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Gutierrez-Castellanos N, Sarra D, Godinho BS, Mainen ZF. Maturation of cortical input to dorsal raphe nucleus increases behavioral persistence in mice. eLife 2024; 13:e93485. [PMID: 38477558 PMCID: PMC10994666 DOI: 10.7554/elife.93485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 02/28/2024] [Indexed: 03/14/2024] Open
Abstract
The ability to persist toward a desired objective is a fundamental aspect of behavioral control whose impairment is implicated in several behavioral disorders. One of the prominent features of behavioral persistence is that its maturation occurs relatively late in development. This is presumed to echo the developmental time course of a corresponding circuit within late-maturing parts of the brain, such as the prefrontal cortex, but the specific identity of the responsible circuits is unknown. Here, we used a genetic approach to describe the maturation of the projection from layer 5 neurons of the neocortex to the dorsal raphe nucleus in mice. Using optogenetic-assisted circuit mapping, we show that this projection undergoes a dramatic increase in synaptic potency between postnatal weeks 3 and 8, corresponding to the transition from juvenile to adult. We then show that this period corresponds to an increase in the behavioral persistence that mice exhibit in a foraging task. Finally, we used a genetic targeting strategy that primarily affected neurons in the medial prefrontal cortex, to selectively ablate this pathway in adulthood and show that mice revert to a behavioral phenotype similar to juveniles. These results suggest that frontal cortical to dorsal raphe input is a critical anatomical and functional substrate of the development and manifestation of behavioral persistence.
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Affiliation(s)
| | - Dario Sarra
- Champalimaud Research, Champalimaud FoundationLisbonPortugal
- Nuffield Department of Clinical Neurosciences, University of OxfordOxfordUnited Kingdom
| | - Beatriz S Godinho
- Champalimaud Research, Champalimaud FoundationLisbonPortugal
- Nuffield Department of Clinical Neurosciences, University of OxfordOxfordUnited Kingdom
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2
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Karmakar S, Lal G. Role of Serotonergic System in Regulating Brain Tumor-Associated Neuroinflammatory Responses. Methods Mol Biol 2024; 2761:181-207. [PMID: 38427238 DOI: 10.1007/978-1-0716-3662-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024]
Abstract
Serotonin signaling regulates wide arrays of both neural and extra-neural functions. Serotonin is also found to affect cancer progression directly as well as indirectly by modulating the immune cells. In the brain, serotonin plays a key role in regulating various functions; disturbance of the normal activities of serotonin leads to various mental illnesses, including the neuroinflammatory response in the central nervous system (CNS). The neuroinflammatory response can be initiated in various psychological illnesses and brain cancer. Serotonergic signaling can impact the functions of both glial as well as the immune cells. It can also affect the tumor immune microenvironment and the inflammatory response associated with brain cancers. Apart from this, many drugs used for treatment of psychological illness are known to modulate serotonergic system and can cross the blood-brain barrier. Understanding the role of serotonergic pathways in regulating neuroinflammatory response and brain cancer will provide a new paradigm in modulating the serotonergic components in treating brain cancer and associated inflammation-induced brain damages.
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Affiliation(s)
- Surojit Karmakar
- National Centre for Cell Science (NCCS), SPPU Campus, Ganeshkhind, Pune, Maharashtra, India
| | - Girdhari Lal
- National Centre for Cell Science (NCCS), SPPU Campus, Ganeshkhind, Pune, Maharashtra, India.
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3
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De-Miguel FF. The Thermodynamically Expensive Contribution of Three Calcium Sources to Somatic Release of Serotonin. Int J Mol Sci 2022; 23:1495. [PMID: 35163419 PMCID: PMC8836226 DOI: 10.3390/ijms23031495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 12/28/2021] [Accepted: 12/30/2021] [Indexed: 02/01/2023] Open
Abstract
The soma, dendrites and axon of neurons may display calcium-dependent release of transmitters and peptides. Such release is named extrasynaptic for occurring in absence of synaptic structures. This review describes the cooperative actions of three calcium sources on somatic exocytosis. Emphasis is given to the somatic release of serotonin by the classical leech Retzius neuron, which has allowed detailed studies on the fine steps from excitation to exocytosis. Trains of action potentials induce transmembrane calcium entry through L-type channels. For action potential frequencies above 5 Hz, summation of calcium transients on individual action potentials activates the second calcium source: ryanodine receptors produce calcium-induced calcium release. The resulting calcium tsunami activates mitochondrial ATP synthesis to fuel transport of vesicles to the plasma membrane. Serotonin that is released maintains a large-scale exocytosis by activating the third calcium source: serotonin autoreceptors coupled to phospholipase C promote IP3 production. Activated IP3 receptors in peripheral endoplasmic reticulum release calcium that promotes vesicle fusion. The Swiss-clock workings of the machinery for somatic exocytosis has a striking disadvantage. The essential calcium-releasing endoplasmic reticulum near the plasma membrane hinders the vesicle transport, drastically reducing the thermodynamic efficiency of the ATP expenses and elevating the energy cost of release.
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Affiliation(s)
- Francisco F De-Miguel
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
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4
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Aguiar RPD, Newman-Tancredi A, Prickaerts J, Oliveira RMWD. The 5-HT 1A receptor as a serotonergic target for neuroprotection in cerebral ischemia. Prog Neuropsychopharmacol Biol Psychiatry 2021; 109:110210. [PMID: 33333136 DOI: 10.1016/j.pnpbp.2020.110210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/01/2020] [Accepted: 12/10/2020] [Indexed: 12/13/2022]
Abstract
Cerebral ischemia due to stroke or cardiac arrest greatly affects daily functioning and the quality of life of patients and has a high socioeconomic impact due to the surge in their prevalence. Advances in the identification of an effective pharmacotherapy to promote neuroprotection and recovery after a cerebral ischemic insult are, however, limited. The serotonin 1A (5-HT1A) receptor has been implicated in the regulation of several brain functions, including mood, emotions, memory, and neuroplasticity, all of which are deleteriously affected by cerebral ischemia. This review focuses on the specific roles and mechanisms of 5-HT1A receptors in neuroprotection in experimental models of cerebral ischemia. We present experimental evidence that 5-HT1A receptor agonists can prevent neuronal damage and promote functional recovery induced by focal and transient global ischemia in rodents. However, indiscriminate activation of pre-and postsynaptic by non-biased 5-HT1A receptor agonists may be a limiting factor in the anti-ischemic clinical efficacy of these compounds since 5-HT1A receptors in different brain regions can mediate diverging or even contradictory responses. Current insights are presented into the 'biased' 5-HT1A post-synaptic heteroreceptor agonist NLX-101 (also known as F15599), a compound that preferentially and potently stimulates postsynaptic cortical pyramidal neurons without inhibiting firing of serotoninergic neurons, as a potential strategy providing neuroprotection in cerebral ischemic conditions.
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Affiliation(s)
- Rafael Pazinatto de Aguiar
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, CEP 87020-900, Maringá, Paraná, Brazil
| | | | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Rúbia Maria Weffort de Oliveira
- Department of Pharmacology and Therapeutics, State University of Maringá, Av. Colombo, 5790, CEP 87020-900, Maringá, Paraná, Brazil.
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5
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Jansch C, Ziegler GC, Forero A, Gredy S, Wäldchen S, Vitale MR, Svirin E, Zöller JEM, Waider J, Günther K, Edenhofer F, Sauer M, Wischmeyer E, Lesch KP. Serotonin-specific neurons differentiated from human iPSCs form distinct subtypes with synaptic protein assembly. J Neural Transm (Vienna) 2021; 128:225-241. [PMID: 33560471 PMCID: PMC7914246 DOI: 10.1007/s00702-021-02303-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/10/2021] [Indexed: 02/06/2023]
Abstract
Human induced pluripotent stem cells (hiPSCs) have revolutionized the generation of experimental disease models, but the development of protocols for the differentiation of functionally active neuronal subtypes with defined specification is still in its infancy. While dysfunction of the brain serotonin (5-HT) system has been implicated in the etiology of various neuropsychiatric disorders, investigation of functional human 5-HT specific neurons in vitro has been restricted by technical limitations. We describe an efficient generation of functionally active neurons from hiPSCs displaying 5-HT specification by modification of a previously reported protocol. Furthermore, 5-HT specific neurons were characterized using high-end fluorescence imaging including super-resolution microscopy in combination with electrophysiological techniques. Differentiated hiPSCs synthesize 5-HT, express specific markers, such as tryptophan hydroxylase 2 and 5-HT transporter, and exhibit an electrophysiological signature characteristic of serotonergic neurons, with spontaneous rhythmic activities, broad action potentials and large afterhyperpolarization potentials. 5-HT specific neurons form synapses reflected by the expression of pre- and postsynaptic proteins, such as Bassoon and Homer. The distribution pattern of Bassoon, a marker of the active zone along the soma and extensions of neurons, indicates functionality via volume transmission. Among the high percentage of 5-HT specific neurons (~ 42%), a subpopulation of CDH13 + cells presumably designates dorsal raphe neurons. hiPSC-derived 5-HT specific neuronal cell cultures reflect the heterogeneous nature of dorsal and median raphe nuclei and may facilitate examining the association of serotonergic neuron subpopulations with neuropsychiatric disorders.
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Affiliation(s)
- Charline Jansch
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
| | - Georg C Ziegler
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany.
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University of Würzburg, Würzburg, Germany.
| | - Andrea Forero
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
| | - Sina Gredy
- Institute of Physiology, Molecular Electrophysiology, University of Würzburg, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Sina Wäldchen
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Maria Rosaria Vitale
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Evgeniy Svirin
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - Johanna E M Zöller
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Department of Translational Neuroscience, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands
| | - Jonas Waider
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
| | - Katharina Günther
- Department of Genomics, Stem Cell Biology and Regenerative Medicine, Institute of Molecular Biology and CMBI, Leopold-Franzens-University Innsbruck, Innsbruck, Austria
- Institute of Molecular Regenerative Medicine, SCI-TReCS, Paracelsus Medical University, Salzburg, Austria
| | - Frank Edenhofer
- Department of Genomics, Stem Cell Biology and Regenerative Medicine, Institute of Molecular Biology and CMBI, Leopold-Franzens-University Innsbruck, Innsbruck, Austria
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Erhard Wischmeyer
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany
- Institute of Physiology, Molecular Electrophysiology, University of Würzburg, Würzburg, Germany
| | - Klaus-Peter Lesch
- Division of Molecular Psychiatry, Center of Mental Health, University of Würzburg, Margarete-Höppel-Platz 1, 97080, Würzburg, Germany.
- Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia.
- Department of Translational Neuroscience, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands.
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6
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Huang KW, Ochandarena NE, Philson AC, Hyun M, Birnbaum JE, Cicconet M, Sabatini BL. Molecular and anatomical organization of the dorsal raphe nucleus. eLife 2019; 8:e46464. [PMID: 31411560 PMCID: PMC6726424 DOI: 10.7554/elife.46464] [Citation(s) in RCA: 130] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/13/2019] [Indexed: 12/20/2022] Open
Abstract
The dorsal raphe nucleus (DRN) is an important source of neuromodulators and has been implicated in a wide variety of behavioral and neurological disorders. The DRN is subdivided into distinct anatomical subregions comprised of multiple cell types, and its complex cellular organization has impeded efforts to investigate the distinct circuit and behavioral functions of its subdomains. Here we used single-cell RNA sequencing, in situ hybridization, anatomical tracing, and spatial correlation analysis to map the transcriptional and spatial profiles of cells from the mouse DRN. Our analysis of 39,411 single-cell transcriptomes revealed at least 18 distinct neuron subtypes and 5 serotonergic neuron subtypes with distinct molecular and anatomical properties, including a serotonergic neuron subtype that preferentially innervates the basal ganglia. Our study lays out the molecular organization of distinct serotonergic and non-serotonergic subsystems, and will facilitate the design of strategies for further dissection of the DRN and its diverse functions.
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Affiliation(s)
- Kee Wui Huang
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Nicole E Ochandarena
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Adrienne C Philson
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Minsuk Hyun
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Jaclyn E Birnbaum
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
| | - Marcelo Cicconet
- Image and Data Analysis CoreHarvard Medical SchoolBostonUnited States
| | - Bernardo L Sabatini
- Department of NeurobiologyHoward Hughes Medical Institute, Harvard Medical SchoolBostonUnited States
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7
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Engram-specific transcriptome profiling of contextual memory consolidation. Nat Commun 2019; 10:2232. [PMID: 31110186 PMCID: PMC6527697 DOI: 10.1038/s41467-019-09960-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 03/29/2019] [Indexed: 12/20/2022] Open
Abstract
Sparse populations of neurons in the dentate gyrus (DG) of the hippocampus are causally implicated in the encoding of contextual fear memories. However, engram-specific molecular mechanisms underlying memory consolidation remain largely unknown. Here we perform unbiased RNA sequencing of DG engram neurons 24 h after contextual fear conditioning to identify transcriptome changes specific to memory consolidation. DG engram neurons exhibit a highly distinct pattern of gene expression, in which CREB-dependent transcription features prominently (P = 6.2 × 10−13), including Atf3 (P = 2.4 × 10−41), Penk (P = 1.3 × 10−15), and Kcnq3 (P = 3.1 × 10−12). Moreover, we validate the functional relevance of the RNAseq findings by establishing the causal requirement of intact CREB function specifically within the DG engram during memory consolidation, and identify a novel group of CREB target genes involved in the encoding of long-term memory. The molecular mechanisms underlying contextual fear memory consolidation by sparse dentate gyrus (DG) neuronal populations remain unclear. Here using unbiased RNA sequencing of DG engram neurons the authors identify persistent transcriptome modifications during memory consolidation, in which CREB-dependent transcription features prominently
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8
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Kasture AS, Bartel D, Steinkellner T, Sucic S, Hummel T, Freissmuth M. Distinct contribution of axonal and somatodendritic serotonin transporters in drosophila olfaction. Neuropharmacology 2019; 161:107564. [PMID: 30851308 DOI: 10.1016/j.neuropharm.2019.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 02/11/2019] [Accepted: 03/03/2019] [Indexed: 01/07/2023]
Abstract
The serotonin transporter (SERT) regulates serotonergic neurotransmission by retrieving released serotonin and replenishing vesicular stores. SERT is not only delivered to axons but it is also present on the neuronal soma and on dendrites. It has not been possible to restrict the distribution of SERT without affecting transporter function. Hence, the physiological role of somatodendritic SERT remains enigmatic. The SERT C-terminus harbors a conserved RI-motif, which recruits SEC24C, a cargo receptor in the coatomer protein-II coat. Failure to engage SEC24C precludes axonal enrichment of SERT. Here we introduced a point mutation into the RI-motif of human SERT causing confinement of the resulting - otherwise fully functional - hSERT-R607A on the somatodendritic membrane of primary rat dorsal raphe neurons. Transgenic expression of the corresponding Drosophila mutant dSERT-R599A led to its enrichment in the somatodendritic compartment of serotonergic neurons in the fly brain. We explored the possible physiological role of somatodendritic SERT by comparing flies harboring wild type SERT and dSERT-R599A in a behavioral paradigm for serotonin-modulated odor perception. When globally re-expressed in serotonergic neurons, wild type SERT but not dSERT-R599A restored ethanol preference. In contrast, dSERT-R599A restored ethanol preference after targeted expression in contralaterally projecting, serotonin-immunoreactive deuterocerebral (CSD) interneurons, while expression of wild type SERT caused ethanol aversion. We conclude that, in CSD neurons, (i) somatodendritic SERT supports ethanol attraction, (ii) axonal SERT specifies ethanol aversion, (iii) the effect of axonal SERT can override that of somatodendritic SERT. These observations demonstrate a distinct biological role of somatodendritic and axonal serotonin transport. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Ameya Sanjay Kasture
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria; Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Daniela Bartel
- Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Thomas Steinkellner
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Thomas Hummel
- Department of Neurobiology, University of Vienna, A-1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
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9
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Quentin E, Belmer A, Maroteaux L. Somato-Dendritic Regulation of Raphe Serotonin Neurons; A Key to Antidepressant Action. Front Neurosci 2018; 12:982. [PMID: 30618598 PMCID: PMC6307465 DOI: 10.3389/fnins.2018.00982] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/07/2018] [Indexed: 11/22/2022] Open
Abstract
Several lines of evidence implicate serotonin (5-hydroxytryptamine, 5-HT)in regulating personality traits and mood control. Serotonergic neurons are classically thought to be tonic regular-firing, “clock-like” neurons. Neurotransmission by serotonin is tightly regulated by the serotonin transporter (SERT) and by autoreceptors (serotonin receptors expressed by serotonin neurons) through negative feedback inhibition at the cell bodies and dendrites (5-HT1A receptors) of the dorsal raphe nuclei or at the axon terminals (5-HT1B receptors). In dorsal raphe neurons, the release of serotonin from vesicles in the soma, dendrites, and/or axonal varicosities is independent of classical synapses and can be induced by neuron depolarization, by the stimulation of L-type calcium channels, by activation of glutamatergic receptors, and/or by activation of 5-HT2 receptors. The resulting serotonin release displays a slow kinetic and a large diffusion. This process called volume transmission may ultimately affect the rate of discharge of serotonergic neurons, and their tonic activity. The therapeutic effects induced by serotonin-selective reuptake inhibitor (SSRI) antidepressants are initially triggered by blocking SERT but rely on consequences of chronic exposure, i.e., a selective desensitization of somatodendritic 5-HT1A autoreceptors. Agonist stimulation of 5-HT2B receptors mimicked behavioral and neurogenic SSRI actions, and increased extracellular serotonin in dorsal raphe. By contrast, a lack of effects of SSRIs was observed in the absence of 5-HT2B receptors (knockout-KO), even restricted to serotonergic neurons (Htr2b5-HTKO mice). The absence of 5-HT2B receptors in serotonergic neurons is associated with a higher 5-HT1A-autoreceptor reactivity and thus a lower firing activity of these neurons. In agreement, mice with overexpression of 5-HT1A autoreceptor show decreased neuronal activity and increased depression-like behavior that is resistant to SSRI treatment. We propose thus that the serotonergic tone results from the opposite control exerted by somatodendritic (Gi-coupled) 5-HT1A and (Gq-coupled) 5-HT2B receptors on dorsal raphe neurons. Therefore, 5-HT2B receptors may contribute to SSRI therapeutic effects by their positive regulation of adult raphe serotonergic neurons. Deciphering the molecular mechanism controlling extrasynaptic release of serotonin, and how autoreceptors interact in regulating the tonic activity of serotonergic neurons, is critical to fully understand the therapeutic effect of SSRIs.
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Affiliation(s)
- Emily Quentin
- INSERM UMR-S 839, Institut du Fer à Moulin, Paris, France.,Sorbonne Universités, UPMC University Paris 6, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Arnauld Belmer
- INSERM UMR-S 839, Institut du Fer à Moulin, Paris, France.,Sorbonne Universités, UPMC University Paris 6, Paris, France.,Institut du Fer à Moulin, Paris, France
| | - Luc Maroteaux
- INSERM UMR-S 839, Institut du Fer à Moulin, Paris, France.,Sorbonne Universités, UPMC University Paris 6, Paris, France.,Institut du Fer à Moulin, Paris, France
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10
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Belmer A, Quentin E, Diaz SL, Guiard BP, Fernandez SP, Doly S, Banas SM, Pitychoutis PM, Moutkine I, Muzerelle A, Tchenio A, Roumier A, Mameli M, Maroteaux L. Positive regulation of raphe serotonin neurons by serotonin 2B receptors. Neuropsychopharmacology 2018; 43:1623-1632. [PMID: 29453444 PMCID: PMC5983540 DOI: 10.1038/s41386-018-0013-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 01/10/2018] [Accepted: 01/17/2018] [Indexed: 01/03/2023]
Abstract
Serotonin is a neurotransmitter involved in many psychiatric diseases. In humans, a lack of 5-HT2B receptors is associated with serotonin-dependent phenotypes, including impulsivity and suicidality. A lack of 5-HT2B receptors in mice eliminates the effects of molecules that directly target serotonergic neurons including amphetamine derivative serotonin releasers, and selective serotonin reuptake inhibitor antidepressants. In this work, we tested the hypothesis that 5-HT2B receptors directly and positively regulate raphe serotonin neuron activity. By ex vivo electrophysiological recordings, we report that stimulation by the 5-HT2B receptor agonist, BW723C86, increased the firing frequency of serotonin Pet1-positive neurons. Viral overexpression of 5-HT2B receptors in these neurons increased their excitability. Furthermore, in vivo 5-HT2B-receptor stimulation by BW723C86 counteracted 5-HT1A autoreceptor-dependent reduction in firing rate and hypothermic response in wild-type mice. By a conditional genetic ablation that eliminates 5-HT2B receptor expression specifically and exclusively from Pet1-positive serotonin neurons (Htr2b 5-HTKO mice), we demonstrated that behavioral and sensitizing effects of MDMA (3,4-methylenedioxy-methamphetamine), as well as acute behavioral and chronic neurogenic effects of the antidepressant fluoxetine, require 5-HT2B receptor expression in serotonergic neurons. In Htr2b 5-HTKO mice, dorsal raphe serotonin neurons displayed a lower firing frequency compared to control Htr2b lox/lox mice as assessed by in vivo extracellular recordings and a stronger hypothermic effect of 5-HT1A-autoreceptor stimulation was observed. The increase in head-twitch response to DOI (2,5-dimethoxy-4-iodoamphetamine) further confirmed the lower serotonergic tone resulting from the absence of 5-HT2B receptors in serotonin neurons. Together, these observations indicate that the 5-HT2B receptor acts as a direct positive modulator of serotonin Pet1-positive neurons in an opposite way as the known 5-HT1A-negative autoreceptor.
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Affiliation(s)
- Arnauld Belmer
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000000089150953grid.1024.7Translational Research Institute, Queensland University of Technology, Brisbane, QLD 4059 Australia
| | - Emily Quentin
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Silvina L. Diaz
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,grid.441705.3Instituto de Biología Celular y Neurociencia, Fac. de Cs. Exactas, Químicas y Naturales, Universidad de Morón, UBA-CONICET – Paraguay 2155, 3° piso, C1121ABG Buenos Aires, Argentina
| | - Bruno P. Guiard
- Research Center on Animal Cognition, Center for Integrative Biology, 31062 Toulouse, France ,0000 0001 0723 035Xgrid.15781.3aUniversité Paul Sabatier, 31062 Toulouse, France ,UMR5169 CNRS, 31062 Toulouse, France
| | - Sebastian P. Fernandez
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0004 0638 0649grid.429194.3IPMC – CNRS UMR7275 660 Route des Lucioles Sophia-Antipolis, 06560 Valbonne, France
| | - Stéphane Doly
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,grid.503334.2Université Clermont Auvergne, INSERM, NEURO-DOL, 63000 Clermont-Ferrand, France
| | - Sophie M. Banas
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Pothitos M. Pitychoutis
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0001 2175 167Xgrid.266231.2Department of Biology and Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH USA
| | - Imane Moutkine
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Aude Muzerelle
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Anna Tchenio
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0001 2165 4204grid.9851.5Dept. Fundamental Neurosciences (DNF) The University of Lausanne, Lausanne, Switzerland
| | - Anne Roumier
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France
| | - Manuel Mameli
- 0000000121866389grid.7429.8INSERM UMR-S 839, 75005 Paris, France ,0000 0001 2308 1657grid.462844.8Sorbonne Universités, UPMC Univ Paris 6, 75005 Paris, France ,0000 0004 0520 8345grid.462192.aInstitut du Fer à Moulin, 75005 Paris, France ,0000 0001 2165 4204grid.9851.5Dept. Fundamental Neurosciences (DNF) The University of Lausanne, Lausanne, Switzerland
| | - Luc Maroteaux
- INSERM UMR-S 839, 75005, Paris, France. .,Sorbonne Universités, UPMC Univ Paris 6, 75005, Paris, France. .,Institut du Fer à Moulin, 75005, Paris, France.
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11
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Gölöncsér F, Baranyi M, Balázsfi D, Demeter K, Haller J, Freund TFF, Zelena D, Sperlágh B. Regulation of Hippocampal 5-HT Release by P2X7 Receptors in Response to Optogenetic Stimulation of Median Raphe Terminals of Mice. Front Mol Neurosci 2017; 10:325. [PMID: 29075178 PMCID: PMC5643475 DOI: 10.3389/fnmol.2017.00325] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 09/27/2017] [Indexed: 01/01/2023] Open
Abstract
Serotonergic and glutamatergic neurons of median raphe region (MRR) play a pivotal role in the modulation of affective and cognitive functions. These neurons synapse both onto themselves and remote cortical areas. P2X7 receptors (P2rx7) are ligand gated ion channels expressed by central presynaptic excitatory nerve terminals and involved in the regulation of neurotransmitter release. P2rx7s are implicated in various neuropsychiatric conditions such as schizophrenia and depression. Here we investigated whether 5-HT release released from the hippocampal terminals of MRR is subject to modulation by P2rx7s. To achieve this goal, an optogenetic approach was used to selectively activate subpopulation of serotonergic terminals derived from the MRR locally, and one of its target area, the hippocampus. Optogenetic activation of neurons in the MRR with 20 Hz was correlated with freezing and enhanced locomotor activity of freely moving mice and elevated extracellular levels of 5-HT, glutamate but not GABA in vivo. Similar optical stimulation (OS) significantly increased [3H]5-HT and [3H]glutamate release in acute MRR and hippocampal slices. We examined spatial and temporal patterns of [3H]5-HT release and the interaction between the serotonin and glutamate systems. Whilst [3H]5-HT release from MRR neurons was [Ca2+]o-dependent and sensitive to TTX, CNQX and DL-AP-5, release from hippocampal terminals was not affected by the latter drugs. Hippocampal [3H]5-HT released by electrical but not OS was subject to modulation by 5- HT1B/D receptors agonist sumatriptan (1 μM), whereas the selective 5-HT1A agonist buspirone (0.1 μM) was without effect. [3H]5-HT released by electrical and optical stimulation was decreased in mice genetically deficient in P2rx7s, and after perfusion with selective P2rx7 antagonists, JNJ-47965567 (0.1 μM), and AZ-10606120 (0.1 μM). Optical and electrical stimulation elevated the extracellular level of ATP. Our results demonstrate for the first time the modulation of 5-HT release from hippocampal MRR terminals by the endogenous activation of P2rx7s. P2rx7 mediated modulation of 5-HT release could contribute to various physiological and pathophysiological phenomena, related to hippocampal serotonergic transmission.
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Affiliation(s)
- Flóra Gölöncsér
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.,János Szentágothai School of Neurosciences, Semmelweis University School of Ph.D. Studies, Budapest, Hungary
| | - Mária Baranyi
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Diána Balázsfi
- János Szentágothai School of Neurosciences, Semmelweis University School of Ph.D. Studies, Budapest, Hungary.,Laboratory of Stress and Behavior Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Kornél Demeter
- Unit of Behavioral Studies, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - József Haller
- Laboratory of Stress and Behavior Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.,Unit of Behavioral Studies, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Tamás F F Freund
- Laboratory of Cerebral Cortex, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Dóra Zelena
- Laboratory of Stress and Behavior Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Beáta Sperlágh
- Laboratory of Molecular Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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12
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Jean A, Laurent L, Delaunay S, Doly S, Dusticier N, Linden D, Neve R, Maroteaux L, Nieoullon A, Compan V. Adaptive Control of Dorsal Raphe by 5-HT4 in the Prefrontal Cortex Prevents Persistent Hypophagia following Stress. Cell Rep 2017; 21:901-909. [DOI: 10.1016/j.celrep.2017.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/13/2017] [Accepted: 09/30/2017] [Indexed: 12/18/2022] Open
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13
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Ludwig M, Apps D, Menzies J, Patel JC, Rice ME. Dendritic Release of Neurotransmitters. Compr Physiol 2016; 7:235-252. [PMID: 28135005 DOI: 10.1002/cphy.c160007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Release of neuroactive substances by exocytosis from dendrites is surprisingly widespread and is not confined to a particular class of transmitters: it occurs in multiple brain regions, and includes a range of neuropeptides, classical neurotransmitters, and signaling molecules, such as nitric oxide, carbon monoxide, ATP, and arachidonic acid. This review is focused on hypothalamic neuroendocrine cells that release vasopressin and oxytocin and midbrain neurons that release dopamine. For these two model systems, the stimuli, mechanisms, and physiological functions of dendritic release have been explored in greater detail than is yet available for other neurons and neuroactive substances. © 2017 American Physiological Society. Compr Physiol 7:235-252, 2017.
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Affiliation(s)
- Mike Ludwig
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - David Apps
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - John Menzies
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Jyoti C Patel
- Department of Neurosurgery, New York University School of Medicine, New York, USA
| | - Margaret E Rice
- Department of Neurosurgery, New York University School of Medicine, New York, USA.,Department of Neuroscience and Physiology, New York University School of Medicine, New York, USA
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14
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Cui SY, Li SJ, Cui XY, Zhang XQ, Yu B, Huang YL, Cao Q, Xu YP, Yang G, Ding H, Song JZ, Ye H, Sheng ZF, Wang ZJ, Zhang YH. Ca(2+) in the dorsal raphe nucleus promotes wakefulness via endogenous sleep-wake regulating pathway in the rats. Mol Brain 2016; 9:71. [PMID: 27456222 PMCID: PMC4960696 DOI: 10.1186/s13041-016-0252-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/19/2016] [Indexed: 01/09/2023] Open
Abstract
Serotonergic neurons in the dorsal raphe nucleus (DRN) are involved in the control of sleep-wake states. Our previous studies have indicated that calcium (Ca(2+)) modulation in the DRN plays an important role in rapid-eye-movement sleep (REMS) and non-REMS (NREMS) regulation during pentobarbital hypnosis. The present study investigated the effects of Ca(2+) in the DRN on sleep-wake regulation and the related neuronal mechanism in freely moving rats. Our results showed that microinjection of CaCl2 (25 or 50 nmol) in the DRN promoted wakefulness and suppressed NREMS including slow wave sleep and REMS in freely moving rats. Application of CaCl2 (25 or 50 nmol) in the DRN significantly increased serotonin in the DRN and hypothalamus, and noradrenaline in the locus coeruleus and hypothalamus. Immunohistochemistry study indicated that application of CaCl2 (25 or 50 nmol) in the DRN significantly increased c-Fos expression ratio in wake-promoting neurons including serotonergic neurons in the DRN, noradrenergic neurons in the locus coeruleus, and orxinergic neurons in the perifornical nucleus, but decreased c-Fos expression ratio of GABAergic sleep-promoting neurons in the ventrolateral preoptic nucleus. These results suggest that Ca(2+) in the DRN exert arousal effects via up-regulating serotonergic functions in the endogenous sleep-wake regulating pathways.
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Affiliation(s)
- Su-Ying Cui
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Sheng-Jie Li
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Xiang-Yu Cui
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Xue-Qiong Zhang
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Bin Yu
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Yuan-Li Huang
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Qing Cao
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Ya-Ping Xu
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Guang Yang
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Hui Ding
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Jin-Zhi Song
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Hui Ye
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Zhao-Fu Sheng
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Zi-Jun Wang
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
| | - Yong-He Zhang
- Department of pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing, 100191 China
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15
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Mlinar B, Montalbano A, Baccini G, Tatini F, Berlinguer Palmini R, Corradetti R. Nonexocytotic serotonin release tonically suppresses serotonergic neuron activity. ACTA ACUST UNITED AC 2016; 145:225-51. [PMID: 25712017 PMCID: PMC4338157 DOI: 10.1085/jgp.201411330] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The firing activity of serotonergic neurons in raphe nuclei is regulated by negative feedback exerted by extracellular serotonin (5-HT)o acting through somatodendritic 5-HT1A autoreceptors. The steady-state [5-HT]o, sensed by 5-HT1A autoreceptors, is determined by the balance between the rates of 5-HT release and reuptake. Although it is well established that reuptake of 5-HTo is mediated by 5-HT transporters (SERT), the release mechanism has remained unclear. It is also unclear how selective 5-HT reuptake inhibitor (SSRI) antidepressants increase the [5-HT]o in raphe nuclei and suppress serotonergic neuron activity, thereby potentially diminishing their own therapeutic effect. Using an electrophysiological approach in a slice preparation, we show that, in the dorsal raphe nucleus (DRN), continuous nonexocytotic 5-HT release is responsible for suppression of phenylephrine-facilitated serotonergic neuron firing under basal conditions as well as for autoinhibition induced by SSRI application. By using 5-HT1A autoreceptor-activated G protein-gated inwardly rectifying potassium channels of patched serotonergic neurons as 5-HTo sensors, we show substantial nonexocytotic 5-HT release under conditions of abolished firing activity, Ca(2+) influx, vesicular monoamine transporter 2-mediated vesicular accumulation of 5-HT, and SERT-mediated 5-HT transport. Our results reveal a cytosolic origin of 5-HTo in the DRN and suggest that 5-HTo may be supplied by simple diffusion across the plasma membrane, primarily from the dense network of neurites of serotonergic neurons surrounding the cell bodies. These findings indicate that the serotonergic system does not function as a sum of independently acting neurons but as a highly interdependent neuronal network, characterized by a shared neurotransmitter pool and the regulation of firing activity by an interneuronal, yet activity-independent, nonexocytotic mechanism.
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Affiliation(s)
- Boris Mlinar
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Alberto Montalbano
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Gilda Baccini
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Francesca Tatini
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Rolando Berlinguer Palmini
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
| | - Renato Corradetti
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, 50121 Florence, Italy
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16
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17
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De-Miguel FF, Leon-Pinzon C, Noguez P, Mendez B. Serotonin release from the neuronal cell body and its long-lasting effects on the nervous system. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0196. [PMID: 26009775 PMCID: PMC4455765 DOI: 10.1098/rstb.2014.0196] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Serotonin, a modulator of multiple functions in the nervous system, is released predominantly extrasynaptically from neuronal cell bodies, axons and dendrites. This paper describes how serotonin is released from cell bodies of Retzius neurons in the central nervous system (CNS) of the leech, and how it affects neighbouring glia and neurons. The large Retzius neurons contain serotonin packed in electrodense vesicles. Electrical stimulation with 10 impulses at 1 Hz fails to evoke exocytosis from the cell body, but the same number of impulses at 20 Hz promotes exocytosis via a multistep process. Calcium entry into the neuron triggers calcium-induced calcium release, which activates the transport of vesicle clusters to the plasma membrane. Exocytosis occurs there for several minutes. Serotonin that has been released activates autoreceptors that induce an inositol trisphosphate-dependent calcium increase, which produces further exocytosis. This positive feedback loop subsides when the last vesicles in the cluster fuse and calcium returns to basal levels. Serotonin released from the cell body is taken up by glia and released elsewhere in the CNS. Synchronous bursts of neuronal electrical activity appear minutes later and continue for hours. In this way, a brief train of impulses is translated into a long-term modulation in the nervous system.
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Affiliation(s)
- Francisco F De-Miguel
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Circuito Exterior SN, Ciudad Universitaria, Distrito Federal, Mexico
| | - Carolina Leon-Pinzon
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Circuito Exterior SN, Ciudad Universitaria, Distrito Federal, Mexico
| | - Paula Noguez
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Circuito Exterior SN, Ciudad Universitaria, Distrito Federal, Mexico
| | - Bruno Mendez
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México, Circuito Exterior SN, Ciudad Universitaria, Distrito Federal, Mexico
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18
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Rahmani B, Ghasemi R, Dargahi L, Ahmadiani A, Haeri A. Neurosteroids; potential underpinning roles in maintaining homeostasis. Gen Comp Endocrinol 2016; 225:242-250. [PMID: 26432100 DOI: 10.1016/j.ygcen.2015.09.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/14/2015] [Accepted: 09/28/2015] [Indexed: 12/31/2022]
Abstract
The neuroactive steroids which are synthesized in the brain and nervous system are known as "Neurosteroids". These steroids have crucial functions such as contributing to the myelination and organization of the brain connectivity. Under the stressful circumstances, the concentrations of neurosteroid products such as allopregnanolone (ALLO) and allotetrahydrodeoxycorticosterone (THDOC) alter. It has been suggested that these stress-derived neurosteroids modulate the physiological response to stress. Moreover, it has been demonstrated that the hypothalamic-pituitary-adrenal (HPA) axis mediates the physiological adaptation following stress in order to maintain homeostasis. Although several regulatory pathways have been introduced, the exact role of neurosteroids in controlling HPA axis is not clear to date. In this review, we intend to discern specific pathways associated with regulation of HPA axis in which neuroactive steroids have the main role. In this respect, we propose pathways that may be initiated after neurosteroidogenesis in different brain subregions following acute stress which are potentially capable of activating or inhibiting the HPA axis.
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Affiliation(s)
- Behrouz Rahmani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Rasoul Ghasemi
- Department of Physiology and Neurophysiology Research Center, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Leila Dargahi
- NeuroBiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abolhassan Ahmadiani
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Ali Haeri
- Department of Pharmacology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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19
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Courtney NA, Ford CP. Mechanisms of 5-HT1A receptor-mediated transmission in dorsal raphe serotonin neurons. J Physiol 2015; 594:953-65. [PMID: 26634643 DOI: 10.1113/jp271716] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/30/2015] [Indexed: 02/01/2023] Open
Abstract
KEY POINTS In the dorsal raphe nucleus, it is known that serotonin release activates metabotropic 5-HT1A autoreceptors located on serotonin neurons that leads to an inhibition of firing through the activation of G-protein-coupled inwardly rectifying potassium channels. We found that in mouse brain slices evoked serotonin release produced a 5-HT1A receptor-mediated inhibitory postsynaptic current (IPSC) that resulted in only a transient pause in firing. While spillover activation of receptors contributed to evoked IPSCs, serotonin reuptake transporters prevented pooling of serotonin in the extrasynaptic space from activating 5-HT1A -IPSCs. As a result, the decay of 5-HT1A -IPSCs was independent of the intensity of stimulation or the probability of transmitter release. These results indicate that evoked serotonin transmission in the dorsal raphe nucleus mediated by metabotropic 5-HT1A autoreceptors may occur via point-to-point synapses rather than by paracrine mechanisms. ABSTRACT In the dorsal raphe nucleus (DRN), feedback activation by Gαi/o -coupled 5-HT1A autoreceptors reduces the excitability of serotoninergic neurons, which decreases serotonin release both locally within the DRN and in projection regions. Serotonin transmission within the DRN is thought to occur via transmitter spillover and paracrine activation of extrasynaptic receptors. Here, we tested the volume transmission hypothesis in mouse DRN brain slices by recording 5-HT1A receptor-mediated inhibitory postsynaptic currents (5-HT1A -IPSCs) generated by the activation of G-protein-coupled inwardly rectifying potassium channels (GIRKs). We found that in the DRN of ePET1-EYFP mice, which selectively express enhanced yellow fluorescent protein in serontonergic neurons, the local release of serotonin generated 5-HT1A -IPSCs in serotonin neurons that rose and fell within a second. The transient activation of 5-HT1A autoreceptors resulted in brief pauses in neuron firing that did not alter the overall firing rate. The duration of 5-HT1A -IPSCs was primarily shaped by receptor deactivation due to clearance via serotonin reuptake transporters. Slowing diffusion with dextran prolonged the rise and reduced the amplitude the IPSCs and the effects were potentiated when uptake was inhibited. By examining the decay kinetics of IPSCs, we found that while spillover may allow for the activation of extrasynaptic receptors, efficient uptake by serotonin reuptake transporters (SERTs) prevented the pooling of serotonin from prolonging the duration of transmission when multiple inputs were active. Together the results suggest that the activation of 5-HT1A receptors in the DRN results from the local release of serotonin rather than the extended diffusion throughout the extracellular space.
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Affiliation(s)
- Nicholas A Courtney
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH, 44106-4970, USA
| | - Christopher P Ford
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH, 44106-4970, USA.,Department of Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Ave, Cleveland, OH, 44106-4970, USA
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20
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Cui SY, Li SJ, Cui XY, Zhang XQ, Yu B, Sheng ZF, Huang YL, Cao Q, Xu YP, Lin ZG, Yang G, Song JZ, Ding H, Wang ZJ, Zhang YH. Phosphorylation of CaMKII in the rat dorsal raphe nucleus plays an important role in sleep-wake regulation. J Neurochem 2015; 136:609-19. [PMID: 26558357 DOI: 10.1111/jnc.13431] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 10/28/2015] [Accepted: 11/02/2015] [Indexed: 12/19/2022]
Abstract
The Ca(2+) modulation in the dorsal raphe nucleus (DRN) plays an important role in sleep-wake regulation. Calmodulin-dependent kinase II (CaMKII) is an important signal-transducing molecule that is activated by Ca(2+) . This study investigated the effects of intracellular Ca(2+) /CaMKII signaling in the DRN on sleep-wake states in rats. Maximum and minimum CaMKII phosphorylation was detected at Zeitgeber time 21 (ZT 21; wakefulness state) and ZT 3 (sleep state), respectively, across the light-dark rhythm in the DRN in rats. Six-hour sleep deprivation significantly reduced CaMKII phosphorylation in the DRN. Microinjection of the CAMKII activation inhibitor KN-93 (5 or 10 nmol) into the DRN suppressed wakefulness and enhanced rapid-eye-movement sleep (REMS) and non-REM sleep (NREMS). Application of a high dose of KN-93 (10 nmol) increased slow-wave sleep (SWS) time, SWS bouts, the mean duration of SWS, the percentage of SWS relative to total sleep, and delta power density during NREMS. Microinjection of CaCl2 (50 nmol) in the DRN increased CaMKII phosphorylation and decreased NREMS, SWS, and REMS. KN-93 abolished the inhibitory effects of CaCl2 on NREMS, SWS, and REMS. These data indicate a novel wake-promoting and sleep-suppressing role for the Ca(2+) /CaMKII signaling pathway in DRN neurons. We propose that the intracellular Ca(2+) /CaMKII signaling in the dorsal raphe nucleus (DRN) plays wake-promoting and sleep-suppressing role in rats. Intra-DRN application of KN-93 (CaMKII activation inhibitor) suppressed wakefulness and enhanced rapid-eye-movement sleep (REMS) and non-REMS (NREMS). Intra-DRN application of CaCl2 attenuated REMS and NREMS. We think these findings should provide a novel cellular and molecular mechanism of sleep-wake regulation.
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Affiliation(s)
- Su-Ying Cui
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Sheng-Jie Li
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Xiang-Yu Cui
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Xue-Qiong Zhang
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Bin Yu
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Zhao-Fu Sheng
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Yuan-Li Huang
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Qing Cao
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Ya-Ping Xu
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Zhi-Ge Lin
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Guang Yang
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Jin-Zhi Song
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Hui Ding
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Zi-Jun Wang
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
| | - Yong-He Zhang
- Department of pharmacology, Peking University, School of Basic Medical Science, Beijing, China
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21
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Antidepressant-like effect of bright light is potentiated by l-serine administration in a mouse model of seasonal affective disorder. Brain Res Bull 2015; 118:25-33. [DOI: 10.1016/j.brainresbull.2015.08.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 08/28/2015] [Accepted: 08/29/2015] [Indexed: 12/11/2022]
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22
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Andrade R, Huereca D, Lyons JG, Andrade EM, McGregor KM. 5-HT1A Receptor-Mediated Autoinhibition and the Control of Serotonergic Cell Firing. ACS Chem Neurosci 2015; 6:1110-5. [PMID: 25913021 DOI: 10.1021/acschemneuro.5b00034] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The idea that serotonergic synaptic transmission plays an essential role in the control of mood and the pharmacotherapy of anxiety and depression is one of the cornerstones of modern biological psychiatry. As a result, there is intense interest in understanding the mechanisms controlling the activity of serotonin-synthesizing (serotonergic) neurons. One of the oldest and most durable ideas emerging from this work is that serotonergic neurons are capable of autonomously regulating their own basal firing rate. Serotonergic neurons express on their surface 5-HT1A receptors (autoreceptors) that, when activated, induce the opening of potassium channels that hyperpolarize and thereby inhibit cell firing. Activity-dependent release of serotonin within serotonergic nuclei is thought to activate these autoreceptors, thus completing an autoinhibitory feedback loop. This concept, which was originally proposed in the 1970s, has proven to be enormously fruitful and has guided the interpretation of a broad range of clinical and preclinical work. Yet, remarkably, electrophysiological studies seeking to directly demonstrate this phenomenon, especially in in vitro brain slices, have produced mixed results. Here, we critically review this work with a focus on electrophysiological studies, which directly assess neuronal activity. We also highlight recent work suggesting that 5-HT1A receptor-mediated autoinhibition may play other roles in the control of firing besides acting as a feedback regulator for the pacemaker-like firing rate of serotonergic neurons.
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Affiliation(s)
- Rodrigo Andrade
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Daniel Huereca
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Joseph G. Lyons
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Elaine M. Andrade
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
| | - Kelly M. McGregor
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan 48201, United States
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Leon-Pinzon C, Cercós MG, Noguez P, Trueta C, De-Miguel FF. Exocytosis of serotonin from the neuronal soma is sustained by a serotonin and calcium-dependent feedback loop. Front Cell Neurosci 2014; 8:169. [PMID: 25018697 PMCID: PMC4072984 DOI: 10.3389/fncel.2014.00169] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/02/2014] [Indexed: 11/25/2022] Open
Abstract
The soma of many neurons releases large amounts of transmitter molecules through an exocytosis process that continues for hundreds of seconds after the end of the triggering stimulus. Transmitters released in this way modulate the activity of neurons, glia and blood vessels over vast volumes of the nervous system. Here we studied how somatic exocytosis is maintained for such long periods in the absence of electrical stimulation and transmembrane Ca(2+) entry. Somatic exocytosis of serotonin from dense core vesicles could be triggered by a train of 10 action potentials at 20 Hz in Retzius neurons of the leech. However, the same number of action potentials produced at 1 Hz failed to evoke any exocytosis. The 20-Hz train evoked exocytosis through a sequence of intracellular Ca(2+) transients, with each transient having a different origin, timing and intracellular distribution. Upon electrical stimulation, transmembrane Ca(2+) entry through L-type channels activated Ca(2+)-induced Ca(2+) release. A resulting fast Ca(2+) transient evoked an early exocytosis of serotonin from sparse vesicles resting close to the plasma membrane. This Ca(2+) transient also triggered the transport of distant clusters of vesicles toward the plasma membrane. Upon exocytosis, the released serotonin activated autoreceptors coupled to phospholipase C, which in turn produced an intracellular Ca(2+) increase in the submembrane shell. This localized Ca(2+) increase evoked new exocytosis as the vesicles in the clusters arrived gradually at the plasma membrane. In this way, the extracellular serotonin elevated the intracellular Ca(2+) and this Ca(2+) evoked more exocytosis. The resulting positive feedback loop maintained exocytosis for the following hundreds of seconds until the last vesicles in the clusters fused. Since somatic exocytosis displays similar kinetics in neurons releasing different types of transmitters, the data presented here contributes to understand the cellular basis of paracrine neurotransmission.
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Affiliation(s)
- Carolina Leon-Pinzon
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de MéxicoMéxico D.F., México
| | - Montserrat G. Cercós
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatriìa Ramoìn de la Fuente MunñizMéxico D.F., México
| | - Paula Noguez
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de MéxicoMéxico D.F., México
| | - Citlali Trueta
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatriìa Ramoìn de la Fuente MunñizMéxico D.F., México
| | - Francisco F. De-Miguel
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de MéxicoMéxico D.F., México
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Son SJ, Filosa JA, Potapenko ES, Biancardi VC, Zheng H, Patel KP, Tobin VA, Ludwig M, Stern JE. Dendritic peptide release mediates interpopulation crosstalk between neurosecretory and preautonomic networks. Neuron 2013; 78:1036-49. [PMID: 23791197 DOI: 10.1016/j.neuron.2013.04.025] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2013] [Indexed: 01/08/2023]
Abstract
Although communication between neurons is considered a function of the synapse, neurons also release neurotransmitter from their dendrites. We found that dendritic transmitter release coordinates activity across distinct neuronal populations to generate integrative homeostatic responses. We show that activity-dependent vasopressin release from hypothalamic neuroendocrine neurons in the paraventricular nucleus stimulates neighboring (~100 μm soma-to-soma) presympathetic neurons, resulting in a sympathoexcitatory population response. This interpopulation crosstalk was engaged by an NMDA-mediated increase in dendritic Ca(2+), influenced by vasopressin's ability to diffuse in the extracellular space, and involved activation of CAN channels at the target neurons. Furthermore, we demonstrate that this interpopulation crosstalk plays a pivotal role in the generation of a systemic, polymodal neurohumoral response to a hyperosmotic challenge. Because dendritic release is emerging as a widespread process, our results suggest that a similar mechanism could mediate interpopulation crosstalk in other brain systems, particularly those involved in generating complex behaviors.
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Affiliation(s)
- Sook Jin Son
- Department of Physiology, Georgia Regents University, Augusta, GA 30912, USA
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25
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Abstract
Numerous studies link decreased serotonin metabolites with increased impulsive and aggressive traits. However, although pharmacological depletion of serotonin is associated with increased aggression, interventions aimed at directly decreasing serotonin neuron activity have supported the opposite association. Furthermore, it is not clear if altered serotonin activity during development may contribute to some of the observed associations. Here, we used two pharmacogenetic approaches in transgenic mice to selectively and reversibly reduce the firing of serotonin neurons in behaving animals. Conditional overexpression of the serotonin 1A receptor (Htr1a) in serotonin neurons showed that a chronic reduction in serotonin neuron firing was associated with heightened aggression. Overexpression of Htr1a in adulthood, but not during development, was sufficient to increase aggression. Rapid suppression of serotonin neuron firing by agonist treatment of mice expressing Htr1a exclusively in serotonin neurons also led to increased aggression. These data confirm a role of serotonin activity in setting thresholds for aggressive behavior and support a direct association between low levels of serotonin homeostasis and increased aggression.
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Action potential-independent and pharmacologically unique vesicular serotonin release from dendrites. J Neurosci 2013; 32:15737-46. [PMID: 23136413 DOI: 10.1523/jneurosci.0020-12.2012] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Serotonin released within the dorsal raphe nucleus (DR) induces feedback inhibition of serotonin neuron activity and consequently regulates mood-controlling serotonin release throughout the forebrain. Serotonin packaged in vesicles is released in response to action potentials by the serotonin neuron soma and terminals, but the potential for release by dendrites is unknown. Here, three-photon microscopy imaging of endogenous serotonin in living rat brain slice, immunofluorescence, and immunogold electron microscopy detection of VMAT2 (vesicular monoamine transporter 2) establish the presence of vesicular serotonin within DR dendrites. Furthermore, activation of glutamate receptors is shown to induce vesicular serotonin release from dendrites. However, unlike release from the soma and terminals, dendritic serotonin release is independent of action potentials, relies on L-type Ca(2+) channels, is induced preferentially by NMDA, and displays distinct sensitivity to the selective serotonin reuptake inhibitor (SSRI) antidepressant fluoxetine. The unique control of dendritic serotonin release has important implications for DR physiology and the antidepressant action of SSRIs, dihydropyridines, and NMDA receptor antagonists.
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Altieri SC, Garcia-Garcia AL, Leonardo ED, Andrews AM. Rethinking 5-HT1A receptors: emerging modes of inhibitory feedback of relevance to emotion-related behavior. ACS Chem Neurosci 2013; 4:72-83. [PMID: 23336046 DOI: 10.1021/cn3002174] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 12/20/2012] [Indexed: 11/27/2022] Open
Abstract
The complexities of the involvement of the serotonin transmitter system in numerous biological processes and psychiatric disorders is, to a substantial degree, attributable to the large number of serotonin receptor families and subtypes that have been identified and characterized for over four decades. Of these, the 5-HT(1A) receptor subtype, which was the first to be cloned and characterized, has received considerable attention based on its purported role in the etiology and treatment of mood and anxiety disorders. 5-HT(1A) receptors function both at presynaptic (autoreceptor) and postsynaptic (heteroreceptor) sites. Recent research has implicated distinct roles for these two populations of receptors in mediating emotion-related behavior. New concepts as to how 5-HT(1A) receptors function to control serotonergic tone throughout life were highlights of the proceedings of the 2012 Serotonin Club Meeting in Montpellier, France. Here, we review recent findings and current perspectives on functional aspects of 5-HT(1A) auto- and heteroreceptors with particular regard to their involvement in altered anxiety and mood states.
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Affiliation(s)
| | - Alvaro L. Garcia-Garcia
- Department of Psychiatry, Division of Integrative Neuroscience, Columbia University and New York State Psychiatric Institute, New York, New York 10032, United States
| | - E. David Leonardo
- Department of Psychiatry, Division of Integrative Neuroscience, Columbia University and New York State Psychiatric Institute, New York, New York 10032, United States
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28
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Pacemaker rate and depolarization block in nigral dopamine neurons: a somatic sodium channel balancing act. J Neurosci 2013; 32:14519-31. [PMID: 23077037 DOI: 10.1523/jneurosci.1251-12.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Midbrain dopamine (DA) neurons are slow intrinsic pacemakers that undergo depolarization (DP) block upon moderate stimulation. Understanding DP block is important because it has been correlated with the clinical efficacy of chronic antipsychotic drug treatment. Here we describe how voltage-gated sodium (Na(V)) channels regulate DP block and pacemaker activity in DA neurons of the substantia nigra using rat brain slices. The distribution, density, and gating of Na(V) currents were manipulated by blocking native channels with tetrodotoxin and by creating virtual channels and anti-channels with dynamic clamp. Although action potentials initiate in the axon initial segment and Na(V) channels are distributed in multiple dendrites, selective reduction of Na(V) channel activity in the soma was sufficient to decrease pacemaker frequency and increase susceptibility to DP block. Conversely, increasing somatic Na(V) current density raised pacemaker frequency and lowered susceptibility to DP block. Finally, when Na(V) currents were restricted to the soma, pacemaker activity occurred at abnormally high rates due to excessive local subthreshold Na(V) current. Together with computational simulations, these data show that both the slow pacemaker rate and the sensitivity to DP block that characterizes DA neurons result from the low density of somatic Na(V) channels. More generally, we conclude that the somatodendritic distribution of Na(V) channels is a major determinant of repetitive spiking frequency.
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29
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Trueta C, De-Miguel FF. Extrasynaptic exocytosis and its mechanisms: a source of molecules mediating volume transmission in the nervous system. Front Physiol 2012; 3:319. [PMID: 22969726 PMCID: PMC3432928 DOI: 10.3389/fphys.2012.00319] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 07/21/2012] [Indexed: 11/14/2022] Open
Abstract
We review the evidence of exocytosis from extrasynaptic sites in the soma, dendrites, and axonal varicosities of central and peripheral neurons of vertebrates and invertebrates, with emphasis on somatic exocytosis, and how it contributes to signaling in the nervous system. The finding of secretory vesicles in extrasynaptic sites of neurons, the presence of signaling molecules (namely transmitters or peptides) in the extracellular space outside synaptic clefts, and the mismatch between exocytosis sites and the location of receptors for these molecules in neurons and glial cells, have long suggested that in addition to synaptic communication, transmitters are released, and act extrasynaptically. The catalog of these molecules includes low molecular weight transmitters such as monoamines, acetylcholine, glutamate, gama-aminobutiric acid (GABA), adenosine-5-triphosphate (ATP), and a list of peptides including substance P, brain-derived neurotrophic factor (BDNF), and oxytocin. By comparing the mechanisms of extrasynaptic exocytosis of different signaling molecules by various neuron types we show that it is a widespread mechanism for communication in the nervous system that uses certain common mechanisms, which are different from those of synaptic exocytosis but similar to those of exocytosis from excitable endocrine cells. Somatic exocytosis has been measured directly in different neuron types. It starts after high-frequency electrical activity or long experimental depolarizations and may continue for several minutes after the end of stimulation. Activation of L-type calcium channels, calcium release from intracellular stores and vesicle transport towards the plasma membrane couple excitation and exocytosis from small clear or large dense core vesicles in release sites lacking postsynaptic counterparts. The presence of synaptic and extrasynaptic exocytosis endows individual neurons with a wide variety of time- and space-dependent communication possibilities. Extrasynaptic exocytosis may be the major source of signaling molecules producing volume transmission and by doing so may be part of a long duration signaling mode in the nervous system.
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Affiliation(s)
- Citlali Trueta
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz México, D.F., México
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30
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Ca2+ modulation in dorsal raphe plays an important role in NREM and REM sleep regulation during pentobarbital hypnosis. Brain Res 2011; 1403:12-8. [DOI: 10.1016/j.brainres.2011.05.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2011] [Revised: 05/02/2011] [Accepted: 05/27/2011] [Indexed: 11/23/2022]
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31
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Lin Z, Canales JJ, Björgvinsson T, Thomsen MM, Qu H, Liu QR, Torres GE, Caine SB. Monoamine transporters: vulnerable and vital doorkeepers. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:1-46. [PMID: 21199769 PMCID: PMC3321928 DOI: 10.1016/b978-0-12-385506-0.00001-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transporters of dopamine, serotonin, and norepinephrine have been empirically used as medication targets for several mental illnesses in the last decades. These protein-targeted medications are effective only for subpopulations of patients with transporter-related brain disorders. Since the cDNA clonings in early 1990s, molecular studies of these transporters have revealed a wealth of information about the transporters' structure-activity relationship (SAR), neuropharmacology, cell biology, biochemistry, pharmacogenetics, and the diseases related to the human genes encoding these transporters among related regulators. Such new information creates a unique opportunity to develop transporter-specific medications based on SAR, mRNA, DNA, and perhaps transporter trafficking regulation for a number of highly relevant diseases including substance abuse, depression, schizophrenia, and Parkinson's disease.
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Affiliation(s)
- Zhicheng Lin
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Juan J. Canales
- Department of Psychology, Behavioural Neuroscience, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - Thröstur Björgvinsson
- Behavioral Health Partial Hospital and Psychology Internship Programs, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA
| | - Morgane M. Thomsen
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
| | - Hong Qu
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University. Beijing, 100871 China
| | - Qing-Rong Liu
- Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, NIH/DHHS, 251 Bayview Boulevard, Baltimore, MD 21224, USA
| | - Gonzalo E. Torres
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - S. Barak Caine
- Department of Psychiatry, Harvard Medical School and Division of Alcohol and Drug Abuse, McLean Hospital, Belmont, MA 02478, USA
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32
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Activity-dependent vesicular monoamine transporter-mediated depletion of the nucleus supports somatic release by serotonin neurons. J Neurosci 2010; 29:15878-87. [PMID: 20016104 DOI: 10.1523/jneurosci.4210-09.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Packaging by the vesicular monoamine transporter (VMAT) is essential for mood-controlling serotonin transmission but has not been assayed during activity. Here, two-photon imaging of the fluorescent serotonin analog 5,7-dihydroxytryptamine and three-photon imaging of endogenous serotonin were used to study vesicular packaging as it supports release from the soma of serotonin neurons. Glutamate receptor activation in dorsal raphe brain slice evoked somatic release that was mediated solely by vesicle exocytosis. This release was accompanied by VMAT-mediated serotonin depletion from the nucleus, a large compartment free of monoaminergic degradation pathways that has not been implicated in neurotransmission previously. Finally, while some monoamine packaged at rest was held in reserve, monoamine packaged during stimulation was released completely. Hence, somatic vesicles loaded by VMAT during activity rapidly undergo exocytosis. In the absence of active zones and with limited neurotransmitter reuptake, somatic release by serotonin neurons is supported by recruitment from a large pool of extravesicular serotonin in the nucleus and cytoplasm, and preferential release of the newly packaged transmitter.
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33
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Activity-dependent regulation of synapses by retrograde messengers. Neuron 2009; 63:154-70. [PMID: 19640475 DOI: 10.1016/j.neuron.2009.06.021] [Citation(s) in RCA: 205] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/19/2009] [Accepted: 06/26/2009] [Indexed: 01/01/2023]
Abstract
Throughout the brain, postsynaptic neurons release substances from their cell bodies and dendrites that regulate the strength of the synapses they receive. Diverse chemical messengers have been implicated in retrograde signaling from postsynaptic neurons to presynaptic boutons. Here, we provide an overview of the signaling systems that lead to rapid changes in synaptic strength. We consider the capabilities, specializations, and physiological roles of each type of signaling system.
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34
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Ca2+ entry through a non-selective cation channel in Aplysia bag cell neurons. Neuroscience 2009; 162:1023-38. [DOI: 10.1016/j.neuroscience.2009.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 05/03/2009] [Accepted: 05/05/2009] [Indexed: 11/20/2022]
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35
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Fonseca FV, Mecawi AS, Araujo IG, Almeida-Pereira G, Magalhães-Nunes AP, Badauê-Passos D, Reis LC. Role of the 5-HT1A somatodendritic autoreceptor in the dorsal raphe nucleus on salt satiety signaling in rats. Exp Neurol 2009; 217:353-60. [DOI: 10.1016/j.expneurol.2009.03.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 03/13/2009] [Accepted: 03/14/2009] [Indexed: 02/04/2023]
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36
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Kaushalya SK, Desai R, Arumugam S, Ghosh H, Balaji J, Maiti S. Three-photon microscopy shows that somatic release can be a quantitatively significant component of serotonergic neurotransmission in the mammalian brain. J Neurosci Res 2009; 86:3469-80. [PMID: 18709651 DOI: 10.1002/jnr.21794] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent experiments on monoaminergic neurons have shown that neurotransmission can originate from somatic release. However, little is known about the quantity of monoamine available to be released through this extrasynaptic pathway or about the intracellular dynamics that mediate such release. Using three-photon microscopy, we directly imaged serotonin autofluorescence and investigated the total serotonin content, release competence, and release kinetics of somatic serotonergic vesicles in the dorsal raphe neurons of the rat. We found that the somata of primary cultured neurons contain a large number of serotonin-filled vesicles arranged in a perinuclear fashion. A similar distribution is also observed in fresh tissue slice preparations obtained from the rat dorsal raphe. We estimate that the soma of a cultured neuron on an average contains about 9 fmoles of serotonin in about 450 vesicles (or vesicle clusters) of < or =370 nm average diameter. A substantial fraction (>30%) of this serotonin is released with a time scale of several minutes by K(+)-induced depolarization or by para-chloroamphetamine treatment. The amount of releasable serotonin stored in the somatic vesicles is comparable to the total serotonin content of all the synaptic vesicles in a raphe neuron, indicating that somatic release can potentially play a major role in serotonergic neurotransmission in the mammalian brain.
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Affiliation(s)
- S K Kaushalya
- Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India
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37
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Evidence for serotonin synthesis-dependent regulation of in vitro neuronal firing rates in the midbrain raphe complex. Eur J Pharmacol 2008; 590:136-49. [DOI: 10.1016/j.ejphar.2008.06.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 05/16/2008] [Accepted: 06/02/2008] [Indexed: 11/22/2022]
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38
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Abstract
Information flow through neurones was historically considered to be linear, with dendrites receiving information from incoming synaptic terminals, the soma processing the information and the axon carrying it to the terminal that synapses upon another cell or end organ. However, recent studies have shown that dendrites can release transmitters themselves, and thereby communicate with neighbouring structures, whether these are adjacent neurones or incoming synapses. Due to their anatomical features, the magnocellular vasopressin and oxytocin containing neurones of the hypothalamic supraoptic and paraventricular nuclei and the dopamine neurones of the substantia nigra have revealed important aspects of dendritic function including mechanisms of dendritic transmitter release.
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Affiliation(s)
- F Bergquist
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
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41
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Glitsch MD. Calcium influx through N-methyl-D-aspartate receptors triggers GABA release at interneuron-Purkinje cell synapse in rat cerebellum. Neuroscience 2007; 151:403-9. [PMID: 18055124 DOI: 10.1016/j.neuroscience.2007.10.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 10/23/2007] [Accepted: 11/01/2007] [Indexed: 11/17/2022]
Abstract
Ca(2+)-dependent neurotransmitter release was originally thought to occur only following activation of presynaptic voltage-gated calcium channels after a presynaptic action potential. Recent evidence suggests that not only opening of voltage-gated but also ligand-gated ion channels, such as neurotransmitter receptors, can trigger exocytosis, as well as Ca(2+) release from intracellular Ca(2+) stores. It was shown that activation of N-methyl-d-aspartate (NMDA) receptors on presynaptic interneurons led to increases in GABA release from these neurons onto postsynaptic Purkinje cells in rat cerebellum in the presence of tetrodotoxin (TTX), suggesting a presynaptic location for the underlying NMDA receptors. However, the mechanism for the NMDA-induced increase in GABA release remained unclear. The present study addresses the question whether Ca(2+) influx through presynaptic NMDA receptors alone is sufficient to trigger presynaptic GABA release at this synapse or whether activation of presynaptic NMDA receptors leads to opening of voltage-gated Ca(2+) channels, thereby increasing exocytosis. The results suggest that the NMDA-induced increase in presynaptic GABA release neither requires activation of presynaptic voltage-gated Ca(2+) channels nor Ca(2+) release from presynaptic Ca(2+) stores. It is concluded that Ca(2+) influx through the NMDA receptor alone is sufficient to drive presynaptic GABA release at the rat interneuron-Purkinje cell synapse.
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Affiliation(s)
- M D Glitsch
- Department of Physiology, Anatomy and Genetics, Sherrington Building, Oxford University, Parks Road, Oxford OX1 3PT, UK.
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