The availability of monoamine neurotransmitters in the brain is under the control of dopamine, norepinephrine, and serotonin transporters expressed on the plasma membrane of monoaminergic neurons. By regulating transmitter levels these proteins mediate crucial functions including cognition, attention, and reward, and dysregulation of their activity is linked to mood and psychiatric disorders of these systems. Amphetamine-based transporter substrates stimulate non-exocytotic transmitter efflux that induces psychomotor stimulation, addiction, altered mood, hallucinations, and psychosis, thus constituting a major component of drug neurochemical and behavioral outcomes. Efflux is under the control of transporter post-translational modifications that synergize with other regulatory events, and this review will summarize our knowledge of these processes and their role in drug mechanisms.
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Affiliation(s)
- Roxanne A Vaughan
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States.
| | - L Keith Henry
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - James D Foster
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
| | - Christopher R Brown
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND, United States
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2
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Brugnoli FR, Holy M, Niello M, Maier J, Hanreich M, Menzel M, Haberler M, Zulus N, Pickl T, Ivanova C, Muiznieks LD, Garlan B, Sitte HH. Development and validation of an automated microfluidic perfusion platform for parallelized screening of compounds in vitro. Basic Clin Pharmacol Toxicol 2023; 133:535-547. [PMID: 37658634 PMCID: PMC10952622 DOI: 10.1111/bcpt.13940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/28/2023] [Accepted: 08/29/2023] [Indexed: 09/03/2023]
Abstract
Monoamine transporters are of great interest for their role in the physiological activity of the body and their link to mental and behavioural disorders. Currently, static well-plate assays or manual perfusion systems are used to characterize the interaction of psychostimulants, antidepressants and drugs of abuse with the transporters but still suffer from significant drawbacks caused by lack of automation, for example, low reproducibility, non-comparability of results. An automated microfluidic platform was developed to address the need for more standardized procedures for cell-based assays. An automated system was used to control and drive the simultaneous perfusion of 12 channels on a microfluidic chip, establishing a more standardized protocol to perform release assays to study monoamine transporter-mediated substrate efflux. D-Amphetamine, GBR12909 (norepinephrine transporter) and p-chloroamphetamine, paroxetine (serotonin transporter) were used as control compounds to validate the system. The platform was able to produce the expected releasing (D-Amphetamine, p-chloroamphetamine) or inhibiting (GBR12909, paroxetine) profiles for the two transporters. The reduction of manual operation and introduction of automated flow control enabled the implementation of stronger standardized protocols and the possibility of obtaining higher throughput by increasing parallelization.
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Affiliation(s)
- Francesca R. Brugnoli
- Elvesys ‐ Microfluidic Innovation CenterParisFrance
- Center for Physiology and Pharmacology, Institute of PharmacologyMedical University of ViennaViennaAustria
| | - Marion Holy
- Center for Physiology and Pharmacology, Institute of PharmacologyMedical University of ViennaViennaAustria
| | - Marco Niello
- Center for Physiology and Pharmacology, Institute of PharmacologyMedical University of ViennaViennaAustria
| | - Julian Maier
- Center for Physiology and Pharmacology, Institute of PharmacologyMedical University of ViennaViennaAustria
| | - Marcus Hanreich
- Höhere Technische Bundeslehr‐ und Versuchsanstalt Mödling (HTL Mödling)MödlingAustria
| | - Mario Menzel
- Höhere Technische Bundeslehr‐ und Versuchsanstalt Mödling (HTL Mödling)MödlingAustria
| | - Matthias Haberler
- Höhere Technische Bundeslehr‐ und Versuchsanstalt Mödling (HTL Mödling)MödlingAustria
| | - Niklas Zulus
- Höhere Technische Bundeslehr‐ und Versuchsanstalt Mödling (HTL Mödling)MödlingAustria
| | - Thomas Pickl
- Höhere Technische Bundeslehr‐ und Versuchsanstalt Mödling (HTL Mödling)MödlingAustria
| | | | | | | | - Harald H. Sitte
- Center for Physiology and Pharmacology, Institute of PharmacologyMedical University of ViennaViennaAustria
- Hourani Center for Applied Scientific ResearchAl‐Ahliyya Amman UniversityAmmanJordan
- Center for Addiction Research and Science ‐ AddRessMedical University ViennaViennaAustria
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3
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Saenz J, Yao O, Khezerlou E, Aggarwal M, Zhou X, Barker DJ, DiCicco-Bloom E, Pan PY. Cocaine-regulated trafficking of dopamine transporters in cultured neurons revealed by a pH sensitive reporter. iScience 2023; 26:105782. [PMID: 36594015 PMCID: PMC9804146 DOI: 10.1016/j.isci.2022.105782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Revised: 11/07/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022] Open
Abstract
Cocaine acts by inhibiting plasma membrane dopamine transporter (DAT) function and altering its surface expression. The precise manner and mechanism by which cocaine regulates DAT trafficking, especially at neuronal processes, are poorly understood. In this study, we engineered and validated the use of DAT-pHluorin for studying DAT localization and its dynamic trafficking at neuronal processes of cultured mouse midbrain neurons. We demonstrate that unlike neuronal soma and dendrites, which contain a majority of the DATs in weakly acidic intracellular compartments, axonal DATs at both shafts and boutons are primarily (75%) localized to the plasma membrane, whereas large varicosities contain abundant intracellular DAT within acidic intracellular structures. We also demonstrate that cocaine exposure leads to a Synaptojanin1-sensitive DAT internalization process followed by membrane reinsertion that lasts for days. Thus, our study reveals the previously unknown dynamics and molecular regulation for cocaine-regulated DAT trafficking in neuronal processes.
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Affiliation(s)
- Jacqueline Saenz
- Rutgers University Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, 675 Hoes Lane West, Piscataway, NJ 08854, USA
- Rutgers Graduate School of Biomedical Sciences, Molecular Biosciences Graduate Program, Piscataway, NJ 08854, USA
| | - Oscar Yao
- Rutgers University Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Elnaz Khezerlou
- Rutgers University Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Meha Aggarwal
- Rutgers University Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, 675 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Xiaofeng Zhou
- Rutgers University Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, 683 Hoes Lane West, Piscataway, NJ 08854, USA
| | - David J. Barker
- Rutgers, The State University of New Jersey, Department of Psychology, 152 Frelinghuysen Road, Piscataway, NJ 08854, USA
| | - Emanuel DiCicco-Bloom
- Rutgers University Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, 683 Hoes Lane West, Piscataway, NJ 08854, USA
| | - Ping-Yue Pan
- Rutgers University Robert Wood Johnson Medical School, Department of Neuroscience and Cell Biology, 675 Hoes Lane West, Piscataway, NJ 08854, USA
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4
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Szego EM, Malz L, Bernhardt N, Rösen-Wolff A, Falkenburger BH, Luksch H. Constitutively active STING causes neuroinflammation and degeneration of dopaminergic neurons in mice. eLife 2022; 11:81943. [PMID: 36314770 PMCID: PMC9767458 DOI: 10.7554/elife.81943] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/31/2022] [Indexed: 12/30/2022] Open
Abstract
Stimulator of interferon genes (STING) is activated after detection of cytoplasmic dsDNA by cGAS (cyclic GMP-AMP synthase) as part of the innate immunity defence against viral pathogens. STING binds TANK-binding kinase 1 (TBK1). TBK1 mutations are associated with familial amyotrophic lateral sclerosis, and the STING pathway has been implicated in the pathogenesis of further neurodegenerative diseases. To test whether STING activation is sufficient to induce neurodegeneration, we analysed a mouse model that expresses the constitutively active STING variant N153S. In this model, we focused on dopaminergic neurons, which are particularly sensitive to stress and represent a circumscribed population that can be precisely quantified. In adult mice expressing N153S STING, the number of dopaminergic neurons was smaller than in controls, as was the density of dopaminergic axon terminals and the concentration of dopamine in the striatum. We also observed alpha-synuclein pathology and a lower density of synaptic puncta. Neuroinflammation was quantified by staining astroglia and microglia, by measuring mRNAs, proteins and nuclear translocation of transcription factors. These neuroinflammatory markers were already elevated in juvenile mice although at this age the number of dopaminergic neurons was still unaffected, thus preceding the degeneration of dopaminergic neurons. More neuroinflammatory markers were blunted in mice deficient for inflammasomes than in mice deficient for signalling by type I interferons. Neurodegeneration, however, was blunted in both mice. Collectively, these findings demonstrate that chronic activation of the STING pathway is sufficient to cause degeneration of dopaminergic neurons. Targeting the STING pathway could therefore be beneficial in Parkinson's disease and further neurodegenerative diseases.
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Affiliation(s)
- Eva M Szego
- Department of Neurology, TU Dresden, Dresden, Germany
| | - Laura Malz
- Departments of Neurology & Pediatrics, TU Dresden, Dresden, Germany
| | | | | | - Björn H Falkenburger
- Department of Neurology, TU Dresden, Dresden, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen, Dresden, Germany
| | - Hella Luksch
- Department of Pediatrics, TU Dresden, Dresden, Germany
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Catale C, Lo Iacono L, Martini A, Heil C, Guatteo E, Mercuri NB, Viscomi MT, Palacios D, Carola V. Early Life Social Stress Causes Sex- and Region-Dependent Dopaminergic Changes that Are Prevented by Minocycline. Mol Neurobiol 2022; 59:3913-3932. [PMID: 35435618 PMCID: PMC9148283 DOI: 10.1007/s12035-022-02830-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 04/02/2022] [Indexed: 02/03/2023]
Abstract
Early life stress (ELS) is known to modify trajectories of brain dopaminergic development, but the mechanisms underlying have not been determined. ELS perturbs immune system and microglia reactivity, and inflammation and microglia influence dopaminergic transmission and development. Whether microglia mediate the effects of ELS on dopamine (DA) system development is still unknown. We explored the effects of repeated early social stress on development of the dopaminergic system in male and female mice through histological, electrophysiological, and transcriptomic analyses. Furthermore, we tested whether these effects could be mediated by ELS-induced altered microglia/immune activity through a pharmacological approach. We found that social stress in early life altered DA neurons morphology, reduced dopamine transporter (DAT) and tyrosine hydroxylase expression, and lowered DAT-mediated currents in the ventral tegmental area but not substantia nigra of male mice only. Notably, stress-induced DA alterations were prevented by minocycline, an inhibitor of microglia activation. Transcriptome analysis in the developing male ventral tegmental area revealed that ELS caused downregulation of dopaminergic transmission and alteration in hormonal and peptide signaling pathways. Results from this study offer new insight into the mechanisms of stress response and altered brain dopaminergic maturation after ELS, providing evidence of neuroimmune interaction, sex differences, and regional specificity.
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Affiliation(s)
- Clarissa Catale
- Division of Experimental Neuroscience, Neurobiology of Behavior Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Luisa Lo Iacono
- Department of Dynamic and Clinical Psychology, and Health Studies, Sapienza University of Rome, Via degli Apuli 1, Rome, Italy
| | - Alessandro Martini
- Division of Experimental Neuroscience, Experimental Neurology Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Constantin Heil
- Division of Experimental Neuroscience, Epigenetics and Signal Transduction Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
| | - Ezia Guatteo
- Division of Experimental Neuroscience, Experimental Neurology Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Motor Science and Wellness, University of Naples Parthenope, Naples, Italy
| | - Nicola Biagio Mercuri
- Division of Experimental Neuroscience, Experimental Neurology Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
- Department of Systems Medicine, Università Degli Studi Di Roma Tor Vergata, Rome, Italy
| | - Maria Teresa Viscomi
- Department of Life Science and Public Health, Section of Histology and Embryology, Università Cattolica Del S. Cuore, Rome, Italy
- IRCCS Fondazione Policlinico Universitario A. Gemelli, Rome, Italy
| | - Daniela Palacios
- Division of Experimental Neuroscience, Epigenetics and Signal Transduction Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy
- IRCCS Fondazione Policlinico Universitario A. Gemelli, Rome, Italy
- Department of Life Science and Public Health, Section of Biology, Università Cattolica Del S. Cuore, Rome, Italy
| | - Valeria Carola
- Division of Experimental Neuroscience, Neurobiology of Behavior Laboratory, IRCCS Santa Lucia Foundation, Rome, Italy.
- Department of Dynamic and Clinical Psychology, and Health Studies, Sapienza University of Rome, Via degli Apuli 1, Rome, Italy.
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Delignat-Lavaud B, Ducrot C, Kouwenhoven W, Feller N, Trudeau LÉ. Implication of synaptotagmins 4 and 7 in activity-dependent somatodendritic dopamine release in the ventral midbrain. Open Biol 2022; 12:210339. [PMID: 35232250 PMCID: PMC8889187 DOI: 10.1098/rsob.210339] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/31/2022] [Indexed: 01/07/2023] Open
Abstract
Dopamine (DA) neurons can release DA not just from axon terminals, but also from their somatodendritic (STD) compartment through a mechanism that is still incompletely understood. Using voltammetry in mouse mesencephalic brain slices, we find that STD DA release has low capacity and shows a calcium sensitivity that is comparable to that of axonal release. We find that the molecular mechanism of STD DA release differs from axonal release with regard to the implication of synaptotagmin (Syt) calcium sensors. While individual constitutive knockout of Syt4 or Syt7 is not sufficient to reduce STD DA release, the removal of both isoforms reduces this release by approximately 50%, leaving axonal release unimpaired. Our work unveils clear differences in the mechanisms of STD and axonal DA release.
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Affiliation(s)
- Benoît Delignat-Lavaud
- Department of Pharmacology and Physiology, Université de Montréal, QC, Canada H3T 1J4
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, QC, Canada H3T 1J4
- Neural Signaling and Circuitry Research Group (SNC), Montréal, QC, Canada H3C 3J7
| | - Charles Ducrot
- Department of Pharmacology and Physiology, Université de Montréal, QC, Canada H3T 1J4
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, QC, Canada H3T 1J4
- Neural Signaling and Circuitry Research Group (SNC), Montréal, QC, Canada H3C 3J7
| | - Willemieke Kouwenhoven
- Department of Pharmacology and Physiology, Université de Montréal, QC, Canada H3T 1J4
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, QC, Canada H3T 1J4
- Neural Signaling and Circuitry Research Group (SNC), Montréal, QC, Canada H3C 3J7
| | - Nina Feller
- Department of Pharmacology and Physiology, Université de Montréal, QC, Canada H3T 1J4
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, QC, Canada H3T 1J4
- Neural Signaling and Circuitry Research Group (SNC), Montréal, QC, Canada H3C 3J7
| | - Louis-Éric Trudeau
- Department of Pharmacology and Physiology, Université de Montréal, QC, Canada H3T 1J4
- Department of Neurosciences, Faculty of Medicine, Université de Montréal, QC, Canada H3T 1J4
- Neural Signaling and Circuitry Research Group (SNC), Montréal, QC, Canada H3C 3J7
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7
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Edvardsson CE, Vestlund J, Jerlhag E. A ghrelin receptor antagonist reduces the ability of ghrelin, alcohol or amphetamine to induce a dopamine release in the ventral tegmental area and in nucleus accumbens shell in rats. Eur J Pharmacol 2021; 899:174039. [PMID: 33737011 DOI: 10.1016/j.ejphar.2021.174039] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 03/10/2021] [Accepted: 03/11/2021] [Indexed: 11/24/2022]
Abstract
The orexigenic peptide ghrelin increases the release of dopamine in the nucleus accumbens (NAc) shell via central ghrelin receptors, especially those located in the ventral tegmental area (VTA). The activity of the VTA dopamine neurons projecting to NAc shell, involves somatodendritic dopamine release within the VTA. However, the effects of ghrelin on the concomitant dopamine release in the VTA and NAc shell is unknown. It is further unknown whether addictive drugs, such as alcohol and amphetamine, enhance the dopamine levels in both these areas via ghrelin receptor dependent mechanisms. Thus, the effects of a ghrelin receptor antagonist, JMV2959, on the ability of i) central ghrelin ii) systemic alcohol or iii) systemic amphetamine to increase the dopamine release in the VTA and in the NAc shell in rats by using in vivo microdialysis was explored. We showed that systemic administration of JMV2959 blocks the ability of central ghrelin to increases dopamine release in the VTA and the NAc shell, and reduces the alcohol- and amphetamine-induced dopamine release in both these areas. Locomotor activity studies was then conducted in an attempt to correlate the ghrelin-induced dopamine release in the VTA to a behavioural outcome. These revealed that local infusion of a dopamine D1 receptor antagonist into the VTA blocks the ability of central ghrelin to cause a locomotor stimulation in mice. Collectively, this study adds to the growing body of evidence indicating that ghrelin signalling modulates the ability of ghrelin, and addictive drugs, to activate the mesoaccumbal dopamine pathway.
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Affiliation(s)
- Christian E Edvardsson
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Jesper Vestlund
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Elisabet Jerlhag
- Institute of Neuroscience and Physiology, Department of Pharmacology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
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8
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Altered baseline and amphetamine-mediated behavioral profiles in dopamine transporter Cre (DAT-Ires-Cre) mice compared to tyrosine hydroxylase Cre (TH-Cre) mice. Psychopharmacology (Berl) 2020; 237:3553-3568. [PMID: 32778904 PMCID: PMC10120402 DOI: 10.1007/s00213-020-05635-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023]
Abstract
RATIONALE Transgenic mouse lines expressing Cre-recombinase under the regulation of either dopamine transporter (DAT) or tyrosine hydroxylase (TH) promoters are commonly used to study the dopamine (DA) system. While use of the TH promoter appears to have less liability to changes in native gene expression, transgene insertion in the DAT locus results in reduced DAT expression and function. This confound is sometimes overlooked in genetically targeted behavioral experiments. OBJECTIVES We sought to evaluate the suitability of DAT-Ires-Cre and TH-Cre transgenic lines for behavioral pharmacology experiments with DA agonists. We hypothesized that DAT-Ires-Cre expression would impact DAT-mediated behaviors, but no impact of TH-Cre expression would be observed. METHODS DAT-Ires-Cre and TH-Cre mice bred on mixed 129S6/C57BL/6 and pure C57BL/6 backgrounds were evaluated for novelty-induced, baseline, and amphetamine (AMPH)-induced locomotion, and for AMPH and D1 agonist (SKF-38393)-induced preservative behaviors. RESULTS DAT-Ires-Cre mice on both mixed 129S6/C57BL/6 and pure C57BL/6 backgrounds displayed increased novelty-induced activity and decreased AMPH-induced locomotion, with mixed results for AMPH-induced stereotypy. TH-Cre mice on both backgrounds showed typical baseline activity and AMPH-induced stereotypy, with a difference in AMPH-induced locomotion observed only on the mixed background. Both transgenic lines displayed unaltered SKF-38393-induced grooming behavior. CONCLUSIONS Our findings indicate that the DAT-Ires-Cre transgenic line may lead to confounds for experiments that are dependent on DAT expression. The TH-Cre transgenic line studied here may be a more useful option, depending on background strain, because of its lack of baseline and drug-induced phenotypes. These data highlight the importance of appropriate controls in studies employing transgenic mice.
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9
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Jayaraman K, Das AK, Luethi D, Szöllősi D, Schütz GJ, Reith MEA, Sitte HH, Stockner T. SLC6 transporter oligomerization. J Neurochem 2020; 157:919-929. [PMID: 32767560 PMCID: PMC8247324 DOI: 10.1111/jnc.15145] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/31/2020] [Accepted: 07/31/2020] [Indexed: 12/18/2022]
Abstract
Transporters of the solute carrier 6 (SLC6) family mediate the reuptake of neurotransmitters such as dopamine, norepinephrine, serotonin, GABA, and glycine. SLC6 family members are 12 transmembrane helix‐spanning proteins that operate using the transmembrane sodium gradient for transport. These transporters assume various quaternary arrangements ranging from monomers to complex stoichiometries with multiple subunits. Dopamine and serotonin transporter oligomerization has been implicated in trafficking of newly formed proteins from the endoplasmic reticulum to the plasma membrane with a pre‐fixed assembly. Once at the plasma membrane, oligomers are kept fixed in their quaternary assembly by interaction with phosphoinositides. While it remains unclear how oligomer formation precisely affects physiological transporter function, it has been shown that oligomerization supports the activity of release‐type psychostimulants. Most recently, single molecule microscopy experiments unveiled that the stoichiometry differs between individual members of the SLC6 family. The present overview summarizes our understanding of the influence of plasma membrane constituents on transporter oligomerization, describes the known interfaces between protomers and discusses open questions. ![]()
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Affiliation(s)
- Kumaresan Jayaraman
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Anand K Das
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Dino Luethi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.,Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Dániel Szöllősi
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Gerhard J Schütz
- Institute of Applied Physics, Vienna University of Technology, Vienna, Austria
| | - Maarten E A Reith
- Department of Psychiatry, New York University School of Medicine, New York City, NY, USA
| | - Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Thomas Stockner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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10
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Niello M, Gradisch R, Loland CJ, Stockner T, Sitte HH. Allosteric Modulation of Neurotransmitter Transporters as a Therapeutic Strategy. Trends Pharmacol Sci 2020; 41:446-463. [PMID: 32471654 PMCID: PMC7610661 DOI: 10.1016/j.tips.2020.04.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/21/2020] [Accepted: 04/22/2020] [Indexed: 12/11/2022]
Abstract
Neurotransmitter transporters (NTTs) are involved in the fine-tuning of brain neurotransmitter homeostasis. As such, they are implicated in a plethora of complex behaviors, including reward, movement, and cognition. During recent decades, compounds that modulate NTT functions have been developed. Some of them are in clinical use for the management of different neuropsychiatric conditions. The majority of these compounds have been found to selectively interact with the orthosteric site of NTTs. Recently, diverse allosteric sites have been described in a number of NTTs, modulating their function. A more complex NTT pharmacology may be useful in the development of novel therapeutics. Here, we summarize current knowledge on such modulatory allosteric sites, with specific focus on their pharmacological and therapeutic potential.
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Affiliation(s)
- Marco Niello
- Centre for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Ralph Gradisch
- Centre for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Claus Juul Loland
- Laboratory for Membrane Protein Dynamics. Department of Neuroscience. University of Copenhagen, Copenhagen, Denmark
| | - Thomas Stockner
- Centre for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Harald H Sitte
- Centre for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Vienna, Austria; AddRess, Centre for Addiction Research and Science, Medical University of Vienna, Vienna, Austria.
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11
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Go J, Ryu YK, Park HY, Choi DH, Choi YK, Hwang DY, Lee CH, Kim KS. NQO1 regulates pharmaco-behavioral effects of d-amphetamine in striatal dopaminergic system in mice. Neuropharmacology 2020; 170:108039. [PMID: 32165217 DOI: 10.1016/j.neuropharm.2020.108039] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/11/2020] [Accepted: 03/04/2020] [Indexed: 11/18/2022]
Abstract
The NAD(P)H:quinone oxidoreductase 1 (NQO1) gene encodes a cytosolic flavoenzyme that catalyzes the two-electron reduction of quinones to hydroquinones. A polymorphic form of NQO1 is associated with mood disorders such as schizophrenia. However, the role of NQO1 in dopaminergic system has not yet been elucidated. To determine the role of NQO1 in the dopaminergic system, we investigated pharmaco-behavioral effects of d-amphetamine using NQO1-deficienct mice. According to our comparative study involving NQO1+/+ and NQO1-/- mice, NQO1 deficiency increased d-amphetamine-induced psychomotor activity and psychological dependency compared to wild-type mice. Basal and d-amphetamine-induced dopamine levels were also enhanced by NQO1 deficiency. In NQO1-/- mice, neural activation induced by d-amphetamine was higher in dorsolateral striatum, but not in dorsomedial and ventral striata. Although protein level of CaMKIIα, which is a key player in amphetamine-induced dopamine efflux, was decreased in striata of NQO1-/- mice, phosphorylation of CaMKIIα was markedly enhanced in NQO1-/- mice compared to wild-type mice. Interestingly, experiments with pharmacological antagonist showed that D2 antagonist-induced suppression of locomotion required activation of NQO1. Moreover, the rewarding effect in response to D1 agonist was increased by NQO1 deficiency. These results suggest that striatal NQO1 is of considerable interest to understand the mechanism of dopaminergic regulation of psychiatric disorders.
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Affiliation(s)
- Jun Go
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea; Department of Biomaterials Science, College of Natural Resources and Life Science/Life and Industry Convergence Research Institute, Pusan National University, Miryang, 50463, Republic of Korea
| | - Young-Kyoung Ryu
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea; College of Biosciences & Biotechnology, Chung-Nam National University, Daejeon, 34134, Republic of Korea
| | - Hye-Yeon Park
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea; Department of Brain & Cognitive Sciences, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Dong-Hee Choi
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
| | - Young-Keun Choi
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea
| | - Dae Youn Hwang
- Department of Biomaterials Science, College of Natural Resources and Life Science/Life and Industry Convergence Research Institute, Pusan National University, Miryang, 50463, Republic of Korea
| | - Chul-Ho Lee
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea; Department of Functional Genomics, University of Science and Technology, Daejeon, 34113, Republic of Korea.
| | - Kyoung-Shim Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, Republic of Korea; Department of Functional Genomics, University of Science and Technology, Daejeon, 34113, Republic of Korea.
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12
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Lebowitz JJ, Khoshbouei H. Heterogeneity of dopamine release sites in health and degeneration. Neurobiol Dis 2019; 134:104633. [PMID: 31698055 DOI: 10.1016/j.nbd.2019.104633] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 09/12/2019] [Accepted: 10/02/2019] [Indexed: 02/06/2023] Open
Abstract
Despite comprising only ~ 0.001% of all neurons in the human brain, ventral midbrain dopamine neurons exert a profound influence on human behavior and cognition. As a neuromodulator, dopamine selectively inhibits or enhances synaptic signaling to coordinate neural output for action, attention, and affect. Humans invariably lose brain dopamine during aging, and this can be exacerbated in disease states such as Parkinson's Disease. Further, it is well established in multiple disease states that cell loss is selective for a subset of highly sensitive neurons within the nigrostriatal dopamine tract. Regional differences in dopamine tone are regulated pre-synaptically, with subcircuits of projecting dopamine neurons exhibiting distinct molecular and physiological signatures. Specifically, proteins at dopamine release sites that synthesize and package cytosolic dopamine, modulate its release and reuptake, and alter neuronal excitability show regional differences that provide linkages to the observed sensitivity to neurodegeneration. The aim of this review is to outline the major components of dopamine homeostasis at neurotransmitter release sites and describe the regional differences most relevant to understanding why some, but not all, dopamine neurons exhibit heightened vulnerability to neurodegeneration.
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Affiliation(s)
- Joseph J Lebowitz
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Habibeh Khoshbouei
- Department of Neuroscience, University of Florida College of Medicine, Gainesville, FL 32610, USA.
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13
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Green AL, Eid A, Zhan L, Zarbl H, Guo GL, Richardson JR. Epigenetic Regulation of the Ontogenic Expression of the Dopamine Transporter. Front Genet 2019; 10:1099. [PMID: 31749842 PMCID: PMC6844290 DOI: 10.3389/fgene.2019.01099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/11/2019] [Indexed: 01/19/2023] Open
Abstract
The dopamine transporter (DAT) is a plasma membrane transport protein responsible for regulating the duration and intensity of dopaminergic signaling. Altered expression of DAT is linked to neurodevelopmental disorders, including attention deficit hyperactivity disorder and autism spectrum disorder, and is shown to contribute to the response of psychotropic drugs and neurotoxicants. Although the postnatal levels of DAT have been characterized, there are few data regarding the mechanisms that regulate postnatal DAT expression. Here, we examine the ontogeny of DAT mRNA from postnatal days 0 to 182 in the rat brain and define a role for epigenetic mechanisms regulating DAT expression. DAT mRNA and protein significantly increased between PND 0 and 6 months in rat midbrain and striatum, respectively. The epigenetic modifiers Dnmt1, Dnmt3a, Dnmt3b, and Hdac2 demonstrated age associated decreases in mRNA expression whereas Hdac5 and Hdac8 showed increased mRNA expression with age. Chromatin immunoprecipitation studies revealed increased protein enrichment of acetylated histone 3 at lysines 9 and 14 and the dopaminergic transcription factors Nurr1 and Pitx3 within the DAT promoter in an age-related manner. Together these studies provide evidence for the role of epigenetic modifications in the regulation of DAT during development. The identification of these mechanisms may contribute to potential therapeutic interventions aimed at neurodevelopmental disorders of the dopaminergic system.
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Affiliation(s)
- Ashley L. Green
- Environmental and Occupational Health Sciences Institute and Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States
| | - Aseel Eid
- Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, FL, United States
| | - Le Zhan
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ, United States
| | - Helmut Zarbl
- Environmental and Occupational Health Sciences Institute and Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States
| | - Grace L. Guo
- Environmental and Occupational Health Sciences Institute and Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States,Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers University, Piscataway, NJ, United States
| | - Jason R. Richardson
- Environmental and Occupational Health Sciences Institute and Department of Environmental and Occupational Medicine, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ, United States,Department of Environmental Health Sciences, Robert Stempel School of Public Health and Social Work, Florida International University, Miami, FL, United States,*Correspondence: Jason R. Richardson,
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14
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Kinetic Models of Secondary Active Transporters. Int J Mol Sci 2019; 20:ijms20215365. [PMID: 31661895 PMCID: PMC6862442 DOI: 10.3390/ijms20215365] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 10/24/2019] [Accepted: 10/26/2019] [Indexed: 01/18/2023] Open
Abstract
Kinetic models have been employed to understand the logic of substrate transport through transporters of the Solute Carrier (SLC) family. All SLC transporters operate according to the alternate access model, which posits that substrate transport occurs in a closed loop of partial reactions (i.e., a transport cycle). Kinetic models can help to find realistic estimates for conformational transitions between individual states of the transport cycle. When constrained by experimental results, kinetic models can faithfully describe the function of a candidate transporter at a pre-steady state. In addition, we show that kinetic models can accurately predict the intra- and extracellular substrate concentrations maintained by the transporter at a steady state, even under the premise of loose coupling between the electrochemical gradient of the driving ion and of the substrate. We define the criteria for the design of a credible kinetic model of the SLC transporter. Parsimony is the guiding principle of kinetic modeling. We argue, however, that the level of acceptable parsimony is limited by the need to account for the substrate gradient established by a secondary active transporter, and for random order binding of co-substrates and substrate. Random order binding has consistently been observed in transporters of the SLC group.
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15
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Liu C, Kaeser PS. Mechanisms and regulation of dopamine release. Curr Opin Neurobiol 2019; 57:46-53. [PMID: 30769276 PMCID: PMC6629510 DOI: 10.1016/j.conb.2019.01.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/03/2019] [Accepted: 01/04/2019] [Indexed: 01/17/2023]
Abstract
Dopamine controls motor functions, motivation, and reward-related learning through G-protein coupled receptor signaling. The current working model is that upon release, dopamine diffuses to influence many target cells via wide-spread receptors. Recent studies, however, suggest that dopamine release is fast and generates small signaling hotspots. In this review, we summarize progress on the understanding of the dopamine release apparatus and evaluate how its properties may shape dopamine signaling during firing. We discuss how mechanisms of regulation may act through this machinery and propose that striatal architecture for dopamine signaling may have evolved to support rapid dopamine coding.
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Affiliation(s)
- Changliang Liu
- Department of Neurobiology, Harvard Medical School, United States
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, United States.
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16
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Wu Y, Proch KL, Teran FA, Lechtenberg RJ, Kothari H, Richerson GB. Chemosensitivity of Phox2b-expressing retrotrapezoid neurons is mediated in part by input from 5-HT neurons. J Physiol 2019; 597:2741-2766. [PMID: 30866045 PMCID: PMC6826216 DOI: 10.1113/jp277052] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 03/07/2019] [Indexed: 01/18/2023] Open
Abstract
KEY POINTS Neurons of the retrotrapezoid nucleus (RTN) and medullary serotonin (5-HT) neurons are both candidates for central CO2 /pH chemoreceptors, but it is not known how interactions between them influence their responses to pH. We found that RTN neurons in brain slices were stimulated by exogenous 5-HT and by heteroexchange release of endogenous 5-HT, and these responses were blocked by antagonists of 5-HT7 receptors. The pH response of RTN neurons in brain slices was markedly reduced by the same antagonists of 5-HT7 receptors. Similar results were obtained in dissociated, primary cell cultures prepared from the ventral medulla, where it was also found that the pH response of RTN neurons was blocked by preventing 5-HT synthesis and enhanced by blocking 5-HT reuptake. Exogenous 5-HT did not enable latent intrinsic RTN chemosensitivity. RTN neurons may play more of a role as relays from other central and peripheral chemoreceptors than as CO2 sensors. ABSTRACT Phox2b-expressing neurons in the retrotrapezoid nucleus (RTN) and serotonin (5-HT) neurons in the medullary raphe have both been proposed to be central respiratory chemoreceptors. How interactions between these two sets of neurons influence their responses to acidosis is not known. Here we recorded from mouse Phox2b+ RTN neurons in brain slices, and found that their response to moderate hypercapnic acidosis (pH 7.4 to ∼7.2) was markedly reduced by antagonists of 5-HT7 receptors. RTN neurons were stimulated in response to heteroexchange release of 5-HT, indicating that RTN neurons are sensitive to endogenous 5-HT. This electrophysiological behaviour was replicated in primary, dissociated cell cultures containing 5-HT and RTN neurons grown together. In addition, pharmacological inhibition of 5-HT synthesis in culture reduced RTN neuron chemosensitivity, and blocking 5-HT reuptake enhanced chemosensitivity. The effect of 5-HT on RTN neuron chemosensitivity was not explained by a mechanism whereby activation of 5-HT7 receptors enables or potentiates intrinsic chemosensitivity of RTN neurons, as exogenous 5-HT did not enhance the pH response. The ventilatory response to inhaled CO2 of mice was markedly decreased in vivo after systemic treatment with ketanserin, an antagonist of 5-HT2 and 5-HT7 receptors. These data indicate that 5-HT and RTN neurons may interact synergistically in a way that enhances the respiratory chemoreceptor response. The primary role of RTN neurons may be as relays and amplifiers of the pH response from 5-HT neurons and other chemoreceptors rather than as pH sensors themselves.
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Affiliation(s)
- Yuanming Wu
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
| | - Katherine L. Proch
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
- Graduate Program in NeuroscienceUniversity of IowaIowa CityIA52242USA
| | - Frida A. Teran
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
- Graduate Program in NeuroscienceUniversity of IowaIowa CityIA52242USA
- Iowa Neuroscience InstituteUniversity of IowaIowa CityIA52242USA
| | | | - Harsh Kothari
- Department of PediatricsUniversity of IowaIowa CityIA52242USA
| | - George B. Richerson
- Department of NeurologyUniversity of IowaIowa CityIA52242USA
- Graduate Program in NeuroscienceUniversity of IowaIowa CityIA52242USA
- Department of Molecular Physiology & BiophysicsUniversity of IowaIowa CityIA52242USA
- Neurology ServiceVeterans Affairs Medical CenterIowa CityIA52242USA
- Iowa Neuroscience InstituteUniversity of IowaIowa CityIA52242USA
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17
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Azadi M, Azizi H, Haghparast A. Paternal exposure to morphine during adolescence induces reward-resistant phenotype to morphine in male offspring. Brain Res Bull 2019; 147:124-132. [DOI: 10.1016/j.brainresbull.2019.02.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/06/2019] [Indexed: 12/29/2022]
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18
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Kasture AS, Bartel D, Steinkellner T, Sucic S, Hummel T, Freissmuth M. Distinct contribution of axonal and somatodendritic serotonin transporters in drosophila olfaction. Neuropharmacology 2019; 161:107564. [PMID: 30851308 DOI: 10.1016/j.neuropharm.2019.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/11/2019] [Accepted: 03/03/2019] [Indexed: 01/07/2023]
Abstract
The serotonin transporter (SERT) regulates serotonergic neurotransmission by retrieving released serotonin and replenishing vesicular stores. SERT is not only delivered to axons but it is also present on the neuronal soma and on dendrites. It has not been possible to restrict the distribution of SERT without affecting transporter function. Hence, the physiological role of somatodendritic SERT remains enigmatic. The SERT C-terminus harbors a conserved RI-motif, which recruits SEC24C, a cargo receptor in the coatomer protein-II coat. Failure to engage SEC24C precludes axonal enrichment of SERT. Here we introduced a point mutation into the RI-motif of human SERT causing confinement of the resulting - otherwise fully functional - hSERT-R607A on the somatodendritic membrane of primary rat dorsal raphe neurons. Transgenic expression of the corresponding Drosophila mutant dSERT-R599A led to its enrichment in the somatodendritic compartment of serotonergic neurons in the fly brain. We explored the possible physiological role of somatodendritic SERT by comparing flies harboring wild type SERT and dSERT-R599A in a behavioral paradigm for serotonin-modulated odor perception. When globally re-expressed in serotonergic neurons, wild type SERT but not dSERT-R599A restored ethanol preference. In contrast, dSERT-R599A restored ethanol preference after targeted expression in contralaterally projecting, serotonin-immunoreactive deuterocerebral (CSD) interneurons, while expression of wild type SERT caused ethanol aversion. We conclude that, in CSD neurons, (i) somatodendritic SERT supports ethanol attraction, (ii) axonal SERT specifies ethanol aversion, (iii) the effect of axonal SERT can override that of somatodendritic SERT. These observations demonstrate a distinct biological role of somatodendritic and axonal serotonin transport. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Ameya Sanjay Kasture
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria; Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Daniela Bartel
- Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Thomas Steinkellner
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Thomas Hummel
- Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
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19
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Yee AG, Forbes B, Cheung PY, Martini A, Burrell MH, Freestone PS, Lipski J. Action potential and calcium dependence of tonic somatodendritic dopamine release in the Substantia Nigra pars compacta. J Neurochem 2018; 148:462-479. [PMID: 30203851 DOI: 10.1111/jnc.14587] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/09/2018] [Accepted: 09/04/2018] [Indexed: 12/31/2022]
Abstract
Despite the importance of somatodendritic dopamine (DA) release in the Substantia Nigra pars compacta (SNc), its mechanism remains poorly understood. Using a novel approach combining fast-scan controlled-adsorption voltammetry (FSCAV) and single-unit electrophysiology, we have investigated the mechanism of somatodendritic release by directly correlating basal (non-stimulated) extracellular DA concentration ([DA]out ), with pharmacologically-induced changes of firing of nigral dopaminergic neurons in rat brain slices. FSCAV measurements indicated that basal [DA]out in the SNc was 40.7 ± 2.0 nM (at 34 ± 0.5°C), which was enhanced by amphetamine, cocaine, and L-DOPA, and reduced by VMAT2 inhibitor, Ro4-1284. Complete inhibition of firing by TTX decreased basal [DA]out , but this reduction was smaller than the effect of D2 receptor agonist, quinpirole. Despite similar effects on neuronal firing, the larger decrease in [DA]out evoked by quinpirole was attributed to cell membrane hyperpolarization and greater reduction in cytosolic free Ca2+ ([Ca2+ ]in ). Decreasing extracellular Ca2+ also reduced basal [DA]out , despite increasing firing frequency. Furthermore, inhibiting L-type Ca2+ channels decreased basal [DA]out , although specific Cav 1.3 channel inhibition did not affect firing rate. Inhibition of sarcoplasmic/endoplasmic reticulum Ca2+ -ATPase (SERCA) also decreased [DA]out , demonstrating the importance of intracellular Ca2+ stores for somatodendritic release. Finally, in vivo FSCAV measurements showed that basal [DA]out in the SNc was 79.8 ± 10.9 nM in urethane-anesthetized rats, which was enhanced by amphetamine. Overall, our findings indicate that although tonic somatodendritic DA release is largely independent of action potentials, basal [DA]out is strongly regulated by voltage-dependent Ca2+ influx and release of intracellular Ca2+ . OPEN SCIENCE BADGES: This article has received a badge for *Open Materials* because it provided all relevant information to reproduce the study in the manuscript. The complete Open Science Disclosure form for this article can be found at the end of the article. More information about the Open Practices badges can be found at https://cos.io/our-services/open-science-badges/.
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Affiliation(s)
- Andrew G Yee
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Blaze Forbes
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Pang-Ying Cheung
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | | | - Mark H Burrell
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand.,Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK
| | - Peter S Freestone
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Janusz Lipski
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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20
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Garcia-Olivares J, Baust T, Harris S, Hamilton P, Galli A, Amara SG, Torres GE. Gβγ subunit activation promotes dopamine efflux through the dopamine transporter. Mol Psychiatry 2017; 22:1673-1679. [PMID: 28894302 PMCID: PMC5996372 DOI: 10.1038/mp.2017.176] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 07/05/2017] [Accepted: 07/28/2017] [Indexed: 01/30/2023]
Abstract
The dopamine transporter (DAT) is an important regulator of brain dopamine (DA) homeostasis, controlling the intensity and duration of DA signaling. DAT is the target for psychostimulants-like cocaine and amphetamine-and plays an important role in neuropsychiatric disorders, including attention-deficit hyperactivity disorder and drug addiction. Thus, a thorough understanding of the mechanisms that regulate DAT function is necessary for the development of clinical interventions to treat DA-related brain disorders. Previous studies have revealed a plethora of protein-protein interactions influencing DAT cellular localization and activity, suggesting that the fine-tuning of DA homeostasis involves multiple mechanisms. We recently reported that G-protein beta-gamma (Gβγ) subunits bind directly to DAT and decrease DA clearance. Here we show that Gβγ induces the release of DA through DAT. Specifically, a Gβγ-binding/activating peptide, mSIRK, increases DA efflux through DAT in heterologous cells and primary dopaminergic neurons in culture. Addition of the Gβγ inhibitor gallein or DAT inhibitors prevents this effect. Residues 582 to 596 in the DAT carboxy terminus were identified as the primary binding site of Gβγ. A TAT peptide containing the Gβγ-interacting domain of DAT blocked the ability of mSIRK to induce DA efflux, consistent with a direct interaction of Gβγ with the transporter. Finally, activation of a G-protein-coupled receptor, the muscarinic M5R, results in DAT-mediated DA efflux through a Gβγ-dependent mechanism. Collectively, our data show that Gβγ interacts with DAT to promote DA efflux. This novel mechanism may have important implications in the regulation of brain DA homeostasis.
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Affiliation(s)
- J Garcia-Olivares
- Laboratory of Cellular and Molecular Neurobiology, National Institute of Mental Health, Bethesda, MD, USA
| | - T Baust
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA
| | - S Harris
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA
| | - P Hamilton
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - A Galli
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - SG Amara
- Laboratory of Cellular and Molecular Neurobiology, National Institute of Mental Health, Bethesda, MD, USA
| | - GE Torres
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA
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21
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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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22
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Fox ME, Wightman RM. Contrasting Regulation of Catecholamine Neurotransmission in the Behaving Brain: Pharmacological Insights from an Electrochemical Perspective. Pharmacol Rev 2017; 69:12-32. [PMID: 28267676 DOI: 10.1124/pr.116.012948] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Catecholamine neurotransmission plays a key role in regulating a variety of behavioral and physiologic processes, and its dysregulation is implicated in both neurodegenerative and neuropsychiatric disorders. Over the last four decades, in vivo electrochemistry has enabled the discovery of contrasting catecholamine regulation in the brain. These rapid and spatially resolved measurements have been conducted in brain slices, and in anesthetized and freely behaving animals. In this review, we describe the methods enabling in vivo measurements of dopamine and norepinephrine, and subsequent findings regarding their release and regulation in intact animals. We thereafter discuss key studies in awake animals, demonstrating that these catecholamines are not only differentially regulated, but are released in opposition of each other during appetitive and aversive stimuli.
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Affiliation(s)
- Megan E Fox
- Department of Chemistry and Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina
| | - R Mark Wightman
- Department of Chemistry and Neuroscience Center, University of North Carolina, Chapel Hill, North Carolina
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23
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Nagatomo K, Suga S, Saitoh M, Kogawa M, Kobayashi K, Yamamoto Y, Yamada K. Dopamine D1 Receptor Immunoreactivity on Fine Processes of GFAP-Positive Astrocytes in the Substantia Nigra Pars Reticulata of Adult Mouse. Front Neuroanat 2017; 11:3. [PMID: 28203148 PMCID: PMC5285371 DOI: 10.3389/fnana.2017.00003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 01/13/2017] [Indexed: 12/20/2022] Open
Abstract
Substantia nigra pars reticulata (SNr), the major output nucleus of the basal ganglia, receives dopamine from dendrites extending from dopaminergic neurons of the adjacent nucleus pars compacta (SNc), which is known for its selective degeneration in Parkinson's disease. As a recipient for dendritically released dopamine, the dopamine D1 receptor (D1R) is a primary candidate due to its very dense immunoreactivity in the SNr. However, the precise location of D1R remains unclear at the cellular level in the SNr except for that reported on axons/axon terminals of presumably striatal GABAergic neurons. To address this, we used D1R promotor-controlled, mVenus-expressing transgenic mice. When cells were acutely dissociated from SNr of mouse brain, prominent mVenus fluorescence was detected in fine processes of glia-like cells, but no such fluorescence was detected from neurons in the same preparation, except for the synaptic bouton-like structure on the neurons. Double immunolabeling of SNr cells dissociated from adult wild-type mice brain further revealed marked D1R immunoreactivity in the processes of glial fibrillary acidic protein (GFAP)-positive astrocytes. Such D1R imunoreactivity was significantly stronger in the SNr astrocytes than that in those of the visual cortex in the same preparation. Interestingly, GFAP-positive astrocytes dissociated from the striatum demonstrated D1R immunoreactivity, either remarkable or minimal, similarly to that shown in neurons in this nucleus. In contrast, in the SNr and visual cortex, only weak D1R immunoreactivity was detected in the neurons tested. These results suggest that the SNr astrocyte may be a candidate recipient for dendritically released dopamine. Further study is required to fully elucidate the physiological roles of divergent dopamine receptor immunoreactivity profiles in GFAP-positive astrocytes.
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Affiliation(s)
- Katsuhiro Nagatomo
- Department of Physiology, Hirosaki University Graduate School of Medicine Aomori, Japan
| | - Sechiko Suga
- Department of Physiology, Hirosaki University Graduate School of MedicineAomori, Japan; Department of Emergency Medical Technology, Hirosaki University of Health and WelfareAomori, Japan
| | - Masato Saitoh
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University Iwate, Japan
| | - Masahito Kogawa
- Department of Physiology, Hirosaki University Graduate School of Medicine Aomori, Japan
| | - Kazuto Kobayashi
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University School of Medicine Fukushima, Japan
| | - Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University Iwate, Japan
| | - Katsuya Yamada
- Department of Physiology, Hirosaki University Graduate School of Medicine Aomori, Japan
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24
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Ludwig M, Apps D, Menzies J, Patel JC, Rice ME. Dendritic Release of Neurotransmitters. Compr Physiol 2016; 7:235-252. [PMID: 28135005 DOI: 10.1002/cphy.c160007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Release of neuroactive substances by exocytosis from dendrites is surprisingly widespread and is not confined to a particular class of transmitters: it occurs in multiple brain regions, and includes a range of neuropeptides, classical neurotransmitters, and signaling molecules, such as nitric oxide, carbon monoxide, ATP, and arachidonic acid. This review is focused on hypothalamic neuroendocrine cells that release vasopressin and oxytocin and midbrain neurons that release dopamine. For these two model systems, the stimuli, mechanisms, and physiological functions of dendritic release have been explored in greater detail than is yet available for other neurons and neuroactive substances. © 2017 American Physiological Society. Compr Physiol 7:235-252, 2017.
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Affiliation(s)
- Mike Ludwig
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - David Apps
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - John Menzies
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Jyoti C Patel
- Department of Neurosurgery, New York University School of Medicine, New York, USA
| | - Margaret E Rice
- Department of Neurosurgery, New York University School of Medicine, New York, USA.,Department of Neuroscience and Physiology, New York University School of Medicine, New York, USA
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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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Zuo W, Wang L, Chen L, Krnjević K, Fu R, Feng X, He W, Kang S, Shah A, Bekker A, Ye JH. Ethanol potentiates both GABAergic and glutamatergic signaling in the lateral habenula. Neuropharmacology 2016; 113:178-187. [PMID: 27678415 DOI: 10.1016/j.neuropharm.2016.09.026] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 10/21/2022]
Abstract
Ethanol's aversive property may limit it's use, but the underlying mechanisms are no well-understood. Emerging evidence suggests a critical role for the lateral habenula (LHb) in the aversive response to various drugs, including ethanol. We previously showed that ethanol enhances glutamatergic transmission and stimulates LHb neurons. GABAergic transmission, a major target of ethanol in many brain regions, also tightly regulates LHb activity. This study assessed the action of ethanol on LHb GABAergic transmission in rat brain slices. Application of ethanol accelerated spontaneous action potential firing of LHb neurons, and LHb activity was increased by the GABAA receptor antagonist gabazine, and ethanol-induced acceleration of LHb firing was further increased by gabazine. Additionally, ethanol potentiated GABAergic transmission (inhibitory postsynaptic currents, IPSCs) with an EC50 of 1.5 mM. Ethanol-induced potentiation of IPSCs was increased by a GABAB receptor antagonist; it was mimicked by dopamine, dopamine receptor agonists, and dopamine reuptake blocker, and was completely prevented by reserpine, which depletes store of catecholamine. Moreover, ethanol-induced potentiation of IPSCs involved cAMP signaling. Finally, ethanol enhanced simultaneously glutamatergic and GABAergic transmissions to the majority of LHb neurons: the potentiation of the former being greater than that of the latter, the net effect was increased firing. Since LHb excitation may contribute to aversion, ethanol-induced potentiation of GABAergic inhibition tends to reduce aversion.
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Affiliation(s)
- Wanhong Zuo
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, USA
| | - Liwei Wang
- Department of Physiology, Medical College, Jinan University, Guangzhou, China
| | - Lixin Chen
- Department of Pharmacology, Medical College, Jinan University, Guangzhou, China
| | - Krešimir Krnjević
- Department of Physiology, McGill University, McIntyre Centre, 3655 Promenade Sir William Osler, Montréal, QC H3G 1Y6, Canada
| | - Rao Fu
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, USA
| | - Xia Feng
- Department of Anesthesiology, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Wen He
- Department of Geriatrics, First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Seungwoo Kang
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, USA
| | - Avi Shah
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, USA
| | - Alex Bekker
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, USA
| | - Jiang-Hong Ye
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, 185 South Orange Avenue, Newark, NJ, USA.
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Pittman JT, Dodd CA, Klein BG. Immunohistochemical Changes in the Mouse Striatum Induced by the Pyrethroid Insecticide Permethrin. Int J Toxicol 2016; 22:359-70. [PMID: 14555407 DOI: 10.1177/109158180302200504] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Epidemiological studies have linked insecticide exposure and Parkinson's disease. In addition, some insecticides produce damage or physiological disruption within the dopaminergic nigrostriatal pathway of non-humans. This study employed immunohistochemical analysis in striatum of the C57BL/6 mouse to clarify tissue changes suggested by previous pharmacological studies of the pyrethroid insecticide permethrin. Dopamine transporter, tyrosine hydroxylase, and glial fibrillary acidic protein immunoreactivities were examined in caudate-putamen to distinguish changes in amount of dopamine transporter immunoreactive protein from degeneration or other damage to dopaminergic neuropil. Weight-matched pairs of pesticide-treated and vehicle-control mice were dosed and sacrificed on the same days. Permethrin at 0.8, 1.5 and 3.0 mg/kg were the low doses and at 200 mg/kg the high dose. Brains from matched pairs of mice were processed on the same slides using the avidin-biotin technique. Four fields were morphometrically located in each of the serial sections of caudateputamen, digitally photographed, and immunopositive image pixels were counted and compared between members of matched pairs of permethrin-treated and vehicle-control mice. For low doses, only 3.0 mg/kg produced a significant decrease in dopamine transporter immunostaining. The high dose of permethrin did not produce a significant change in dopamine transporter or tyrosine hydroxylase immunostaining, but resulted in a significant increase in glial fibrillary acidic protein immunostaining. These data suggest that a low dose of permethrin can reduce the amount of dopamine transporter immunoreactive protein in the caudate-putamen. They also suggest that previously reported reductions in dopamine uptake of striatal synaptosomes of high-dose mice may be due to nondegenerative tissue damage within this region as opposed to reductions of dopamine transporter protein or death of nigrostriatal terminals. These data provide further evidence that insecticides can affect the primary neurodegenerative substrate of Parkinson's disease.
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Affiliation(s)
- Julian T Pittman
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland Regional College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia 24061, USA
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Tarasenko AS. Effect of nitric oxide donor SNAP on GABA release from rat brain nerve terminals. UKRAINIAN BIOCHEMICAL JOURNAL 2016; 88:82-9. [PMID: 29235815 DOI: 10.15407/ubj88.05.082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In this work we investigated the effect of nanomolar concentrations of nitric oxide on the release of gamma-aminobutyric acid (GABA) from rat brain nerve terminals using a radioisotope method with [3H]GABA and a spectrofluorimetric method with Ca2+-sensitive probe Fluo-4 AM. It was shown that in the presence of dithiothreitol (DTT), nitric oxide donor SNAP at concentration, in which it produces NO in the nanomolar range, caused Ca2+-independent [3H]GABA release from nerve terminals. The applications of 4-aminopyridine (4-AP) and nipecotic acid (NA), as the inducers of GABA release from vesicular and cytoplasmic pools, showed that the maximum of SNAP/+DTT-induced [3H]GABA release was registered at 10th min of incubation and coincided in time with significant increase (almost double) in NA-induced [3H]GABA release. At this time point, 4-AP-induced release of [3H]GABA was drastically reduced. At the 15th min of incubation of nerve terminals with SNAP/+DTT, the opposite picture was observed: the decrease in NA- and increase in 4-AP-induced [3H]GABA release. Thus, nitric oxide in the form of S-nitrosothiols at nanomolar concentrations causes Ca2+-independent GABA leakage from synaptic vesicles into cytosol with subsequent release from nerve terminals. The reuptake of the neurotransmitter and its re-accumulation in synaptic vesicles occur later.
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Rice ME, Patel JC. Somatodendritic dopamine release: recent mechanistic insights. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0185. [PMID: 26009764 DOI: 10.1098/rstb.2014.0185] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Dopamine (DA) is a key transmitter in motor, reward and cogitative pathways, with DA dysfunction implicated in disorders including Parkinson's disease and addiction. Located in midbrain, DA neurons of the substantia nigra pars compacta project via the medial forebrain bundle to the dorsal striatum (caudate putamen), and DA neurons in the adjacent ventral tegmental area project to the ventral striatum (nucleus accumbens) and prefrontal cortex. In addition to classical vesicular release from axons, midbrain DA neurons exhibit DA release from their cell bodies and dendrites. Somatodendritic DA release leads to activation of D2 DA autoreceptors on DA neurons that inhibit their firing via G-protein-coupled inwardly rectifying K(+) channels. This helps determine patterns of DA signalling at distant axonal release sites. Somatodendritically released DA also acts via volume transmission to extrasynaptic receptors that modulate local transmitter release and neuronal activity in the midbrain. Thus, somatodendritic release is a pivotal intrinsic feature of DA neurons that must be well defined in order to fully understand the physiology and pathophysiology of DA pathways. Here, we review recent mechanistic aspects of somatodendritic DA release, with particular emphasis on the Ca(2+) dependence of release and the potential role of exocytotic proteins.
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Affiliation(s)
- Margaret E Rice
- Department of Neurosurgery, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA Department of Neuroscience and Physiology, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Jyoti C Patel
- Department of Neurosurgery, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA
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Freestone PS, Wu XH, de Guzman G, Lipski J. Excitatory drive from the Subthalamic nucleus attenuates GABAergic transmission in the Substantia Nigra pars compacta via endocannabinoids. Eur J Pharmacol 2015; 767:144-51. [DOI: 10.1016/j.ejphar.2015.09.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/19/2015] [Accepted: 09/21/2015] [Indexed: 01/23/2023]
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Pearlstein E, Gouty-Colomer LA, Michel FJ, Cloarec R, Hammond C. Glutamatergic synaptic currents of nigral dopaminergic neurons follow a postnatal developmental sequence. Front Cell Neurosci 2015; 9:210. [PMID: 26074777 PMCID: PMC4448554 DOI: 10.3389/fncel.2015.00210] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 05/15/2015] [Indexed: 01/20/2023] Open
Abstract
The spontaneous activity pattern of adult dopaminergic (DA) neurons of the substantia nigra pars compacta (SNc) results from interactions between intrinsic membrane conductances and afferent inputs. In adult SNc DA neurons, low-frequency tonic background activity is generated by intrinsic pacemaker mechanisms, whereas burst generation depends on intact synaptic inputs in particular the glutamatergic ones. Tonic DA release in the striatum during pacemaking is required to maintain motor activity, and burst firing evokes phasic DA release, necessary for cue-dependent learning tasks. However, it is still unknown how the firing properties of SNc DA neurons mature during postnatal development before reaching the adult state. We studied the postnatal developmental profile of spontaneous and evoked AMPA and NMDA (N-Methyl-D-aspartic acid) receptor-mediated excitatory postsynaptic currents (EPSCs) in SNc DA neurons in brain slices from immature (postnatal days P4–P10) and young adult (P30–P50) tyrosine hydroxylase (TH)-green fluorescent protein mice. We found that somato-dendritic fields of SNc DA neurons are already mature at P4–P10. In contrast, spontaneous glutamatergic EPSCs show a developmental sequence. Spontaneous NMDA EPSCs in particular are larger and more frequent in immature SNc DA neurons than in young adult ones and have a bursty pattern. They are mediated by GluN2B and GluN2D subunit-containing NMDA receptors. The latter generate long-lasting, DQP 1105-sensitive, spontaneous EPSCs, which are transiently recorded during this early period. Due to high NMDA activity, immature SNc DA neurons generate large and long lasting NMDA receptor-dependent (APV-sensitive) bursts in response to the stimulation of the subthalamic nucleus. We conclude that the transient high NMDA activity allows calcium influx into the dendrites of developing SNc DA neurons.
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Affiliation(s)
- Edouard Pearlstein
- UMR 901, Aix-Marseille Université Marseille, France ; Institut de Neurobiologie de la Méditerranée, Inserm UMR 901 Marseille, France
| | - Laurie-Anne Gouty-Colomer
- UMR 901, Aix-Marseille Université Marseille, France ; Institut de Neurobiologie de la Méditerranée, Inserm UMR 901 Marseille, France
| | - François J Michel
- UMR 901, Aix-Marseille Université Marseille, France ; Institut de Neurobiologie de la Méditerranée, Inserm UMR 901 Marseille, France
| | - Robin Cloarec
- UMR 901, Aix-Marseille Université Marseille, France ; Institut de Neurobiologie de la Méditerranée, Inserm UMR 901 Marseille, France
| | - Constance Hammond
- UMR 901, Aix-Marseille Université Marseille, France ; Institut de Neurobiologie de la Méditerranée, Inserm UMR 901 Marseille, France
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32
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Sitte HH, Freissmuth M. Amphetamines, new psychoactive drugs and the monoamine transporter cycle. Trends Pharmacol Sci 2014; 36:41-50. [PMID: 25542076 PMCID: PMC4502921 DOI: 10.1016/j.tips.2014.11.006] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 11/25/2014] [Accepted: 11/25/2014] [Indexed: 01/05/2023]
Abstract
In monoaminergic neurons, the vesicular transporters and the plasma membrane transporters operate in a relay. Amphetamine and its congeners target this relay to elicit their actions: most amphetamines are substrates, which pervert the relay to elicit efflux of monoamines into the synaptic cleft. However, some amphetamines act as transporter inhibitors. Both compound classes elicit profound psychostimulant effects, which render them liable to recreational abuse. Currently, a surge of new psychoactive substances occurs on a global scale. Chemists bypass drug bans by ingenuous structural variations, resulting in a rich pharmacology. A credible transport model must account for their distinct mode of action and link this to subtle differences in activity and undesired, potentially deleterious effects.
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Affiliation(s)
- Harald H Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria; Center for Addiction Research and Science (AddRess), Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria.
| | - Michael Freissmuth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University Vienna, Waehringerstrasse 13A, 1090 Vienna, Austria
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Abstract
Among the largest cells in the body, neurons possess an immense surface area and intricate geometry that poses many unique cell biological challenges. This morphological complexity is critical for neural circuit formation and enables neurons to compartmentalize cell-cell communication and local intracellular signalling to a degree that surpasses other cell types. The adaptive plastic properties of neurons, synapses and circuits have been classically studied by measurement of electrophysiological properties, ionic conductances and excitability. Over the last 15 years, the field of synaptic and neural electrophysiology has collided with neuronal cell biology to produce a more integrated understanding of how these remarkable highly differentiated cells utilize common eukaryotic cellular machinery to decode, integrate and propagate signals in the nervous system. The present article gives a very brief and personal overview of the organelles and trafficking machinery of neuronal dendrites and their role in dendritic and synaptic plasticity.
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Affiliation(s)
- Michael D Ehlers
- *Neuroscience Research Unit, Pfizer Worldwide Research and Development, 700 Main Street, Cambridge, MA 02139, U.S.A
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Gowrishankar R, Hahn MK, Blakely RD. Good riddance to dopamine: roles for the dopamine transporter in synaptic function and dopamine-associated brain disorders. Neurochem Int 2013; 73:42-8. [PMID: 24231471 DOI: 10.1016/j.neuint.2013.10.016] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/29/2013] [Accepted: 10/31/2013] [Indexed: 11/25/2022]
Abstract
The neurotransmitter dopamine (DA) plays a critical role in CNS circuits that provide for attention, executive function, reward responses, motivation and movement. DA is inactivated by the cocaine- and amphetamine-sensitive DA transporter (DAT), a protein that also provides a pathway for non-vesicular DA release. After a brief review of DAT function and psychostimulant actions, we consider the importance DAT in relation to the distinct firing patterns of DA neurons that permit awareness of novelty and reward. Finally, we review recent efforts to gather direct support for DAT-linked disorders, with a specific focus on DAT mutations recently identified in subjects with ADHD.
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Affiliation(s)
- Raajaram Gowrishankar
- Vanderbilt International Scholars Program, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States; Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Maureen K Hahn
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States; Department of Genetic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States
| | - Randy D Blakely
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States; Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, TN 37232-8548, United States.
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Stutz B, da Conceição FSL, Santos LE, Cadilhe DV, Fleming RL, Acquarone M, Gardino PF, de Melo Reis RA, Dickson PW, Dunkley PR, Rehen S, Houzel JC, de Mello FG. Murine dopaminergic Müller cells restore motor function in a model of Parkinson's disease. J Neurochem 2013; 128:829-40. [DOI: 10.1111/jnc.12475] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/27/2013] [Accepted: 09/27/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Bernardo Stutz
- Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | | | - Luís Eduardo Santos
- Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Daniel Veloso Cadilhe
- Instituto de Ciências Biomédicas; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Renata L. Fleming
- Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Mariana Acquarone
- Instituto de Ciências Biomédicas; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Patrícia F. Gardino
- Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Ricardo A. de Melo Reis
- Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Phillip W. Dickson
- School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - Peter R. Dunkley
- School of Biomedical Sciences and Pharmacy; University of Newcastle; Callaghan NSW Australia
| | - Stevens Rehen
- Instituto de Ciências Biomédicas; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Jean-Christophe Houzel
- Instituto de Ciências Biomédicas; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
| | - Fernando G. de Mello
- Instituto de Biofísica Carlos Chagas Filho; Universidade Federal do Rio de Janeiro; Rio de Janeiro RJ Brazil
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Stockner T, Montgomery TR, Kudlacek O, Weissensteiner R, Ecker GF, Freissmuth M, Sitte HH. Mutational analysis of the high-affinity zinc binding site validates a refined human dopamine transporter homology model. PLoS Comput Biol 2013; 9:e1002909. [PMID: 23436987 PMCID: PMC3578762 DOI: 10.1371/journal.pcbi.1002909] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Accepted: 12/16/2012] [Indexed: 11/24/2022] Open
Abstract
The high-resolution crystal structure of the leucine transporter (LeuT) is frequently used as a template for homology models of the dopamine transporter (DAT). Although similar in structure, DAT differs considerably from LeuT in a number of ways: (i) when compared to LeuT, DAT has very long intracellular amino and carboxyl termini; (ii) LeuT and DAT share a rather low overall sequence identity (22%) and (iii) the extracellular loop 2 (EL2) of DAT is substantially longer than that of LeuT. Extracellular zinc binds to DAT and restricts the transporter‚s movement through the conformational cycle, thereby resulting in a decrease in substrate uptake. Residue H293 in EL2 praticipates in zinc binding and must be modelled correctly to allow for a full understanding of its effects. We exploited the high-affinity zinc binding site endogenously present in DAT to create a model of the complete transmemberane domain of DAT. The zinc binding site provided a DAT-specific molecular ruler for calibration of the model. Our DAT model places EL2 at the transporter lipid interface in the vicinity of the zinc binding site. Based on the model, D206 was predicted to represent a fourth co-ordinating residue, in addition to the three previously described zinc binding residues H193, H375 and E396. This prediction was confirmed by mutagenesis: substitution of D206 by lysine and cysteine affected the inhibitory potency of zinc and the maximum inhibition exerted by zinc, respectively. Conversely, the structural changes observed in the model allowed for rationalizing the zinc-dependent regulation of DAT: upon binding, zinc stabilizes the outward-facing state, because its first coordination shell can only be completed in this conformation. Thus, the model provides a validated solution to the long extracellular loop and may be useful to address other aspects of the transport cycle. The dopamine transporter (DAT) regulates dopaminergic neurotransmission in the brain and is implicated in numerous human disease states. DAT is unique among the monoamine neurotransmitter transporter family because its substrate transport is inhibited by extracellular zinc. DAT homology models rely upon the crystal structure of LeuT solved in 2005. LeuT and DAT share a relatively low overall sequence identity of 22%. In addition, the length of the second extracellular loop of DAT exceeds that of LeuT by 21 residues. The zinc binding site cannot be directly modeled from the LeuT template alone because of these differences. Current available homology models of DAT focused on substrate or inhibitor binding rather than on the second extracellular loop. We exploited the specificity of the zinc binding site to build and calibrate a DAT homology model of the complete transmembrane domain. Our model predicted that the zinc binding site in DAT consists of four zinc co-ordinating residues rather than three that had been previously identified. We verified this hypothesis by site-directed mutagenesis and uptake inhibition studies.
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Affiliation(s)
- Thomas Stockner
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Vienna, Austria
| | - Therese R. Montgomery
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Vienna, Austria
| | - Oliver Kudlacek
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Vienna, Austria
| | | | - Gerhard F. Ecker
- Department of Medicinal Chemistry, University of Vienna, Vienna, Austria
| | - Michael Freissmuth
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Vienna, Austria
| | - Harald H. Sitte
- Center of Physiology and Pharmacology, Institute of Pharmacology, Medical University Vienna, Vienna, Austria
- * E-mail:
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37
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Striatal interaction among dopamine, glutamate and ascorbate. Neuropharmacology 2012; 63:1308-14. [DOI: 10.1016/j.neuropharm.2012.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/24/2012] [Accepted: 08/13/2012] [Indexed: 11/23/2022]
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38
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Murali D, Barnhart TE, Vandehey NT, Christian BT, Nickles RJ, Converse AK, Larson JA, Holden JE, Schneider ML, Dejesus OT. An efficient synthesis of dopamine transporter tracer [¹⁸F]FECNT. Appl Radiat Isot 2012. [PMID: 23208243 DOI: 10.1016/j.apradiso.2012.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A simple synthesis of the dopamine transporter ligand [(18)F]FECNT with high radiochemical yield and short synthesis time, suitable for routine production is reported. Reaction of 2β-carbomethoxy-3β-(4-chlorophenyl)nortropane with [(18)F]2-fluoroethyl triflate ([(18)F]FEtOTf) at room temperature for 4 min provided [(18)F]FECNT in 84% decay corrected radiochemical yield. Since [(18)F]FEtOTf was prepared from [(18)F]2-fluoroethyl bromide that was isolated from its starting material, formation of unwanted side products and the amount of expensive precursor used could be greatly reduced. The overall radiochemical yields of [(18)F]FECNT were 40% (n=29) and the total synthesis time was ca. 100 min. The average specific activity of [(18)F]FECNT was 377.4 GBq/μmol (10.2 Ci/μmol).
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Affiliation(s)
- D Murali
- Department of Medical Physics, University of Wisconsin-Madison, Madison, 1111 Highland Ave, 1005 WIMR, Madison, WI 53705, United States.
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Jones KT, Zhen J, Reith MEA. Importance of cholesterol in dopamine transporter function. J Neurochem 2012; 123:700-15. [PMID: 22957537 DOI: 10.1111/jnc.12007] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Revised: 08/31/2012] [Accepted: 09/01/2012] [Indexed: 11/28/2022]
Abstract
The conformation and function of the dopamine transporter (DAT) can be affected by manipulating membrane cholesterol, yet there is no agreement as to the impact of cholesterol on the activity of lipid-raft localized DATs compared with non-raft DATs. Given the paucity of information regarding the impact of cholesterol on substrate efflux by the DAT, this study explores its influence on the kinetics of DAT-mediated DA efflux induced by dextroamphetamine, as measured by rotating disk electrode voltammetry (RDEV). Treatment with methyl-β-cyclodextrin (mβCD), which effectively depletes total membrane cholesterol--uniformly affecting cholesterol-DAT interactions in both raft and non-raft membrane domains--reduced both DA uptake and efflux rate. In contrast, disruption of raft-localized DAT by cholesterol chelation with nystatin had no effect, arguing against a vital role for raft-localized DAT in substrate uptake or efflux. Supranormal repletion of cholesterol-depleted cells with the analog desmosterol, a non-raft promoting sterol, was as effective as cholesterol itself in restoring transport rates. Further studies with Zn(2+) and the conformationally biased W84L DAT mutant supported the idea that cholesterol is important for maintaining the outward-facing DAT with normal rates of conformational interconversions. Collectively, these results point to a role for direct cholesterol-DAT interactions in regulating DAT function.
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Affiliation(s)
- Kymry T Jones
- Department of Psychiatry, New York University School of Medicine, New York, New York, USA
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Rodriguez-Menchaca AA, Solis E, Cameron K, De Felice LJ. S(+)amphetamine induces a persistent leak in the human dopamine transporter: molecular stent hypothesis. Br J Pharmacol 2012; 165:2749-57. [PMID: 22014068 DOI: 10.1111/j.1476-5381.2011.01728.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Wherever they are located, dopamine transporters (DATs) clear dopamine (DA) from the extracellular milieu to help regulate dopaminergic signalling. Exposure to amphetamine (AMPH) increases extracellular DA in the synaptic cleft, which has been ascribed to DAT reverse transport. Increased extracellular DA prolongs postsynaptic activity and reinforces abuse and hedonic behaviour. EXPERIMENTAL APPROACH Xenopus laevis oocytes expressing human (h) DAT were voltage-clamped and exposed to DA, R(-)AMPH, or S(+)AMPH. KEY RESULTS At -60mV, near neuronal resting potentials, S(+)AMPH induced a depolarizing current through hDAT, which after removing the drug, persisted for more than 30 min. This persistent leak in the absence of S(+)AMPH was in contrast to the currents induced by R(-)AMPH and DA, which returned to baseline immediately after their removal. Our data suggest that S(+)AMPH and Na(+) carry the initial S(+)AMPH-induced current, whereas Na+ and Cl(-) carry the persistent leak current. We propose that the persistent current results from the internal action of S(+)AMPH on hDAT because the temporal effect was consistent with S(+)AMPH influx, and intracellular S(+)AMPH activated the effect. The persistent current was dependent on Na(+) and was blocked by cocaine. Intracellular injection of S(+)AMPH also activated a DA-induced persistent leak current. CONCLUSIONS AND IMPLICATIONS We report a hitherto unknown action of S(+)AMPH on hDAT that potentially affects AMPH-induced DA release. We propose that internal S(+)AMPH acts as a molecular stent that holds the transporter open even after external S(+)AMPH is removed. Amphetamine-induced persistent leak currents are likely to influence dopaminergic signalling, DA release mechanisms, and amphetamine abuse.
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Affiliation(s)
- Aldo A Rodriguez-Menchaca
- Department of Physiology and Biophysics, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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Steinkellner T, Yang JW, Montgomery TR, Chen WQ, Winkler MT, Sucic S, Lubec G, Freissmuth M, Elgersma Y, Sitte HH, Kudlacek O. Ca(2+)/calmodulin-dependent protein kinase IIα (αCaMKII) controls the activity of the dopamine transporter: implications for Angelman syndrome. J Biol Chem 2012; 287:29627-35. [PMID: 22778257 PMCID: PMC3436163 DOI: 10.1074/jbc.m112.367219] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The dopamine transporter (DAT) is a crucial regulator of dopaminergic neurotransmission, controlling the length and brevity of dopaminergic signaling. DAT is also the primary target of psychostimulant drugs such as cocaine and amphetamines. Conversely, methylphenidate and amphetamine are both used clinically in the treatment of attention-deficit hyperactivity disorder and narcolepsy. The action of amphetamines, which induce transport reversal, relies primarily on the ionic composition of the intra- and extracellular milieus. Recent findings suggest that DAT interacting proteins may also play a significant role in the modulation of reverse dopamine transport. The pharmacological inhibition of the serine/threonine kinase αCaMKII attenuates amphetamine-triggered DAT-mediated 1-methyl-4-phenylpyridinium (MPP(+)) efflux. More importantly, αCaMKII has also been shown to bind DAT in vitro and is therefore believed to be an important player within the DAT interactome. Herein, we show that αCaMKII co-immunoprecipitates with DAT in mouse striatal synaptosomes. Mice, which lack αCaMKII or which express a permanently self-inhibited αCaMKII (αCaMKII(T305D)), exhibit significantly reduced amphetamine-triggered DAT-mediated MPP(+) efflux. Additionally, we investigated mice that mimic a neurogenetic disease known as Angelman syndrome. These mice possess reduced αCaMKII activity. Angelman syndrome mice demonstrated an impaired DAT efflux function, which was comparable with that of the αCaMKII mutant mice, indicating that DAT-mediated dopaminergic signaling is affected in Angelman syndrome.
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Affiliation(s)
- Thomas Steinkellner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
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Mebel DM, Wong JCY, Dong YJ, Borgland SL. Insulin in the ventral tegmental area reduces hedonic feeding and suppresses dopamine concentration via increased reuptake. Eur J Neurosci 2012; 36:2336-46. [PMID: 22712725 DOI: 10.1111/j.1460-9568.2012.08168.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mesolimbic dopamine (DA) signaling has been implicated in the incentive, reinforcing and motivational aspects of food intake. Insulin receptors are expressed on dopaminergic neurons of the ventral tegmental area (VTA), and insulin may act in the VTA to suppress feeding. However, the neural mechanisms underlying insulin effects in the VTA are poorly understood. Here, we measured the effects of insulin on evoked DA concentration in the VTA using fast-scan cyclic voltammetry. Insulin concentration-dependently reduced evoked somatodendritic DA in the VTA, requiring activation of phosphoinositol 3-kinase and mTOR signaling. Insulin depression of somatodendritic DA was abolished in the presence of a selective DA transporter (DAT) inhibitor, GBR 12909, as well as in VTA slices of DAT knockout mice, suggesting that insulin upregulated the number or function of DAT to reduce DA concentration. Finally, insulin administered to the VTA depressed sated feeding of sweetened high-fat food. Taken together, these results indicate that insulin depresses DA concentration in the VTA via increased reuptake of DA through DAT. Insulin-mediated decrease of DA in the VTA may suppress salience of food once satiety is reached.
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Affiliation(s)
- Dmitry M Mebel
- Department of Anesthesiology, Pharmacology and Therapeutics, The University of British Columbia, 212-2176 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3
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Blakely RD, Edwards RH. Vesicular and plasma membrane transporters for neurotransmitters. Cold Spring Harb Perspect Biol 2012; 4:a005595. [PMID: 22199021 PMCID: PMC3281572 DOI: 10.1101/cshperspect.a005595] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The regulated exocytosis that mediates chemical signaling at synapses requires mechanisms to coordinate the immediate response to stimulation with the recycling needed to sustain release. Two general classes of transporter contribute to release, one located on synaptic vesicles that loads them with transmitter, and a second at the plasma membrane that both terminates signaling and serves to recycle transmitter for subsequent rounds of release. Originally identified as the target of psychoactive drugs, these transport systems have important roles in transmitter release, but we are only beginning to understand their contribution to synaptic transmission, plasticity, behavior, and disease. Recent work has started to provide a structural basis for their activity, to characterize their trafficking and potential for regulation. The results indicate that far from the passive target of psychoactive drugs, neurotransmitter transporters undergo regulation that contributes to synaptic plasticity.
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Affiliation(s)
- Randy D Blakely
- Department of Pharmacology and Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-8548, USA
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Abstract
AbstractThe development of effective therapeutic interventions for neurodegeneration requires a better understanding of the early events that precede neuronal loss. Recent work in various disease models has begun to emphasize the significance of presynaptic dysfunction as an early event that occurs before manifestation of neurological disorders. Dysregulation of dopamine (DA) homeostasis is implicated in neurodegenerative diseases, drug addiction, and neuropsychiatric disorders. The neuronal plasma membrane dopamine transporter (DAT) is essential for the maintenance of DA homeostasis in the brain. α-synuclein is a 140-amino acid protein that forms a stable complex with DAT and is linked to the pathogenesis of neurodegenerative disease. In this review we will examine the prevailing hypotheses for α-synuclein-regulation of DAT biology.
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45
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Rice ME, Patel JC, Cragg SJ. Dopamine release in the basal ganglia. Neuroscience 2011; 198:112-37. [PMID: 21939738 PMCID: PMC3357127 DOI: 10.1016/j.neuroscience.2011.08.066] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/22/2011] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
Abstract
Dopamine (DA) is a key transmitter in the basal ganglia, yet DA transmission does not conform to several aspects of the classic synaptic doctrine. Axonal DA release occurs through vesicular exocytosis and is action potential- and Ca²⁺-dependent. However, in addition to axonal release, DA neurons in midbrain exhibit somatodendritic release by an incompletely understood, but apparently exocytotic, mechanism. Even in striatum, axonal release sites are controversial, with evidence for DA varicosities that lack postsynaptic specialization, and largely extrasynaptic DA receptors and transporters. Moreover, DA release is often assumed to reflect a global response to a population of activities in midbrain DA neurons, whether tonic or phasic, with precise timing and specificity of action governed by other basal ganglia circuits. This view has been reinforced by anatomical evidence showing dense axonal DA arbors throughout striatum, and a lattice network formed by DA axons and glutamatergic input from cortex and thalamus. Nonetheless, localized DA transients are seen in vivo using voltammetric methods with high spatial and temporal resolution. Mechanistic studies using similar methods in vitro have revealed local regulation of DA release by other transmitters and modulators, as well as by proteins known to be disrupted in Parkinson's disease and other movement disorders. Notably, the actions of most other striatal transmitters on DA release also do not conform to the synaptic doctrine, with the absence of direct synaptic contacts for glutamate, GABA, and acetylcholine (ACh) on striatal DA axons. Overall, the findings reviewed here indicate that DA signaling in the basal ganglia is sculpted by cooperation between the timing and pattern of DA input and those of local regulatory factors.
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Affiliation(s)
- M E Rice
- Department of Neurosurgery, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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Mendez JA, Bourque MJ, Fasano C, Kortleven C, Trudeau LE. Somatodendritic dopamine release requires synaptotagmin 4 and 7 and the participation of voltage-gated calcium channels. J Biol Chem 2011; 286:23928-37. [PMID: 21576241 PMCID: PMC3129174 DOI: 10.1074/jbc.m111.218032] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Revised: 05/09/2011] [Indexed: 11/06/2022] Open
Abstract
Somatodendritic (STD) dopamine (DA) release is a key mechanism for the autoregulatory control of DA release in the brain. However, its molecular mechanism remains undetermined. We tested the hypothesis that differential expression of synaptotagmin (Syt) isoforms explains some of the differential properties of terminal and STD DA release. Down-regulation of the dendritically expressed Syt4 and Syt7 severely reduced STD DA release, whereas terminal release required Syt1. Moreover, we found that although mobilization of intracellular Ca(2+) stores is inefficient, Ca(2+) influx through N- and P/Q-type voltage-gated channels is critical to trigger STD DA release. Our findings provide an explanation for the differential Ca(2+) requirement of terminal and STD DA release. In addition, we propose that not all sources of intracellular Ca(2+) are equally efficient to trigger this release mechanism. Our findings have implications for a better understanding of a fundamental cell biological process mediating transcellular signaling in a system critical for diseases such as Parkinson disease.
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Affiliation(s)
- Jose Alfredo Mendez
- From the Department of Pharmacology, Groupe de Recherche sur le Système Nerveux Central, Faculty of Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Marie-Josée Bourque
- From the Department of Pharmacology, Groupe de Recherche sur le Système Nerveux Central, Faculty of Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Caroline Fasano
- From the Department of Pharmacology, Groupe de Recherche sur le Système Nerveux Central, Faculty of Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Christian Kortleven
- From the Department of Pharmacology, Groupe de Recherche sur le Système Nerveux Central, Faculty of Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
| | - Louis-Eric Trudeau
- From the Department of Pharmacology, Groupe de Recherche sur le Système Nerveux Central, Faculty of Medicine, Université de Montréal, Montréal, Québec H3C 3J7, Canada
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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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48
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Kennedy MJ, Ehlers MD. Mechanisms and function of dendritic exocytosis. Neuron 2011; 69:856-75. [PMID: 21382547 DOI: 10.1016/j.neuron.2011.02.032] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2011] [Indexed: 12/30/2022]
Abstract
Dendritic exocytosis is required for a broad array of neuronal functions including retrograde signaling, neurotransmitter release, synaptic plasticity, and establishment of neuronal morphology. While the details of synaptic vesicle exocytosis from presynaptic terminals have been intensely studied for decades, the mechanisms of dendritic exocytosis are only now emerging. Here we review the molecules and mechanisms of dendritic exocytosis and discuss how exocytosis from dendrites influences neuronal function and circuit plasticity.
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Affiliation(s)
- Matthew J Kennedy
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
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Abstract
The substantia nigra pars reticulata (SNr) is a key basal ganglia output nucleus critical for movement control. A hallmark of the SNr gamma-aminobutyric acid (GABA)-containing projection neurons is their depolarized membrane potential, accompanied by rapid spontaneous spikes. Parkinsonian movement disorders are often associated with abnormalities in SNr GABA neuron firing intensity and/or pattern. A fundamental question is the molecular identity of the ion channels that drive these neurons to a depolarized membrane potential. Recent data show that SNr GABA projection neurons selectively express type 3 canonical transient receptor potential (TRPC3) channels. Such channels are tonically active and mediate an inward, Na(+)-dependent current, leading to a substantial depolarization and ensuring appropriate firing intensity and pattern in SNr GABA projection neurons. Equally important, TRPC3 channels in SNr GABA neurons are up-regulated by dopamine (DA) released from neighboring nigral DA neuron dendrites. Co-activation of D1 and D5 DA receptors leads to a TRPC3 channel-mediated inward current and increased firing in SNr GABA neurons, whereas D1-like receptor blockade reduces SNr GABA neuron firing frequency and increases their firing irregularity. TRPC3 channels serve as the effector channels mediating an ultra-short SNc-->SNr DA pathway that regulates the firing intensity and pattern of the basal ganglia output neurons.
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Affiliation(s)
- Fu-Ming Zhou
- Department of Pharmacology, University of Tennessee College of Medicine, Memphis TN 38163, USA.
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50
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Kreissl S, Strasser C, Galizia CG. Allatostatin immunoreactivity in the honeybee brain. J Comp Neurol 2010; 518:1391-417. [PMID: 20187126 DOI: 10.1002/cne.22343] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Information transmission and processing in the brain is achieved through a small family of chemical neurotransmitters and neuromodulators and a very large family of neuropeptides. In order to understand neural networks in the brain it will be necessary, therefore, to understand the connectivity, morphology, and distribution of peptidergic neurons, and to elucidate their function in the brain. In this study we characterize the distribution of substances related to Dip-allatostatin I in the honeybee brain, which belongs to the allatostatin-A (AST) peptide family sharing the conserved c-terminal sequence -YXFGL-NH(2). We found about 500 AST-immunoreactive (ASTir) neurons in the brain, scattered in 18 groups that varied in their precise location across individuals. Almost all areas of the brain were innervated by ASTir fibers. Most ASTir neurites formed networks within functionally distinct areas, e.g., the antennal lobes, the mushroom bodies, or the optic lobes, indicating local functions of the peptide. A small number of very large neurons had widespread arborizations and neurites were found in the corpora cardiaca and in the cervical connectives, suggesting that AST also has global functions. We double-stained AST and GABA and found that a subset of ASTir neurons were GABA-immunoreactive (GABAir). Double staining AST with backfills of olfactory receptor neurons or mass fills of neurons in the antennal lobes and in the mushroom bodies allowed a more fine-grained description of ASTir networks. Together, this first comprehensive description of AST in the bee brain suggests a diverse functional role of AST, including local and global computational tasks.
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Affiliation(s)
- Sabine Kreissl
- Department of Biology, University of Konstanz, D-78457 Konstanz, Germany
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