51
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Kim Y, Jang J, Kim HJ, Park MK. Regional difference in spontaneous firing inhibition by GABA A and GABA B receptors in nigral dopamine neurons. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2018; 22:721-729. [PMID: 30402033 PMCID: PMC6205942 DOI: 10.4196/kjpp.2018.22.6.721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/04/2018] [Accepted: 10/04/2018] [Indexed: 01/18/2023]
Abstract
GABAergic control over dopamine (DA) neurons in the substantia nigra is crucial for determining firing rates and patterns. Although GABA activates both GABAA and GABAB receptors distributed throughout the somatodendritic tree, it is currently unclear how regional GABA receptors in the soma and dendritic compartments regulate spontaneous firing. Therefore, the objective of this study was to determine actions of regional GABA receptors on spontaneous firing in acutely dissociated DA neurons from the rat using patch-clamp and local GABA-uncaging techniques. Agonists and antagonists experiments showed that activation of either GABAA receptors or GABAB receptors in DA neurons is enough to completely abolish spontaneous firing. Local GABA-uncaging along the somatodendritic tree revealed that activation of regional GABA receptors limited within the soma, proximal, or distal dendritic region, can completely suppress spontaneous firing. However, activation of either GABAA or GABAB receptor equally suppressed spontaneous firing in the soma, whereas GABAB receptor inhibited spontaneous firing more strongly than GABAA receptor in the proximal and distal dendrites. These regional differences of GABA signals between the soma and dendritic compartments could contribute to our understanding of many diverse and complex actions of GABA in midbrain DA neurons.
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Affiliation(s)
- Yumi Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Jinyoung Jang
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea
| | - Hyun Jin Kim
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 06351, Korea
| | - Myoung Kyu Park
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon 16419, Korea.,Samsung Biomedical Research Institute, Samsung Medical Center, Seoul 06351, Korea
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52
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Liu C, Xue Y, Liu MF, Wang Y, Liu ZR, Diao HL, Chen L. Orexins increase the firing activity of nigral dopaminergic neurons and participate in motor control in rats. J Neurochem 2018; 147:380-394. [DOI: 10.1111/jnc.14568] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/06/2018] [Accepted: 08/07/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Cui Liu
- Department of Physiology; Qingdao University; Qingdao China
| | - Yan Xue
- Department of Physiology; Qingdao University; Qingdao China
| | - Mei-Fang Liu
- Department of Physiology; Qingdao University; Qingdao China
| | - Ying Wang
- Department of Physiology; Qingdao University; Qingdao China
| | - Zi-Ran Liu
- Department of Physiology; Qingdao University; Qingdao China
| | - Hui-Ling Diao
- Department of Physiology; Qingdao University; Qingdao China
| | - Lei Chen
- Department of Physiology; Qingdao University; Qingdao China
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53
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Schoonover KE, Queern SL, Lapi SE, Roberts RC. Impaired copper transport in schizophrenia results in a copper-deficient brain state: A new side to the dysbindin story. World J Biol Psychiatry 2018; 21:13-28. [PMID: 30230404 PMCID: PMC6424639 DOI: 10.1080/15622975.2018.1523562] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Objectives: Several schizophrenia brain regions exhibit decreased dysbindin. Dysbindin modulates copper transport crucial for myelination, monoamine metabolism and cellular homeostasis. Schizophrenia patients (SZP) exhibit increased plasma copper, while copper-decreasing agents produce schizophrenia-like behavioural and pathological abnormalities. Therefore, we sought to determine dysbindin and copper transporter protein expression and copper content in SZP.Methods: We studied the copper-rich substantia nigra (SN) using Western blot and inductively-coupled plasma mass spectrometry. We characterised specific protein domains of copper transporters ATP7A, CTR1, ATP7B and dysbindin isoforms 1 A and 1B/C in SZP (n = 15) and matched controls (n = 11), and SN copper content in SZP (n = 14) and matched controls (n = 11). As a preliminary investigation, we compared medicated (ON; n = 11) versus unmedicated SZP (OFF; n = 4).Results: SZP exhibited increased C terminus, but not N terminus, ATP7A. SZP expressed less transmembrane CTR1 and dysbindin 1B/C than controls. ON exhibited increased C terminus ATP7A protein versus controls. OFF exhibited less N terminus ATP7A protein than controls and ON, suggesting medication-induced rescue of the ATP7A N terminus. SZP exhibited less SN copper content than controls.Conclusions: These results provide the first evidence of disrupted copper transport in schizophrenia SN that appears to result in a copper-deficient state. Furthermore, copper homeostasis may be modulated by specific dysbindin isoforms and antipsychotic treatment.
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Affiliation(s)
- Kirsten E. Schoonover
- Department of Psychology and Behavioral Neuroscience, University of Alabama at Birmingham
| | - Stacy L. Queern
- Department of Radiology, University of Alabama at Birmingham,Department of Chemistry, Washington University in St. Louis
| | - Suzanne E. Lapi
- Department of Radiology, University of Alabama at Birmingham,Department of Chemistry, Washington University in St. Louis
| | - Rosalinda C. Roberts
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham
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54
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Bortz DM, Grace AA. Medial septum activation produces opposite effects on dopamine neuron activity in the ventral tegmental area and substantia nigra in MAM vs. normal rats. NPJ SCHIZOPHRENIA 2018; 4:17. [PMID: 30177811 PMCID: PMC6120917 DOI: 10.1038/s41537-018-0059-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/30/2018] [Accepted: 08/06/2018] [Indexed: 11/08/2022]
Abstract
The medial septum (MS) differentially impacts midbrain dopamine (DA) neuron activity via the ventral hippocampus, a region implicated in DA-related disorders. However, whether MS regulation of ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) is disrupted in a developmental disruption model of schizophrenia is unknown. Male Sprague-Dawley rats were exposed at gestational day 17 to methylazoxymethanol (MAM) or saline. As adults, NMDA (0.75 µg/0.2 µL) was infused into the MS, and either DA neuron activity in the VTA and SNc (7-9 anesthetized rats per group) or amphetamine-induced hyperlocomotion (AIH, 11-13 rats per group) was measured. MS activation produced a 58% increase in the number of spontaneously active DA neurons in VTA and a 37% decrease in SNc in saline rats. However, MS activation produced opposite effects on DA population activity in MAM rats, decreasing VTA DA activity by 51% and increasing SNc DA activity by 47%. MS activation also increased AIH by 113% in MAM rats, opposite of what is seen in intact rats. The effect in behavioral output may be due to disrupted GABAergic regulation of SNc as bicuculline infusion into vSub, which selectively prevented the MS activation-induced decrease in SNc DA activity in intact rats, prevented the increase in AIH and SNc DA activity in MAM rats. These findings demonstrate that the regulation of midbrain DA neurons by the MS is disrupted in this well-validated animal model, suggesting that it could be a potential locus for pharmacological intervention in disorders such as schizophrenia.
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Affiliation(s)
- David M Bortz
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
| | - Anthony A Grace
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
- Department of Psychology, University of Pittsburgh, Pittsburgh, PA, 15260, USA
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55
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Bortz DM, Grace AA. Medial septum differentially regulates dopamine neuron activity in the rat ventral tegmental area and substantia nigra via distinct pathways. Neuropsychopharmacology 2018; 43:2093-2100. [PMID: 29654260 PMCID: PMC6098086 DOI: 10.1038/s41386-018-0048-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 03/06/2018] [Accepted: 03/12/2018] [Indexed: 01/12/2023]
Abstract
The medial septum (MS) impacts hippocampal activity and the hippocampus, in turn, regulates midbrain dopamine (DA) neuron activity. However, it remains to be determined how MS activation impacts midbrain DA activity. This question was addressed by infusing NMDA (0.75 µg/0.2 µL) into the medial septum of anesthetized male Sprague-Dawley rats and recording dopamine neuron activity in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). MS activation increased (71%) the number of spontaneously active DA neurons in the VTA, and decreased (40%) the number of active DA neurons in the SNc. Effects in both the VTA and SNc required the ventral subiculum, but were differentially dependent on cholinergic and GABAergic mechanisms within the vSub and rostral and caudal subregions of the ventral pallidum, respectively. MS activation also decreased amphetamine-induced locomotor behavior, which was dependent on GABAergic inputs to the hippocampus. These findings demonstrate that the MS differentially regulates meso-striatal DA transmission via distinct pathways.
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Affiliation(s)
- David M. Bortz
- 0000 0004 1936 9000grid.21925.3dDepartments of Neuroscience, Psychiatry, and Psychology, University of Pittsburgh, Pittsburgh, PA 15260 USA
| | - Anthony A. Grace
- 0000 0004 1936 9000grid.21925.3dDepartments of Neuroscience, Psychiatry, and Psychology, University of Pittsburgh, Pittsburgh, PA 15260 USA
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56
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Wouterlood FG, Engel A, Daal M, Houwen G, Meinderts A, Jordà Siquier T, Beliën JAM, van Dongen YC, Scheel-Krüger J, Thierry AM, Groenewegen HJ, Deniau JM. Mesencephalic dopamine neurons interfacing the shell of nucleus accumbens and the dorsolateral striatum in the rat. J Neurosci Res 2018; 96:1518-1542. [PMID: 29696690 PMCID: PMC6099426 DOI: 10.1002/jnr.24242] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 02/26/2018] [Accepted: 03/15/2018] [Indexed: 11/18/2022]
Abstract
Parallel corticostriatonigral circuits have been proposed that separately process motor, cognitive, and emotional‐motivational information. Functional integration requires that interactions exist between neurons participating in these circuits. This makes it imperative to study the complex anatomical substrate underlying corticostriatonigral circuits. It has previously been proposed that dopaminergic neurons in the ventral mesencephalon may play a role in this circuit interaction. Therefore, we studied in rats convergence of basal ganglia circuits by depositing an anterograde neuroanatomical tracer into the ventral striatum together with a retrograde fluorescent tracer ipsilaterally in the dorsolateral striatum. In the mesencephalon, using confocal microscopy, we looked for possible appositions of anterogradely labeled fibers and retrogradely labeled neurons, “enhancing” the latter via intracellular injection of Lucifer Yellow. Tyrosine hydroxylase (TH) immunofluorescence served to identify dopaminergic neurons. In neurophysiological experiments, we combined orthodromic stimulation in the medial ventral striatum with recording from ventral mesencephalic neurons characterized by antidromic stimulation from the dorsal striatum. We observed terminal fields of anterogradely labeled fibers that overlap populations of retrogradely labeled nigrostriatal cell bodies in the substantia nigra pars compacta and lateral ventral tegmental area (VTA), with numerous close appositions between boutons of anterogradely labeled fibers and nigrostriatal, TH‐immunopositive neurons. Neurophysiological stimulation in the medial ventral striatum caused inhibition of dopaminergic nigrostriatal neurons projecting to the ventrolateral striatal territory. Responding nigrostriatal neurons were located in the medial substantia nigra and adjacent VTA. Our results strongly suggest a functional link between ventromedial, emotional‐motivational striatum, and the sensorimotor dorsal striatum via dopaminergic nigrostriatal neurons.
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Affiliation(s)
- Floris G Wouterlood
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Angela Engel
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Mariah Daal
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Gertjan Houwen
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Aileen Meinderts
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Tomàs Jordà Siquier
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Jeroen A M Beliën
- Department of Pathology, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB, Amsterdam, The Netherlands
| | - Yvette C van Dongen
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands.,Institut National de la Santé et de la Recherche Médicale, U114, Chaire de Neuropharmacologie, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Jørgen Scheel-Krüger
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Nørrebrogade 44, 8000 Aarhus C, Denmark
| | - Anne-Marie Thierry
- Institut National de la Santé et de la Recherche Médicale, U114, Chaire de Neuropharmacologie, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Henk J Groenewegen
- Department of Anatomy & Neurosciences, VU University Medical Center, Neuroscience Campus Amsterdam, 1007 MB Amsterdam, The Netherlands
| | - Jean-Michel Deniau
- Institut National de la Santé et de la Recherche Médicale, U114, Chaire de Neuropharmacologie, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
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57
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A Neural Circuit Mechanism for the Involvements of Dopamine in Effort-Related Choices: Decay of Learned Values, Secondary Effects of Depletion, and Calculation of Temporal Difference Error. eNeuro 2018; 5:eN-NWR-0021-18. [PMID: 29468191 PMCID: PMC5820541 DOI: 10.1523/eneuro.0021-18.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 01/11/2018] [Indexed: 12/17/2022] Open
Abstract
Dopamine has been suggested to be crucially involved in effort-related choices. Key findings are that dopamine depletion (i) changed preference for a high-cost, large-reward option to a low-cost, small-reward option, (ii) but not when the large-reward option was also low-cost or the small-reward option gave no reward, (iii) while increasing the latency in all the cases but only transiently, and (iv) that antagonism of either dopamine D1 or D2 receptors also specifically impaired selection of the high-cost, large-reward option. The underlying neural circuit mechanisms remain unclear. Here we show that findings i–iii can be explained by the dopaminergic representation of temporal-difference reward-prediction error (TD-RPE), whose mechanisms have now become clarified, if (1) the synaptic strengths storing the values of actions mildly decay in time and (2) the obtained-reward-representing excitatory input to dopamine neurons increases after dopamine depletion. The former is potentially caused by background neural activity–induced weak synaptic plasticity, and the latter is assumed to occur through post-depletion increase of neural activity in the pedunculopontine nucleus, where neurons representing obtained reward exist and presumably send excitatory projections to dopamine neurons. We further show that finding iv, which is nontrivial given the suggested distinct functions of the D1 and D2 corticostriatal pathways, can also be explained if we additionally assume a proposed mechanism of TD-RPE calculation, in which the D1 and D2 pathways encode the values of actions with a temporal difference. These results suggest a possible circuit mechanism for the involvements of dopamine in effort-related choices and, simultaneously, provide implications for the mechanisms of TD-RPE calculation.
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58
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Gantz SC, Ford CP, Morikawa H, Williams JT. The Evolving Understanding of Dopamine Neurons in the Substantia Nigra and Ventral Tegmental Area. Annu Rev Physiol 2018; 80:219-241. [PMID: 28938084 DOI: 10.1146/annurev-physiol-021317-121615] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In recent years, the population of neurons in the ventral tegmental area (VTA) and substantia nigra (SN) has been examined at multiple levels. The results indicate that the projections, neurochemistry, and receptor and ion channel expression in this cell population vary widely. This review centers on the intrinsic properties and synaptic regulation that control the activity of dopamine neurons. Although all dopamine neurons fire action potentials in a pacemaker pattern in the absence of synaptic input, the intrinsic properties that underlie this activity differ considerably. Likewise, the transition into a burst/pause pattern results from combinations of intrinsic ion conductances, inhibitory and excitatory synaptic inputs that differ among this cell population. Finally, synaptic plasticity is a key regulator of the rate and pattern of activity in different groups of dopamine neurons. Through these fundamental properties, the activity of dopamine neurons is regulated and underlies the wide-ranging functions that have been attributed to dopamine.
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Affiliation(s)
- Stephanie C Gantz
- Intramural Research Program, National Institute on Drug Abuse, Baltimore, Maryland 21224, USA
| | - Christopher P Ford
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Hitoshi Morikawa
- Department of Neuroscience and Waggoner Center for Alcohol and Addiction Research, University of Texas, Austin, Texas 78712, USA
| | - John T Williams
- Vollum Institute, Oregon Health Sciences University, Portland, Oregon 97239, USA;
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59
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Tschumi CW, Beckstead MJ. Neurotensin speeds inhibition of dopamine neurons through temporal modulation of GABA A and GABA B receptor-mediated synaptic input. Neuropharmacology 2018; 131:414-423. [PMID: 29307543 DOI: 10.1016/j.neuropharm.2018.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 12/02/2017] [Accepted: 01/02/2018] [Indexed: 01/20/2023]
Abstract
Midbrain dopamine neurons play physiological roles in many processes including reward learning and motivated behavior, and are tonically inhibited by γ-aminobutyric acid (GABA)ergic input from multiple brain regions. Neurotensin (NT) is a neuropeptide which acutely modulates midbrain dopamine neuron excitability through multiple mechanisms, one of which is a decrease of GABA-mediated inhibition. However, the mechanisms through which NT depresses GABA signaling are not known. Here we used whole cell patch-clamp electrophysiology of dopamine neurons in mouse brain slices to show that NT acts both presynaptically to increase GABAA and postsynaptically to decrease GABAB receptor-mediated currents in the substantia nigra. The active peptide fragment NT8-13 enhanced GABAA signaling presynaptically by causing an increase in the size of the readily releasable pool of GABA via activation of the NT type-1 receptor and protein kinase A. Conversely, NT8-13 depressed GABAB signaling postsynaptically via the NT type-2 receptor in a process that was modulated by protein kinase C. Both forms of plasticity could be observed simultaneously in single dopamine neurons. Thus, as the kinetics of GABAA signaling are significantly faster than those of GABAB signaling, NT functionally speeds GABAergic input to midbrain dopamine neurons. This finding contributes to our understanding of how neuropeptide-induced plasticity can simultaneously differentiate and integrate signaling by a single neurotransmitter in a single cell and provides a basis for understanding how neuropeptides use temporal shifts in synaptic strength to encode information.
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Affiliation(s)
- Christopher W Tschumi
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA; Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, San Antonio, TX, 78229, USA
| | - Michael J Beckstead
- Aging and Metabolism Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104-5005, USA; Department of Cellular and Integrative Physiology, University of Texas Health, San Antonio, San Antonio, TX, 78229, USA.
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60
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Hirabayashi KE, Vagefi MR. Oral Pharmacotherapy for Benign Essential Blepharospasm. Int Ophthalmol Clin 2017; 58:33-47. [PMID: 29239876 DOI: 10.1097/iio.0000000000000208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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61
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Metzger FL, Auer T, Helms G, Paulus W, Frahm J, Sommer M, Neef NE. Shifted dynamic interactions between subcortical nuclei and inferior frontal gyri during response preparation in persistent developmental stuttering. Brain Struct Funct 2017; 223:165-182. [PMID: 28741037 PMCID: PMC5772149 DOI: 10.1007/s00429-017-1476-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 07/07/2017] [Indexed: 11/29/2022]
Abstract
Persistent developmental stuttering is associated with basal ganglia dysfunction or dopamine dysregulation. Here, we studied whole-brain functional connectivity to test how basal ganglia structures coordinate and reorganize sensorimotor brain networks in stuttering. To this end, adults who stutter and fluent speakers (control participants) performed a response anticipation paradigm in the MRI scanner. The preparation of a manual Go/No-Go response reliably produced activity in the basal ganglia and thalamus and particularly in the substantia nigra. Strikingly, in adults who stutter, substantia nigra activity correlated positively with stuttering severity. Furthermore, functional connectivity analyses yielded altered task-related network formations in adults who stutter compared to fluent speakers. Specifically, in adults who stutter, the globus pallidus and the thalamus showed increased network synchronization with the inferior frontal gyrus. This implies dynamic shifts in the response preparation-related network organization through the basal ganglia in the context of a non-speech motor task in stuttering. Here we discuss current findings in the traditional framework of how D1 and D2 receptor activity shapes focused movement selection, thereby suggesting a disproportional involvement of the direct and the indirect pathway in stuttering.
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Affiliation(s)
- F Luise Metzger
- Department of Clinical Neurophysiology, Georg August University, Göttingen, Germany
| | - Tibor Auer
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany.,MRC Cognition and Brain Sciences Unit, Cambridge, UK.,Department of Psychology, Royal Holloway, University of London, Egham, UK
| | - Gunther Helms
- Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Walter Paulus
- Department of Clinical Neurophysiology, Georg August University, Göttingen, Germany
| | - Jens Frahm
- Biomedizinische NMR Forschungs GmbH am Max-Planck-Institut für Biophysikalische Chemie, Göttingen, Germany
| | - Martin Sommer
- Department of Clinical Neurophysiology, Georg August University, Göttingen, Germany
| | - Nicole E Neef
- Department of Clinical Neurophysiology, Georg August University, Göttingen, Germany. .,Department of Neuropsychology, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstraße 1a, 04103, Leipzig, Germany.
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62
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Interleukin-6-Mediated Induced Pluripotent Stem Cell (iPSC)-Derived Neural Differentiation. Mol Neurobiol 2017; 55:3513-3522. [PMID: 28509081 DOI: 10.1007/s12035-017-0594-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/02/2017] [Indexed: 12/11/2022]
Abstract
In an aging society with an increasing threat to higher brain cognitive functions due to dementia, it becomes imperative to identify new molecular remedies for supporting adult neurogenesis. Interleukin-6 (IL-6) is a promising cytokine that can support neurogenesis under conditions of neurodegeneration, and neuron replacement is eventually possible due to its agonistic acting soluble receptor sIL-6R. Here, we report that activation of the IL-6-signal transducer and activator of transcription 3 (STAT3) axis is neurogenic and has potential therapeutic applications for the treatment of neurodegenerative diseases such as Parkinson's disease (PD).
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63
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Tekko T, Lakspere T, Allikalt A, End J, Kõlvart KR, Jagomäe T, Terasmaa A, Philips MA, Visnapuu T, Väärtnõu F, Gilbert SF, Rinken A, Vasar E, Lilleväli K. Wfs1 is expressed in dopaminoceptive regions of the amniote brain and modulates levels of D1-like receptors. PLoS One 2017; 12:e0172825. [PMID: 28267787 PMCID: PMC5436468 DOI: 10.1371/journal.pone.0172825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 02/10/2017] [Indexed: 11/27/2022] Open
Abstract
During amniote evolution, the construction of the forebrain has diverged across
different lineages, and accompanying the structural changes, functional
diversification of the homologous brain regions has occurred. This can be
assessed by studying the expression patterns of marker genes that are relevant
in particular functional circuits. In all vertebrates, the dopaminergic system
is responsible for the behavioral responses to environmental stimuli. Here we
show that the brain regions that receive dopaminergic input through dopamine
receptor D1 are relatively conserved, but with some important
variations between three evolutionarily distant vertebrate lines–house mouse
(Mus musculus), domestic chick (Gallus gallus
domesticus) / common quail (Coturnix coturnix) and
red-eared slider turtle (Trachemys scripta). Moreover, we find
that in almost all instances, those brain regions expressing D1-like dopamine
receptor genes also express Wfs1. Wfs1 has been studied
primarily in the pancreas, where it regulates the endoplasmic reticulum (ER)
stress response, cellular Ca2+ homeostasis, and insulin production
and secretion. Using radioligand binding assays in wild type and
Wfs1-/- mouse brains, we show that the number of
binding sites of D1-like dopamine receptors is increased in the hippocampus of
the mutant mice. We propose that the functional link between Wfs1 and D1-like
dopamine receptors is evolutionarily conserved and plays an important role in
adjusting behavioral reactions to environmental stimuli.
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Affiliation(s)
- Triin Tekko
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Triin Lakspere
- Department of Developmental Biology, Institute of Molecular and Cell
Biology, University of Tartu, Tartu, Estonia
| | - Anni Allikalt
- Institute of Chemistry, University of Tartu, Tartu,
Estonia
| | - Jaanus End
- Department of Developmental Biology, Institute of Molecular and Cell
Biology, University of Tartu, Tartu, Estonia
| | | | - Toomas Jagomäe
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Anton Terasmaa
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Mari-Anne Philips
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Tanel Visnapuu
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Fred Väärtnõu
- Department of Developmental Biology, Institute of Molecular and Cell
Biology, University of Tartu, Tartu, Estonia
| | - Scott F. Gilbert
- Department of Biology, Swarthmore College, Swarthmore, PA, United States
of America
| | - Ago Rinken
- Institute of Chemistry, University of Tartu, Tartu,
Estonia
| | - Eero Vasar
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
| | - Kersti Lilleväli
- Department of Physiology, Institute of Biomedicine and Translational
Medicine, University of Tartu, Tartu, Estonia
- Centre of Excellence in Genomics and Translational Medicine, University
of Tartu, Tartu, Estonia
- * E-mail:
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Enhanced Sensitivity to Hyperpolarizing Inhibition in Mesoaccumbal Relative to Nigrostriatal Dopamine Neuron Subpopulations. J Neurosci 2017; 37:3311-3330. [PMID: 28219982 DOI: 10.1523/jneurosci.2969-16.2017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 02/02/2017] [Accepted: 02/10/2017] [Indexed: 11/21/2022] Open
Abstract
Midbrain dopamine neurons recorded in vivo pause their firing in response to reward omission and aversive stimuli. While the initiation of pauses typically involves synaptic or modulatory input, intrinsic membrane properties may also enhance or limit hyperpolarization, raising the question of how intrinsic conductances shape pauses in dopamine neurons. Using retrograde labeling and electrophysiological techniques combined with computational modeling, we examined the intrinsic conductances that shape pauses evoked by current injections and synaptic stimulation in subpopulations of dopamine neurons grouped according to their axonal projections to the nucleus accumbens or dorsal striatum in mice. Testing across a range of conditions and pulse durations, we found that mesoaccumbal and nigrostriatal neurons differ substantially in rebound properties with mesoaccumbal neurons displaying significantly longer delays to spiking following hyperpolarization. The underlying mechanism involves an inactivating potassium (IA) current with decay time constants of up to 225 ms, and small-amplitude hyperpolarization-activated currents (IH), characteristics that were most often observed in mesoaccumbal neurons. Pharmacological block of IA completely abolished rebound delays and, importantly, shortened synaptically evoked inhibitory pauses, thereby demonstrating the involvement of A-type potassium channels in prolonging pauses evoked by GABAergic inhibition. Therefore, these results show that mesoaccumbal and nigrostriatal neurons display differential responses to hyperpolarizing inhibitory stimuli that favors a higher sensitivity to inhibition in mesoaccumbal neurons. These findings may explain, in part, observations from in vivo experiments that ventral tegmental area neurons tend to exhibit longer aversive pauses relative to SNc neurons.SIGNIFICANCE STATEMENT Our study examines rebound, postburst, and synaptically evoked inhibitory pauses in subpopulations of midbrain dopamine neurons. We show that pauses in dopamine neuron firing, evoked by either stimulation of GABAergic inputs or hyperpolarizing current injections, are enhanced by a subclass of potassium conductances that are recruited at voltages below spike threshold. Importantly, A-type potassium currents recorded in mesoaccumbal neurons displayed substantially slower inactivation kinetics, which, combined with weaker expression of hyperpolarization-activated currents, lengthened hyperpolarization-induced delays in spiking relative to nigrostriatal neurons. These results suggest that input integration differs among dopamine neurons favoring higher sensitivity to inhibition in mesoaccumbal neurons and may partially explain in vivo observations that ventral tegmental area neurons exhibit longer aversive pauses relative to SNc neurons.
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Oh YM, Karube F, Takahashi S, Kobayashi K, Takada M, Uchigashima M, Watanabe M, Nishizawa K, Kobayashi K, Fujiyama F. Using a novel PV-Cre rat model to characterize pallidonigral cells and their terminations. Brain Struct Funct 2016; 222:2359-2378. [PMID: 27995326 DOI: 10.1007/s00429-016-1346-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/25/2016] [Indexed: 10/20/2022]
Abstract
In the present study, we generated a novel parvalbumin (PV)-Cre rat model and conducted detailed morphological and electrophysiological investigations of axons from PV neurons in globus pallidus (GP). The GP is considered as a relay nucleus in the indirect pathway of the basal ganglia (BG). Previous studies have used molecular profiling and projection patterns to demonstrate cellular heterogeneity in the GP; for example, PV-expressing neurons are known to comprise approximately 50% of GP neurons and represent majority of prototypic neurons that project to the subthalamic nucleus and/or output nuclei of BG, entopeduncular nucleus and substantia nigra (SN). The present study aimed to identify the characteristic projection patterns of PV neurons in the GP (PV-GP neurons) and determine whether these neurons target dopaminergic or GABAergic neurons in SN pars compacta (SNc) or reticulata (SNr), respectively. We initially found that (1) 57% of PV neurons co-expressed Lim-homeobox 6, (2) the PV-GP terminals were preferentially distributed in the ventral part of dorsal tier of SNc, (3) PV-GP neurons formed basket-like appositions with the somata of tyrosine hydroxylase, PV, calretinin and cholecystokinin immunoreactive neurons in the SN, and (4) in vitro whole-cell recording during optogenetic photo-stimulation of PV-GP terminals in SNc demonstrated that PV-GP neurons strongly inhibited dopamine neurons via GABAA receptors. These results suggest that dopamine neurons receive direct focal inputs from PV-GP prototypic neurons. The identification of high-contrast inhibitory systems on dopamine neurons might represent a key step toward understanding the BG function.
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Affiliation(s)
- Yoon-Mi Oh
- Laboratory of Neural Circuitry, Graduate School of Brain Science, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Fuyuki Karube
- Laboratory of Neural Circuitry, Graduate School of Brain Science, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Susumu Takahashi
- Laboratory of Neural Circuitry, Graduate School of Brain Science, Doshisha University, Kyotanabe, 610-0394, Japan
| | - Kenta Kobayashi
- Section of Viral Vector Development, National Institute for Physiological Sciences, Okazaki, 444-8585, Japan
| | - Masahiko Takada
- Systems Neuroscience Section, Primate Research Institute, Kyoto University, Inuyama, 484-8506, Japan
| | - Motokazu Uchigashima
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan
| | - Kayo Nishizawa
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Kazuto Kobayashi
- Department of Molecular Genetics, Institute of Biomedical Sciences, Fukushima Medical University, Fukushima, 960-1295, Japan
| | - Fumino Fujiyama
- Laboratory of Neural Circuitry, Graduate School of Brain Science, Doshisha University, Kyotanabe, 610-0394, Japan.
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Morozova EO, Zakharov D, Gutkin BS, Lapish CC, Kuznetsov A. Dopamine Neurons Change the Type of Excitability in Response to Stimuli. PLoS Comput Biol 2016; 12:e1005233. [PMID: 27930673 PMCID: PMC5145155 DOI: 10.1371/journal.pcbi.1005233] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 11/02/2016] [Indexed: 11/18/2022] Open
Abstract
The dynamics of neuronal excitability determine the neuron's response to stimuli, its synchronization and resonance properties and, ultimately, the computations it performs in the brain. We investigated the dynamical mechanisms underlying the excitability type of dopamine (DA) neurons, using a conductance-based biophysical model, and its regulation by intrinsic and synaptic currents. Calibrating the model to reproduce low frequency tonic firing results in N-methyl-D-aspartate (NMDA) excitation balanced by γ-Aminobutyric acid (GABA)-mediated inhibition and leads to type I excitable behavior characterized by a continuous decrease in firing frequency in response to hyperpolarizing currents. Furthermore, we analyzed how excitability type of the DA neuron model is influenced by changes in the intrinsic current composition. A subthreshold sodium current is necessary for a continuous frequency decrease during application of a negative current, and the low-frequency "balanced" state during simultaneous activation of NMDA and GABA receptors. Blocking this current switches the neuron to type II characterized by the abrupt onset of repetitive firing. Enhancing the anomalous rectifier Ih current also switches the excitability to type II. Key characteristics of synaptic conductances that may be observed in vivo also change the type of excitability: a depolarized γ-Aminobutyric acid receptor (GABAR) reversal potential or co-activation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) leads to an abrupt frequency drop to zero, which is typical for type II excitability. Coactivation of N-methyl-D-aspartate receptors (NMDARs) together with AMPARs and GABARs shifts the type I/II boundary toward more hyperpolarized GABAR reversal potentials. To better understand how altering each of the aforementioned currents leads to changes in excitability profile of DA neuron, we provide a thorough dynamical analysis. Collectively, these results imply that type I excitability in dopamine neurons might be important for low firing rates and fine-tuning basal dopamine levels, while switching excitability to type II during NMDAR and AMPAR activation may facilitate a transient increase in dopamine concentration, as type II neurons are more amenable to synchronization by mutual excitation.
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Affiliation(s)
- Ekaterina O. Morozova
- Department of Physics, Indiana University, Bloomington, Indiana, United States of America
- Department of Mathematical sciences, Indiana University - Purdue University, Indianapolis, Indiana, United States of America
- * E-mail:
| | | | - Boris S. Gutkin
- Group of Neural Theory, INSERM U960 LNC, IEC, Ecole Normale Superieure PSL University, Paris
- Center for Cognition and Decision Making, NRU HSE, Moscow, Russia
| | - Christopher C. Lapish
- Addiction Neuroscience Program, Indiana University - Purdue University, Indianapolis, Indiana, United States of America
| | - Alexey Kuznetsov
- Department of Mathematical sciences, Indiana University - Purdue University, Indianapolis, Indiana, United States of America
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Karunasinghe RN, Grey AC, Telang R, Vlajkovic SM, Lipski J. Differential spread of anoxic depolarization contributes to the pattern of neuronal injury after oxygen and glucose deprivation (OGD) in the Substantia Nigra in rat brain slices. Neuroscience 2016; 340:359-372. [PMID: 27826106 DOI: 10.1016/j.neuroscience.2016.10.067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 10/14/2016] [Accepted: 10/29/2016] [Indexed: 12/21/2022]
Abstract
Anoxic depolarization (AD) is an acute event evoked by brain ischemia, involving a profound loss of cell membrane potential and swelling that spreads over susceptible parts of the gray matter. Its occurrence is a strong predictor of the severity of neuronal injury. Little is known about this event in the Substantia Nigra, a midbrain nucleus critical for motor control. We tested the effects of oxygen and glucose deprivation (OGD), an in vitro model of brain ischemia, in rat midbrain slices. AD developed within 4min from OGD onset and spread in the Substantia Nigra pars reticulata (SNr), but not through the Substantia Nigra pars compacta (SNc). This differential effect involved a contrasting pattern of changes in membrane potential between dopamine-producing SNc and non-dopaminergic SNr neurons. A fast depolarization in SNr neurons was not followed by repolarization after the end of OGD, and was associated with swollen somata and beaded dendrites. In contrast, slowly developing depolarization of SNc neurons led to repolarization after OGD ended, and no changes in neuronal morphology were observed. The AD-resistance of the SNc involved smaller dysregulations of K+ and Ca2+ ions, and a slower loss of energy metabolites. Our results show that acute ischemia profoundly impairs the function and morphology of SNr neurons but not adjacent SNc neurons, and that the surprising higher tolerance of SNc neurons correlates with the resistance of the SNc region to AD. This differential response may affect the pattern of early neuronal injury that develops in the brainstem after acute ischemic insults.
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Affiliation(s)
- Rashika N Karunasinghe
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Angus C Grey
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Ravindra Telang
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Srdjan M Vlajkovic
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand
| | - Janusz Lipski
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Auckland 1023, New Zealand.
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Morozova EO, Myroshnychenko M, Zakharov D, di Volo M, Gutkin B, Lapish CC, Kuznetsov A. Contribution of synchronized GABAergic neurons to dopaminergic neuron firing and bursting. J Neurophysiol 2016; 116:1900-1923. [PMID: 27440240 PMCID: PMC5144690 DOI: 10.1152/jn.00232.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 07/17/2016] [Indexed: 12/29/2022] Open
Abstract
In the ventral tegmental area (VTA), interactions between dopamine (DA) and γ-aminobutyric acid (GABA) neurons are critical for regulating DA neuron activity and thus DA efflux. To provide a mechanistic explanation of how GABA neurons influence DA neuron firing, we developed a circuit model of the VTA. The model is based on feed-forward inhibition and recreates canonical features of the VTA neurons. Simulations revealed that γ-aminobutyric acid (GABA) receptor (GABAR) stimulation can differentially influence the firing pattern of the DA neuron, depending on the level of synchronization among GABA neurons. Asynchronous activity of GABA neurons provides a constant level of inhibition to the DA neuron and, when removed, produces a classical disinhibition burst. In contrast, when GABA neurons are synchronized by common synaptic input, their influence evokes additional spikes in the DA neuron, resulting in increased measures of firing and bursting. Distinct from previous mechanisms, the increases were not based on lowered firing rate of the GABA neurons or weaker hyperpolarization by the GABAR synaptic current. This phenomenon was induced by GABA-mediated hyperpolarization of the DA neuron that leads to decreases in intracellular calcium (Ca2+) concentration, thus reducing the Ca2+-dependent potassium (K+) current. In this way, the GABA-mediated hyperpolarization replaces Ca2+-dependent K+ current; however, this inhibition is pulsatile, which allows the DA neuron to fire during the rhythmic pauses in inhibition. Our results emphasize the importance of inhibition in the VTA, which has been discussed in many studies, and suggest a novel mechanism whereby computations can occur locally.
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Affiliation(s)
- Ekaterina O Morozova
- Department of Physics, Indiana University, Bloomington, Indiana; Department of Mathematical Sciences, Indiana University-Purdue University, Indianapolis, Indiana;
| | - Maxym Myroshnychenko
- Program in Neuroscience, Indiana University, Bloomington, Indiana; Addiction Neuroscience Program, Indiana University-Purdue University, Indianapolis, Indiana; and
| | - Denis Zakharov
- Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia
| | - Matteo di Volo
- Department of Mathematical Sciences, Indiana University-Purdue University, Indianapolis, Indiana; Group of Neural Theory, INSERM U960, Laboratoire de Neurosciences Cognitives, Institut d'Etude de Cognition, Ecole Normale Superieure, Paris Sciences et Lettres Research University, Paris, France
| | - Boris Gutkin
- Group of Neural Theory, INSERM U960, Laboratoire de Neurosciences Cognitives, Institut d'Etude de Cognition, Ecole Normale Superieure, Paris Sciences et Lettres Research University, Paris, France; Center for Cognition and Decision Making, National Research University Higher School of Economics, Moscow, Russia
| | - Christopher C Lapish
- Addiction Neuroscience Program, Indiana University-Purdue University, Indianapolis, Indiana; and
| | - Alexey Kuznetsov
- Department of Mathematical Sciences, Indiana University-Purdue University, Indianapolis, Indiana
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Tian J, Huang R, Cohen JY, Osakada F, Kobak D, Machens CK, Callaway EM, Uchida N, Watabe-Uchida M. Distributed and Mixed Information in Monosynaptic Inputs to Dopamine Neurons. Neuron 2016; 91:1374-1389. [PMID: 27618675 DOI: 10.1016/j.neuron.2016.08.018] [Citation(s) in RCA: 143] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/28/2016] [Accepted: 07/25/2016] [Indexed: 01/29/2023]
Abstract
Dopamine neurons encode the difference between actual and predicted reward, or reward prediction error (RPE). Although many models have been proposed to account for this computation, it has been difficult to test these models experimentally. Here we established an awake electrophysiological recording system, combined with rabies virus and optogenetic cell-type identification, to characterize the firing patterns of monosynaptic inputs to dopamine neurons while mice performed classical conditioning tasks. We found that each variable required to compute RPE, including actual and predicted reward, was distributed in input neurons in multiple brain areas. Further, many input neurons across brain areas signaled combinations of these variables. These results demonstrate that even simple arithmetic computations such as RPE are not localized in specific brain areas but, rather, distributed across multiple nodes in a brain-wide network. Our systematic method to examine both activity and connectivity revealed unexpected redundancy for a simple computation in the brain.
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Affiliation(s)
- Ju Tian
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Ryan Huang
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Jeremiah Y Cohen
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA; The Solomon H. Snyder Department of Neuroscience, Brain Science Institute, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Fumitaka Osakada
- Systems Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Laboratory of Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Dmitry Kobak
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon 1400-038, Portugal
| | - Christian K Machens
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon 1400-038, Portugal
| | - Edward M Callaway
- Systems Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Naoshige Uchida
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
| | - Mitsuko Watabe-Uchida
- Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
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Violante IR, Patricio M, Bernardino I, Rebola J, Abrunhosa AJ, Ferreira N, Castelo-Branco M. GABA deficiency in NF1: A multimodal [11C]-flumazenil and spectroscopy study. Neurology 2016; 87:897-904. [PMID: 27473134 PMCID: PMC5035153 DOI: 10.1212/wnl.0000000000003044] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 05/17/2016] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To provide a comprehensive investigation of the γ-aminobutyric acid (GABA) system in patients with neurofibromatosis type 1 (NF1) that allows understanding the nature of the GABA imbalance in humans at pre- and postsynaptic levels. METHODS In this cross-sectional study, we employed multimodal imaging and spectroscopy measures to investigate GABA type A (GABAA) receptor binding, using [(11)C]-flumazenil PET, and GABA concentration, using magnetic resonance spectroscopy (MRS). Fourteen adult patients with NF1 and 13 matched controls were included in the study. MRS was performed in the occipital cortex and in a frontal region centered in the functionally localized frontal eye fields. PET and MRS acquisitions were performed in the same day. RESULTS Patients with NF1 have reduced concentration of GABA+ in the occipital cortex (p = 0.004) and frontal eye fields (p = 0.026). PET results showed decreased binding of GABAA receptors in patients in the parieto-occipital cortex, midbrain, and thalamus, which are not explained by decreased gray matter levels. CONCLUSIONS Abnormalities in the GABA system in NF1 involve both GABA concentration and GABAA receptor density suggestive of neurodevelopmental synaptopathy with both pre- and postsynaptic involvement.
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Affiliation(s)
- Inês R Violante
- From the Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine (I.R.V., M.P., I.B., J.R., M.C.-B.), Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine (M.P., M.C.-B.), and Institute of Nuclear Sciences Applied to Health (A.J.A., N.F., M.C.-B.), University of Coimbra, Portugal; and Division of Brain Sciences (I.R.V.), Department of Medicine, Hammersmith Hospital Campus, Imperial College London, UK.
| | - Miguel Patricio
- From the Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine (I.R.V., M.P., I.B., J.R., M.C.-B.), Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine (M.P., M.C.-B.), and Institute of Nuclear Sciences Applied to Health (A.J.A., N.F., M.C.-B.), University of Coimbra, Portugal; and Division of Brain Sciences (I.R.V.), Department of Medicine, Hammersmith Hospital Campus, Imperial College London, UK
| | - Inês Bernardino
- From the Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine (I.R.V., M.P., I.B., J.R., M.C.-B.), Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine (M.P., M.C.-B.), and Institute of Nuclear Sciences Applied to Health (A.J.A., N.F., M.C.-B.), University of Coimbra, Portugal; and Division of Brain Sciences (I.R.V.), Department of Medicine, Hammersmith Hospital Campus, Imperial College London, UK
| | - José Rebola
- From the Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine (I.R.V., M.P., I.B., J.R., M.C.-B.), Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine (M.P., M.C.-B.), and Institute of Nuclear Sciences Applied to Health (A.J.A., N.F., M.C.-B.), University of Coimbra, Portugal; and Division of Brain Sciences (I.R.V.), Department of Medicine, Hammersmith Hospital Campus, Imperial College London, UK
| | - Antero J Abrunhosa
- From the Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine (I.R.V., M.P., I.B., J.R., M.C.-B.), Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine (M.P., M.C.-B.), and Institute of Nuclear Sciences Applied to Health (A.J.A., N.F., M.C.-B.), University of Coimbra, Portugal; and Division of Brain Sciences (I.R.V.), Department of Medicine, Hammersmith Hospital Campus, Imperial College London, UK
| | - Nuno Ferreira
- From the Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine (I.R.V., M.P., I.B., J.R., M.C.-B.), Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine (M.P., M.C.-B.), and Institute of Nuclear Sciences Applied to Health (A.J.A., N.F., M.C.-B.), University of Coimbra, Portugal; and Division of Brain Sciences (I.R.V.), Department of Medicine, Hammersmith Hospital Campus, Imperial College London, UK
| | - Miguel Castelo-Branco
- From the Institute for Biomedical Imaging and Life Sciences, Faculty of Medicine (I.R.V., M.P., I.B., J.R., M.C.-B.), Laboratory of Biostatistics and Medical Informatics, Faculty of Medicine (M.P., M.C.-B.), and Institute of Nuclear Sciences Applied to Health (A.J.A., N.F., M.C.-B.), University of Coimbra, Portugal; and Division of Brain Sciences (I.R.V.), Department of Medicine, Hammersmith Hospital Campus, Imperial College London, UK
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Abstract
This review is an attempt to explain the role of basal ganglia (BG) outputs in generating movements. Recent work showed that opponent outputs from the BG represent instantaneous body position coordinates during behavior. On the other hand, projection neurons in the striatum, the major input nucleus, as well as dopaminergic neurons that form the nigrostriatal pathway, can represent movement velocity. To explain these findings, a new model is proposed, in which the BG implement the level of transition control in an extended control hierarchy. BG outputs represent descending reference signals that command diverse lower-level position controllers. This model not only explains major neurological symptoms but also makes quantitative and testable predictions.
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Affiliation(s)
- Henry H Yin
- Department of Psychology & Neuroscience, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA
- Department of Neurobiology, Center for Cognitive Neuroscience, Duke University, Durham, NC 27708, USA
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Keiflin R, Janak PH. Dopamine Prediction Errors in Reward Learning and Addiction: From Theory to Neural Circuitry. Neuron 2016; 88:247-63. [PMID: 26494275 DOI: 10.1016/j.neuron.2015.08.037] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Midbrain dopamine (DA) neurons are proposed to signal reward prediction error (RPE), a fundamental parameter in associative learning models. This RPE hypothesis provides a compelling theoretical framework for understanding DA function in reward learning and addiction. New studies support a causal role for DA-mediated RPE activity in promoting learning about natural reward; however, this question has not been explicitly tested in the context of drug addiction. In this review, we integrate theoretical models with experimental findings on the activity of DA systems, and on the causal role of specific neuronal projections and cell types, to provide a circuit-based framework for probing DA-RPE function in addiction. By examining error-encoding DA neurons in the neural network in which they are embedded, hypotheses regarding circuit-level adaptations that possibly contribute to pathological error signaling and addiction can be formulated and tested.
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Affiliation(s)
- Ronald Keiflin
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Patricia H Janak
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD 21218, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Paladini C, Tepper J. Neurophysiology of Substantia Nigra Dopamine Neurons: Modulation by GABA and Glutamate. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2016. [DOI: 10.1016/b978-0-12-802206-1.00017-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Aumann TD. Environment- and activity-dependent dopamine neurotransmitter plasticity in the adult substantia nigra. J Chem Neuroanat 2015; 73:21-32. [PMID: 26718607 DOI: 10.1016/j.jchemneu.2015.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 12/15/2015] [Accepted: 12/16/2015] [Indexed: 01/10/2023]
Abstract
The ability of neurons to change the amount or type of neurotransmitter they use, or 'neurotransmitter plasticity', is an emerging new form of adult brain plasticity. For example, it has recently been shown that neurons in the adult rat hypothalamus up- or down-regulate dopamine (DA) neurotransmission in response to the amount of light the animal receives (photoperiod), and that this in turn affects anxiety- and depressive-like behaviors (Dulcis et al., 2013). In this Chapter I consolidate recent evidence from my laboratory suggesting neurons in the adult mouse substantia nigra pars compacta (SNc) also undergo DA neurotransmitter plasticity in response to persistent changes in their electrical activity, including that driven by the mouse's environment or behavior. Specifically, we have shown that the amounts of tyrosine hydroxylase (TH, the rate-limiting enzyme in DA synthesis) gene promoter activity, TH mRNA and TH protein in SNc neurons increases or decreases after ∼20h of altered electrical activity. Also, infusion of ion-channel agonists or antagonists into the midbrain for 2 weeks results in ∼10% (∼500 neurons) more or fewer TH immunoreactive (TH+) SNc neurons, with no change in the total number of SNc neurons (TH+ and TH-). Targeting ion-channels mediating cell-autonomous pacemaker activity in, or synaptic input and afferent pathways to, SNc neurons are equally effective in this regard. In addition, exposing mice to different environments (sex pairing or environment enrichment) for 1-2 weeks induces ∼10% more or fewer TH+ SNc (and ventral tegmental area or VTA) neurons and this is abolished by concurrent blockade of synaptic transmission in midbrain. Although further research is required to establish SNc (and VTA) DA neurotransmitter plasticity, and to determine whether it alters brain function and behavior, it is an exciting prospect because: (1) It may play important roles in movement, motor learning, reward, motivation, memory and cognition; and (2) Imbalances in midbrain DA cause symptoms associated with several prominent brain and behavioral disorders such as schizophrenia, addiction, obsessive-compulsive disorder, depression, Parkinson's disease and attention-deficit and hyperactivity disorder. Midbrain DA neurotransmitter plasticity may therefore play a role in the etiology of these symptoms, and might also offer new treatment options.
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Affiliation(s)
- Tim D Aumann
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia.
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Quinn JC. Complex Membrane Channel Blockade: A Unifying Hypothesis for the Prodromal and Acute Neuropsychiatric Sequelae Resulting from Exposure to the Antimalarial Drug Mefloquine. J Parasitol Res 2015; 2015:368064. [PMID: 26576290 PMCID: PMC4630403 DOI: 10.1155/2015/368064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 09/28/2015] [Indexed: 12/18/2022] Open
Abstract
The alkaloid toxin quinine and its derivative compounds have been used for many centuries as effective medications for the prevention and treatment of malaria. More recently, synthetic derivatives, such as the quinoline derivative mefloquine (bis(trifluoromethyl)-(2-piperidyl)-4-quinolinemethanol), have been widely used to combat disease caused by chloroquine-resistant strains of the malaria parasite, Plasmodium falciparum. However, the parent compound quinine, as well as its more recent counterparts, suffers from an incidence of adverse neuropsychiatric side effects ranging from mild mood disturbances and anxiety to hallucinations, seizures, and psychosis. This review considers how the pharmacology, cellular neurobiology, and membrane channel kinetics of mefloquine could lead to the significant and sometimes life-threatening neurotoxicity associated with mefloquine exposure. A key role for mefloquine blockade of ATP-sensitive potassium channels and connexins in the substantia nigra is considered as a unifying hypothesis for the pathogenesis of severe neuropsychiatric events after mefloquine exposure in humans.
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Affiliation(s)
- Jane C. Quinn
- Plant and Animal Toxicology Group, School of Animal and Veterinary Sciences, Graham Centre for Agricultural Innovation, Charles Sturt University, Boorooma Street, Wagga Wagga, NSW 2650, Australia
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Transcription factors FOXA1 and FOXA2 maintain dopaminergic neuronal properties and control feeding behavior in adult mice. Proc Natl Acad Sci U S A 2015; 112:E4929-38. [PMID: 26283356 DOI: 10.1073/pnas.1503911112] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Midbrain dopaminergic (mDA) neurons are implicated in cognitive functions, neuropsychiatric disorders, and pathological conditions; hence understanding genes regulating their homeostasis has medical relevance. Transcription factors FOXA1 and FOXA2 (FOXA1/2) are key determinants of mDA neuronal identity during development, but their roles in adult mDA neurons are unknown. We used a conditional knockout strategy to specifically ablate FOXA1/2 in mDA neurons of adult mice. We show that deletion of Foxa1/2 results in down-regulation of tyrosine hydroxylase, the rate-limiting enzyme of dopamine (DA) biosynthesis, specifically in dopaminergic neurons of the substantia nigra pars compacta (SNc). In addition, DA synthesis and striatal DA transmission were reduced after Foxa1/2 deletion. Furthermore, the burst-firing activity characteristic of SNc mDA neurons was drastically reduced in the absence of FOXA1/2. These molecular and functional alterations lead to a severe feeding deficit in adult Foxa1/2 mutant mice, independently of motor control, which could be rescued by L-DOPA treatment. FOXA1/2 therefore control the maintenance of molecular and physiological properties of SNc mDA neurons and impact on feeding behavior in adult mice.
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78
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Dorofeeva NA, Glazova MV, Khudik KA, Nikitina LS, Kirillova OD, Chernigovskaya EV. Comparative analysis of the nigrostriatal system in Wistar rats and rats prone to seizures. J EVOL BIOCHEM PHYS+ 2015. [DOI: 10.1134/s0022093015030088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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79
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Morita K, Kawaguchi Y. Computing reward-prediction error: an integrated account of cortical timing and basal-ganglia pathways for appetitive and aversive learning. Eur J Neurosci 2015; 42:2003-21. [PMID: 26095906 PMCID: PMC5034842 DOI: 10.1111/ejn.12994] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 06/11/2015] [Accepted: 06/17/2015] [Indexed: 12/12/2022]
Abstract
There are two prevailing notions regarding the involvement of the corticobasal ganglia system in value‐based learning: (i) the direct and indirect pathways of the basal ganglia are crucial for appetitive and aversive learning, respectively, and (ii) the activity of midbrain dopamine neurons represents reward‐prediction error. Although (ii) constitutes a critical assumption of (i), it remains elusive how (ii) holds given (i), with the basal‐ganglia influence on the dopamine neurons. Here we present a computational neural‐circuit model that potentially resolves this issue. Based on the latest analyses of the heterogeneous corticostriatal neurons and connections, our model posits that the direct and indirect pathways, respectively, represent the values of upcoming and previous actions, and up‐regulate and down‐regulate the dopamine neurons via the basal‐ganglia output nuclei. This explains how the difference between the upcoming and previous values, which constitutes the core of reward‐prediction error, is calculated. Simultaneously, it predicts that blockade of the direct/indirect pathway causes a negative/positive shift of reward‐prediction error and thereby impairs learning from positive/negative error, i.e. appetitive/aversive learning. Through simulation of reward‐reversal learning and punishment‐avoidance learning, we show that our model could indeed account for the experimentally observed features that are suggested to support notion (i) and could also provide predictions on neural activity. We also present a behavioral prediction of our model, through simulation of inter‐temporal choice, on how the balance between the two pathways relates to the subject's time preference. These results indicate that our model, incorporating the heterogeneity of the cortical influence on the basal ganglia, is expected to provide a closed‐circuit mechanistic understanding of appetitive/aversive learning.
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Affiliation(s)
- Kenji Morita
- Physical and Health Education, Graduate School of Education, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yasuo Kawaguchi
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki, Japan.,Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan.,Japan Science and Technology Agency, Core Research for Evolutional Science and Technology, Tokyo, Japan
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80
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Tonic firing rate controls dendritic Ca2+ signaling and synaptic gain in substantia nigra dopamine neurons. J Neurosci 2015; 35:5823-36. [PMID: 25855191 DOI: 10.1523/jneurosci.3904-14.2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Substantia nigra dopamine neurons fire tonically resulting in action potential backpropagation and dendritic Ca(2+) influx. Using Ca(2+) imaging in acute mouse brain slices, we find a surprisingly steep relationship between tonic firing rate and dendritic Ca(2+). Increasing the tonic rate from 1 to 6 Hz generated Ca(2+) signals up to fivefold greater than predicted by linear summation of single spike-evoked Ca(2+)-transients. This "Ca(2+) supralinearity" was produced largely by depolarization of the interspike voltage leading to activation of subthreshold Ca(2+) channels and was present throughout the proximal and distal dendrites. Two-photon glutamate uncaging experiments show somatic depolarization enhances NMDA receptor-mediated Ca(2+) signals >400 μm distal to the soma, due to unusually tight electrotonic coupling of the soma to distal dendrites. Consequently, we find that fast tonic firing intensifies synaptically driven burst firing output in dopamine neurons. These results show that modulation of background firing rate precisely tunes dendritic Ca(2+) signaling and provides a simple yet powerful mechanism to dynamically regulate the gain of synaptic input.
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81
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Barter JW, Li S, Lu D, Bartholomew RA, Rossi MA, Shoemaker CT, Salas-Meza D, Gaidis E, Yin HH. Beyond reward prediction errors: the role of dopamine in movement kinematics. Front Integr Neurosci 2015; 9:39. [PMID: 26074791 PMCID: PMC4444742 DOI: 10.3389/fnint.2015.00039] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 05/06/2015] [Indexed: 11/13/2022] Open
Abstract
We recorded activity of dopamine (DA) neurons in the substantia nigra pars compacta in unrestrained mice while monitoring their movements with video tracking. Our approach allows an unbiased examination of the continuous relationship between single unit activity and behavior. Although DA neurons show characteristic burst firing following cue or reward presentation, as previously reported, their activity can be explained by the representation of actual movement kinematics. Unlike neighboring pars reticulata GABAergic output neurons, which can represent vector components of position, DA neurons represent vector components of velocity or acceleration. We found neurons related to movements in four directions-up, down, left, right. For horizontal movements, there is significant lateralization of neurons: the left nigra contains more rightward neurons, whereas the right nigra contains more leftward neurons. The relationship between DA activity and movement kinematics was found on both appetitive trials using sucrose and aversive trials using air puff, showing that these neurons belong to a velocity control circuit that can be used for any number of purposes, whether to seek reward or to avoid harm. In support of this conclusion, mimicry of the phasic activation of DA neurons with selective optogenetic stimulation could also generate movements. Contrary to the popular hypothesis that DA neurons encode reward prediction errors, our results suggest that nigrostriatal DA plays an essential role in controlling the kinematics of voluntary movements. We hypothesize that DA signaling implements gain adjustment for adaptive transition control, and describe a new model of the basal ganglia (BG) in which DA functions to adjust the gain of the transition controller. This model has significant implications for our understanding of movement disorders implicating DA and the BG.
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Affiliation(s)
- Joseph W Barter
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Suellen Li
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Dongye Lu
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Ryan A Bartholomew
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Mark A Rossi
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Charles T Shoemaker
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Daniel Salas-Meza
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Erin Gaidis
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
| | - Henry H Yin
- Department of Psychology and Neuroscience, Department of Neurobiology, Center for Cognitive Neuroscience, Duke University Durham, NC, USA
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82
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Desynchronization of fast-spiking interneurons reduces β-band oscillations and imbalance in firing in the dopamine-depleted striatum. J Neurosci 2015; 35:1149-59. [PMID: 25609629 DOI: 10.1523/jneurosci.3490-14.2015] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Oscillations in the β-band (8-30 Hz) that emerge in the output nuclei of the basal ganglia during Parkinson's disease, along with an imbalanced activation of the direct and indirect pathways, have been linked to the hypokinetic motor output associated with the disease. Although dopamine depletion causes a change in cellular and network properties in the striatum, it is unclear whether abnormal activity measured in the globus pallidus and substantia nigra pars reticulata is caused by abnormal striatal activity. Here we use a computational network model of medium spiny neurons (MSNs)-fast-spiking interneurons (FSIs), based on data from several mammalian species, and find that robust β-band oscillations and imbalanced firing emerge from implementation of changes to cellular and circuit properties caused by dopamine depletion. These changes include a reduction in connections between MSNs, a doubling of FSI inhibition to D2 MSNs, an increase in D2 MSN dendritic excitability, and a reduction in D2 MSN somatic excitability. The model reveals that the reduced decorrelation between MSNs attributable to weakened lateral inhibition enables the strong influence of synchronous FSIs on MSN firing and oscillations. Weakened lateral inhibition also produces an increased sensitivity of MSN output to cortical correlation, a condition relevant to the parkinsonian striatum. The oscillations of FSIs, in turn, are strongly modulated by fast electrical transmission between FSIs through gap junctions. These results suggest that pharmaceuticals that desynchronize FSI activity may provide a novel treatment for the enhanced β-band oscillations, imbalanced firing, and motor dysfunction in Parkinson's disease.
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83
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Harrill JA, Chen H, Streifel KM, Yang D, Mundy WR, Lein PJ. Ontogeny of biochemical, morphological and functional parameters of synaptogenesis in primary cultures of rat hippocampal and cortical neurons. Mol Brain 2015; 8:10. [PMID: 25757474 PMCID: PMC4339650 DOI: 10.1186/s13041-015-0099-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 01/30/2015] [Indexed: 11/23/2022] Open
Abstract
Background Synaptogenesis is a critical neurodevelopmental process whereby pre- and postsynaptic neurons form apposed sites of contact specialized for chemical neurotransmission. Many neurodevelopmental disorders are thought to reflect altered patterns of synaptic connectivity, including imbalances between excitatory and inhibitory synapses. Developing rapid throughput approaches for assessing synaptogenesis will facilitate toxicologic and drug screening studies of neurodevelopmental disorders. The current study describes the use of high-content imaging to quantify the ontogeny of excitatory and inhibitory synapses using in vitro models of neurodevelopment. These data are compared to biochemical and functional measures of synaptogenesis. Results The ontogenetic patterns of synapse formation were compared between primary rodent hippocampal and cortical neurons over 28 days in vitro (DIV). As determined by ELISA, the increase in synaptophysin expression levels as cultures matured was similar between hippocampal and cortical cultures. High-content imaging of immunoreactivity of excitatory and inhibitory synaptic biomarkers demonstrated an overall greater number of synapses in hippocampal relative to cortical neurons with marked differences in the pattern of inhibitory synapse development between these two neuronal cell types. Functional assays revealed that both the mean firing rates and mean bursting rates were significantly increased in cortical cultures relative to hippocampal cultures. This difference may reflect decreased inhibitory synaptic tone in cortical versus hippocampal cultures. Conclusions These data demonstrate differences and similarities in the ontogeny of synaptogenesis between hippocampal and cortical neurons, depending on the biological level examined. Assessment of synaptophysin protein levels by ELISA showed a general increase in synapse formation in both cell types with increasing time in culture, while high-content imaging was able to delineate cell type-dependent differences in formation of excitatory versus inhibitory synapses. The functional significance of differences in the balance of excitatory to inhibitory synapses was confirmed by the assessment of network activity using microelectrode arrays. These results suggest that high-content imaging and microelectrode arrays provide complementary approaches for quantitative assessment of synaptogenesis, which should provide a robust readout of toxicologic and pharmacologic effects on this critical neurodevelopmental event.
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84
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Fujiyama F, Takahashi S, Karube F. Morphological elucidation of basal ganglia circuits contributing reward prediction. Front Neurosci 2015; 9:6. [PMID: 25698913 PMCID: PMC4318281 DOI: 10.3389/fnins.2015.00006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 01/08/2015] [Indexed: 11/26/2022] Open
Abstract
Electrophysiological studies in monkeys have shown that dopaminergic neurons respond to the reward prediction error. In addition, striatal neurons alter their responsiveness to cortical or thalamic inputs in response to the dopamine signal, via the mechanism of dopamine-regulated synaptic plasticity. These findings have led to the hypothesis that the striatum exhibits synaptic plasticity under the influence of the reward prediction error and conduct reinforcement learning throughout the basal ganglia circuits. The reinforcement learning model is useful; however, the mechanism by which such a process emerges in the basal ganglia needs to be anatomically explained. The actor–critic model has been previously proposed and extended by the existence of role sharing within the striatum, focusing on the striosome/matrix compartments. However, this hypothesis has been difficult to confirm morphologically, partly because of the complex structure of the striosome/matrix compartments. Here, we review recent morphological studies that elucidate the input/output organization of the striatal compartments.
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Affiliation(s)
- Fumino Fujiyama
- Laboratory of Neural Circuitry, Department of Systems Neuroscience, Graduate School of Brain Science, Doshisha University Kyoto, Japan ; Core Research for Evolutional Science and Technology, Japan Science and Technology Agency Tokyo, Japan
| | - Susumu Takahashi
- Laboratory of Neural Circuitry, Department of Systems Neuroscience, Graduate School of Brain Science, Doshisha University Kyoto, Japan
| | - Fuyuki Karube
- Laboratory of Neural Circuitry, Department of Systems Neuroscience, Graduate School of Brain Science, Doshisha University Kyoto, Japan
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85
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Tomas D, Prijanto AH, Burrows EL, Hannan AJ, Horne MK, Aumann TD. Environmental modulations of the number of midbrain dopamine neurons in adult mice. J Vis Exp 2015:52329. [PMID: 25650697 DOI: 10.3791/52329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Long-lasting changes in the brain or 'brain plasticity' underlie adaptive behavior and brain repair following disease or injury. Furthermore, interactions with our environment can induce brain plasticity. Increasingly, research is trying to identify which environments stimulate brain plasticity beneficial for treating brain and behavioral disorders. Two environmental manipulations are described which increase or decrease the number of tyrosine hydroxylase immunopositive (TH+, the rate-limiting enzyme in dopamine (DA) synthesis) neurons in the adult mouse midbrain. The first comprises pairing male and female mice together continuously for 1 week, which increases midbrain TH+ neurons by approximately 12% in males, but decreases midbrain TH+ neurons by approximately 12% in females. The second comprises housing mice continuously for 2 weeks in 'enriched environments' (EE) containing running wheels, toys, ropes, nesting material, etc., which increases midbrain TH+ neurons by approximately 14% in males. Additionally, a protocol is described for concurrently infusing drugs directly into the midbrain during these environmental manipulations to help identify mechanisms underlying environmentally-induced brain plasticity. For example, EE-induction of more midbrain TH+ neurons is abolished by concurrent blockade of synaptic input onto midbrain neurons. Together, these data indicate that information about the environment is relayed via synaptic input to midbrain neurons to switch on or off expression of 'DA' genes. Thus, appropriate environmental stimulation, or drug targeting of the underlying mechanisms, might be helpful for treating brain and behavioral disorders associated with imbalances in midbrain DA (e.g. Parkinson's disease, attention deficit and hyperactivity disorder, schizophrenia, and drug addiction).
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Affiliation(s)
- Doris Tomas
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne
| | | | - Emma L Burrows
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne
| | - Malcolm K Horne
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne
| | - Tim D Aumann
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne;
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86
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Dopamine midbrain neurons in health and Parkinson’s disease: Emerging roles of voltage-gated calcium channels and ATP-sensitive potassium channels. Neuroscience 2015; 284:798-814. [DOI: 10.1016/j.neuroscience.2014.10.037] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 12/14/2022]
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87
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Meng T, Yuan S, Zheng Z, Liu T, Lin L. Effects of endogenous melatonin on glutamate and GABA rhythms in the striatum of unilateral 6-hydroxydopamine-lesioned rats. Neuroscience 2014; 286:308-15. [PMID: 25499317 DOI: 10.1016/j.neuroscience.2014.11.062] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 11/26/2014] [Accepted: 11/27/2014] [Indexed: 10/24/2022]
Abstract
We have previously reported a time-dependent increase in melatonin (MLT) and decrease in dopamine (DA) in striatal dialysate 3 weeks after unilateral 6-hydroxydopamine (6-OHDA) lesioning in the rat substantia nigra pars compacta (SNc) and medial forebrain bundle (MFB). This study aimed to investigate dynamic and circadian variations in DA, MLT, glutamate (Glu) and γ-aminobutyric acid (GABA) in striatal dialysates in the same 6-OHDA animal model. These neurotransmitters were determined using high-performance liquid chromatography (HPLC). Three weeks following 6-OHDA lesioning, there was a significant increase in extracellular Glu (156%) and decrease in GABA (15%) and DA (85%) in the lesioned striatum. These changes continued over time. Concomitantly, MLT was increased by 107% in the lesioned striatal dialysates after 4 weeks, and continued to increase gradually over time. Six weeks post-treatment, levels of MLT secretion at 12 time points were higher, and the peak time of MLT secretion was earlier, in 6-OHDA-lesioned rats compared with vehicle-treated rats. In addition, significant variations in extracellular levels of Glu and GABA between day and night were observed in vehicle-treated rat striatum. However, no circadian variations were observed in the striatum of unilateral 6-OHDA-lesioned rats. Six weeks post-treatment, MLT levels correlated well with Glu and GABA levels at corresponding time-points in the striatum ipsilateral to the injected side in both groups, and increased MLT levels also correlated well with changes in Glu and GABA in the striatum in 6-OHDA-lesioned rats. These data suggest that 6-OHDA lesioning affects the endogenous productions of DA, MLT, Glu and GABA, and changes the MLT secretion pattern. Augmented striatal MLT levels and advanced MLT secretion pattern caused by unilateral intracerebral injection of 6-OHDA may influence the variations in Glu and GABA between day and night.
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Affiliation(s)
- T Meng
- Research Center of Neurobiology, Fujian Medical University, Fuzhou 350108, China; Key Laboratory of Chemical Safety and Health, National Institute for Occupational Health and Poison Control, Chinese Center for Disease Control and Prevention, Beijing 100050, China.
| | - S Yuan
- Department of Neurosurgery, Fujian Provincial Hospital, Fuzhou 350001, China.
| | - Z Zheng
- Research Center of Neurobiology, Fujian Medical University, Fuzhou 350108, China; Department of Biochemistry and Molecular Biology, Fujian Medical University, Fuzhou 350108, China.
| | - T Liu
- Department of Biochemistry and Molecular Biology, Fujian Medical University, Fuzhou 350108, China.
| | - L Lin
- Research Center of Neurobiology, Fujian Medical University, Fuzhou 350108, China; Department of Biochemistry and Molecular Biology, Fujian Medical University, Fuzhou 350108, China.
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88
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Control of the nigrostriatal dopamine neuron activity and motor function by the tail of the ventral tegmental area. Neuropsychopharmacology 2014; 39:2788-98. [PMID: 24896615 PMCID: PMC4200489 DOI: 10.1038/npp.2014.129] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/16/2014] [Accepted: 05/29/2014] [Indexed: 01/10/2023]
Abstract
Midbrain dopamine neurons are implicated in various psychiatric and neurological disorders. The GABAergic tail of the ventral tegmental area (tVTA), also named the rostromedial tegmental nucleus (RMTg), displays dense projections to the midbrain and exerts electrophysiological control over dopamine cells of the VTA. However, the influence of the tVTA on the nigrostriatal pathway, from the substantia nigra pars compacta (SNc) to the dorsal striatum, and on related functions remains to be addressed. The present study highlights the role played by the tVTA as a GABA brake for the nigrostriatal system, demonstrating a critical influence over motor functions. Using neuroanatomical approaches with tract tracing and electron microscopy, we reveal the presence of a tVTA-SNc-dorsal striatum pathway. Using in vivo electrophysiology, we prove that the tVTA is a major inhibitory control center for SNc dopamine cells. Using behavioral approaches, we demonstrate that the tVTA controls rotation behavior, motor coordination, and motor skill learning. The motor enhancements observed after ablation of the tVTA are in this regard comparable with the performance-enhancing properties of amphetamine, a drug used in doping. These findings demonstrate that the tVTA is a major GABA brake for nigral dopamine systems and nigrostriatal functions, and they raise important questions about how the tVTA is integrated within the basal ganglia circuitry. They also warrant further research on the tVTA's role in motor and dopamine-related pathological contexts such as Parkinson's disease.
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89
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Adenosine A1 receptor stimulation reduces D1 receptor-mediated GABAergic transmission from striato-nigral terminals and attenuates l-DOPA-induced dyskinesia in dopamine-denervated mice. Exp Neurol 2014; 261:733-43. [DOI: 10.1016/j.expneurol.2014.08.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/30/2014] [Accepted: 08/02/2014] [Indexed: 11/18/2022]
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90
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Burke MV, Nocjar C, Sonneborn AJ, McCreary AC, Pehek EA. Striatal serotonin 2C receptors decrease nigrostriatal dopamine release by increasing GABA-A receptor tone in the substantia nigra. J Neurochem 2014; 131:432-43. [PMID: 25073477 DOI: 10.1111/jnc.12842] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 07/24/2014] [Accepted: 07/28/2014] [Indexed: 11/29/2022]
Abstract
Drugs acting at the serotonin-2C (5-HT2C) receptor subtype have shown promise as therapeutics in multiple syndromes including obesity, depression, and Parkinson's disease. While it is established that 5-HT2C receptor stimulation inhibits DA release, the neural circuits and the localization of the relevant 5-HT2C receptors remain unknown. This study used dual-probe in vivo microdialysis to investigate the relative contributions of 5-HT2C receptors localized in the rat substantia nigra (SN) and caudate-putamen (CP) in the control of nigrostriatal DA release. Systemic administration (3.0 mg/kg) of the 5-HT2C receptor selective agonist Ro 60-0175 [(αS)-6-Chloro-5-fluoro-α-methyl-1H-indole-1-ethanamine fumarate] decreased, whereas intrastriatal infusions of the selective 5-HT2C antagonist SB 242084 [6-Chloro-2,3-dihydro-5-methyl-N-[6-[(2-methyl-3-pyridinyl)oxy]-3-pyridinyl]-1H-indole-1-carboxyamide; 1.0 μM] increased, basal DA in the CP. Depending on the site within the SN pars reticulata (SNpr), infusions of SB 242084 had more modest but significant effects. Moreover, infusions of the GABA-A receptor agonist muscimol (10 μM) into the SNpr completely reversed the increases in striatal DA release produced by intrastriatal infusions of SB 242084. These findings suggest a role for 5-HT2C receptors regulating striatal DA release that is highly localized. 5-HT2C receptors localized in the striatum may represent a primary site of action that is mediated by the actions on GABAergic activity in the SN. Dopamine (DA) neurons in the substantia nigra pars compacta (SNpc) project to the caudate-putamen (CP; striatum). This circuitry is implicated in numerous pathologies including Parkinson's disease. Using in vivo microdialysis, we demonstrated that blockade of serotonin (5-HT) 2C receptors in the CP increased nigrostriatal DA release. Infusions of a GABA-A agonist into the substantia nigra pars reticulata (SNpr) blocked this increase. This work indicates that striatal serotonin 2C receptors regulate GABAergic tone in the SNpr, which in turn regulates nigrostriatal DA release.
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Affiliation(s)
- Mary V Burke
- Research, Louis Stokes Cleveland Department of Veterans Affairs, Cleveland, Ohio, USA; Interdepartmental Neuroscience Program, Yale University, New Haven, Connecticut, USA
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91
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Role of nicotinic acetylcholine receptors in regulating dopamine neuron activity. Neuroscience 2014; 282:86-100. [PMID: 24881574 DOI: 10.1016/j.neuroscience.2014.05.040] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 05/20/2014] [Accepted: 05/21/2014] [Indexed: 01/04/2023]
Abstract
Midbrain dopamine (DA) neurons play a central role in a wide range of behaviors, from attention and motivation to motor control and reinforcement. The release of DA is modulated by a number of factors, and its deregulation has been implicated in multiple psychiatric disorders, such as addiction. In particular, nicotinic acetylcholine receptors (nAChRs) are key modulators of DA cells. Nicotine, the main addictive component in tobacco, strongly interacts with these receptors in the midbrain DA systems, resulting in reinforcing effects that are at the core of tobacco addiction. nAChRs are virtually expressed on every cell of the DA system, both at pre-, post- and extra-synaptic locations. The complex issue of interpreting the role of the large portfolio of different nAChR subtypes expressed on ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) neurons, and especially their role in defining functional DAergic subpopulations, is far from being solved. In this review we will try to provide the reader with an integrative view of the nicotinic modulation of DA neurons and its influence at the cellular, systemic and behavioral levels (exploratory behavior), as well as its implication in the reinforcing effects of nicotine.
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Williams MR, Galvin K, O'Sullivan B, MacDonald CD, Ching EWK, Turkheimer F, Howes OD, Pearce RKB, Hirsch SR, Maier M. Neuropathological changes in the substantia nigra in schizophrenia but not depression. Eur Arch Psychiatry Clin Neurosci 2014; 264:285-96. [PMID: 24374935 DOI: 10.1007/s00406-013-0479-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 12/18/2013] [Indexed: 01/02/2023]
Abstract
Schizophrenia is a chronic, disabling neuropsychiatric disorder characterised by positive, negative and cognitive symptoms. The aetiology is not known, although genetic, imaging and pathological studies have implicated both neurodevelopmental and neurodegenerative processes. The substantia nigra is a basal ganglia nucleus responsible for the production of dopamine and projection of dopaminergic neurons to the striatum. The substantia nigra is implicated in schizophrenia as dopamine has been heavily implicated in the dopamine hypothesis of schizophrenia and the prevalent psychotic symptoms and the monoamine theory of depression, and is a target for the development of new therapies. Studies into the major dopamine delivery pathways in the brain will therefore provide a strong base in improving knowledge of these psychiatric disorders. This post-mortem study examines the cytoarchitecture of dopaminergic neurons of the substantia nigra in schizophrenia (n = 12) and depression (n = 13) compared to matched controls (n = 13). Measures of nucleolar volume, nuclear length and nuclear area were taken in patients with chronic schizophrenia and major depressive disorder against matched controls. Astrocyte density was decreased in schizophrenia compared to controls (p = 0.030), with no change in oligodendrocyte density observed. Significantly increased nuclear cross-sectional area (p = 0.017) and length (p = 0.021), and increased nucleolar volume (p = 0.037) in dopaminergic neurons were observed in schizophrenia patients compared with controls, suggesting nuclear pleomorphic changes. No changes were observed in depression cases compared to control group. These changes may reflect pathological alterations in gene expression, neuronal structure and function in schizophrenia.
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Affiliation(s)
- M R Williams
- Institute of Psychiatry, King's College London, De Crespigny Park, London, SE5 8AF, UK,
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93
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Matsui A, Jarvie BC, Robinson BG, Hentges ST, Williams JT. Separate GABA afferents to dopamine neurons mediate acute action of opioids, development of tolerance, and expression of withdrawal. Neuron 2014; 82:1346-56. [PMID: 24857021 DOI: 10.1016/j.neuron.2014.04.030] [Citation(s) in RCA: 159] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/11/2014] [Indexed: 01/01/2023]
Abstract
GABA release from interneurons in VTA, projections from the nucleus accumbens (NAc), and rostromedial tegmental nucleus (RMTg) was selectively activated in rat brain slices. The inhibition induced by μ-opioid agonists was pathway dependent. Morphine induced a 46% inhibition of IPSCs evoked from the RMTg, 18% from NAc, and IPSCs evoked from VTA interneurons were almost insensitive (11% inhibition). In vivo morphine treatment resulted in tolerance to the inhibition of RMTg, but not local interneurons or NAc, inputs. One common sign of opioid withdrawal is an increase in adenosine-dependent inhibition. IPSCs evoked from the NAc were potently inhibited by activation of presynaptic adenosine receptors, whereas IPSCs evoked from RMTg were not changed. Blockade of adenosine receptors selectively increased IPSCs evoked from the NAc during morphine withdrawal. Thus, the acute action of opioids, the development of tolerance, and the expression of withdrawal are mediated by separate GABA afferents to dopamine neurons.
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Affiliation(s)
- Aya Matsui
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Brooke C Jarvie
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Brooks G Robinson
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA
| | - Shane T Hentges
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - John T Williams
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239, USA.
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94
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Brown J, Pan WX, Dudman JT. The inhibitory microcircuit of the substantia nigra provides feedback gain control of the basal ganglia output. eLife 2014; 3:e02397. [PMID: 24849626 PMCID: PMC4067753 DOI: 10.7554/elife.02397] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 05/17/2014] [Indexed: 12/26/2022] Open
Abstract
Dysfunction of the basal ganglia produces severe deficits in the timing, initiation, and vigor of movement. These diverse impairments suggest a control system gone awry. In engineered systems, feedback is critical for control. By contrast, models of the basal ganglia highlight feedforward circuitry and ignore intrinsic feedback circuits. In this study, we show that feedback via axon collaterals of substantia nigra projection neurons control the gain of the basal ganglia output. Through a combination of physiology, optogenetics, anatomy, and circuit mapping, we elaborate a general circuit mechanism for gain control in a microcircuit lacking interneurons. Our data suggest that diverse tonic firing rates, weak unitary connections and a spatially diffuse collateral circuit with distinct topography and kinetics from feedforward input is sufficient to implement divisive feedback inhibition. The importance of feedback for engineered systems implies that the intranigral microcircuit, despite its absence from canonical models, could be essential to basal ganglia function. DOI: http://dx.doi.org/10.7554/eLife.02397.001.
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Affiliation(s)
- Jennifer Brown
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn , United States Department of Physiology, Development and Neuroscience , University of Cambridge, Cambridge , United Kingdom
| | - Wei-Xing Pan
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn , United States
| | - Joshua Tate Dudman
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn , United States
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95
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Shibasaki M, Tsuyuki T, Ando K, Otokozawa A, Udagawa Y, Watanabe K, Shibasaki Y, Mori T, Suzuki T. Implication of KCC2 in the sensitization to morphine by chronic ethanol treatment in mice. Synapse 2014; 68:39-43. [PMID: 23760976 DOI: 10.1002/syn.21688] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 05/30/2013] [Indexed: 12/30/2022]
Affiliation(s)
- Masahiro Shibasaki
- Department of Toxicology, Hoshi University School of Pharmacy and Pharmaceutical Sciences, Shinagawa-Ku, Tokyo, Japan
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96
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Freestone PS, Guatteo E, Piscitelli F, di Marzo V, Lipski J, Mercuri NB. Glutamate spillover drives endocannabinoid production and inhibits GABAergic transmission in the Substantia Nigra pars compacta. Neuropharmacology 2013; 79:467-75. [PMID: 24334069 DOI: 10.1016/j.neuropharm.2013.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/19/2013] [Accepted: 12/03/2013] [Indexed: 12/11/2022]
Abstract
Endocannabinoids (eCBs) modulate synaptic transmission in the brain, but little is known of their regulatory role in nigral dopaminergic neurons, and whether transmission to these neurons is tonically inhibited by eCBs as seen in some other brain regions. Using whole-cell recording in midbrain slices, we observed potentiation of evoked IPSCs (eIPSCs) in these neurons after blocking CB1 receptors with rimonabant or LY-320,135, indicating the presence of an eCB tone reducing inhibitory synaptic transmission. Increased postsynaptic calcium buffering and block of mGluR1 or postsynaptic G-protein coupled receptors prevented this potentiation. Increasing spillover of endogenous glutamate by inhibiting uptake attenuated eIPSC amplitude, while enhancing the potentiation by rimonabant. Group I mGluR activation transiently inhibited eIPSCs, which could be prevented by GDP-β-S, increased calcium buffering or rimonabant. We explored the possibility that the dopamine-derived eCB N-arachidonoyl dopamine (NADA) is involved. The eCB tone was abolished by preventing dopamine synthesis, and enhanced by l-DOPA. It was not detected in adjacent non-dopaminergic neurons. Preventing 2-AG synthesis did not affect the tone, while inhibition of NADA production abolished it. Quantification of ventral midbrain NADA suggested a basal level that increased following prolonged depolarization or mGluR activation. Since block of the tone was not always accompanied by attenuation of depolarization-induced suppression of inhibition (DSI) and vice versa, our results indicate DSI and the eCB tone are mediated by distinct eCBs. This study provides evidence that dopamine modulates the activity of SNc neurons not only by conventional dopamine receptors, but also by CB1 receptors, potentially via NADA.
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Affiliation(s)
- Peter S Freestone
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, New Zealand; Laboratorio di Neurologia Sperimentale, Fondazione Santa Lucia IRCCS, Rome, Italy
| | - Ezia Guatteo
- Laboratorio di Neurologia Sperimentale, Fondazione Santa Lucia IRCCS, Rome, Italy
| | - Fabiana Piscitelli
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, CNR, Pozzuoli, Italy
| | - Vincenzo di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, CNR, Pozzuoli, Italy
| | - Janusz Lipski
- Department of Physiology and Centre for Brain Research, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
| | - Nicola B Mercuri
- Laboratorio di Neurologia Sperimentale, Fondazione Santa Lucia IRCCS, Rome, Italy; Dipartimento di Medicina dei Sistemi, Universitá di Tor Vergata, Rome, Italy.
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97
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Damodaran S, Evans RC, Blackwell KT. Synchronized firing of fast-spiking interneurons is critical to maintain balanced firing between direct and indirect pathway neurons of the striatum. J Neurophysiol 2013; 111:836-48. [PMID: 24304860 DOI: 10.1152/jn.00382.2013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The inhibitory circuits of the striatum are known to be critical for motor function, yet their contributions to Parkinsonian motor deficits are not clear. Altered firing in the globus pallidus suggests that striatal medium spiny neurons (MSN) of the direct (D1 MSN) and indirect pathway (D2 MSN) are imbalanced during dopamine depletion. Both MSN classes receive inhibitory input from each other and from inhibitory interneurons within the striatum, specifically the fast-spiking interneurons (FSI). To investigate the role of inhibition in maintaining striatal balance, we developed a biologically-realistic striatal network model consisting of multicompartmental neuron models: 500 D1 MSNs, 500 D2 MSNs and 49 FSIs. The D1 and D2 MSN models are differentiated based on published experiments of individual channel modulations by dopamine, with D2 MSNs being more excitable than D1 MSNs. Despite this difference in response to current injection, in the network D1 and D2 MSNs fire at similar frequencies in response to excitatory synaptic input. Simulations further reveal that inhibition from FSIs connected by gap junctions is critical to produce balanced firing. Although gap junctions produce only a small increase in synchronization between FSIs, removing these connections resulted in significant firing differences between D1 and D2 MSNs, and balanced firing was restored by providing synchronized cortical input to the FSIs. Together these findings suggest that desynchronization of FSI firing is sufficient to alter balanced firing between D1 and D2 MSNs.
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Affiliation(s)
- Sriraman Damodaran
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, Virginia
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98
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Tønnesen J, Kokaia M. Electrophysiological investigations of synaptic connectivity between host and graft neurons. PROGRESS IN BRAIN RESEARCH 2013. [PMID: 23195416 DOI: 10.1016/b978-0-444-59575-1.00005-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The functional synaptic integration of grafted stem cell-derived neurons is one of the key aspects of neural cell replacement therapies for neurological disorders such as Parkinson's disease. However, little is currently known about the synaptic connectivity between graft and host cells after transplantation, not only in the settings of clinical trials but also in experimental studies. This knowledge gap is primarily due to the lack of experimental electrophysiological approaches allowing interrogation of synaptic connectivity between prospectively identified host and graft neurons and hampers our understanding of the mechanisms underlying functional integration of stem cell-derived neurons in the host brain, as well as the optimization of protocols for deriving stem cells for neural cell replacement therapy. Recent optogenetic tools allow for direct investigation of connectivity between host and graft neural populations and have already been applied to show bidirectional integration of dopaminergic neurons in a host tissue. These new tools have potential to advance our understanding of functional integration in the near future. Here, we provide an overview of the current literature addressing functional integration of stem cell-derived neurons in the settings of Parkinson's disease models and discuss some experimental paradigms to approach this issue.
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Affiliation(s)
- Jan Tønnesen
- Synaptic Plasticity and Superresolution Microscopy Group, Interdisciplinary Institute for Neurosciences, Université de Bordeaux Segalen, Bordeaux, France
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99
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Aumann TD, Tomas D, Horne MK. Environmental and behavioral modulation of the number of substantia nigra dopamine neurons in adult mice. Brain Behav 2013; 3:617-25. [PMID: 24363965 PMCID: PMC3868167 DOI: 10.1002/brb3.163] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 06/25/2013] [Accepted: 07/26/2013] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Recent evidence indicates that hypothalamic neurons acquire or lose the capacity to synthesize and release dopamine (DA) in response to environmental stimuli, and this has functional and behavioral consequences for adult rats. We have evidence that neuronal activity, including that driven by afferent input, regulates acquisition and loss of the DA phenotype by substantia nigra pars compacta (SNc) neurons in adult mice. Hypotheses The aims of the present study were to determine whether the environment or behavior regulates the number of SNc DA neurons in adult mice, and whether this is mediated by afferent input. METHODS ADULT MICE WERE SUBJECT TO TWO DIFFERENT ENVIRONMENTS/BEHAVIORS: "mating" for 1 week or "environment enrichment" (EE) for 2 weeks; then the numbers of tyrosine hydroxylase (TH, the rate limiting enzyme in DA synthesis) immunopositive (TH+) and immunonegative (TH-) SNc neurons were counted. RESULTS More TH+ neurons were present in mated males whereas less TH+ neurons were present in mated females. Also, more TH+ neurons were present in EE males, and this increase was completely abolished by concurrent local infusion of GABAA receptor antagonists. CONCLUSIONS The number of DA neurons in the adult SNc is not fixed, but readily increases and decreases in response to environmental stimuli and/or behaviors. These changes are mediated by afferent input relaying information about the environment or behavior to SNc neurons.
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Affiliation(s)
- Tim D Aumann
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, Victoria, Australia, 3010
| | - Doris Tomas
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, Victoria, Australia, 3010
| | - Malcolm K Horne
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne Parkville, Victoria, Australia, 3010
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100
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Soden ME, Jones GL, Sanford CA, Chung AS, Güler AD, Chavkin C, Luján R, Zweifel LS. Disruption of dopamine neuron activity pattern regulation through selective expression of a human KCNN3 mutation. Neuron 2013; 80:997-1009. [PMID: 24206670 DOI: 10.1016/j.neuron.2013.07.044] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2013] [Indexed: 11/19/2022]
Abstract
The calcium-activated small conductance potassium channel SK3 plays an essential role in the regulation of dopamine neuron activity patterns. Here we demonstrate that expression of a human disease-related SK3 mutation (hSK3Δ) in dopamine neurons of mice disrupts the balance between tonic and phasic dopamine neuron activity. Expression of hSK3Δ suppressed endogenous SK currents, reducing coupling between SK channels and NMDA receptors (NMDARs) and increasing permissiveness for burst firing. Consistent with enhanced excitability of dopamine neurons, hSK3Δ increased evoked calcium signals in dopamine neurons in vivo and potentiated evoked dopamine release. Specific expression of hSK3Δ led to deficits in attention and sensory gating and heightened sensitivity to a psychomimetic drug. Sensory-motor alterations and psychomimetic sensitivity were recapitulated in a mouse model of transient, reversible dopamine neuron activation. These results demonstrate the cell-autonomous effects of a human ion channel mutation on dopamine neuron physiology and the impact of activity pattern disruption on behavior.
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Affiliation(s)
- Marta E Soden
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
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