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Özçete ÖD, Banerjee A, Kaeser PS. Mechanisms of neuromodulatory volume transmission. Mol Psychiatry 2024:10.1038/s41380-024-02608-3. [PMID: 38789677 DOI: 10.1038/s41380-024-02608-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/07/2024] [Accepted: 05/10/2024] [Indexed: 05/26/2024]
Abstract
A wealth of neuromodulatory transmitters regulate synaptic circuits in the brain. Their mode of signaling, often called volume transmission, differs from classical synaptic transmission in important ways. In synaptic transmission, vesicles rapidly fuse in response to action potentials and release their transmitter content. The transmitters are then sensed by nearby receptors on select target cells with minimal delay. Signal transmission is restricted to synaptic contacts and typically occurs within ~1 ms. Volume transmission doesn't rely on synaptic contact sites and is the main mode of monoamines and neuropeptides, important neuromodulators in the brain. It is less precise than synaptic transmission, and the underlying molecular mechanisms and spatiotemporal scales are often not well understood. Here, we review literature on mechanisms of volume transmission and raise scientific questions that should be addressed in the years ahead. We define five domains by which volume transmission systems can differ from synaptic transmission and from one another. These domains are (1) innervation patterns and firing properties, (2) transmitter synthesis and loading into different types of vesicles, (3) architecture and distribution of release sites, (4) transmitter diffusion, degradation, and reuptake, and (5) receptor types and their positioning on target cells. We discuss these five domains for dopamine, a well-studied monoamine, and then compare the literature on dopamine with that on norepinephrine and serotonin. We include assessments of neuropeptide signaling and of central acetylcholine transmission. Through this review, we provide a molecular and cellular framework for volume transmission. This mechanistic knowledge is essential to define how neuromodulatory systems control behavior in health and disease and to understand how they are modulated by medical treatments and by drugs of abuse.
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Affiliation(s)
- Özge D Özçete
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Aditi Banerjee
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA, 02115, USA.
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2
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Molinari M, Lieberman OJ, Sulzer D, Santini E, Borgkvist A. 5-HT1B receptors mediate dopaminergic inhibition of vesicular fusion and GABA release from striatonigral synapses. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.14.584991. [PMID: 38559006 PMCID: PMC10980074 DOI: 10.1101/2024.03.14.584991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The substantia nigra pars reticulata (SNr), a crucial basal ganglia output nucleus, contains a dense expression of dopamine D1 receptors (D1Rs), along with dendrites belonging to dopaminergic neurons of substantia nigra pars compacta. These D1Rs are primarily located on the terminals of striatonigral medium spiny neurons, suggesting their involvement in the regulation of neurotransmitter release from the direct pathway in response to somatodendritic dopamine release. To explore the hypothesis that D1Rs modulate GABA release from striatonigral synapses, we conducted optical recordings of striatonigral activity and postsynaptic patch-clamp recordings from SNr neurons in the presence of dopamine and D1R agonists. We found that dopamine inhibits optogenetically triggered striatonigral GABA release by modulating vesicle fusion and Ca 2+ influx in striatonigral boutons. Notably, the effect of DA was independent of D1R activity but required activation of 5-HT1B receptors. Our results suggest a serotonergic mechanism involved in the therapeutic actions of dopaminergic medications for Parkinson's disease and psychostimulant-related disorders.
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3
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Cho W, Jung M, Yoon SH, Jeon J, Oh MA, Kim JY, Park M, Kang CM, Chung TD. On-Site Formation of Functional Dopaminergic Presynaptic Terminals on Neuroligin-2-Modified Gold-Coated Microspheres. ACS APPLIED MATERIALS & INTERFACES 2024; 16:3082-3092. [PMID: 38206769 DOI: 10.1021/acsami.3c13829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Advancements in neural interface technologies have enabled the direct connection of neurons and electronics, facilitating chemical communication between neural systems and external devices. One promising approach is a synaptogenesis-involving method, which offers an opportunity for synaptic signaling between these systems. Janus synapses, one type of synaptic interface utilizing synaptic cell adhesion molecules for interface construction, possess unique features that enable the determination of location, direction of signal flow, and types of neurotransmitters involved, promoting directional and multifaceted communication. This study presents the first successful establishment of a Janus synapse between dopaminergic (DA) neurons and abiotic substrates by using a neuroligin-2 (NLG2)-mediated synapse-inducing method. NLG2 immobilized on gold-coated microspheres can induce synaptogenesis upon contact with spatially isolated DA axons. The induced DA Janus synapses exhibit stable synaptic activities comparable to that of native synapses over time, suggesting their suitability for application in neural interfaces. By calling for DA presynaptic organizations, the NLG2-immobilized abiotic substrate is a promising tool for the on-site detection of synaptic dopamine release.
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Affiliation(s)
- Wonkyung Cho
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Minji Jung
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Sun-Heui Yoon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Joohee Jeon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Min-Ah Oh
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Ji Yong Kim
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Minjung Park
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Chung Mu Kang
- Advanced Institutes of Convergence Technology, Suwon-si 16229, Gyeonggi-do, Republic of Korea
| | - Taek Dong Chung
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
- Advanced Institutes of Convergence Technology, Suwon-si 16229, Gyeonggi-do, Republic of Korea
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4
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Xu C, Chen S, Chen X, Ho KH, Park C, Yoo H, Lee SH, Park H. Altered exocytosis of inhibitory synaptic vesicles at single presynaptic terminals of cultured striatal neurons in a knock-in mouse model of Huntington's disease. Front Mol Neurosci 2023; 16:1175522. [PMID: 37664244 PMCID: PMC10470468 DOI: 10.3389/fnmol.2023.1175522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 07/24/2023] [Indexed: 09/05/2023] Open
Abstract
Huntington's disease (HD) is a progressive dominantly inherited neurodegenerative disease caused by the expansion of a cytosine-adenine-guanine (CAG) trinucleotide repeat in the huntingtin gene, which encodes the mutant huntingtin protein containing an expanded polyglutamine tract. One of neuropathologic hallmarks of HD is selective degeneration in the striatum. Mechanisms underlying selective neurodegeneration in the striatum of HD remain elusive. Neurodegeneration is suggested to be preceded by abnormal synaptic transmission at the early stage of HD. However, how mutant huntingtin protein affects synaptic vesicle exocytosis at single presynaptic terminals of HD striatal neurons is poorly understood. Here, we measured synaptic vesicle exocytosis at single presynaptic terminals of cultured striatal neurons (mainly inhibitory neurons) in a knock-in mouse model of HD (zQ175) during electrical field stimulation using real-time imaging of FM 1-43 (a lipophilic dye). We found a significant decrease in bouton density and exocytosis of synaptic vesicles at single presynaptic terminals in cultured striatal neurons. Real-time imaging of VGAT-CypHer5E (a pH sensitive dye conjugated to an antibody against vesicular GABA transporter (VGAT)) for inhibitory synaptic vesicles revealed a reduction in bouton density and exocytosis of inhibitory synaptic vesicles at single presynaptic terminals of HD striatal neurons. Thus, our results suggest that the mutant huntingtin protein decreases bouton density and exocytosis of inhibitory synaptic vesicles at single presynaptic terminals of striatal neurons, causing impaired inhibitory synaptic transmission, eventually leading to the neurodegeneration in the striatum of HD.
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Affiliation(s)
- Chen Xu
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Sidong Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Xingxiang Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Ka Hei Ho
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Chungwon Park
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Hong Kong Center for Construction Robotics (InnoHK-HKCRC), Hong Kong Science Park, Sha Tin, Hong Kong SAR, China
| | - Hanna Yoo
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
| | - Suk-Ho Lee
- Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hyokeun Park
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
- State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong SAR, China
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5
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Kershberg L, Banerjee A, Kaeser PS. Protein composition of axonal dopamine release sites in the striatum. eLife 2022; 11:e83018. [PMID: 36579890 PMCID: PMC9937654 DOI: 10.7554/elife.83018] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/22/2022] [Indexed: 12/30/2022] Open
Abstract
Dopamine is an important modulator of cognition and movement. We recently found that evoked dopamine secretion is fast and relies on active zone-like release sites. Here, we used in vivo biotin identification (iBioID) proximity proteomics in mouse striatum to assess which proteins are present at these sites. Using three release site baits, we identified proteins that are enriched over the general dopamine axonal protein content, and they fell into several categories, including active zone, Ca2+ regulatory, and synaptic vesicle proteins. We also detected many proteins not previously associated with vesicular exocytosis. Knockout of the presynaptic organizer protein RIM strongly decreased the hit number obtained with iBioID, while Synaptotagmin-1 knockout did not. α-Synuclein, a protein linked to Parkinson's disease, was enriched at release sites, and its enrichment was lost in both tested mutants. We conclude that RIM organizes scaffolded dopamine release sites and provide a proteomic assessment of the composition of these sites.
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Affiliation(s)
- Lauren Kershberg
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Aditi Banerjee
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical SchoolBostonUnited States
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6
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A fluorescent nanosensor paint detects dopamine release at axonal varicosities with high spatiotemporal resolution. Proc Natl Acad Sci U S A 2022; 119:e2202842119. [PMID: 35613050 DOI: 10.1073/pnas.2202842119] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
SignificanceThe neurotransmitter dopamine controls normal behavior and dopaminergic dysfunction is prevalent in multiple brain diseases. To reach a detailed understanding of how dopamine release and signaling are regulated at the subcellular level, we developed a near infrared fluorescent dopamine nanosensor 'paint' (AndromeDA) to directly image dopamine release and its spatiotemporal characteristics. With AndromeDA, we can ascribe discrete DA release events to defined axonal varicosities, directly assess the heterogeneity of DA release events across such release sites, and determine the molecular components of the DA release machinery. AndromeDA thus provides a new method for gaining fundamental insights into the core mechanisms of dopamine release, which with greatly benefit our knowledge of dopamine biology and pathobiology.
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7
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Banerjee A, Imig C, Balakrishnan K, Kershberg L, Lipstein N, Uronen RL, Wang J, Cai X, Benseler F, Rhee JS, Cooper BH, Liu C, Wojcik SM, Brose N, Kaeser PS. Molecular and functional architecture of striatal dopamine release sites. Neuron 2022; 110:248-265.e9. [PMID: 34767769 PMCID: PMC8859508 DOI: 10.1016/j.neuron.2021.10.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 09/22/2021] [Accepted: 10/19/2021] [Indexed: 01/21/2023]
Abstract
Despite the importance of dopamine for striatal circuit function, mechanistic understanding of dopamine transmission remains incomplete. We recently showed that dopamine secretion relies on the presynaptic scaffolding protein RIM, indicating that it occurs at active zone-like sites similar to classical synaptic vesicle exocytosis. Here, we establish using a systematic gene knockout approach that Munc13 and Liprin-α, active zone proteins for vesicle priming and release site organization, are important for dopamine secretion. Furthermore, RIM zinc finger and C2B domains, which bind to Munc13 and Liprin-α, respectively, are needed to restore dopamine release after RIM ablation. In contrast, and different from typical synapses, the active zone scaffolds RIM-BP and ELKS, and RIM domains that bind to them, are expendable. Hence, dopamine release necessitates priming and release site scaffolding by RIM, Munc13, and Liprin-α, but other active zone proteins are dispensable. Our work establishes that efficient release site architecture mediates fast dopamine exocytosis.
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Affiliation(s)
- Aditi Banerjee
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Cordelia Imig
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | | | - Lauren Kershberg
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Noa Lipstein
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Riikka-Liisa Uronen
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Jiexin Wang
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Xintong Cai
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Fritz Benseler
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Jeong Seop Rhee
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Benjamin H Cooper
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Changliang Liu
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Sonja M Wojcik
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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8
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Ducrot C, Bourque MJ, Delmas CVL, Racine AS, Guadarrama Bello D, Delignat-Lavaud B, Domenic Lycas M, Fallon A, Michaud-Tardif C, Burke Nanni S, Herborg F, Gether U, Nanci A, Takahashi H, Parent M, Trudeau LE. Dopaminergic neurons establish a distinctive axonal arbor with a majority of non-synaptic terminals. FASEB J 2021; 35:e21791. [PMID: 34320240 DOI: 10.1096/fj.202100201rr] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 06/20/2021] [Accepted: 06/25/2021] [Indexed: 12/11/2022]
Abstract
Chemical neurotransmission typically occurs through synapses. Previous ultrastructural examinations of monoamine neuron axon terminals often failed to identify a pre- and postsynaptic coupling, leading to the concept of "volume" transmission. Whether this results from intrinsic properties of these neurons remains undefined. We find that dopaminergic neurons in vitro establish a distinctive axonal arbor compared to glutamatergic or GABAergic neurons in both size and propensity of terminals to avoid direct contact with target neurons. While most dopaminergic varicosities are active and contain exocytosis proteins like synaptotagmin 1, only ~20% of these are synaptic. The active zone protein bassoon was found to be enriched in dopaminergic terminals that are in proximity to a target cell. Finally, we found that the proteins neurexin-1αSS4- and neuroligin-1A+B play a critical role in the formation of synapses by dopamine (DA) neurons. Our findings suggest that DA neurons are endowed with a distinctive developmental connectivity program.
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Affiliation(s)
- Charles Ducrot
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,CNS Research Group (GRSNC), Montréal, QC, Canada
| | - Marie-Josée Bourque
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,CNS Research Group (GRSNC), Montréal, QC, Canada
| | - Constantin V L Delmas
- Department of Psychiatry and Neurosciences, Faculty of Medicine, CERVO Brain Research Centre, Université Laval, Québec, QC, Canada
| | - Anne-Sophie Racine
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,CNS Research Group (GRSNC), Montréal, QC, Canada
| | - Dainelys Guadarrama Bello
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Benoît Delignat-Lavaud
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,CNS Research Group (GRSNC), Montréal, QC, Canada
| | - Matthew Domenic Lycas
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC, Canada
| | - Aurélie Fallon
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada.,Department of Medicine, Université de Montréal, Montréal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, QC, Canada
| | - Charlotte Michaud-Tardif
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,CNS Research Group (GRSNC), Montréal, QC, Canada
| | - Samuel Burke Nanni
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,CNS Research Group (GRSNC), Montréal, QC, Canada
| | - Freja Herborg
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC, Canada
| | - Ulrik Gether
- Department of Stomatology, Faculty of Dental Medicine, Université de Montréal, Montréal, QC, Canada
| | - Antonio Nanci
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hideto Takahashi
- Synapse Development and Plasticity Research Unit, Institut de Recherches Cliniques de Montréal, Montréal, QC, Canada.,Department of Medicine, Université de Montréal, Montréal, QC, Canada.,Integrated Program in Neuroscience, McGill University, Montréal, QC, Canada
| | - Martin Parent
- Department of Psychiatry and Neurosciences, Faculty of Medicine, CERVO Brain Research Centre, Université Laval, Québec, QC, Canada
| | - Louis-Eric Trudeau
- Department of Pharmacology and Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Department of Neurosciences, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,CNS Research Group (GRSNC), Montréal, QC, Canada
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9
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Liu C, Goel P, Kaeser PS. Spatial and temporal scales of dopamine transmission. Nat Rev Neurosci 2021; 22:345-358. [PMID: 33837376 PMCID: PMC8220193 DOI: 10.1038/s41583-021-00455-7] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2021] [Indexed: 02/02/2023]
Abstract
Dopamine is a prototypical neuromodulator that controls circuit function through G protein-coupled receptor signalling. Neuromodulators are volume transmitters, with release followed by diffusion for widespread receptor activation on many target cells. Yet, we are only beginning to understand the specific organization of dopamine transmission in space and time. Although some roles of dopamine are mediated by slow and diffuse signalling, recent studies suggest that certain dopamine functions necessitate spatiotemporal precision. Here, we review the literature describing dopamine signalling in the striatum, including its release mechanisms and receptor organization. We then propose the domain-overlap model, in which release and receptors are arranged relative to one another in micrometre-scale structures. This architecture is different from both point-to-point synaptic transmission and the widespread organization that is often proposed for neuromodulation. It enables the activation of receptor subsets that are within micrometre-scale domains of release sites during baseline activity and broader receptor activation with domain overlap when firing is synchronized across dopamine neuron populations. This signalling structure, together with the properties of dopamine release, may explain how switches in firing modes support broad and dynamic roles for dopamine and may lead to distinct pathway modulation.
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Affiliation(s)
- Changliang Liu
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Pragya Goel
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
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10
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Dinarvand M, Elizarova S, Daniel J, Kruss S. Imaging of Monoamine Neurotransmitters with Fluorescent Nanoscale Sensors. Chempluschem 2020; 85:1465-1480. [DOI: 10.1002/cplu.202000248] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/05/2020] [Indexed: 12/12/2022]
Affiliation(s)
- Meshkat Dinarvand
- Institute of Physical ChemistryGöttingen University Tammannstrasse 2 37077 Göttingen Germany
| | - Sofia Elizarova
- Department of Molecular NeurobiologyMax Planck Institute of Experimental Medicine 37077 Göttingen Germany
| | - James Daniel
- Department of Molecular NeurobiologyMax Planck Institute of Experimental Medicine 37077 Göttingen Germany
| | - Sebastian Kruss
- Institute of Physical ChemistryGöttingen University Tammannstrasse 2 37077 Göttingen Germany
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11
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Targeting the cholinergic system in Parkinson's disease. Acta Pharmacol Sin 2020; 41:453-463. [PMID: 32132659 PMCID: PMC7468250 DOI: 10.1038/s41401-020-0380-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 02/13/2020] [Indexed: 12/15/2022] Open
Abstract
Motor control in the striatum is an orchestra played by various neuronal populations. Loss of harmony due to dopamine deficiency is considered the primary pathological cause of the symptoms of Parkinson’s disease (PD). Recent progress in experimental approaches has enabled us to examine the striatal circuitry in a much more comprehensive manner, not only reshaping our understanding of striatal functions in movement regulation but also leading to new opportunities for the development of therapeutic strategies for treating PD. In addition to dopaminergic innervation, giant aspiny cholinergic interneurons (ChIs) within the striatum have long been recognized as a critical node for balancing dopamine signaling and regulating movement. With the roles of ChIs in motor control further uncovered and more specific manipulations available, striatal ChIs and their corresponding receptors are emerging as new promising therapeutic targets for PD. This review summarizes recent progress in functional studies of striatal circuitry and discusses the translational implications of these new findings for the treatment of PD.
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12
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Liu C, Kaeser PS. Mechanisms and regulation of dopamine release. Curr Opin Neurobiol 2019; 57:46-53. [PMID: 30769276 PMCID: PMC6629510 DOI: 10.1016/j.conb.2019.01.001] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/03/2019] [Accepted: 01/04/2019] [Indexed: 01/17/2023]
Abstract
Dopamine controls motor functions, motivation, and reward-related learning through G-protein coupled receptor signaling. The current working model is that upon release, dopamine diffuses to influence many target cells via wide-spread receptors. Recent studies, however, suggest that dopamine release is fast and generates small signaling hotspots. In this review, we summarize progress on the understanding of the dopamine release apparatus and evaluate how its properties may shape dopamine signaling during firing. We discuss how mechanisms of regulation may act through this machinery and propose that striatal architecture for dopamine signaling may have evolved to support rapid dopamine coding.
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Affiliation(s)
- Changliang Liu
- Department of Neurobiology, Harvard Medical School, United States
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, United States.
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13
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The effects of proteasome on baseline and methamphetamine-dependent dopamine transmission. Neurosci Biobehav Rev 2019; 102:308-317. [DOI: 10.1016/j.neubiorev.2019.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 04/29/2019] [Accepted: 05/09/2019] [Indexed: 12/16/2022]
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14
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Chen S, Yu C, Rong L, Li CH, Qin X, Ryu H, Park H. Altered Synaptic Vesicle Release and Ca 2+ Influx at Single Presynaptic Terminals of Cortical Neurons in a Knock-in Mouse Model of Huntington's Disease. Front Mol Neurosci 2018; 11:478. [PMID: 30618623 PMCID: PMC6311661 DOI: 10.3389/fnmol.2018.00478] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 12/06/2018] [Indexed: 12/21/2022] Open
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disorder caused by the abnormal expansion of CAG repeats in the huntingtin (HTT) gene, which leads to progressive loss of neurons starting in the striatum and cortex. One possible mechanism for this selective loss of neurons in the early stage of HD is altered neurotransmission at synapses. Despite the recent finding that presynaptic terminals play an important role in HD, neurotransmitter release at synapses in HD remains poorly understood. Here, we measured synaptic vesicle release in real time at single presynaptic terminals during electrical field stimulation. We found the increase in synaptic vesicle release at presynaptic terminals in primary cortical neurons in a knock-in mouse model of HD (zQ175). We also found the increase in Ca2+ influx at presynaptic terminals in HD neurons during the electrical stimulation. Consistent with increased Ca2+-dependent neurotransmission in HD neurons, the increase in vesicle release and Ca2+ influx was rescued with Ca2+ chelators or by blocking N-type voltage-gated Ca2+ channels, suggesting N-type voltage-gated Ca2+ channels play an important role in HD. Taken together, our results suggest that the increased synaptic vesicles release due to increased Ca2+ influx at presynaptic terminals in cortical neurons contributes to the selective neurodegeneration of these neurons in early HD and provide a possible therapeutic target.
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Affiliation(s)
- Sidong Chen
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Chenglong Yu
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Li Rong
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Chun Hei Li
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Xianan Qin
- Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
| | - Hoon Ryu
- Department of Neurology, Boston University School of Medicine, Boston, MA, United States
| | - Hyokeun Park
- Division of Life Science, The Hong Kong University of Science and Technology, Kowloon, Hong Kong.,Department of Physics, The Hong Kong University of Science and Technology, Kowloon, Hong Kong.,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Kowloon, Hong Kong
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15
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Pereira DB, Schmitz Y, Mészáros J, Merchant P, Hu G, Li S, Henke A, Lizardi-Ortiz JE, Karpowicz RJ, Morgenstern TJ, Sonders MS, Kanter E, Rodriguez PC, Mosharov EV, Sames D, Sulzer D. Fluorescent false neurotransmitter reveals functionally silent dopamine vesicle clusters in the striatum. Nat Neurosci 2016; 19:578-86. [PMID: 26900925 PMCID: PMC4853199 DOI: 10.1038/nn.4252] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 01/15/2016] [Indexed: 12/16/2022]
Abstract
Neurotransmission at dopaminergic synapses has been studied with techniques that provide high temporal resolution, but cannot resolve individual synapses. To elucidate the spatial dynamics and heterogeneity of individual dopamine boutons, we developed fluorescent false neurotransmitter 200 (FFN200), a vesicular monoamine transporter 2 (VMAT2) substrate that selectively traces monoamine exocytosis in both neuronal cell culture and brain tissue. By monitoring electrically evoked Ca(2+) transients with GCaMP3 and FFN200 release simultaneously, we found that only a small fraction of dopamine boutons that exhibited Ca(2+) influx engaged in exocytosis, a result confirmed with activity-dependent loading of the endocytic probe FM1-43. Thus, only a low fraction of striatal dopamine axonal sites with uptake-competent VMAT2 vesicles are capable of transmitter release. This is consistent with the presence of functionally 'silent' dopamine vesicle clusters and represents, to the best of our knowledge, the first report suggestive of presynaptically silent neuromodulatory synapses.
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Affiliation(s)
- Daniela B. Pereira
- Department of Neurology, Columbia University Medical Center, New York, NY
| | - Yvonne Schmitz
- Department of Neurology, Columbia University Medical Center, New York, NY
| | - József Mészáros
- Department of Psychiatry, Columbia University Medical Center, New York, NY
| | | | - Gang Hu
- Department of Chemistry, Columbia University, New York, NY
| | - Shu Li
- Department of Chemistry, Columbia University, New York, NY
| | - Adam Henke
- Department of Chemistry, Columbia University, New York, NY
| | | | | | | | - Mark S. Sonders
- Department of Neurology, Columbia University Medical Center, New York, NY
- Department of Psychiatry, Columbia University Medical Center, New York, NY
| | - Ellen Kanter
- Department of Neurology, Columbia University Medical Center, New York, NY
| | | | - Eugene V. Mosharov
- Department of Neurology, Columbia University Medical Center, New York, NY
| | - Dalibor Sames
- Department of Chemistry, Columbia University, New York, NY
| | - David Sulzer
- Department of Neurology, Columbia University Medical Center, New York, NY
- Department of Psychiatry, Columbia University Medical Center, New York, NY
- Department of Pharmacology, Columbia University Medical Center, New York, NY
- Department of Neuroscience, New York Psychiatric Institute, New York, NY
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16
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Koh JY, Iwabuchi S, Huang Z, Harata NC. Rapid genotyping of animals followed by establishing primary cultures of brain neurons. J Vis Exp 2015. [PMID: 25742545 DOI: 10.3791/51879] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
High-resolution analysis of the morphology and function of mammalian neurons often requires the genotyping of individual animals followed by the analysis of primary cultures of neurons. We describe a set of procedures for: labeling newborn mice to be genotyped, rapid genotyping, and establishing low-density cultures of brain neurons from these mice. Individual mice are labeled by tattooing, which allows for long-term identification lasting into adulthood. Genotyping by the described protocol is fast and efficient, and allows for automated extraction of nucleic acid with good reliability. This is useful under circumstances where sufficient time for conventional genotyping is not available, e.g., in mice that suffer from neonatal lethality. Primary neuronal cultures are generated at low density, which enables imaging experiments at high spatial resolution. This culture method requires the preparation of glial feeder layers prior to neuronal plating. The protocol is applied in its entirety to a mouse model of the movement disorder DYT1 dystonia (ΔE-torsinA knock-in mice), and neuronal cultures are prepared from the hippocampus, cerebral cortex and striatum of these mice. This protocol can be applied to mice with other genetic mutations, as well as to animals of other species. Furthermore, individual components of the protocol can be used for isolated sub-projects. Thus this protocol will have wide applications, not only in neuroscience but also in other fields of biological and medical sciences.
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Affiliation(s)
- Jin-Young Koh
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine; Department of Psychiatry, University of Iowa Carver College of Medicine
| | - Sadahiro Iwabuchi
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine
| | | | - N Charles Harata
- Department of Molecular Physiology & Biophysics, University of Iowa Carver College of Medicine;
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17
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Abstract
Few other neurotransmitters are of as intense interest to neuropsychiatry and neurology as dopamine, yet existing techniques to monitor dopamine release leave an important spatiotemporal gap in our understanding. Electrochemistry and fluorescence imaging tools have been developed to fill the gap, but these methods have important limitations. We circumvent these limitations by introducing a dopamine-gated chloride channel into rat dorsal striatal medium spiny neurons, targets of strong dopamine innervation, thereby transforming dopamine from a slow transmitter into a fast transmitter and revealing new opportunities for studying moment-to-moment regulation of dopamine release. We demonstrate pharmacological and biophysical properties of the channel that make it suitable for fast, local dopamine measurements, and we demonstrate for the first time spontaneous and evoked responses to vesicular dopamine release in the dorsal striatum. Evoked dopamine currents were separated into a fast, monosynaptic component and a slower-rising and decaying disynaptic component mediated by nicotinic receptor activation. In summary, LGC-53 represents a dopamine biosensor with properties suitable for temporal separation of distinct dopamine signals in targets of dopamine innervation.
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18
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Morris GP, Clark IA, Zinn R, Vissel B. Microglia: a new frontier for synaptic plasticity, learning and memory, and neurodegenerative disease research. Neurobiol Learn Mem 2013; 105:40-53. [PMID: 23850597 DOI: 10.1016/j.nlm.2013.07.002] [Citation(s) in RCA: 176] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 07/03/2013] [Indexed: 12/25/2022]
Abstract
We focus on emerging roles for microglia in synaptic plasticity, cognition and disease. We outline evidence that ramified microglia, traditionally thought to be functionally "resting" (i.e. quiescent) in the normal brain, in fact are highly dynamic and plastic. Ramified microglia continually and rapidly extend processes, contact synapses in an activity and experience dependent manner, and play a functionally dynamic role in synaptic plasticity, possibly through release of cytokines and growth factors. Ramified microglial also contribute to structural plasticity through the elimination of synapses via phagocytic mechanisms, which is necessary for normal cognition. Microglia have numerous mechanisms to monitor neuronal activity and numerous mechanisms also exist to prevent them transitioning to an activated state, which involves retraction of their surveying processes. Based on the evidence, we suggest that maintaining the ramified state of microglia is essential for normal synaptic and structural plasticity that supports cognition. Further, we propose that change of their ramified morphology and function, as occurs in inflammation associated with numerous neurological disorders such as Alzheimer's and Parkinson's disease, disrupts their intricate and essential synaptic functions. In turn altered microglia function could cause synaptic dysfunction and excess synapse loss early in disease, initiating a range of pathologies that follow. We conclude that the future of learning and memory research depends on an understanding of the role of non-neuronal cells and that this should include using sophisticated molecular, cellular, physiological and behavioural approaches combined with imaging to causally link the role of microglia to brain function and disease including Alzheimer's and Parkinson's disease and other neuropsychiatric disorders.
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Affiliation(s)
- Gary P Morris
- Neurodegenerative Disorders, Garvan Institute of Medical Research, Neuroscience Department, Sydney, Australia; Faculty of Medicine, University of New South Wales, Sydney, Australia.
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19
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Daniel JA, Malladi CS, Kettle E, McCluskey A, Robinson PJ. Analysis of synaptic vesicle endocytosis in synaptosomes by high-content screening. Nat Protoc 2012; 7:1439-55. [PMID: 22767087 DOI: 10.1038/nprot.2012.070] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Small molecules modulating synaptic vesicle endocytosis (SVE) may ultimately be useful for diseases where pathological neurotransmission is implicated. Only a small number of specific SVE modulators have been identified to date. Slow progress is due to the laborious nature of traditional approaches to study SVE, in which nerve terminals are identified and studied in cultured neurons, typically yielding data from 10-20 synapses per experiment. We provide a protocol for a quantitative, high-throughput method for studying SVE in thousands of nerve terminals. Rat forebrain synaptosomes are attached to 96-well microplates and depolarized; SVE is then quantified by uptake of the dye FM4-64, which is imaged by high-content screening. Synaptosomes that have been frozen and stored can be used in place of fresh synaptosomes, reducing the experimental time and animal numbers required. With a supply of frozen synaptosomes, the assay can be performed within a day, including data analysis.
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Affiliation(s)
- James A Daniel
- Cell Signalling Unit, Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, Australia
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20
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Hernandez D, Torres CA, Setlik W, Cebrián C, Mosharov EV, Tang G, Cheng HC, Kholodilov N, Yarygina O, Burke RE, Gershon M, Sulzer D. Regulation of presynaptic neurotransmission by macroautophagy. Neuron 2012; 74:277-84. [PMID: 22542182 PMCID: PMC3578406 DOI: 10.1016/j.neuron.2012.02.020] [Citation(s) in RCA: 254] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2012] [Indexed: 01/11/2023]
Abstract
mTOR is a regulator of cell growth and survival, protein synthesis-dependent synaptic plasticity, and autophagic degradation of cellular components. When triggered by mTOR inactivation, macroautophagy degrades long-lived proteins and organelles via sequestration into autophagic vacuoles. mTOR further regulates synaptic plasticity, and neurodegeneration occurs when macroautophagy is deficient. It is nevertheless unknown whether macroautophagy modulates presynaptic function. We find that the mTOR inhibitor rapamycin induces formation of autophagic vacuoles in prejunctional dopaminergic axons with associated decreased axonal profile volumes, synaptic vesicle numbers, and evoked dopamine release. Evoked dopamine secretion was enhanced and recovery was accelerated in transgenic mice in which macroautophagy deficiency was restricted to dopaminergic neurons; rapamycin failed to decrease evoked dopamine release in the striatum of these mice. Macroautophagy that follows mTOR inhibition in presynaptic terminals, therefore, rapidly alters presynaptic structure and neurotransmission.
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Affiliation(s)
- Daniela Hernandez
- Department of Neuroscience, Columbia University Medical Campus, New York NY 10013
| | - Ciara A. Torres
- Department of Integrated Program in Cellular, Molecular and Biomedical Studies, Columbia University Medical Campus, New York NY 10013
| | - Wanda Setlik
- Department of Pathology, Columbia University Medical Campus, New York NY 10013
| | - Carolina Cebrián
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
| | - Eugene V. Mosharov
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
| | - Guomei Tang
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
| | - Hsiao-Chun Cheng
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
| | - Nikolai Kholodilov
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
| | - Olga Yarygina
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
| | - Robert E. Burke
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
| | - Michael Gershon
- Department of Pathology, Columbia University Medical Campus, New York NY 10013
| | - David Sulzer
- Department of Neurology, Columbia University Medical Campus, New York NY 10013
- Department of Psychiatry and Pharmacology, Columbia University Medical Campus, New York NY 10013
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21
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Zhang H, Sulzer D. Regulation of striatal dopamine release by presynaptic auto- and heteroreceptors. ACTA ACUST UNITED AC 2012; 2:5-13. [PMID: 22712055 DOI: 10.1016/j.baga.2011.11.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Striatal dopamine neurotransmission is critical for normal voluntary movement, affect and cognition. Dysfunctions of its regulation are implicated in a broad range of behaviors and disorders including Parkinson's disease, schizophrenia and drug abuse. Extracellular dopamine levels result from a dynamic equilibrium between release and reuptake by dopaminergic terminals. Both processes are regulated by multiple mechanisms. Here we review data characterizing how dopamine levels are regulated by presynaptic autoreceptors and heteroreceptors, an area intensively investigated due to advances in real time electrochemical detection of extracellular dopamine, i.e., fast-scan cyclic voltammetry and amperometry, and the development of mutant mouse lines with deletions for specific receptors.
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Affiliation(s)
- Hui Zhang
- Department of Psychiatry and Neurology, Columbia University, New York
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22
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Kakazu Y, Koh JY, Ho KWD, Gonzalez-Alegre P, Harata NC. Synaptic vesicle recycling is enhanced by torsinA that harbors the DYT1 dystonia mutation. Synapse 2012; 66:453-64. [PMID: 22213465 DOI: 10.1002/syn.21534] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 11/20/2011] [Accepted: 12/17/2011] [Indexed: 11/08/2022]
Abstract
Early-onset generalized dystonia, DYT1, is caused by a mutation in the gene encoding the evolutionarily conserved AAA+ ATPase torsinA. Synaptic abnormalities have been implicated in DYT1 dystonia, but the details of the synaptic pathophysiology are only partially understood. Here, we demonstrate a novel role for torsinA in synaptic vesicle recycling, using cultured hippocampal neurons from a knock-in mouse model of DYT1 dystonia (ΔE-torsinA) and live-cell imaging with styryl FM dyes. Neurons from heterozygous ΔE-torsinA mice released a larger fraction of the total recycling pool (TRP) during a single round of electrical stimulation than did wild-type neurons. Moreover, when the neurons were subjected to prior high activity, the time course of release was shortened. In neurons from homozygous mice, these enhanced exocytosis phenotypes were similar, but in addition the size of the TRP was reduced. Notably, when release was triggered by applying a calcium ionophore rather than electrical stimuli, neither a single nor two ΔE-torsinA alleles affected the time course of release. Thus, the site of action of ΔE-torsinA is at or upstream of the rise in calcium concentration in nerve terminals. Our results suggest that torsinA regulates synaptic vesicle recycling in central neurons. They also indicate that this regulation is influenced by neuronal activity, further supporting the idea that synaptic abnormalities contribute to the pathophysiology of DYT1 dystonia.
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Affiliation(s)
- Yasuhiro Kakazu
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
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23
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Rao A, Richards TL, Simmons D, Zahniser NR, Sorkin A. Epitope-tagged dopamine transporter knock-in mice reveal rapid endocytic trafficking and filopodia targeting of the transporter in dopaminergic axons. FASEB J 2012; 26:1921-33. [PMID: 22267337 DOI: 10.1096/fj.11-196113] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The plasma membrane dopamine (DA) transporter (DAT) is essential for reuptake of extracellular DA. DAT function in heterologous cells is regulated by subcellular targeting, endocytosis, and intracellular trafficking, but the mechanisms regulating neuronal DAT remain poorly understood. Hence, we generated a knock-in mouse expressing a hemagglutinin (HA)-epitope-tagged DAT to study endogenous transporter trafficking. Introduction of the HA tag into the second extracellular loop of mouse DAT did not perturb its expression level, distribution pattern, or substrate uptake kinetics. Live-cell fluorescence microscopy imaging using fluorescently labeled HA-specific antibody and a quantitative HA-antibody endocytosis assay demonstrated that in axons HA-DAT was primarily located in the plasma membrane and internalized mostly in growth cones and varicosities, where synaptic vesicle markers were also concentrated. Formation of varicosities was frequently preceded or accompanied by highly dynamic filopodia-like membrane protrusions. Remarkably, HA-DAT often concentrated at the tips of these filopodia. This pool of HA-DATs exhibited low lateral membrane mobility. Thus, DAT-containing filopodia may be involved in synaptogenesis in developing DA neurons. Treatment of neurons with amphetamine increased mobility of filopodial HA-DAT and accelerated HA-DAT endocytosis in axons, suggesting that chronic amphetamine may interfere with DA synapse development. Interestingly, phorbol esters did not accelerate endocytosis of axonal DAT.
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Affiliation(s)
- Anjali Rao
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine, S368 Biomedical Science Tower South, 3500 Terrace St., Pittsburgh, PA 15261, USA
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24
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Rice ME, Patel JC, Cragg SJ. Dopamine release in the basal ganglia. Neuroscience 2011; 198:112-37. [PMID: 21939738 PMCID: PMC3357127 DOI: 10.1016/j.neuroscience.2011.08.066] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/22/2011] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
Abstract
Dopamine (DA) is a key transmitter in the basal ganglia, yet DA transmission does not conform to several aspects of the classic synaptic doctrine. Axonal DA release occurs through vesicular exocytosis and is action potential- and Ca²⁺-dependent. However, in addition to axonal release, DA neurons in midbrain exhibit somatodendritic release by an incompletely understood, but apparently exocytotic, mechanism. Even in striatum, axonal release sites are controversial, with evidence for DA varicosities that lack postsynaptic specialization, and largely extrasynaptic DA receptors and transporters. Moreover, DA release is often assumed to reflect a global response to a population of activities in midbrain DA neurons, whether tonic or phasic, with precise timing and specificity of action governed by other basal ganglia circuits. This view has been reinforced by anatomical evidence showing dense axonal DA arbors throughout striatum, and a lattice network formed by DA axons and glutamatergic input from cortex and thalamus. Nonetheless, localized DA transients are seen in vivo using voltammetric methods with high spatial and temporal resolution. Mechanistic studies using similar methods in vitro have revealed local regulation of DA release by other transmitters and modulators, as well as by proteins known to be disrupted in Parkinson's disease and other movement disorders. Notably, the actions of most other striatal transmitters on DA release also do not conform to the synaptic doctrine, with the absence of direct synaptic contacts for glutamate, GABA, and acetylcholine (ACh) on striatal DA axons. Overall, the findings reviewed here indicate that DA signaling in the basal ganglia is sculpted by cooperation between the timing and pattern of DA input and those of local regulatory factors.
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Affiliation(s)
- M E Rice
- Department of Neurosurgery, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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25
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Bergstrom BP, Sanberg SG, Andersson M, Mithyantha J, Carroll FI, Garris PA. Functional reorganization of the presynaptic dopaminergic terminal in parkinsonism. Neuroscience 2011; 193:310-22. [PMID: 21787843 PMCID: PMC3171576 DOI: 10.1016/j.neuroscience.2011.07.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Revised: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 11/20/2022]
Abstract
Whether dopamine (DA) release is compensated during the presymptomatic phase of Parkinson's disease (PD) is controversial. Here we use in vivo voltammetry in the parkinsonian rat and an electrical stimulation protocol established to fatigue nigrostriatal dopaminergic (DAergic) neurons to investigate the plasticity of DA-release mechanisms. Amplitudes of evoked voltammetric signals recorded in intact rat striata decreased with repetitive, high-frequency stimulation (60 Hz, every 5 min/60 min). Strikingly, DA levels were maintained during an identical "fatiguing" protocol in 6-hydroxydopamine-lesioned (<40% denervation) striata in the absence of enhanced DA synthesis. In contrast, more severely lesioned striata (>55% denervation) also appeared to sustain DA release, however, this was demonstrated in the presence of enhanced synthesis. Sustained release was replicated in intact animals after irreversible blockade of the dopamine transporter (DAT) via RTI-76, implicating neuronal uptake as a trigger. We further demonstrate through kinetic analysis that lesions and compromised uptake target a "long-term" (time constant of minutes) presynaptic depression, which underlies the maintenance of release. Taken together, our findings identify a denervation-induced maintenance of DA release that was independent of activated synthesis and driven by altered uptake. This novel neuroadaptation may contribute to early preclinical normalization of function and help resolve discrepant findings regarding compensatory changes in DA release during progression of the parkinsonian state.
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Affiliation(s)
- B P Bergstrom
- Department of Biology, Neuroscience Program, Muskingum University, New Concord, OH 43762, USA.
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26
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Abstract
Statistical analysis is critical in the interpretation of experimental data across the life sciences, including neuroscience. The nature of the data collected has a critical role in determining the best statistical approach to take. One particularly prevalent type of data is referred to as "clustered data." Clustered data are characterized as data that can be classified into a number of distinct groups or "clusters" within a particular study. Clustered data arise most commonly in neuroscience when data are compiled across multiple experiments, for example in electrophysiological or optical recordings taken from synaptic terminals, with each experiment providing a distinct cluster of data. However, there are many other types of experimental design that can yield clustered data. Here, we provide a statistical model for intracluster correlation and systematically investigate a range of methods for analyzing clustered data. Our analysis reveals that it is critical to take data clustering into account and suggests appropriate statistical approaches that can be used to account for data clustering.
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27
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Vesicular monoamine and glutamate transporters select distinct synaptic vesicle recycling pathways. J Neurosci 2010; 30:7917-27. [PMID: 20534840 DOI: 10.1523/jneurosci.5298-09.2010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Previous work has characterized the properties of neurotransmitter release at excitatory and inhibitory synapses, but we know remarkably little about the properties of monoamine release, because these neuromodulators do not generally produce a fast ionotropic response. Since dopamine and serotonin neurons can also release glutamate in vitro and in vivo, we have used the vesicular monoamine transporter VMAT2 and the vesicular glutamate transporter VGLUT1 to compare the localization and recycling of synaptic vesicles that store, respectively, monoamines and glutamate. First, VMAT2 segregates partially from VGLUT1 in the boutons of midbrain dopamine neurons, indicating the potential for distinct release sites. Second, endocytosis after stimulation is slower for VMAT2 than VGLUT1. During the stimulus, however, the endocytosis of VMAT2 (but not VGLUT1) accelerates dramatically in midbrain dopamine but not hippocampal neurons, indicating a novel, cell-specific mechanism to sustain high rates of release. On the other hand, we find that in both midbrain dopamine and hippocampal neurons, a substantially smaller proportion of VMAT2 than VGLUT1 is available for evoked release, and VMAT2 shows considerably more dispersion along the axon after exocytosis than VGLUT1. Even when expressed in the same neuron, the two vesicular transporters thus target to distinct populations of synaptic vesicles, presumably due to their selection of distinct recycling pathways.
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28
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Samson RD, Frank MJ, Fellous JM. Computational models of reinforcement learning: the role of dopamine as a reward signal. Cogn Neurodyn 2010; 4:91-105. [PMID: 21629583 DOI: 10.1007/s11571-010-9109-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Revised: 02/17/2010] [Accepted: 02/24/2010] [Indexed: 11/27/2022] Open
Abstract
Reinforcement learning is ubiquitous. Unlike other forms of learning, it involves the processing of fast yet content-poor feedback information to correct assumptions about the nature of a task or of a set of stimuli. This feedback information is often delivered as generic rewards or punishments, and has little to do with the stimulus features to be learned. How can such low-content feedback lead to such an efficient learning paradigm? Through a review of existing neuro-computational models of reinforcement learning, we suggest that the efficiency of this type of learning resides in the dynamic and synergistic cooperation of brain systems that use different levels of computations. The implementation of reward signals at the synaptic, cellular, network and system levels give the organism the necessary robustness, adaptability and processing speed required for evolutionary and behavioral success.
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