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F Amil A, Rubio Ballester B, Maier M, F M J Verschure P. Chronic use of cannabis might impair sensory error processing in the cerebellum through endocannabinoid dysregulation. Addict Behav 2022; 131:107297. [PMID: 35417840 DOI: 10.1016/j.addbeh.2022.107297] [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] [Received: 12/02/2020] [Revised: 09/08/2021] [Accepted: 02/25/2022] [Indexed: 11/20/2022]
Abstract
Chronic use of cannabis leads to both motor deficits and the downregulation of CB1 receptors (CB1R) in the cerebellum. In turn, cerebellar damage is often related to impairments in motor learning and control. Further, a recent motor learning task that measures cerebellar-dependent adaptation has been shown to distinguish well between healthy subjects and chronic cannabis users. Thus, the deteriorating effects of chronic cannabis use in motor performance point to cerebellar adaptation as a key process to explain such deficits. We review the literature relating chronic cannabis use, the endocannabinoid system in the cerebellum, and different forms of cerebellar-dependent motor learning, to suggest that CB1R downregulation leads to a generalized underestimation and misprocessing of the sensory errors driving synaptic updates in the cerebellar cortex. Further, we test our hypothesis with a computational model performing a motor adaptation task and reproduce the behavioral effect of decreased implicit adaptation that appears to be a sign of chronic cannabis use. Finally, we discuss the potential of our hypothesis to explain similar phenomena related to motor impairments following chronic alcohol dependency.
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Affiliation(s)
- Adrián F Amil
- Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
| | | | - Martina Maier
- Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.
| | - Paul F M J Verschure
- Donders Center for Neuroscience (DCN) - Radboud University, Nijmegen, The Netherlands.
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2
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Lalo U, Koh W, Lee CJ, Pankratov Y. The tripartite glutamatergic synapse. Neuropharmacology 2021; 199:108758. [PMID: 34433089 DOI: 10.1016/j.neuropharm.2021.108758] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 07/25/2021] [Accepted: 08/20/2021] [Indexed: 12/31/2022]
Abstract
Astroglial cells were long considered as structural and metabolic supporting cells are which do not directly participate in information processing in the brain. Discoveries of responsiveness of astrocytes to synaptically-released glutamate and their capability to release agonists of glutamate receptors awakened extensive studies of glia-neuron communications and led to the revolutionary changes in our understanding of brain cellular networks. Nowadays, astrocytes are widely acknowledged as inseparable element of glutamatergic synapses and role for glutamatergic astrocyte-neuron interactions in the brain computation is emerging. Astroglial glutamate receptors, in particular of NMDA, mGluR3 and mGluR5 types, can activate a variety of molecular cascades leading astroglial-driven modulation of extracellular levels of glutamate and activity of neuronal glutamate receptors. Their preferential location to the astroglial perisynaptic processes facilitates interaction of astrocytes with individual excitatory synapses. Bi-directional glutamatergic communication between astrocytes and neurons underpins a complex, spatially-distributed modulation of synaptic signalling thus contributing to the enrichment of information processing by the neuronal networks. Still, further research is needed to bridge the substantial gaps in our understanding of mechanisms and physiological relevance of astrocyte-neuron glutamatergic interactions, in particular ability of astrocytes directly activate neuronal glutamate receptors by releasing glutamate and, arguably, d-Serine. An emerging roles for aberrant changes in glutamatergic astroglial signalling, both neuroprotective and pathogenic, in neurological and neurodegenerative diseases also require further investigation. This article is part of the special Issue on 'Glutamate Receptors - The Glutamatergic Synapse'.
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Affiliation(s)
- Ulyana Lalo
- School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, South Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, South Korea
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom.
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3
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Kula B, Chen T, Kukley M. Glutamatergic signaling between neurons and oligodendrocyte lineage cells: Is it synaptic or non‐synaptic? Glia 2019; 67:2071-2091. [DOI: 10.1002/glia.23617] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/12/2019] [Accepted: 03/18/2019] [Indexed: 12/18/2022]
Affiliation(s)
- Bartosz Kula
- Group of Neuron Glia InteractionUniversity of Tübingen Tübingen Germany
- Graduate Training Centre for NeuroscienceUniversity of Tübingen Tübingen Germany
| | - Ting‐Jiun Chen
- Center for Neuroscience ResearchChildren's Research Institute, Children's National Medical Center Washington District of Columbia
| | - Maria Kukley
- Group of Neuron Glia InteractionUniversity of Tübingen Tübingen Germany
- Research Institute for OphthalmologyUniversity Hospital Tübingen Tübingen Germany
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4
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Lalo U, Bogdanov A, Pankratov Y. Diversity of Astroglial Effects on Aging- and Experience-Related Cortical Metaplasticity. Front Mol Neurosci 2018; 11:239. [PMID: 30057525 PMCID: PMC6053488 DOI: 10.3389/fnmol.2018.00239] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/21/2018] [Indexed: 11/13/2022] Open
Abstract
Activity-dependent regulation of synaptic plasticity, or metaplasticity, plays a key role in the adaptation of neuronal networks to physiological and biochemical changes in aging brain. There is a growing evidence that experience-related alterations in the mechanisms of synaptic plasticity can underlie beneficial effects of physical exercise and caloric restriction (CR) on brain health and cognition. Astrocytes, which form neuro-vascular interface and can modulate synaptic plasticity by release of gliotransmitters, attract an increasing attention as important element of brain metaplasticity. We investigated the age- and experience-related alterations in astroglial calcium signaling and stimulus-dependence of long-term synaptic plasticity in the neocortex of mice exposed to the mild CR and environmental enrichment (EE) which included ad libitum physical exercise. We found out that astrocytic Ca2+-signaling underwent considerable age-related decline but EE and CR enhanced astroglial signaling, in particular mediated by noradrenaline (NA) and endocannabinoid receptors. The release of ATP and D-Serine from astrocytes followed the same trends of age-related declined and EE-induced increase. Our data also showed that astrocyte-derived ATP and D-Serine can have diverse effects on the threshold and magnitude of long-term changes in the strength of neocortical synapses; these effects were age-dependent. The CR- and EE-induced enhancement of astroglial Ca2+-signaling had more stronger effect on synaptic plasticity in the old (14–18 months) than in the young (2–5 months) wild-type (WT) mice. The effects of CR and EE on synaptic plasticity were significantly altered in both young and aged dnSNARE mice. Combined, our data suggest astrocyte-neuron interactions are important for dynamic regulation of cortical synaptic plasticity. This interaction can significantly decline with aging and thus contributes to the age-related cognitive impairment. On another hand, experience-related increase in the astroglial Ca2+-signaling can ameliorate the age-related decline.
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Affiliation(s)
- Ulyana Lalo
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Alexander Bogdanov
- Institute for Chemistry and Biology, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
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5
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Falgairolle M, Puhl JG, Pujala A, Liu W, O'Donovan MJ. Motoneurons regulate the central pattern generator during drug-induced locomotor-like activity in the neonatal mouse. eLife 2017; 6. [PMID: 28671548 PMCID: PMC5550280 DOI: 10.7554/elife.26622] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/30/2017] [Indexed: 12/17/2022] Open
Abstract
Motoneurons are traditionally viewed as the output of the spinal cord that do not influence locomotor rhythmogenesis. We assessed the role of motoneuron firing during ongoing locomotor-like activity in neonatal mice expressing archaerhopsin-3 (Arch), halorhodopsin (eNpHR), or channelrhodopsin-2 (ChR2) in Choline acetyltransferase neurons (ChAT+) or Arch in LIM-homeodomain transcription factor Isl1+ neurons. Illumination of the lumbar cord in mice expressing eNpHR or Arch in ChAT+ or Isl1+ neurons, depressed motoneuron discharge, transiently decreased the frequency, and perturbed the phasing of the locomotor-like rhythm. When the light was turned off motoneuron firing and locomotor frequency both transiently increased. These effects were not due to cholinergic neurotransmission, persisted during partial blockade of gap junctions and were mediated, in part, by AMPAergic transmission. In spinal cords expressing ChR2, illumination increased motoneuron discharge and transiently accelerated the rhythm. We conclude that motoneurons provide feedback to the central pattern generator (CPG) during drug-induced locomotor-like activity. DOI:http://dx.doi.org/10.7554/eLife.26622.001
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Affiliation(s)
- Melanie Falgairolle
- Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Joshua G Puhl
- Department of Entomology, University of Minnesota, Saint Paul, United States
| | - Avinash Pujala
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Wenfang Liu
- Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Michael J O'Donovan
- Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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6
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Lalo U, Pankratov Y. Exploring the Ca 2+-dependent synaptic dynamics in vibro-dissociated cells. Cell Calcium 2017; 64:91-101. [PMID: 28143648 DOI: 10.1016/j.ceca.2017.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/15/2017] [Accepted: 01/16/2017] [Indexed: 12/18/2022]
Abstract
Dynamic alteration of the synaptic strength is one of the most important processes occurring in the nervous system. Combination of electrophysiology, confocal imaging and molecular biology led to significant advances in this research field. Yet, a progress in this area, in particular in studies of changes in the quantal behavior of central synapses and impact of glial cells on individual synapses, is hampered by technical difficulties of resolving small quantal synaptic currents. In this paper we will show how the technique of non-enzymatic vibro-dissociation, which enables to isolate living neurons avoiding artifacts of cell culture and preserving functional synapse, can be used to obtain a valuable information on fine details and mechanisms of synaptic plasticity. In particular, we will describe our recent results on Ca2+-dependent modulation of the postsynaptic AMPA and NMDA receptors in the individual synaptic boutons.
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Affiliation(s)
- Ulyana Lalo
- The University of Warwick, School of Life Sciences, Coventry, UK
| | - Yuriy Pankratov
- The University of Warwick, School of Life Sciences, Coventry, UK; School of Life Sciences, Immanuel Kant Baltic Federal University, 2 Universitetskaya str., Kaliningrad, Russia.
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7
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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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8
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ATP from synaptic terminals and astrocytes regulates NMDA receptors and synaptic plasticity through PSD-95 multi-protein complex. Sci Rep 2016; 6:33609. [PMID: 27640997 PMCID: PMC5027525 DOI: 10.1038/srep33609] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 08/30/2016] [Indexed: 12/13/2022] Open
Abstract
Recent studies highlighted the importance of astrocyte-secreted molecules, such as ATP, for the slow modulation of synaptic transmission in central neurones. Biophysical mechanisms underlying the impact of gliotransmitters on the strength of individual synapse remain, however, unclear. Here we show that purinergic P2X receptors can bring significant contribution to the signalling in the individual synaptic boutons. ATP released from astrocytes facilitates a recruitment of P2X receptors into excitatory synapses by Ca2+-dependent mechanism. P2X receptors, co-localized with NMDA receptors in the excitatory synapses, can be activated by ATP co-released with glutamate from pre-synaptic terminals and by glia-derived ATP. An activation of P2X receptors in turn leads to down-regulation of postsynaptic NMDA receptors via Ca2+-dependent de-phosphorylation and interaction with PSD-95 multi-protein complex. Genetic deletion of the PSD-95 or P2X4 receptors obliterated ATP-mediated down-regulation of NMDA receptors. Impairment of purinergic modulation of NMDA receptors in the PSD-95 mutants dramatically decreased the threshold of LTP induction and increased the net magnitude of LTP. Our findings show that synergistic action of glia- and neurone-derived ATP can pre-modulate efficacy of excitatory synapses and thereby can have an important role in the glia-neuron communications and brain meta-plasticity.
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9
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Ludwig M, Stern J. Multiple signalling modalities mediated by dendritic exocytosis of oxytocin and vasopressin. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0182. [PMID: 26009761 DOI: 10.1098/rstb.2014.0182] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The mammalian hypothalamic magnocellular neurons of the supraoptic and paraventricular nuclei are among the best understood of all peptidergic neurons. Through their anatomical features, vasopressin- and oxytocin-containing neurons have revealed many important aspects of dendritic functions. Here, we review our understanding of the mechanisms of somato-dendritic peptide release, and the effects of autocrine, paracrine and hormone-like signalling on neuronal networks and behaviour.
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Affiliation(s)
- Mike Ludwig
- Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - Javier Stern
- Department of Physiology, Medical College of Georgia, Georgia Regents University, Augusta, GA, USA
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10
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Dubois CJ, Lachamp PM, Sun L, Mishina M, Liu SJ. Presynaptic GluN2D receptors detect glutamate spillover and regulate cerebellar GABA release. J Neurophysiol 2016; 115:271-85. [PMID: 26510761 PMCID: PMC4760459 DOI: 10.1152/jn.00687.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Accepted: 10/23/2015] [Indexed: 01/31/2023] Open
Abstract
Glutamate directly activates N-methyl-d-aspartate (NMDA) receptors on presynaptic inhibitory interneurons and enhances GABA release, altering the excitatory-inhibitory balance within a neuronal circuit. However, which class of NMDA receptors is involved in the detection of glutamate spillover is not known. GluN2D subunit-containing NMDA receptors are ideal candidates as they exhibit a high affinity for glutamate. We now show that cerebellar stellate cells express both GluN2B and GluN2D NMDA receptor subunits. Genetic deletion of GluN2D subunits prevented a physiologically relevant, stimulation-induced, lasting increase in GABA release from stellate cells [long-term potentiation of inhibitory transmission (I-LTP)]. NMDA receptors are tetramers composed of two GluN1 subunits associated to either two identical subunits (di-heteromeric receptors) or to two different subunits (tri-heteromeric receptors). To determine whether tri-heteromeric GluN2B/2D NMDA receptors mediate I-LTP, we tested the prediction that deletion of GluN2D converts tri-heteromeric GluN2B/2D to di-heteromeric GluN2B NMDA receptors. We find that prolonged stimulation rescued I-LTP in GluN2D knockout mice, and this was abolished by GluN2B receptor blockers that failed to prevent I-LTP in wild-type mice. Therefore, NMDA receptors that contain both GluN2D and GluN2B mediate the induction of I-LTP. Because these receptors are not present in the soma and dendrites, presynaptic tri-heteromeric GluN2B/2D NMDA receptors in inhibitory interneurons are likely to mediate the cross talk between excitatory and inhibitory transmission.
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Affiliation(s)
- Christophe J Dubois
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana
| | - Philippe M Lachamp
- Department of Biology, Penn State University, State College, Pennsylvania; and
| | - Lu Sun
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana; Department of Biology, Penn State University, State College, Pennsylvania; and
| | - Masayoshi Mishina
- Brain Science Laboratory, The Research Organization of Science and Technology, Ritsumeikan University, Kyoto, Japan
| | - Siqiong June Liu
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana; Department of Biology, Penn State University, State College, Pennsylvania; and
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11
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Banerjee A, Larsen RS, Philpot BD, Paulsen O. Roles of Presynaptic NMDA Receptors in Neurotransmission and Plasticity. Trends Neurosci 2015; 39:26-39. [PMID: 26726120 DOI: 10.1016/j.tins.2015.11.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/30/2015] [Accepted: 11/10/2015] [Indexed: 01/01/2023]
Abstract
Presynaptic NMDA receptors (preNMDARs) play pivotal roles in excitatory neurotransmission and synaptic plasticity. They facilitate presynaptic neurotransmitter release and modulate mechanisms controlling synaptic maturation and plasticity during formative periods of brain development. There is an increasing understanding of the roles of preNMDARs in experience-dependent synaptic and circuit-specific computation. In this review we summarize the latest understanding of compartment-specific expression and function of preNMDARs, and how they contribute to synapse-specific and circuit-level information processing.
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Affiliation(s)
- Abhishek Banerjee
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Benjamin D Philpot
- Department of Cell Biology and Physiology, Neuroscience Center, and Carolina Institute for Developmental Disabilities, University of North Carolina, Chapel Hill, NC, USA.
| | - Ole Paulsen
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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12
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Zhang W, Schmelzeisen S, Parthier D, Frings S, Möhrlen F. Anoctamin Calcium-Activated Chloride Channels May Modulate Inhibitory Transmission in the Cerebellar Cortex. PLoS One 2015; 10:e0142160. [PMID: 26558388 PMCID: PMC4641602 DOI: 10.1371/journal.pone.0142160] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/19/2015] [Indexed: 01/18/2023] Open
Abstract
Calcium-activated chloride channels of the anoctamin (alias TMEM16) protein family fulfill critical functions in epithelial fluid transport, smooth muscle contraction and sensory signal processing. Little is known, however, about their contribution to information processing in the central nervous system. Here we examined the recent finding that a calcium-dependent chloride conductance impacts on GABAergic synaptic inhibition in Purkinje cells of the cerebellum. We asked whether anoctamin channels may underlie this chloride conductance. We identified two anoctamin channel proteins, ANO1 and ANO2, in the cerebellar cortex. ANO1 was expressed in inhibitory interneurons of the molecular layer and the granule cell layer. Both channels were expressed in Purkinje cells but, while ANO1 appeared to be retained in the cell body, ANO2 was targeted to the dendritic tree. Functional studies confirmed that ANO2 was involved in a calcium-dependent mode of ionic plasticity that reduces the efficacy of GABAergic synapses. ANO2 channels attenuated GABAergic transmission by increasing the postsynaptic chloride concentration, hence reducing the driving force for chloride influx. Our data suggest that ANO2 channels are involved in a Ca2+-dependent regulation of synaptic weight in GABAergic inhibition. Thus, in balance with the chloride extrusion mechanism via the co-transporter KCC2, ANO2 appears to regulate ionic plasticity in the cerebellum.
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Affiliation(s)
- Weiping Zhang
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Im Neuenheimer Feld 504, Heidelberg University, Heidelberg, Germany
| | - Steffen Schmelzeisen
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Im Neuenheimer Feld 504, Heidelberg University, Heidelberg, Germany
| | - Daniel Parthier
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Im Neuenheimer Feld 504, Heidelberg University, Heidelberg, Germany
| | - Stephan Frings
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Im Neuenheimer Feld 504, Heidelberg University, Heidelberg, Germany
| | - Frank Möhrlen
- Department of Animal Molecular Physiology, Centre of Organismal Studies, Im Neuenheimer Feld 504, Heidelberg University, Heidelberg, Germany
- * E-mail:
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13
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Rasooli-Nejad S, Palygin O, Lalo U, Pankratov Y. Cannabinoid receptors contribute to astroglial Ca²⁺-signalling and control of synaptic plasticity in the neocortex. Philos Trans R Soc Lond B Biol Sci 2015; 369:20140077. [PMID: 25225106 PMCID: PMC4173298 DOI: 10.1098/rstb.2014.0077] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Communication between neuronal and glial cells is thought to be very important for many brain functions. Acting via release of gliotransmitters, astrocytes can modulate synaptic strength. The mechanisms underlying ATP release from astrocytes remain uncertain with exocytosis being the most intriguing and debated pathway. We have demonstrated that ATP and d-serine can be released from cortical astrocytes in situ by a SNARE-complex-dependent mechanism. Exocytosis of ATP from astrocytes can activate post-synaptic P2X receptors in the adjacent neurons, causing a downregulation of synaptic and extrasynaptic GABA receptors in cortical pyramidal neurons. We showed that release of gliotransmitters is important for the NMDA receptor-dependent synaptic plasticity in the neocortex. Firstly, induction of long-term potentiation (LTP) by five episodes of theta-burst stimulation (TBS) was impaired in the neocortex of dominant-negative (dn)-SNARE mice. The LTP was rescued in the dn-SNARE mice by application of exogenous non-hydrolysable ATP analogues. Secondly, we observed that weak sub-threshold stimulation (two TBS episodes) became able to induce LTP when astrocytes were additionally activated via CB-1 receptors. This facilitation was dependent on activity of ATP receptors and was abolished in the dn-SNARE mice. Our results strongly support the physiological relevance of glial exocytosis for glia-neuron communications and brain function.
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Affiliation(s)
| | - Oleg Palygin
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Ulyana Lalo
- School of Life Sciences, University of Warwick, Coventry, UK
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, Coventry, UK
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14
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Pankratov Y, Lalo U. Role for astroglial α1-adrenoreceptors in gliotransmission and control of synaptic plasticity in the neocortex. Front Cell Neurosci 2015; 9:230. [PMID: 26136663 PMCID: PMC4468378 DOI: 10.3389/fncel.2015.00230] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/02/2015] [Indexed: 01/14/2023] Open
Abstract
Communication between neuronal and glial cells is thought to be very important for many brain functions. Acting via release of gliotransmitters, astrocytes can modulate synaptic strength. The mechanisms underlying gliotransmission remain uncertain with exocytosis being the most intriguing and debated pathway. We demonstrate that astroglial α1-adrenoreceptors are very sensitive to noradrenaline (NA) and make a significant contribution to intracellular Ca2+-signaling in layer 2/3 neocortical astrocytes. We also show that astroglial α1-adrenoreceptors are prone to desensitization upon prolonged exposure to NA. We show that within neocortical slices, α-1adrenoreceptors can activate vesicular release of ATP and D-serine from cortical astrocytes which initiate a burst of ATP receptor-mediated currents in adjacent pyramidal neurons. These purinergic currents can be inhibited by intracellular perfusion of astrocytes with Tetanus Toxin light chain, verifying their origin via astroglial exocytosis. We show that α1 adrenoreceptor-activated release of gliotransmitters is important for the induction of synaptic plasticity in the neocortex:long-term potentiation (LTP) of neocortical excitatory synaptic potentials can be abolished by the selective α1-adrenoreceptor antagonist terazosin. We show that weak sub-threshold theta-burst stimulation (TBS) can induce LTP when astrocytes are additionally activated by 1 μM NA. This facilitation is dependent on the activation of neuronal ATP receptors and is abolished in neocortical slices from dn-SNARE mice which have impaired glial exocytosis. Importantly, facilitation of LTP by NA can be significantly reduced by perfusion of individual astrocytes with Tetanus Toxin. Our results strongly support the physiological importance of astroglial adrenergic signaling and exocytosis of gliotransmitters for modulation of synaptic transmission and plasticity.
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Affiliation(s)
- Yuriy Pankratov
- School of Life Sciences, Gibbet Hill Campus, University of Warwick Coventry, UK
| | - Ulyana Lalo
- School of Life Sciences, Gibbet Hill Campus, University of Warwick Coventry, UK
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15
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Transmembrane AMPAR regulatory protein γ-2 is required for the modulation of GABA release by presynaptic AMPARs. J Neurosci 2015; 35:4203-14. [PMID: 25762667 DOI: 10.1523/jneurosci.4075-14.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Presynaptic ionotropic glutamate receptors (iGluRs) play important roles in the control of synaptogenesis and neurotransmitter release, yet their regulation is poorly understood. In particular, the contribution of transmembrane auxiliary proteins, which profoundly shape the trafficking and gating of somatodendritic iGluRs, is unknown. Here we examined the influence of transmembrane AMPAR regulatory proteins (TARPs) on presynaptic AMPARs in cerebellar molecular layer interneurons (MLIs). 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a partial agonist at TARP-associated AMPARs, enhanced spontaneous GABA release in wild-type mice but not in stargazer mice that lack the prototypical TARP stargazin (γ-2). These findings were replicated in mechanically dissociated Purkinje cells with functional adherent synaptic boutons, demonstrating the presynaptic locus of modulation. In dissociated Purkinje cells from stargazer mice, AMPA was able to enhance mIPSC frequency, but only in the presence of the positive allosteric modulator cyclothiazide. Thus, ordinarily, presynaptic AMPARs are unable to enhance spontaneous release without γ-2, which is required predominantly for its effects on channel gating. Presynaptic AMPARs are known to reduce action potential-driven GABA release from MLIs. Although a G-protein-dependent non-ionotropic mechanism has been suggested to underlie this inhibition, paradoxically we found that γ-2, and thus AMPAR gating, was required. Following glutamate spillover from climbing fibers or application of CNQX, evoked GABA release was reduced; in stargazer mice such effects were markedly attenuated in acute slices and abolished in the dissociated Purkinje cell-nerve bouton preparation. We suggest that γ-2 association, by increasing charge transfer, allows presynaptic AMPARs to depolarize the bouton membrane sufficiently to modulate both phasic and spontaneous release.
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Fuchs JR, Robinson GM, Dean AM, Schoenberg HE, Williams MR, Morielli AD, Green JT. Cerebellar secretin modulates eyeblink classical conditioning. ACTA ACUST UNITED AC 2014; 21:668-75. [PMID: 25403455 PMCID: PMC4236411 DOI: 10.1101/lm.035766.114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have previously shown that intracerebellar infusion of the neuropeptide secretin enhances the acquisition phase of eyeblink conditioning (EBC). Here, we sought to test whether endogenous secretin also regulates EBC and to test whether the effect of exogenous and endogenous secretin is specific to acquisition. In Experiment 1, rats received intracerebellar infusions of the secretin receptor antagonist 5-27 secretin or vehicle into the lobulus simplex of cerebellar cortex immediately prior to sessions 1-3 of acquisition. Antagonist-infused rats showed a reduction in the percentage of eyeblink CRs compared with vehicle-infused rats. In Experiment 2, rats received intracerebellar infusions of secretin or vehicle immediately prior to sessions 1-2 of extinction. Secretin did not significantly affect extinction performance. In Experiment 3, rats received intracerebellar infusions of 5-27 secretin or vehicle immediately prior to sessions 1-2 of extinction. The secretin antagonist did not significantly affect extinction performance. Together, our current and previous results indicate that both exogenous and endogenous cerebellar secretin modulate acquisition, but not extinction, of EBC. We have previously shown that (1) secretin reduces surface expression of the voltage-gated potassium channel α-subunit Kv1.2 in cerebellar cortex and (2) intracerebellar infusions of a Kv1.2 blocker enhance EBC acquisition, much like secretin. Kv1.2 is almost exclusively expressed in cerebellar cortex at basket cell-Purkinje cell pinceaus and Purkinje cell dendrites; we propose that EBC-induced secretin release from PCs modulates EBC acquisition by reducing surface expression of Kv1.2 at one or both of these sites.
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Affiliation(s)
- Jason R Fuchs
- Department of Psychology, University of Vermont, Burlington, Vermont 05405, USA
| | - Gain M Robinson
- Department of Psychology, University of Vermont, Burlington, Vermont 05405, USA
| | - Aaron M Dean
- Department of Psychology, University of Vermont, Burlington, Vermont 05405, USA
| | - Heidi E Schoenberg
- Department of Psychology, University of Vermont, Burlington, Vermont 05405, USA
| | - Michael R Williams
- Department of Pharmacology, University of Vermont, Burlington, Vermont 05405, USA
| | - Anthony D Morielli
- Department of Pharmacology, University of Vermont, Burlington, Vermont 05405, USA
| | - John T Green
- Department of Psychology, University of Vermont, Burlington, Vermont 05405, USA
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Mansouri M, Kasugai Y, Fukazawa Y, Bertaso F, Raynaud F, Perroy J, Fagni L, Kaufmann WA, Watanabe M, Shigemoto R, Ferraguti F. Distinct subsynaptic localization of type 1 metabotropic glutamate receptors at glutamatergic and
GABA
ergic synapses in the rodent cerebellar cortex. Eur J Neurosci 2014; 41:157-67. [DOI: 10.1111/ejn.12779] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 09/26/2014] [Accepted: 10/05/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Mahnaz Mansouri
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | - Yu Kasugai
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | - Yugo Fukazawa
- Division of Cerebral Structure National Institute for Physiological Sciences Okazaki Japan
| | - Federica Bertaso
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Fabrice Raynaud
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Julie Perroy
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Laurent Fagni
- CNRS UMR‐5203 Institut de Génomique Fonctionnelle Montpellier France
- INSERM U661 Montpellier France
- Universités de Montpellier 1 & 2 UMR‐5203 Montpellier France
| | - Walter A. Kaufmann
- Department of Pharmacology Innsbruck Medical University Innsbruck Austria
| | | | - Ryuichi Shigemoto
- Division of Cerebral Structure National Institute for Physiological Sciences Okazaki Japan
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18
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Pankratov Y, Lalo U. Calcium permeability of ligand-gated Ca2+ channels. Eur J Pharmacol 2014; 739:60-73. [DOI: 10.1016/j.ejphar.2013.11.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 10/22/2013] [Accepted: 11/07/2013] [Indexed: 11/28/2022]
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Balakrishnan S, Dobson KL, Jackson C, Bellamy TC. Ectopic release of glutamate contributes to spillover at parallel fibre synapses in the cerebellum. J Physiol 2014; 592:1493-503. [PMID: 24421351 DOI: 10.1113/jphysiol.2013.267039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In the rat cerebellar molecular layer, spillover of glutamate between parallel fibre synapses can lead to activation of perisynaptic receptors that mediate short- and long-term plasticity. This effect is greatest when clusters of fibres are stimulated at high frequencies, suggesting that glutamate clearance mechanisms must be overwhelmed before spillover can occur. However, parallel fibres can also release transmitter directly into the extracellular space, from 'ectopic' release sites. Ectopic transmission activates AMPA receptors on the Bergmann glial cell processes that envelop parallel fibre synapses, but the possible contribution of this extrasynaptic release to intersynaptic communication has not been explored. We exploited long-term depression of ectopic transmission, and selective pharmacology, to investigate the impact of these release sites on the time course of Purkinje neuron excitatory postsynaptic currents (EPSCs). Depletion of ectopic release pools by activity-dependent long-term depression decreased EPSC decay time, revealing a 'late' current that is present when fibres are stimulated at low frequencies. This effect was enhanced when glutamate transporters were inhibited, and reduced when extracellular diffusion was impeded. Blockade of N-type Ca(2+) channels inhibited ectopic transmission to Bergmann glia and decreased EPSC decay time. Similarly, perfusion of the Ca(2+) chelator EGTA-AM into the slice progressively eliminated ectopic transmission to glia and decreased EPSC decay time with closely similar time courses. Collectively, this evidence suggests that ectopically released glutamate contributes to spillover transmission, and that ectopic release therefore degrades the spatial precision of synapses that fire infrequently, and may make them more prone to exhibit plasticity.
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Affiliation(s)
- Saju Balakrishnan
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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20
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Satoh H, Qu L, Suzuki H, Saitow F. Depolarization-induced depression of inhibitory transmission in cerebellar Purkinje cells. Physiol Rep 2013; 1:e00061. [PMID: 24303140 PMCID: PMC3835016 DOI: 10.1002/phy2.61] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 07/24/2013] [Accepted: 07/25/2013] [Indexed: 11/07/2022] Open
Abstract
Several forms of depolarization-induced plasticity in inhibitory transmission have been reported to occur in cerebellar Purkinje cells (PCs), namely depolarization-induced suppression of inhibition (DSI), depolarization-induced potentiation of inhibition (DPI), and rebound potentiation (RP). Here, we describe another form of synaptic plasticity for gamma-amino butyric acid (GABA)ergic transmission in PCs. Immediately following depolarization trains in a PC, evoked inhibitory postsynaptic currents (eIPSCs) changed their direction from outward to inward currents under a recording condition in which eIPSCs were elicited as an outward current. Subsequently, the eIPSC amplitude remained depressed (depolarization-induced depression of inhibition [DDI]) for more than 20 min under the blockade of cannabinoid and N-methyl-D-aspartic acid (NMDA) receptor-mediated DSI and DPI, respectively. This DDI was completely abolished by intracellular infusion of the fast Ca(2+)-chelating agent BAPTA and by inhibition of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). Furthermore, DDI was strongly suppressed by calcium-activated chloride channel (CaCC) blockers, while an inhibitor of cation-chloride cotransporters (CCCs) partially blocked DDI during the early phase. Exogenous GABA-induced inhibition of spontaneous spike activity was attenuated in ∼50% of the PCs by climbing fiber stimulation-induced depolarization. These results suggest that activation of both CaCCs and CCCs was necessary for alteration of [Cl(-)]i after activation of CaMKII following elevation of [Ca(2+)]i in PCs. DDI may provide another mechanism for regulation of inhibitory inputs to PCs within the neuronal networks of the cerebellar cortex.
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Affiliation(s)
- Hiromasa Satoh
- Department of Pharmacology, Nippon Medical School Tokyo, 113-8602, Japan
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21
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Persistent posttetanic depression at cerebellar parallel fiber to Purkinje cell synapses. PLoS One 2013; 8:e70277. [PMID: 23922966 PMCID: PMC3726549 DOI: 10.1371/journal.pone.0070277] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/20/2013] [Indexed: 01/28/2023] Open
Abstract
Plasticity at the cerebellar parallel fiber to Purkinje cell synapse may underlie information processing and motor learning. In vivo, parallel fibers appear to fire in short high frequency bursts likely to activate sparsely distributed synapses over the Purkinje cell dendritic tree. Here, we report that short parallel fiber tetanic stimulation evokes a ∼7–15% depression which develops over 2 min and lasts for at least 20 min. In contrast to the concomitantly evoked short-term endocannabinoid-mediated depression, this persistent posttetanic depression (PTD) does not exhibit a dependency on the spatial pattern of synapse activation and is not caused by any detectable change in presynaptic calcium signaling. This persistent PTD is however associated with increased paired-pulse facilitation and coefficient of variation of synaptic responses, suggesting that its expression is presynaptic. The chelation of postsynaptic calcium prevents its induction, suggesting that post- to presynaptic (retrograde) signaling is required. We rule out endocannabinoid signaling since the inhibition of type 1 cannabinoid receptors, monoacylglycerol lipase or vanilloid receptor 1, or incubation with anandamide had no detectable effect. The persistent PTD is maximal in pre-adolescent mice, abolished by adrenergic and dopaminergic receptors block, but unaffected by adrenergic and dopaminergic agonists. Our data unveils a novel form of plasticity at parallel fiber synapses: a persistent PTD induced by physiologically relevant input patterns, age-dependent, and strongly modulated by the monoaminergic system. We further provide evidence supporting that the plasticity mechanism involves retrograde signaling and presynaptic diacylglycerol.
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Iremonger KJ, Wamsteeker Cusulin JI, Bains JS. Changing the tune: plasticity and adaptation of retrograde signals. Trends Neurosci 2013; 36:471-9. [PMID: 23706151 DOI: 10.1016/j.tins.2013.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/18/2013] [Accepted: 04/18/2013] [Indexed: 11/25/2022]
Abstract
Retrograde signaling is a fundamental means by which neurons communicate. The acceptance of this statement has required a revision of how we view transmission and storage of information at the synapse. Although there is a substantial body of literature on the diverse molecules that serve as retrograde signals, less is known about how retrograde signal capacity can be modified. Is retrograde signaling plastic? How does this plasticity manifest? Are there behavioral correlates that may bias a neuron towards 'changing its tune', retrogradely speaking, of course? Here, we review recent findings that retrograde signaling is a highly labile process that adds additional layers of complexity that must be untangled to understand information processing in the nervous system.
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Affiliation(s)
- Karl J Iremonger
- Centre for Neuroendocrinology and Department of Physiology, University of Otago, PO Box 913, Dunedin 9054, New Zealand
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23
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Rossi B, Collin T. Presynaptic NMDA receptors act as local high-gain glutamate detector in developing cerebellar molecular layer interneurons. J Neurochem 2013; 126:47-57. [DOI: 10.1111/jnc.12279] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 03/22/2013] [Accepted: 04/18/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Bénédicte Rossi
- Laboratoire de Physiologie Cérébrale; CNRS-UMR 8118; Université Paris Descartes; Université Paris Diderot; Paris France
| | - Thibault Collin
- Laboratoire de Physiologie Cérébrale; CNRS-UMR 8118; Université Paris Descartes; Université Paris Diderot; Paris France
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24
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Duguid IC. Presynaptic NMDA receptors: are they dendritic receptors in disguise? Brain Res Bull 2012; 93:4-9. [PMID: 23279913 DOI: 10.1016/j.brainresbull.2012.12.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 12/19/2012] [Accepted: 12/20/2012] [Indexed: 02/07/2023]
Abstract
The N-methyl-D-aspartate (NMDA) receptor plays an essential role in excitatory transmission, synaptic integration, and learning and memory. In the classical view, postsynaptic NMDA receptors act as canonical coincidence detectors providing a 'molecular switch' for the induction of various forms of short- and long-term synaptic plasticity. Over the past twenty years there has been accumulating evidence to suggest that NMDA receptors are also expressed presynaptically and are involved in the regulation of synaptic transmission and specific forms of activity-dependent plasticity in developing neural circuits. However, the existence of presynaptic NMDA receptors remains a contentious issue. In this review, I will discuss the criteria required for identifying functional presynaptic receptors, novel methods for probing NMDA receptor function, and recent evidence to suggest that NMDA receptors are expressed at presynaptic sites in a target-specific manner.
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Affiliation(s)
- Ian C Duguid
- Centre for Integrative Physiology, School of Biomedical Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, Scotland, UK.
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25
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Isope P, Hildebrand ME, Snutch TP. Contributions of T-type voltage-gated calcium channels to postsynaptic calcium signaling within Purkinje neurons. THE CEREBELLUM 2012; 11:651-65. [PMID: 20734177 PMCID: PMC3411289 DOI: 10.1007/s12311-010-0195-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Low threshold voltage-gated T-type calcium channels have long been implicated in the electrical excitability and calcium signaling of cerebellar Purkinje neurons although the molecular composition, localization, and modulation of T-type channels within Purkinje cells have only recently been addressed. The specific functional roles that T-type channels play in local synaptic integration within Purkinje spines are also currently being unraveled. Overall, Purkinje neurons represent a powerful model system to explore the potential roles of postsynaptic T-type channels throughout the nervous system. In this review, we present an overview of T-type calcium channel biophysical, pharmacological, and physiological characteristics that provides a foundation for understanding T-type channels within Purkinje neurons. We also describe the biophysical properties of T-type channels in context of other voltage-gated calcium channel currents found within Purkinje cells. The data thus far suggest that one specific T-type isoform, Cav3.1, is highly expressed within Purkinje spines and both physically and functionally couples to mGluR1 and other effectors within putative signaling microdomains. Finally, we discuss how the selective potentiation of Cav3.1 channels via activation of mGluR1 by parallel fiber inputs affects local synaptic integration and how this interaction may relate to the overall excitability of Purkinje neuron dendrites.
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Affiliation(s)
- Philippe Isope
- Institut des Neurosciences Cellulaires et Intégratives, CNRS-Université de Strasbourg, 5 rue Blaise Pascal, Strasbourg, France.
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26
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Kim YS, Kang E, Makino Y, Park S, Shin JH, Song H, Launay P, Linden DJ. Characterizing the conductance underlying depolarization-induced slow current in cerebellar Purkinje cells. J Neurophysiol 2012. [PMID: 23197456 DOI: 10.1152/jn.01168.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Brief strong depolarization of cerebellar Purkinje cells produces a slow inward cation current [depolarization-induced slow current (DISC)]. Previous work has shown that DISC is triggered by voltage-sensitive Ca influx in the Purkinje cell and is attenuated by blockers of vesicular loading and fusion. Here, we have sought to characterize the ion channel(s) underlying the DISC conductance. While the brief depolarizing steps that triggered DISC were associated with a large Ca transient, the onset of DISC current corresponded only with the Ca transient decay phase. Furthermore, substitution of external Na with the impermeant cation N-methyl-d-glucamine produced a complete and reversible block of DISC, suggesting that the DISC conductance was not Ca permeant. Transient receptor potential cation channel, subfamily M, members 4 (TRPM4) and 5 (TRPM5) are nonselective cation channels that are opened by Ca transients but do not flux Ca. They are expressed in Purkinje cells of the posterior cerebellum, where DISC is large, and, in these cells, DISC is strongly attenuated by nonselective blockers of TRPM4/5. However, measurement of DISC currents in Purkinje cells derived from TRPM4 null, TRPM5 null, and double null mice as well as wild-type mice with TRPM4 short hairpin RNA knockdown showed a partial attenuation with 35-46% of current remaining. Thus, while the DISC conductance is Ca triggered, Na permeant, and Ca impermeant, suggesting a role for TRPM4 and TRPM5, these ion channels are not absolutely required for DISC.
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Affiliation(s)
- Yu Shin Kim
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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27
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Dendritic calcium signaling in cerebellar Purkinje cell. Neural Netw 2012; 47:11-7. [PMID: 22985934 DOI: 10.1016/j.neunet.2012.08.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Revised: 07/30/2012] [Accepted: 08/09/2012] [Indexed: 11/24/2022]
Abstract
The Purkinje cells in the cerebellum are unique neurons that generate local and global Ca(2+) signals in response to two types of excitatory inputs, parallel fiber and climbing fiber, respectively. The spatiotemporal distribution and interaction of these synaptic inputs produce complex patterns of Ca(2+) dynamics in the Purkinje cell dendrites. The Ca(2+) signals originate from Ca(2+) influx through voltage-gated Ca(2+) channels and Ca(2+) release from intracellular stores that are mediated by the metabotropic glutamate receptor signaling pathway. These Ca(2+) signals are essential for the induction of various forms of synaptic plasticity and for controlling the input-output relationship of Purkinje cells. In this article we review Ca(2+) signaling in Purkinje cell dendrites.
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29
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Nuritova F, Frenguelli BG. Putative depolarisation-induced retrograde signalling accelerates the repeated hypoxic depression of excitatory synaptic transmission in area CA1 of rat hippocampus via group I metabotropic glutamate receptors. Neuroscience 2012; 222:159-72. [PMID: 22842516 DOI: 10.1016/j.neuroscience.2012.07.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 07/16/2012] [Accepted: 07/17/2012] [Indexed: 02/08/2023]
Abstract
Excitatory synaptic transmission in area CA1 of the mammalian hippocampus is rapidly depressed during hypoxia. The depression is largely attributable to an increase in extracellular adenosine and activation of inhibitory adenosine A(1) receptors on presynaptic glutamatergic terminals. However, sequential exposure to hypoxia results in a slower subsequent hypoxic depression of excitatory synaptic transmission, a phenomenon we have previously ascribed to a reduction in the release of extracellular adenosine. In the present study we show that this delayed depression of excitatory postsynaptic currents (EPSCs) to repeated hypoxia can be reversed by a period of postsynaptic depolarisation delivered to an individual CA1 neuron, under whole-cell voltage clamp, between two periods of hypoxia. The depolarisation-induced acceleration of the hypoxic depression of the EPSC is dependent upon postsynaptic Ca(2+) influx, the activation of PKC and is blocked by intracellular application of GDP-β-S and N-ethylmaleimide (NEM), inhibitors of membrane fusion events. In addition, the acceleration of the hypoxic depression of the EPSC was prevented by the GI mGluR antagonist AIDA, but not by the CB1 cannabinoid receptor antagonist AM251. Our results suggest a process initiated in the postsynaptic cell that can influence glutamate release during subsequent metabolic stress. This may reflect a novel neuroprotective strategy potentially involving retrograde release of adenosine and/or glutamate.
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Affiliation(s)
- F Nuritova
- Neurosciences Institute, Division of Pathology & Neuroscience, University of Dundee, Ninewells Hospital & Medical School, Dundee DD1 9SY, UK
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30
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Rossi B, Ogden D, Llano I, Tan YP, Marty A, Collin T. Current and calcium responses to local activation of axonal NMDA receptors in developing cerebellar molecular layer interneurons. PLoS One 2012; 7:e39983. [PMID: 22761940 PMCID: PMC3384623 DOI: 10.1371/journal.pone.0039983] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 05/30/2012] [Indexed: 11/19/2022] Open
Abstract
In developing cerebellar molecular layer interneurons (MLIs), NMDA increases spontaneous GABA release. This effect had been attributed to either direct activation of presynaptic NMDA receptors (preNMDARs) or an indirect pathway involving activation of somato-dendritic NMDARs followed by passive spread of somatic depolarization along the axon and activation of axonal voltage dependent Ca(2+) channels (VDCCs). Using Ca(2+) imaging and electrophysiology, we searched for preNMDARs by uncaging NMDAR agonists either broadly throughout the whole field or locally at specific axonal locations. Releasing either NMDA or glutamate in the presence of NBQX using short laser pulses elicited current transients that were highly sensitive to the location of the spot and restricted to a small number of varicosities. The signal was abolished in the presence of high Mg(2+) or by the addition of APV. Similar paradigms yielded restricted Ca(2+) transients in interneurons loaded with a Ca(2+) indicator. We found that the synaptic effects of NMDA were not inhibited by blocking VDCCs but were impaired in the presence of the ryanodine receptor antagonist dantrolene. Furthermore, in voltage clamped cells, bath applied NMDA triggers Ca(2+) elevations and induces neurotransmitter release in the axonal compartment. Our results suggest the existence of preNMDARs in developing MLIs and propose their involvement in the NMDA-evoked increase in GABA release by triggering a Ca(2+)-induced Ca(2+) release process mediated by presynaptic Ca(2+) stores. Such a mechanism is likely to exert a crucial role in various forms of Ca(2+)-mediated synaptic plasticity.
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Affiliation(s)
- Bénédicte Rossi
- Laboratoire de Physiologie Cérébrale, CNRS-UMR 8118, Université Paris Descartes, Université Paris Diderot, Paris, France
| | - David Ogden
- Laboratoire de Physiologie Cérébrale, CNRS-UMR 8118, Université Paris Descartes, Université Paris Diderot, Paris, France
| | - Isabel Llano
- Laboratoire de Physiologie Cérébrale, CNRS-UMR 8118, Université Paris Descartes, Université Paris Diderot, Paris, France
| | - Yusuf P. Tan
- Laboratoire de Physiologie Cérébrale, CNRS-UMR 8118, Université Paris Descartes, Université Paris Diderot, Paris, France
| | - Alain Marty
- Laboratoire de Physiologie Cérébrale, CNRS-UMR 8118, Université Paris Descartes, Université Paris Diderot, Paris, France
| | - Thibault Collin
- Laboratoire de Physiologie Cérébrale, CNRS-UMR 8118, Université Paris Descartes, Université Paris Diderot, Paris, France
- * E-mail:
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31
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Wu YW, Grebenyuk S, McHugh TJ, Rusakov DA, Semyanov A. Backpropagating action potentials enable detection of extrasynaptic glutamate by NMDA receptors. Cell Rep 2012; 1:495-505. [PMID: 22832274 PMCID: PMC3740263 DOI: 10.1016/j.celrep.2012.03.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 01/11/2012] [Accepted: 03/22/2012] [Indexed: 12/19/2022] Open
Abstract
Synaptic NMDA receptors (NMDARs) are crucial for neural coding and plasticity. However, little is known about the adaptive function of extrasynaptic NMDARs occurring mainly on dendritic shafts. Here, we find that in CA1 pyramidal neurons, backpropagating action potentials (bAPs) recruit shaft NMDARs exposed to ambient glutamate. In contrast, spine NMDARs are “protected,” under baseline conditions, from such glutamate influences by perisynaptic transporters: we detect bAP-evoked Ca2+ entry through these receptors upon local synaptic or photolytic glutamate release. During theta-burst firing, NMDAR-dependent Ca2+ entry either downregulates or upregulates an h-channel conductance (Gh) of the cell depending on whether synaptic glutamate release is intact or blocked. Thus, the balance between activation of synaptic and extrasynaptic NMDARs can determine the sign of Gh plasticity. Gh plasticity in turn regulates dendritic input probed by local glutamate uncaging. These results uncover a metaplasticity mechanism potentially important for neural coding and memory formation.
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Affiliation(s)
- Yu-Wei Wu
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
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32
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Abstract
Previous studies of NMDA receptor (NMDAR) expression on axons of cerebellar molecular layer interneurons have produced conflicting results. We made use of the calcium sensitivity of vesicular release machinery to test for NMDAR activity in basket cell axons. Iontophoresis of l-aspartate, an NMDAR agonist, onto basket cell axon collaterals had no effect on evoked IPSCs measured in synaptically coupled Purkinje cells. Furthermore, calcium indicators in basket cell varicosities did not report any change in intracellular calcium following iontophoresis of l-aspartate or two-photon uncaging of glutamate. In contrast, activation of presynaptic purinergic receptors by iontophoresis of ATP decreased evoked IPSC amplitudes and action potential-evoked calcium transients in axonal varicosities, demonstrating the effectiveness of activating presynaptic receptors by iontophoresis. We find no evidence for functional NMDARs in basket cell varicosities.
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Nedergaard M, Verkhratsky A. Artifact versus reality--how astrocytes contribute to synaptic events. Glia 2012; 60:1013-23. [PMID: 22228580 DOI: 10.1002/glia.22288] [Citation(s) in RCA: 221] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 12/05/2011] [Indexed: 11/11/2022]
Abstract
The neuronal doctrine, developed a century ago regards neuronal networks as the sole substrate of higher brain function. Recent advances in glial physiology have promoted an alternative hypothesis, which places information processing in the brain into integrated neuronal-glial networks utilizing both binary (neuronal action potentials) and analogue (diffusional propagation of second messengers/metabolites through gap junctions or transmitters through the interstitial space) signal encoding. It has been proposed that the feed-forward and feed-back communication between these two types of neural cells, which underlies information transfer and processing, is accomplished by the release of neurotransmitters from neuronal terminals as well as from astroglial processes. Understanding of this subject, however, remains incomplete and important questions and controversies require resolution. Here we propose that the primary function of perisynaptic glial processes is to create an "astroglial cradle" that shields the synapse from a multitude of extrasynaptic signaling events and provides for multifaceted support and long-term plasticity of synaptic contacts through variety of mechanisms, which may not necessarily involve the release of "glio" transmitters.
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Affiliation(s)
- Maiken Nedergaard
- Division of Glia Disease and Therapeutics, Department of Neurosurgery, Center for Translational Neuromedicine, University of Rochester Medical School, Rochester, NY 14580, USA.
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Abstract
Dendritic exocytosis underpins a broad range of integrative and homeostatic synaptic functions. Emerging data highlight the essential role of SNAREs in trafficking and fusion of secretory organelles with release of peptides and neurotransmitters from dendrites. This Perspective analyzes recent evidence inferring axo-dendritic polarization of vesicular release machinery and pinpoints progress made with existing challenges in this rapidly progressing field of dendritic research. Interpreting the relation of new molecular data to physiological results on secretion from dendrites would greatly advance our understanding of this facet of neuronal mechanisms.
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Affiliation(s)
- Saak V. Ovsepian
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland
| | - J. Oliver Dolly
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland
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Some lumbar sympathetic neurons develop a glutamatergic phenotype after peripheral axotomy with a note on VGLUT₂-positive perineuronal baskets. Exp Neurol 2011; 230:258-72. [PMID: 21596036 DOI: 10.1016/j.expneurol.2011.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 04/27/2011] [Accepted: 05/01/2011] [Indexed: 01/01/2023]
Abstract
Glutamate is the main excitatory neurotransmitter in the nervous system, including in primary afferent neurons. However, to date a glutamatergic phenotype of autonomic neurons has not been described. Therefore, we explored the expression of vesicular glutamate transporter (VGLUT) types 1, 2 and 3 in lumbar sympathetic chain (LSC) and major pelvic ganglion (MPG) of naïve BALB/C mice, as well as after pelvic nerve axotomy (PNA), using immunohistochemistry and in situ hybridization. Colocalization with activating transcription factor-3 (ATF-3), tyrosine hydroxylase (TH), vesicular acetylcholine transporter (VAChT) and calcitonin gene-related peptide was also examined. Sham-PNA, sciatic nerve axotomy (SNA) or naïve mice were included. In naïve mice, VGLUT(2)-like immunoreactivity (LI) was only detected in fibers and varicosities in LSC and MPG; no ATF-3-immunoreactive (IR) neurons were visible. In contrast, PNA induced upregulation of VGLUT(2) protein and transcript, as well as of ATF-3-LI in subpopulations of LSC neurons. Interestingly, VGLUT(2)-IR LSC neurons coexpressed ATF-3, and often lacked the noradrenergic marker TH. SNA only increased VGLUT(2) protein and transcript in scattered LSC neurons. Neither PNA nor SNA upregulated VGLUT(2) in MPG neurons. We also found perineuronal baskets immunoreactive either for VGLUT(2) or the acetylcholinergic marker VAChT in non-PNA MPGs, usually around TH-IR neurons. VGLUT(1)-LI was restricted to some varicosities in MPGs, was absent in LSCs, and remained largely unaffected by PNA or SNA. This was confirmed by the lack of expression of VGLUT(1) or VGLUT(3) mRNAs in LSCs, even after PNA or SNA. Taken together, axotomy of visceral and non-visceral nerves results in a glutamatergic phenotype of some LSC neurons. In addition, we show previously non-described MPG perineuronal glutamatergic baskets.
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36
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Wang X, Chen G, Gao W, Ebner TJ. Parasagittally aligned, mGluR1-dependent patches are evoked at long latencies by parallel fiber stimulation in the mouse cerebellar cortex in vivo. J Neurophysiol 2011; 105:1732-46. [PMID: 21289138 DOI: 10.1152/jn.00717.2010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The parallel fibers (PFs) in the cerebellar cortex extend several millimeters along a folium in the mediolateral direction. The PFs are orthogonal to and cross several parasagittal zones defined by the olivocerebellar and corticonuclear pathways and the expression of molecular markers on Purkinje cells (PCs). The functions of these two organizations remain unclear, including whether the bands respond similarly or differentially to PF input. By using flavoprotein imaging in the anesthetized mouse in vivo, this study demonstrates that high-frequency PF stimulation, which activates a beamlike response at short latency, also evokes patches of activation at long latencies. These patches consist of increased fluorescence along the beam at latencies of 20-25 s with peak activation at 35 s. The long-latency patches are completely blocked by the type 1 metabotropic glutamate receptor (mGluR(1)) antagonist LY367385. Conversely, the AMPA and NMDA glutamate receptor antagonists DNQX and APV have little effect. Organized in parasagittal bands, the long-latency patches align with zebrin II-positive PC stripes. Additional Ca(2+) imaging demonstrates that the patches reflect increases in intracellular Ca(2+). Both the PLCβ inhibitor U73122 and the ryanodine receptor inhibitor ryanodine completely block the long-latency patches, indicating that the patches are due to Ca(2+) release from intracellular stores. Robust, mGluR(1)-dependent long-term potentiation (LTP) of the patches is induced using a high-frequency PF stimulation conditioning paradigm that generates LTP of PF-PC synapses. Therefore, the parasagittal bands, as defined by the molecular compartmentalization of PCs, respond differentially to PF inputs via mGluR(1)-mediated release of internal Ca(2+).
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Affiliation(s)
- Xinming Wang
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, USA
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37
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Crépel F, Galante M, Habbas S, McLean H, Daniel H. Role of the vesicular transporter VGLUT3 in retrograde release of glutamate by cerebellar Purkinje cells. J Neurophysiol 2010; 105:1023-32. [PMID: 21177991 DOI: 10.1152/jn.00736.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the cerebellum, retrograde release of glutamate (Glu) by Purkinje cells (PCs) participates in the control of presynaptic neurotransmitter release responsible for the late component of depolarization-induced suppression of excitation (DSE), as well as for depolarization-induced potentiation of inhibition (DPI). It might also participate in the depolarization-induced slow current (DISC) in PCs, although this contribution was later challenged. We also know that both DPI and DISC are soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-dependent processes, although the molecular nature of the vesicular transporter was not determined. In PCs, VGLUT3 is the only known vesicular glutamate transporter identified and is expressed during the same developmental frame as when DPI, DISC, and the Glu-dependent component of DSE are observed. We therefore tested the hypothesis that all these processes depend on the presence of VGLUT3 by comparing the Glu-dependent component of DSE, DPI, and DISC in nearly mature (2- to 3-wk-old) wild-type and VGLUT3 knockout mice. Our data demonstrate that, in nearly mature mice, the slow component of DSE occurs through vesicular release of Glu that involves VGLUT3. This Glu-dependent component of DSE is no longer present in fully mature mice. This study also establishes that, in nearly mature mice, DPI also depends on the presence of VGLUT3, whereas this is not the case for DISC. Finally, the unusually large basal paired-pulse facilitation observed in nearly mature VGLUT3(-/-) mice but not in adult ones suggests that some basal retrograde release of Glu occurs during development and contributes to basal concentrations of extracellular Glu.
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Affiliation(s)
- Françis Crépel
- Pharmacologie de la Synapse, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, Université Paris-Sud and Centre National de la Recherche Scientifique, Orsay Cedex, France.
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38
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Dendritic spikes mediate negative synaptic gain control in cerebellar Purkinje cells. Proc Natl Acad Sci U S A 2010; 107:22284-9. [PMID: 21131572 DOI: 10.1073/pnas.1008605107] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Dendritic spikes appear to be a ubiquitous feature of dendritic excitability. In cortical pyramidal neurons, dendritic spikes increase the efficacy of distal synapses, providing additional inward current to enhance axonal action potential (AP) output, thus increasing synaptic gain. In cerebellar Purkinje cells, dendritic spikes can trigger synaptic plasticity, but their influence on axonal output is not well understood. We have used simultaneous somatic and dendritic patch-clamp recordings to directly assess the impact of dendritic calcium spikes on axonal AP output of Purkinje cells. Dendritic spikes evoked by parallel fiber input triggered brief bursts of somatic APs, followed by pauses in spiking, which cancelled out the extra spikes in the burst. As a result, average output firing rates during trains of input remained independent of the input strength, thus flattening synaptic gain. We demonstrate that this "clamping" of AP output by the pause following dendritic spikes is due to activation of high conductance calcium-dependent potassium channels by dendritic spikes. Dendritic spikes in Purkinje cells, in contrast to pyramidal cells, thus have differential effects on temporally coded and rate coded information: increasing the impact of transient parallel fiber input, while depressing synaptic gain for sustained parallel fiber inputs.
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39
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Urbanski M, Kovacs F, Szabo B. Endocannabinoid-mediated synaptically evoked suppression of GABAergic transmission in the cerebellar cortex. Neuroscience 2010; 169:1268-78. [DOI: 10.1016/j.neuroscience.2010.05.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 04/23/2010] [Accepted: 05/16/2010] [Indexed: 11/29/2022]
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40
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Branco T, Häusser M. The single dendritic branch as a fundamental functional unit in the nervous system. Curr Opin Neurobiol 2010; 20:494-502. [DOI: 10.1016/j.conb.2010.07.009] [Citation(s) in RCA: 246] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/23/2010] [Accepted: 07/23/2010] [Indexed: 11/28/2022]
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41
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Trigo FF, Bouhours B, Rostaing P, Papageorgiou G, Corrie JET, Triller A, Ogden D, Marty A. Presynaptic miniature GABAergic currents in developing interneurons. Neuron 2010; 66:235-47. [PMID: 20435000 DOI: 10.1016/j.neuron.2010.03.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
Miniature synaptic currents have long been known to represent random transmitter release under resting conditions, but much remains to be learned about their nature and function in central synapses. In this work, we describe a new class of miniature currents ("preminis") that arise by the autocrine activation of axonal receptors following random vesicular release. Preminis are prominent in gabaergic synapses made by cerebellar interneurons during the development of the molecular layer. Unlike ordinary miniature postsynaptic currents in the same cells, premini frequencies are strongly enhanced by subthreshold depolarization, suggesting that the membrane depolarization they produce belongs to a feedback loop regulating neurotransmitter release. Thus, preminis could guide the formation of the interneuron network by enhancing neurotransmitter release at recently formed synaptic contacts.
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Affiliation(s)
- Federico F Trigo
- CNRS, Unité 8118, Université Paris Descartes, 75006 Paris, France
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42
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43
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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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44
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Crépel F. Role of presynaptic kainate receptors at parallel fiber-purkinje cell synapses in induction of cerebellar LTD: interplay with climbing fiber input. J Neurophysiol 2009; 102:965-73. [PMID: 19535482 DOI: 10.1152/jn.00269.2009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Until recently, except for A1 adenosine, N-methyl-d-aspartate, and cannabinoid receptors, little effort has been made to unravel possible roles of parallel fiber (PF) presynaptic receptors in long-term depression (LTD) of synaptic transmission at PF-Purkinje cell (PC) synapses. Presynaptic kainate (KA) receptors are also present on PFs and might also influence LTD induction by modulating glutamate (Glu) release at PF-PC synapses. This hypothesis was tested by comparing the efficacy of two pairing protocols in inducing LTD in adult wild-type and knock-out mice for the Glu receptor 6 (GluR6) subunit of KA receptors. Activation of presynaptic KA receptors was unnecessary for LTD induction when PF inputs were paired with climbing fiber (CF) stimulation but became crucial when CF input was replaced by direct depolarization of PCs. By comparing basal paired-pulse facilitation of PF-excitatory postsynaptic currents (EPSCs) and depolarization-induced suppression of excitation in adult wild-type and GluR6 knock-out mice, it was shown that the participation of PF presynaptic KA receptors in LTD induction was likely to mainly result from their tonic activation by basal extracellular Glu, rather than from their activation by retrograde release of Glu by PCs during pairing protocols. Finally, this study suggests that, in adult mice, CFs not only participate in LTD induction by depolarizing postsynaptic cells but also by activating postsynaptic mGluR1alpha metabotropic glutamate receptors at CF-PC synapses.
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Affiliation(s)
- Francis Crépel
- Pharmacologie de la Synapse, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, Université Paris-Sud and Centre National de la Recherche Scientifique, 91405 Orsay Cedex, France.
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45
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Dopamine signaling is required for depolarization-induced slow current in cerebellar Purkinje cells. J Neurosci 2009; 29:8530-8. [PMID: 19571144 DOI: 10.1523/jneurosci.0468-09.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Brief strong depolarization of cerebellar Purkinje cells produces a slow inward cation current. This current, called depolarization-induced slow current (DISC), is triggered by Ca influx in the Purkinje cell and is attenuated by a blocker of vesicular fusion. Previous work in other brain regions, such as the substantia nigra and ventral tegmental area, has shown that dopamine can be released from dendrites to produce paracrine and autocrine signaling. Here, we test the hypothesis that postsynaptic release of dopamine and autocrine activation of dopamine receptors is involved in DISC. Light immunohistochemistry showed that D(3) dopamine receptors, vesicular monoamine transporter type 2 (VMAT2), and dopamine plasma membrane transporters (DATs) were all expressed in cerebellar Purkinje cells. However, their expression was strongest in the gyrus region of cerebellar lobules IX and X. Comparison of DISC across lobules revealed that it was weak in the anterior portions of the cerebellum (lobules II, V, and VI) and strong in lobules IX and X. DISC was blocked by dopamine receptor antagonists (haloperidol, clozapine, eticlopride, and SCH23390). Likewise, DISC was strongly attenuated by inhibitors of VMAT (reserpine and tetrabenazine) and DAT (GBR12909 and rimcazole). These drugs did not produce DISC attenuation through blockade of depolarization-evoked Purkinje cell Ca transients. Purkinje cells in cerebellar slices derived from DAT-null mice expressed DISC, but this DISC ran down at a significantly higher rate than littermate controls. Together, these results suggest that strong Purkinje cell depolarization produces Ca-dependent release of vesicular postsynaptic dopamine that then excites Purkinje cells in an autocrine manner.
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46
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Szapiro G, Barbour B. Parasynaptic signalling by fast neurotransmitters: the cerebellar cortex. Neuroscience 2009; 162:644-55. [PMID: 19358875 DOI: 10.1016/j.neuroscience.2009.03.077] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 03/26/2009] [Accepted: 03/30/2009] [Indexed: 11/26/2022]
Abstract
Classic central synaptic transmission by fast neurotransmitters-glutamate, GABA or glycine-involves liberation from vesicles directly opposite postsynaptic receptors at junctions containing both a presynaptic active zone and a postsynaptic specialisation. Such classic transmission is thought to underlie much of the information transfer and processing in the brain. However, there also exist a substantial number of reports of signalling by the same transmitters outside this classic framework, whereby liberation and/or receptor activation occur beyond synaptic boundaries. We term these processes collectively parasynaptic signalling. Here, we describe the various forms of parasynaptic signalling and the available methods for distinguishing them from synaptic transmission. We then review the numerous reports of parasynaptic signalling in the cerebellar cortex, a structure whose specialised anatomy and synapses have facilitated studies of these mechanisms. We examine more generally the question of how the multiple signalling pathways might avoid interaction and address the possible functions of parasynaptic transmission, which in the cerebellar cortex include the regulation of network activity, glial tropism and the control of synaptic plasticity.
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Affiliation(s)
- G Szapiro
- Laboratoire de Neurobiologie, CNRS UMR 8544, Ecole Normale Supérieure, 46 rue d'Ulm 75005, Paris, France
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47
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Kano M, Ohno-Shosaku T, Hashimotodani Y, Uchigashima M, Watanabe M. Endocannabinoid-mediated control of synaptic transmission. Physiol Rev 2009; 89:309-80. [PMID: 19126760 DOI: 10.1152/physrev.00019.2008] [Citation(s) in RCA: 1048] [Impact Index Per Article: 69.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The discovery of cannabinoid receptors and subsequent identification of their endogenous ligands (endocannabinoids) in early 1990s have greatly accelerated research on cannabinoid actions in the brain. Then, the discovery in 2001 that endocannabinoids mediate retrograde synaptic signaling has opened up a new era for cannabinoid research and also established a new concept how diffusible messengers modulate synaptic efficacy and neural activity. The last 7 years have witnessed remarkable advances in our understanding of the endocannabinoid system. It is now well accepted that endocannabinoids are released from postsynaptic neurons, activate presynaptic cannabinoid CB(1) receptors, and cause transient and long-lasting reduction of neurotransmitter release. In this review, we aim to integrate our current understanding of functions of the endocannabinoid system, especially focusing on the control of synaptic transmission in the brain. We summarize recent electrophysiological studies carried out on synapses of various brain regions and discuss how synaptic transmission is regulated by endocannabinoid signaling. Then we refer to recent anatomical studies on subcellular distribution of the molecules involved in endocannabinoid signaling and discuss how these signaling molecules are arranged around synapses. In addition, we make a brief overview of studies on cannabinoid receptors and their intracellular signaling, biochemical studies on endocannabinoid metabolism, and behavioral studies on the roles of the endocannabinoid system in various aspects of neural functions.
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Affiliation(s)
- Masanobu Kano
- Department of Neurophysiology, The University of Tokyo, Tokyo, Japan.
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48
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Ferraguti F, Crepaldi L, Nicoletti F. Metabotropic glutamate 1 receptor: current concepts and perspectives. Pharmacol Rev 2009; 60:536-81. [PMID: 19112153 DOI: 10.1124/pr.108.000166] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Almost 25 years after the first report that glutamate can activate receptors coupled to heterotrimeric G-proteins, tremendous progress has been made in the field of metabotropic glutamate receptors. Now, eight members of this family of glutamate receptors, encoded by eight different genes that share distinctive structural features have been identified. The first cloned receptor, the metabotropic glutamate (mGlu) receptor mGlu1 has probably been the most extensively studied mGlu receptor, and in many respects it represents a prototypical subtype for this family of receptors. Its biochemical, anatomical, physiological, and pharmacological characteristics have been intensely investigated. Together with subtype 5, mGlu1 receptors constitute a subgroup of receptors that couple to phospholipase C and mobilize Ca(2+) from intracellular stores. Several alternatively spliced variants of mGlu1 receptors, which differ primarily in the length of their C-terminal domain and anatomical localization, have been reported. Use of a number of genetic approaches and the recent development of selective antagonists have provided a means for clarifying the role played by this receptor in a number of neuronal systems. In this article we discuss recent advancements in the pharmacology and concepts about the intracellular transduction and pathophysiological role of mGlu1 receptors and review earlier data in view of these novel findings. The impact that this new and better understanding of the specific role of these receptors may have on novel treatment strategies for a variety of neurological and psychiatric disorders is considered.
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Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Innsbruck Medical University, Peter-Mayr Strasse 1a, Innsbruck A-6020, Austria.
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Shin JH, Kim YS, Worley PF, Linden DJ. Depolarization-induced slow current in cerebellar Purkinje cells does not require metabotropic glutamate receptor 1. Neuroscience 2009; 162:688-93. [PMID: 19409231 DOI: 10.1016/j.neuroscience.2009.01.044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 01/21/2009] [Accepted: 01/23/2009] [Indexed: 11/16/2022]
Abstract
Activation of cerebellar Purkinje cells by either brief depolarizing steps or bursts of climbing fiber synaptic activation evokes a slow inward current, which we have previously called depolarization-induced slow current or DISC. DISC is triggered by Ca influx via voltage-sensitive Ca channels and is attenuated by inhibitors of vacuolar ATPase or vesicle fusion. This led us to suggest that DISC required vesicular release of glutamate from the somatodendritic region of Purkinje cells. Furthermore, we found that DISC was attenuated by the mGluR1 antagonist 7-(hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester (CPCCOEt), indicating that DISC required autocrine activation of metabotropic glutamate receptor 1 (mGluR1). Here, we have revisited the role of mGluR1 and found that it is, in fact, not required for DISC. CPCCOEt, but not three other specific mGluR1 antagonists (JNJ16259685, alpha-amino-5-carboxy-3-methyl-2-thiopheneacetic acid (3-MATIDA), Bay 36-7620), attenuated DISC, even though all four of these drugs produced near-complete blockade of current evoked by puffs of the exogenous mGluR1/5 agonist DHPG. Cerebellar slices derived from mGluR1 null mice showed substantial DISC that was still attenuated by CPCCOEt. mGluR5 is functionally similar to mGluR1, but is not expressed at high levels in cerebellar Purkinje cells. 2-Methyl-6-(phenylethynyl)pyridine hydrochloride (MPEP), an mGluR5 antagonist, did not attenuate DISC, and DISC was still present in Purkinje cells derived from mGluR1/mGluR5 double null mice. Thus, neither mGluR1 nor mGluR5 is required for DISC in cerebellar Purkinje cells.
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Affiliation(s)
- J H Shin
- Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
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50
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Hartmann J, Konnerth A. Mechanisms of metabotropic glutamate receptor-mediated synaptic signalling in cerebellar Purkinje cells. Acta Physiol (Oxf) 2009. [DOI: 10.1111/j.1748-1716.2008.01923.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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