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Schmidt CC, Tong R, Emptage NJ. GluN2A- and GluN2B-containing pre-synaptic N-methyl-d-aspartate receptors differentially regulate action potential-evoked Ca 2+ influx via modulation of SK channels. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230222. [PMID: 38853550 DOI: 10.1098/rstb.2023.0222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/02/2024] [Indexed: 06/11/2024] Open
Abstract
N-methyl-d-aspartate receptors (NMDARs) play a pivotal role in synaptic plasticity. While the functional role of post-synaptic NMDARs is well established, pre-synaptic NMDAR (pre-NMDAR) function is largely unexplored. Different pre-NMDAR subunit populations are documented at synapses, suggesting that subunit composition influences neuronal transmission. Here, we used electrophysiological recordings at Schaffer collateral-CA1 synapses partnered with Ca2+ imaging and glutamate uncaging at boutons of CA3 pyramidal neurones to reveal two populations of pre-NMDARs that contain either the GluN2A or GluN2B subunit. Activation of the GluN2B population decreases action potential-evoked Ca2+ influx via modulation of small-conductance Ca2+-activated K+ channels, while activation of the GluN2A population does the opposite. Critically, the level of functional expression of the subunits is subject to homeostatic regulation, bidirectionally affecting short-term facilitation, thus providing a capacity for a fine adjustment of information transfer. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Carla C Schmidt
- Department of Pharmacology, University of Oxford , Oxford OX1 3QT, UK
| | - Rudi Tong
- Department of Pharmacology, University of Oxford , Oxford OX1 3QT, UK
- Montreal Neurological Institute, 3801 University Street , Montreal, Quebec H3A 2B4, Canada
| | - Nigel J Emptage
- Department of Pharmacology, University of Oxford , Oxford OX1 3QT, UK
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2
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Savtchenko LP, Rusakov DA. Equal levels of pre- and postsynaptic potentiation produce unequal outcomes. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230235. [PMID: 38853561 DOI: 10.1098/rstb.2023.0235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 01/05/2024] [Indexed: 06/11/2024] Open
Abstract
Which proportion of the long-term potentiation (LTP) expressed in the bulk of excitatory synapses is postsynaptic and which presynaptic remains debatable. To understand better the possible impact of either LTP form, we explored a realistic model of a CA1 pyramidal cell equipped with known membrane mechanisms and multiple, stochastic excitatory axo-spinous synapses. Our simulations were designed to establish an input-output transfer function, the dependence between the frequency of presynaptic action potentials triggering probabilistic synaptic discharges and the average frequency of postsynaptic spiking. We found that, within the typical physiological range, potentiation of the postsynaptic current results in a greater overall output than an equivalent increase in presynaptic release probability. This difference grows stronger at lower input frequencies and lower release probabilities. Simulations with a non-hierarchical circular network of principal neurons indicated that equal increases in either synaptic fidelity or synaptic strength of individual connections also produce distinct changes in network activity, although the network phenomenology is likely to be complex. These observations should help to interpret the machinery of LTP phenomena documented in situ. This article is part of a discussion meeting issue 'Long-term potentiation: 50 years on'.
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Affiliation(s)
- Leonid P Savtchenko
- UCL Queen Square Institute of Neurology, University College London , London WC1N 3BG, UK
| | - Dmitri A Rusakov
- UCL Queen Square Institute of Neurology, University College London , London WC1N 3BG, UK
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3
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Magdalena K, Agnieszka N, Agata K, Joanna S, Agnieszka P, Dziedzicka-Wasylewska M, Ryszard B, Adam H, Andrzej B, Agata FG. Unraveling psilocybin's therapeutic potential: behavioral and neuroplasticity insights in Wistar-Kyoto and Wistar male rat models of treatment-resistant depression. Psychopharmacology (Berl) 2024:10.1007/s00213-024-06644-3. [PMID: 38963553 DOI: 10.1007/s00213-024-06644-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 06/26/2024] [Indexed: 07/05/2024]
Abstract
RATIONALE Our study aimed to unravel the unknown mechanisms behind the exceptional efficacy of Psilocybin (PSI) in treating treatment-resistant depression (TRD). Focusing on Wistar-Kyoto (WKY) rats with a TRD phenotype and Wistar (WIS) rats as a normative comparison, we investigated behavioral and neuroplasticity-related responses to PSI, striving to shed light on the distinctive features of its antidepressant effects. OBJECTIVES We set out to assess the behavioral impact of acute and prolonged PSI administration on WKY and WIS rats, employing Novel Object Recognition (NORT), Social Interaction (SI), and Forced Swimming Test (FST). Our secondary objectives involved exploring strain-specific alterations in neuroplasticity-related parameters, including brain-derived neurotrophic factor (BDNF) and activity-regulated cytoskeleton-associated protein (Arc). METHODS Conducting post-acute and extended assessments after a single PSI administration, we applied behavioral tests and biochemical analyses to measure serum BDNF levels and neuroplasticity-related parameters in the prefrontal cortex. Statistical analyses were deployed to discern significant differences between the rat strains and assess the impact of PSI on behavioral and biochemical outcomes. RESULTS Our findings uncovered significant behavioral disparities between WKY and WIS rats, indicating passive behavior and social withdrawal in the former. PSI demonstrated pronounced pro-social and antidepressant effects in both strains, each with its distinctive temporal trajectory. Notably, we identified strain-specific variations in BDNF-related signaling and observed the modulation of Arc expression in WKY rats. CONCLUSIONS Our study delineated mood-related behavioral nuances between WKY and WIS rat strains, underscoring the antidepressant and pro-social properties of PSI in both groups. The distinct temporal patterns of observed changes and the identified strain-specific neuroplasticity alterations provide valuable insights into the TRD phenotype and the mechanisms underpinning the efficacy of PSI.
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Affiliation(s)
- Kolasa Magdalena
- Department of Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | - Nikiforuk Agnieszka
- Department of Behavioral Neuroscience & Drug Development, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | - Korlatowicz Agata
- Department of Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | - Solich Joanna
- Department of Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | - Potasiewicz Agnieszka
- Department of Behavioral Neuroscience & Drug Development, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | | | - Bugno Ryszard
- Department of Medicinal Chemistry, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | - Hogendorf Adam
- Department of Medicinal Chemistry, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | - Bojarski Andrzej
- Department of Medicinal Chemistry, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland
| | - Faron-Górecka Agata
- Department of Pharmacology, Maj Institute of Pharmacology Polish Academy of Sciences, Kraków, Poland.
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Andrade-Talavera Y, Fisahn A, Rodríguez-Moreno A. Timing to be precise? An overview of spike timing-dependent plasticity, brain rhythmicity, and glial cells interplay within neuronal circuits. Mol Psychiatry 2023; 28:2177-2188. [PMID: 36991134 PMCID: PMC10611582 DOI: 10.1038/s41380-023-02027-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/31/2023]
Abstract
In the mammalian brain information processing and storage rely on the complex coding and decoding events performed by neuronal networks. These actions are based on the computational ability of neurons and their functional engagement in neuronal assemblies where precise timing of action potential firing is crucial. Neuronal circuits manage a myriad of spatially and temporally overlapping inputs to compute specific outputs that are proposed to underly memory traces formation, sensory perception, and cognitive behaviors. Spike-timing-dependent plasticity (STDP) and electrical brain rhythms are suggested to underlie such functions while the physiological evidence of assembly structures and mechanisms driving both processes continues to be scarce. Here, we review foundational and current evidence on timing precision and cooperative neuronal electrical activity driving STDP and brain rhythms, their interactions, and the emerging role of glial cells in such processes. We also provide an overview of their cognitive correlates and discuss current limitations and controversies, future perspectives on experimental approaches, and their application in humans.
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Affiliation(s)
- Yuniesky Andrade-Talavera
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013, Seville, Spain.
| | - André Fisahn
- Department of Biosciences and Nutrition and Department of Women's and Children's Health, Karolinska Institutet, 171 77, Stockholm, Sweden
| | - Antonio Rodríguez-Moreno
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013, Seville, Spain.
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5
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Gambino G, Gallo D, Covelo A, Ferraro G, Sardo P, Giglia G. TRPV1 channels in nitric oxide-mediated signalling: insight on excitatory transmission in rat CA1 pyramidal neurons. Free Radic Biol Med 2022; 191:128-136. [PMID: 36029909 DOI: 10.1016/j.freeradbiomed.2022.08.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/13/2022] [Accepted: 08/15/2022] [Indexed: 11/18/2022]
Abstract
Nitric oxide (NO) is a fascinating signalling molecule implicated in a plethora of biological functions, especially at the synaptic level. Exploring neurotransmission in the hippocampus could be instrumental in the individuation of putative targets for nitric-oxide mediated neuromodulation, especially in terms of the potential repercussions on fundamental processes i.e. synaptic plasticity and excitability-related phenomena. Among these targets, endovanilloid signalling constitutes an object of study since Transient Receptors Vanilloid type 1 (TRPV1) channels possess a NO-sensitive gate modulating its activation. Also, NO has been referred to as a mediator for numerous endocannabinoid effects. Notwithstanding, the linkage between TRPV1 and NO systems in neuromodulation still remains elusive. To this end, we aim at investigating the involvement of TRPV1 in nitric oxide-mediated influence on hippocampal processes. Electrophysiological whole-cell recordings in CA1 pyramidal neurons were applied to evaluate excitatory neurotransmission in rat brain slices. Indeed, miniature excitatory postsynaptic currents (mEPSCs) were analysed upon pharmacological manipulation of TRPV1 and NO signalling pathways. In detail, only the administration of the specific TRPV1 exogenous agonist - capsaicin - reduced the frequency and amplitude of mEPSC similarly to the inhibitor of neuronal nitric oxide synthase (nNOS), 7-nitroindazole (7NI). In contrast, capsazepine, TRPV1 antagonist, does not influence excitatory transmission. The combined TRPV1 activation and nNOS blockade confirm the presence of a putative common mechanism. When we administered the endovanilloid-endocannabinoid ligand, i.e. anandamide, we unveiled a potentiation of neurotransmission that was selectively reverted by 7NI. Our data suggest that nitric oxide influences TRPV1 hippocampal signalling since these channels are not constitutively active, but can be "on-demand" activated to modulate excitation in CA1 pyramidal neurons, and that this effect is linked to nitric oxide production.
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Affiliation(s)
- Giuditta Gambino
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, Italy.
| | - Daniele Gallo
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, Italy
| | - Ana Covelo
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1215 NeuroCentre Magendie, Bordeaux, France
| | - Giuseppe Ferraro
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, Italy
| | - Pierangelo Sardo
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, Italy
| | - Giuseppe Giglia
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BIND), University of Palermo, Italy
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6
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Martínez-Gallego I, Pérez-Rodríguez M, Coatl-Cuaya H, Flores G, Rodríguez-Moreno A. Adenosine and Astrocytes Determine the Developmental Dynamics of Spike Timing-Dependent Plasticity in the Somatosensory Cortex. J Neurosci 2022; 42:6038-6052. [PMID: 35768208 PMCID: PMC9351642 DOI: 10.1523/jneurosci.0115-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 04/18/2022] [Accepted: 05/18/2022] [Indexed: 02/05/2023] Open
Abstract
During development, critical periods of synaptic plasticity facilitate the reordering and refinement of neural connections, allowing the definitive synaptic circuits responsible for correct adult physiology to be established. The L4-L2/3 synapses in the somatosensory cortex (S1) exhibit a presynaptic form of spike timing-dependent long-term depression (t-LTD) that probably fulfills a role in synaptic refinement. This t-LTD persists until the fourth postnatal week in mice, disappearing thereafter. When we investigated the mechanisms underlying this maturation-related loss of t-LTD in either sex mouse slices, we found that it could be completely recovered by antagonizing adenosine type 1 receptors. By contrast, an agonist of A1R impeded the induction of t-LTD at P13-27. Furthermore, we found that the adenosine that mediated the loss of t-LTD at the end of the fourth week of development is most probably supplied by astrocytes. At more mature stages (P38-60), we found that the protocol used to induce t-LTD provokes t-LTP. We characterized the mechanisms underlying the induction of this form of LTP, and we found it to be expressed presynaptically, as witnessed by paired-pulse and coefficient of variation analysis. In addition, this form of presynaptic t-LTP requires the activation of NMDARs and mGlu1Rs, and the entry of Ca2+ into the postsynaptic neuron through L-type voltage-dependent Ca2+ channels. Nitric oxide is also required for t-LTP as a messenger in the postsynaptic neuron as are the adenosine and glutamate that are released in association with astrocyte signaling. These results provide direct evidence of the mechanisms that close the window of plasticity associated with t-LTD and that drive the switch in synaptic transmission from t-LTD to t-LTP at L4-L2/3 synapses, in which astrocytes play a central role.SIGNIFICANCE STATEMENT During development, critical periods of plasticity facilitate the reordering and refining of neural connections, allowing correct adult physiology to be established. The L4-L2/3 synapses in the somatosensory cortex exhibit a presynaptic form plasticity (LTD) that probably fulfills a role in synaptic refinement. It is present until the fourth postnatal week in mice, disappearing thereafter. The mechanisms that are responsible for this loss of plasticity are not clear. We describe here these mechanisms and those involved in the switch from LTD to LTP observed as the brain matures. Defining these events responsible for closing (and opening) plasticity windows may be important for brain repair, sensorial recovery, the treatment of neurodevelopmental disorders, and for educational policy.
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Affiliation(s)
- Irene Martínez-Gallego
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Mikel Pérez-Rodríguez
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Heriberto Coatl-Cuaya
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
| | - Gonzalo Flores
- Instituto de Fisiología, Benemérita Universidad Autónoma de Puebla, Puebla CP 72570, México
| | - Antonio Rodríguez-Moreno
- Laboratory of Cellular Neuroscience and Plasticity, Department of Physiology, Anatomy and Cell Biology, Universidad Pablo de Olavide, ES-41013 Seville, Spain
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7
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Sakimoto Y, Shintani A, Yoshiura D, Goshima M, Kida H, Mitsushima D. A critical period for learning and plastic changes at hippocampal CA1 synapses. Sci Rep 2022; 12:7199. [PMID: 35504922 PMCID: PMC9065057 DOI: 10.1038/s41598-022-10453-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/24/2022] [Indexed: 02/07/2023] Open
Abstract
Postnatal development of hippocampal function has been reported in many mammalian species, including humans. To obtain synaptic evidence, we analyzed developmental changes in plasticity after an inhibitory avoidance task in rats. Learning performance was low in infants (postnatal 2 weeks) but clearly improved from the juvenile period (3–4 weeks) to adulthood (8 weeks). One hour after the training, we prepared brain slices and sequentially recorded miniature excitatory postsynaptic currents (mEPSCs) and inhibitory postsynaptic currents (mIPSCs) from the same hippocampal CA1 neuron. Although the training failed to affect the amplitude of either mEPSCs or mIPSCs at 2 weeks, it increased mEPSC, but not mIPSC, amplitude at 3 weeks. At 4 weeks, the training had increased the amplitude of both mEPSCs and mIPSCs, whereas mIPSC, but not mEPSC, amplitude was increased at 8 weeks. Because early-life physiological functions can affect performance, we also evaluated sensory–motor functions together with emotional state and found adequate sensory/motor functions from infancy to adulthood. Moreover, by analyzing performance of rats in multiple hippocampal-dependent tasks, we found that the developmental changes in the performance are task dependent. Taken together, these findings delineate a critical period for learning and plastic changes at hippocampal CA1 synapses.
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Affiliation(s)
- Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan.
| | - Ako Shintani
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Daiki Yoshiura
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Makoto Goshima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Hiroyuki Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Ube, 755-8505, Japan. .,The Research Institute for Time Studies, Yamaguchi University, Yamaguchi, 753-8511, Japan.
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8
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Di Castro MA, Volterra A. Astrocyte control of the entorhinal cortex-dentate gyrus circuit: Relevance to cognitive processing and impairment in pathology. Glia 2021; 70:1536-1553. [PMID: 34904753 PMCID: PMC9299993 DOI: 10.1002/glia.24128] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 12/20/2022]
Abstract
The entorhinal cortex-dentate gyrus circuit is centrally involved in memory processing conveying to the hippocampus spatial and nonspatial context information via, respectively, medial and lateral perforant path (MPP and LPP) excitatory projections onto dentate granule cells (GCs). Here, we review work of several years from our group showing that astrocytes sense local synaptic transmission and exert in turn a presynaptic control at PP-GC synapses. Modulation of neurotransmitter release probability by astrocytes sets basal synaptic strength and dynamic range for long-term potentiation of PP-GC synapses. Intriguingly, this astrocyte control is circuit-specific, being present only at MPP-GC (not LPP-GC) synapses, which selectively express atypical presynaptic N-methyl-D-aspartate receptors (NMDAR) suitable to activation by astrocyte-released glutamate. Moreover, the astrocytic control is peculiarly dependent on the cytokine TNFα, which at constitutive levels acts as a gating factor for the astrocyte signaling. During inflammation/infection processes, increased levels of TNFα lead to uncontrolled astrocyte glutamate release, altered PP-GC circuit processing and, ultimately, impaired contextual memory performance. The TNFα-dependent pathological switch of the synaptic control from astrocytes and its deleterious consequences are observed in animal models of HIV brain infection and multiple sclerosis, conditions both known to cause cognitive disturbances in up to 50% of patients. The review also discusses open issues related to the identified astrocytic pathway: its role in contextual memory processing, potential damaging role in Alzheimer's disease, the existence of vesicular glutamate release from DG astrocytes, and the possible synaptic-like connectivity between astrocytic output sites and PP receptive sites.
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Affiliation(s)
- Maria Amalia Di Castro
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland.,Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Andrea Volterra
- Department of Fundamental Neuroscience, University of Lausanne, Lausanne, Switzerland
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9
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Li X, Chien C, Han Y, Sun Z, Chen X, Dickman D. Autocrine inhibition by a glutamate-gated chloride channel mediates presynaptic homeostatic depression. SCIENCE ADVANCES 2021; 7:eabj1215. [PMID: 34851664 PMCID: PMC8635443 DOI: 10.1126/sciadv.abj1215] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 10/14/2021] [Indexed: 06/13/2023]
Abstract
Homeostatic modulation of presynaptic neurotransmitter release is a fundamental form of plasticity that stabilizes neural activity, where presynaptic homeostatic depression (PHD) can adaptively diminish synaptic strength. PHD has been proposed to operate through an autocrine mechanism to homeostatically depress release probability in response to excess glutamate release at the Drosophila neuromuscular junction. This model implies the existence of a presynaptic glutamate autoreceptor. We systematically screened all neuronal glutamate receptors in the fly genome and identified the glutamate-gated chloride channel (GluClα) to be required for the expression of PHD. Pharmacological, genetic, and Ca2+ imaging experiments demonstrate that GluClα acts locally at axonal terminals to drive PHD. Unexpectedly, GluClα localizes and traffics with synaptic vesicles to drive presynaptic inhibition through an activity-dependent anionic conductance. Thus, GluClα operates as both a sensor and effector of PHD to adaptively depress neurotransmitter release through an elegant autocrine inhibitory signaling mechanism at presynaptic terminals.
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Affiliation(s)
- Xiling Li
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
- USC Neuroscience Graduate Program, Los Angeles, CA, 90089, USA
| | - Chun Chien
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
- USC Neuroscience Graduate Program, Los Angeles, CA, 90089, USA
| | - Yifu Han
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
- USC Neuroscience Graduate Program, Los Angeles, CA, 90089, USA
| | - Zihan Sun
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
| | - Xun Chen
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
- USC Neuroscience Graduate Program, Los Angeles, CA, 90089, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA, 90089, USA
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10
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NMDARs in granule cells contribute to parallel fiber-Purkinje cell synaptic plasticity and motor learning. Proc Natl Acad Sci U S A 2021; 118:2102635118. [PMID: 34507990 PMCID: PMC8449340 DOI: 10.1073/pnas.2102635118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/07/2021] [Indexed: 11/18/2022] Open
Abstract
Long-term synaptic plasticity is believed to be the cellular substrate of learning and memory. Synaptic plasticity rules are defined by the specific complement of receptors at the synapse and the associated downstream signaling mechanisms. In young rodents, at the cerebellar synapse between granule cells (GC) and Purkinje cells (PC), bidirectional plasticity is shaped by the balance between transcellular nitric oxide (NO) driven by presynaptic N-methyl-D-aspartate receptor (NMDAR) activation and postsynaptic calcium dynamics. However, the role and the location of NMDAR activation in these pathways is still debated in mature animals. Here, we show in adult rodents that NMDARs are present and functional in presynaptic terminals where their activation triggers NO signaling. In addition, we find that selective genetic deletion of presynaptic, but not postsynaptic, NMDARs prevents synaptic plasticity at parallel fiber-PC (PF-PC) synapses. Consistent with this finding, the selective deletion of GC NMDARs affects adaptation of the vestibulo-ocular reflex. Thus, NMDARs presynaptic to PCs are required for bidirectional synaptic plasticity and cerebellar motor learning.
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11
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Rey S, Marra V, Smith C, Staras K. Nanoscale Remodeling of Functional Synaptic Vesicle Pools in Hebbian Plasticity. Cell Rep 2021; 30:2006-2017.e3. [PMID: 32049027 PMCID: PMC7016504 DOI: 10.1016/j.celrep.2020.01.051] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 10/21/2019] [Accepted: 01/14/2020] [Indexed: 12/23/2022] Open
Abstract
Vesicle pool properties are known determinants of synaptic efficacy, but their potential role as modifiable substrates in forms of Hebbian plasticity is still unclear. Here, we investigate this using a nanoscale readout of functionally recycled vesicles in natively wired hippocampal CA3→CA1 circuits undergoing long-term potentiation (LTP). We show that the total recycled vesicle pool is larger after plasticity induction, with the smallest terminals exhibiting the greatest relative expansion. Changes in the spatial organization of vesicles accompany potentiation including a specific increase in the number of recycled vesicles at the active zone, consistent with an ultrastructural remodeling component of synaptic strengthening. The cAMP-PKA pathway activator, forskolin, selectively mimics some features of LTP-driven changes, suggesting that distinct and independent modules of regulation accompany plasticity expression. Our findings provide evidence for a presynaptic locus of LTP encoded in the number and arrangement of functionally recycled vesicles, with relevance for models of long-term plasticity storage.
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Affiliation(s)
- Stephanie Rey
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Vincenzo Marra
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester L1 7RH, United Kingdom
| | - Catherine Smith
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Kevin Staras
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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12
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Heterosynaptic cross-talk of pre- and postsynaptic strengths along segments of dendrites. Cell Rep 2021; 34:108693. [PMID: 33503435 DOI: 10.1016/j.celrep.2021.108693] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/13/2020] [Accepted: 01/05/2021] [Indexed: 11/20/2022] Open
Abstract
Dendrites are crucial for integrating incoming synaptic information. Individual dendritic branches are thought to constitute a signal processing unit, yet how neighboring synapses shape the boundaries of functional dendritic units is not well understood. Here, we address the cellular basis underlying the organization of the strengths of neighboring Schaffer collateral-CA1 synapses by optical quantal analysis and spine size measurements. Inducing potentiation at clusters of spines produces NMDA-receptor-dependent heterosynaptic plasticity. The direction of postsynaptic strength change shows distance dependency to the stimulated synapses where proximal synapses predominantly depress, whereas distal synapses potentiate; potentiation and depression are regulated by CaMKII and calcineurin, respectively. In contrast, heterosynaptic presynaptic plasticity is confined to weakening of presynaptic strength of nearby synapses, which requires CaMKII and the retrograde messenger nitric oxide. Our findings highlight the parallel engagement of multiple signaling pathways, each with characteristic spatial dynamics in shaping the local pattern of synaptic strengths.
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13
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Wong HHW, Rannio S, Jones V, Thomazeau A, Sjöström PJ. NMDA receptors in axons: there's no coincidence. J Physiol 2020; 599:367-387. [PMID: 33141440 DOI: 10.1113/jp280059] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/27/2020] [Indexed: 12/16/2022] Open
Abstract
In the textbook view, N-methyl-d-aspartate (NMDA) receptors are postsynaptically located detectors of coincident activity in Hebbian learning. However, controversial presynaptically located NMDA receptors (preNMDARs) have for decades been repeatedly reported in the literature. These preNMDARs have typically been implicated in the regulation of short-term and long-term plasticity, but precisely how they signal and what their functional roles are have been poorly understood. The functional roles of preNMDARs across several brain regions and different forms of plasticity can differ vastly, with recent discoveries showing key involvement of unusual subunit composition. Increasing evidence shows preNMDAR can signal through both ionotropic action by fluxing calcium and in metabotropic mode even in the presence of magnesium blockade. We argue that these unusual properties may explain why controversy has surrounded this receptor type. In addition, the expression of preNMDARs at some synapse types but not others can underlie synapse-type-specific plasticity. Last but not least, preNMDARs are emerging therapeutic targets in disease states such as neuropathic pain. We conclude that axonally located preNMDARs are required for specific purposes and do not end up there by accident.
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Affiliation(s)
- Hovy Ho-Wai Wong
- Department of Medicine, Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Ave, Montreal, Quebec, H3G 1A4, Canada
| | - Sabine Rannio
- Department of Medicine, Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Ave, Montreal, Quebec, H3G 1A4, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Victoria Jones
- Department of Medicine, Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Ave, Montreal, Quebec, H3G 1A4, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Aurore Thomazeau
- Department of Medicine, Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Ave, Montreal, Quebec, H3G 1A4, Canada
| | - P Jesper Sjöström
- Department of Medicine, Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, 1650 Cedar Ave, Montreal, Quebec, H3G 1A4, Canada
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14
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Chater TE, Goda Y. My Neighbour Hetero-deconstructing the mechanisms underlying heterosynaptic plasticity. Curr Opin Neurobiol 2020; 67:106-114. [PMID: 33160201 DOI: 10.1016/j.conb.2020.10.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/05/2020] [Accepted: 10/11/2020] [Indexed: 02/06/2023]
Abstract
Synapses change in strength following patterns of activity, but in many cases seemingly inactive neighbouring synapses also undergo changes in strength. These heterosynaptic changes occur across developmental time-points in various brain circuits in different species, but their precise molecular mechanisms are not well understood. Additionally, heterosynaptic changes can mirror homosynaptic plasticity or occur in opposition to homosynaptic changes. In this review we consider what useful functionality heterosynaptic dynamics could potentially endow the circuit with, and the underlying signalling events that implement heterosynaptic changes. We discuss what unanswered questions remain, and what the future looks like for understanding the logic of synaptic plasticity.
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Affiliation(s)
- Thomas E Chater
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Yukiko Goda
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan.
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15
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Ebner C, Clopath C, Jedlicka P, Cuntz H. Unifying Long-Term Plasticity Rules for Excitatory Synapses by Modeling Dendrites of Cortical Pyramidal Neurons. Cell Rep 2020; 29:4295-4307.e6. [PMID: 31875541 PMCID: PMC6941234 DOI: 10.1016/j.celrep.2019.11.068] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/02/2019] [Accepted: 11/15/2019] [Indexed: 11/30/2022] Open
Abstract
A large number of experiments have indicated that precise spike times, firing rates, and synapse locations crucially determine the dynamics of long-term plasticity induction in excitatory synapses. However, it remains unknown how plasticity mechanisms of synapses distributed along dendritic trees cooperate to produce the wide spectrum of outcomes for various plasticity protocols. Here, we propose a four-pathway plasticity framework that is well grounded in experimental evidence and apply it to a biophysically realistic cortical pyramidal neuron model. We show in computer simulations that several seemingly contradictory experimental landmark studies are consistent with one unifying set of mechanisms when considering the effects of signal propagation in dendritic trees with respect to synapse location. Our model identifies specific spatiotemporal contributions of dendritic and axo-somatic spikes as well as of subthreshold activation of synaptic clusters, providing a unified parsimonious explanation not only for rate and timing dependence but also for location dependence of synaptic changes. A phenomenological synaptic plasticity rule is applied to a pyramidal neuron model Model reproduces rate-, timing-, and location-dependent plasticity results Active dendrites allow plasticity via dendritic spikes and subthreshold events Cooperative plasticity exists across the dendritic tree and within single branches
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Affiliation(s)
- Christian Ebner
- Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany; Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt am Main, Germany; NeuroCure Cluster of Excellence, Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany; Institute for Biology, Humboldt-Universität zu Berlin, 10117 Berlin, Germany.
| | - Claudia Clopath
- Computational Neuroscience Laboratory, Bioengineering Department, Imperial College London, London SW7 2AZ, UK
| | - Peter Jedlicka
- Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany; Institute of Clinical Neuroanatomy, Neuroscience Center, Goethe University Frankfurt, 60528 Frankfurt am Main, Germany; ICAR3R-Interdisciplinary Centre for 3Rs in Animal Research, Faculty of Medicine, Justus-Liebig-University, 35392 Giessen, Germany
| | - Hermann Cuntz
- Frankfurt Institute for Advanced Studies, 60438 Frankfurt am Main, Germany; Ernst Strüngmann Institute (ESI) for Neuroscience in Cooperation with Max Planck Society, 60528 Frankfurt am Main, Germany
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16
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Astrocyte-mediated switch in spike timing-dependent plasticity during hippocampal development. Nat Commun 2020; 11:4388. [PMID: 32873805 PMCID: PMC7463247 DOI: 10.1038/s41467-020-18024-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 07/31/2020] [Indexed: 01/31/2023] Open
Abstract
Presynaptic spike timing-dependent long-term depression (t-LTD) at hippocampal CA3-CA1 synapses is evident until the 3rd postnatal week in mice, disappearing during the 4th week. At more mature stages, we found that the protocol that induced t-LTD induced t-LTP. We characterized this form of t-LTP and the mechanisms involved in its induction, as well as that driving this switch from t-LTD to t-LTP. We found that this t-LTP is expressed presynaptically at CA3-CA1 synapses, as witnessed by coefficient of variation, number of failures, paired-pulse ratio and miniature responses analysis. Additionally, this form of presynaptic t-LTP does not require NMDARs but the activation of mGluRs and the entry of Ca2+ into the postsynaptic neuron through L-type voltage-dependent Ca2+ channels and the release of Ca2+ from intracellular stores. Nitric oxide is also required as a messenger from the postsynaptic neuron. Crucially, the release of adenosine and glutamate by astrocytes is required for t-LTP induction and for the switch from t-LTD to t-LTP. Thus, we have discovered a developmental switch of synaptic transmission from t-LTD to t-LTP at hippocampal CA3-CA1 synapses in which astrocytes play a central role and revealed a form of presynaptic LTP and the rules for its induction. Presynaptic spike timing-dependent long-term depression at hippocampal CA3-CA1 synapses is evident until the third postnatal week in mice. The authors show that maturation beyond four weeks is associated with a switch to long-term potentiation in which astrocytes play a central role.
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17
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Tong R, Emptage NJ, Padamsey Z. A two-compartment model of synaptic computation and plasticity. Mol Brain 2020; 13:79. [PMID: 32434549 PMCID: PMC7238589 DOI: 10.1186/s13041-020-00617-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 05/06/2020] [Indexed: 11/10/2022] Open
Abstract
The synapse is typically viewed as a single compartment, which acts as a linear gain controller on incoming input. Traditional plasticity rules enable this gain control to be dynamically optimized by Hebbian activity. Whilst this view nicely captures postsynaptic function, it neglects the non-linear dynamics of presynaptic function. Here we present a two-compartment model of the synapse in which the presynaptic terminal first acts to filter presynaptic input before the postsynaptic terminal, acting as a gain controller, amplifies or depresses transmission. We argue that both compartments are equipped with distinct plasticity rules to enable them to optimally adapt synaptic transmission to the statistics of pre- and postsynaptic activity. Specifically, we focus on how presynaptic plasticity enables presynaptic filtering to be optimally tuned to only transmit information relevant for postsynaptic firing. We end by discussing the advantages of having a presynaptic filter and propose future work to explore presynaptic function and plasticity in vivo.
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Affiliation(s)
- Rudi Tong
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK. .,Current address: McGill University, Montreal Neurological Institute, 3801 University Street, Montreal, H3A 2B4, Canada.
| | - Nigel J Emptage
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| | - Zahid Padamsey
- Centre of Discovery Brain Sciences, University of Edinburgh, 9 George Square, Edinburgh, EH8 9XD, UK.
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18
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Paw-Min-Thein-Oo, Sakimoto Y, Kida H, Mitsushima D. Proximodistal Heterogeneity in Learning-promoted Pathway-specific Plasticity at Dorsal CA1 Synapses. Neuroscience 2020; 437:184-195. [PMID: 32360699 DOI: 10.1016/j.neuroscience.2020.04.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 01/28/2023]
Abstract
Contextual learning requires the delivery of AMPA receptors to CA1 synapses in the dorsal hippocampus. However, proximodistal heterogeneity of pathway-specific plasticity remains unclear. Here, we examined the proximodistal heterogeneity in learning-induced plasticity at the CA1 synapses with inputs from the entorhinal cortex layer III (ECIII) or from CA3. We subjected male rats to an inhibitory avoidance task and prepared acute hippocampal slices for whole-cell patch clamp experiments, where we stimulated ECIII-CA1 or CA3-CA1 input fibers to analyze evoked excitatory postsynaptic currents (EPSCs). Compared to untrained controls, trained rats exhibited higher AMPA/NMDA current ratios at CA3-CA1 synapses of proximal and intermediate, but not distal CA1 neurons, which suggested that region-specific plasticity occurred after learning. Moreover, trained rats exhibited higher AMPA/NMDA current ratios at ECIII-CA1 synapses of intermediate and distal, but not proximal CA1 neurons. These findings suggested the presence of proximodistal heterogeneity in pathway-specific postsynaptic plasticity. Regarding presynaptic plasticity, training slightly, but significantly increased the paired-pulse ratios of CA3-CA1 synapses of proximal and intermediate, but not distal CA1 neurons. Moreover, trained rats exhibited higher paired-pulse ratios at ECIII-CA1 synapses of intermediate and distal, but not proximal CA1 neurons, which suggested region-specific presynaptic plasticity. Finally, learning was clearly prevented by the bilateral microinjection of a plasticity blocker in the proximal or intermediate, but not distal CA1 subfields, which suggested functional heterogeneity along the proximodistal axis. Understanding region- and pathway-specific plasticity at dorsal CA1 synapses could aid in controlling encoded memory.
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Affiliation(s)
- Paw-Min-Thein-Oo
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Yuya Sakimoto
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Hiroyuki Kida
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan
| | - Dai Mitsushima
- Department of Physiology, Yamaguchi University Graduate School of Medicine, Yamaguchi 755-8505, Japan; The Research Institute for Time Studies, Yamaguchi University, Yamaguchi 753-8511, Japan.
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19
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Sanderson TM, Georgiou J, Collingridge GL. Illuminating Relationships Between the Pre- and Post-synapse. Front Neural Circuits 2020; 14:9. [PMID: 32308573 PMCID: PMC7146027 DOI: 10.3389/fncir.2020.00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/06/2020] [Indexed: 12/11/2022] Open
Abstract
Excitatory synapses in the mammalian cortex are highly diverse, both in terms of their structure and function. However, relationships between synaptic features indicate they are highly coordinated entities. Imaging techniques, that enable physiology at the resolution of individual synapses to be investigated, have allowed the presynaptic activity level of the synapse to be related to postsynaptic function. This approach has revealed that neuronal activity induces the pre- and post-synapse to be functionally correlated and that subsets of synapses are more susceptible to certain forms of synaptic plasticity. As presynaptic function is often examined in isolation from postsynaptic properties, the effect it has on the post-synapse is not fully understood. However, since postsynaptic receptors at excitatory synapses respond to release of glutamate, it follows that they may be differentially regulated depending on the frequency of its release. Therefore, examining postsynaptic properties in the context of presynaptic function may be a useful way to approach a broad range of questions on synaptic physiology. In this review, we focus on how optophysiology tools have been utilized to study relationships between the pre- and the post-synapse. Multiple imaging techniques have revealed correlations in synaptic properties from the submicron to the dendritic level. Optical tools together with advanced imaging techniques are ideally suited to illuminate this area further, due to the spatial resolution and control they allow.
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Affiliation(s)
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
| | - Graham L Collingridge
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada.,Tanz Centre for Research in Neurodegenerative Diseases, Department of Physiology, University of Toronto, Toronto, ON, Canada.,Glutamate Research Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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20
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Li X, Goel P, Wondolowski J, Paluch J, Dickman D. A Glutamate Homeostat Controls the Presynaptic Inhibition of Neurotransmitter Release. Cell Rep 2019; 23:1716-1727. [PMID: 29742428 PMCID: PMC5973541 DOI: 10.1016/j.celrep.2018.03.130] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 01/24/2018] [Accepted: 03/28/2018] [Indexed: 02/07/2023] Open
Abstract
We have interrogated the synaptic dialog that enables the bi-directional, homeostatic control of pre-synaptic efficacy at the glutamatergic Drosophila neuromuscular junction (NMJ). We find that homeo-static depression and potentiation use disparate genetic, induction, and expression mechanisms. Specifically, homeostatic potentiation is achieved through reduced CaMKII activity postsynaptically and increased abundance of active zone material presynaptically at one of the two neuronal subtypes innervating the NMJ, while homeostatic depression occurs without alterations in CaMKII activity and is expressed at both neuronal subtypes. Furthermore, homeostatic depression is only induced through excess presynaptic glutamate release and operates with disregard to the postsynaptic response. We propose that two independent homeostats modulate presynaptic efficacy at the Drosophila NMJ: one is an intercellular signaling system that potentiates synaptic strength following diminished postsynaptic excitability, while the other adaptively modulates presynaptic glutamate release through an autocrine mechanism without feedback from the postsynaptic compartment.
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Affiliation(s)
- Xiling Li
- Department of Neurobiology, University of Southern California, Los Angeles, CA; USC Neuroscience Graduate Program, University of Southern California, Los Angeles, CA
| | - Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA; USC Graduate Program in Molecular and Computational Biology, University of Southern California, Los Angeles, CA
| | - Joyce Wondolowski
- Department of Neurobiology, University of Southern California, Los Angeles, CA
| | - Jeremy Paluch
- Department of Neurobiology, University of Southern California, Los Angeles, CA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA.
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21
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Padamsey Z, Foster WJ, Emptage NJ. Intracellular Ca 2+ Release and Synaptic Plasticity: A Tale of Many Stores. Neuroscientist 2019; 25:208-226. [PMID: 30014771 DOI: 10.1177/1073858418785334] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ca2+ is an essential trigger for most forms of synaptic plasticity. Ca2+ signaling occurs not only by Ca2+ entry via plasma membrane channels but also via Ca2+ signals generated by intracellular organelles. These organelles, by dynamically regulating the spatial and temporal extent of Ca2+ elevations within neurons, play a pivotal role in determining the downstream consequences of neural signaling on synaptic function. Here, we review the role of three major intracellular stores: the endoplasmic reticulum, mitochondria, and acidic Ca2+ stores, such as lysosomes, in neuronal Ca2+ signaling and plasticity. We provide a comprehensive account of how Ca2+ release from these stores regulates short- and long-term plasticity at the pre- and postsynaptic terminals of central synapses.
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Affiliation(s)
- Zahid Padamsey
- 1 Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, 15 George Square, Edinburgh, UK
| | - William J Foster
- 2 Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, Oxfordshire, UK
| | - Nigel J Emptage
- 2 Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, Oxfordshire, UK
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22
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Padamsey Z, Tong R, Emptage N. Optical Quantal Analysis Using Ca 2+ Indicators: A Robust Method for Assessing Transmitter Release Probability at Excitatory Synapses by Imaging Single Glutamate Release Events. Front Synaptic Neurosci 2019; 11:5. [PMID: 30886576 PMCID: PMC6409341 DOI: 10.3389/fnsyn.2019.00005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 02/14/2019] [Indexed: 11/13/2022] Open
Abstract
Despite evidence that presynaptic efficacy and plasticity influence circuit function and behavior in vivo, studies of presynaptic function remain challenging owing to the difficulty of assessing transmitter release in intact tissue. Electrophysiological analyses of transmitter release are indirect and cannot readily resolve basic presynaptic parameters, most notably transmitter release probability (p r), at single synapses. These issues can be circumvented by optical quantal analysis, which uses the all-or-none optical detection of transmitter release in order to calculate p r. Over the past two decades, we and others have successfully demonstrated that Ca2+ indicators can be strategically implemented to perform optical quantal analysis at single glutamatergic synapses in ex vivo and in vitro preparations. We have found that high affinity Ca2+ indicators can reliably detect spine Ca2+ influx generated by single quanta of glutamate, thereby enabling precise calculation of pr at single synapses. Importantly, we have shown this method to be robust to changes in postsynaptic efficacy, and to be sensitive to activity-dependent presynaptic changes at central synapses following the induction of long-term potentiation (LTP) and long-term depression (LTD). In this report, we describe how to use Ca2+-sensitive dyes to perform optical quantal analysis at single synapses in hippocampal slice preparations. The general technique we describe here can be applied to other glutamatergic synapses and can be used with other reporters of glutamate release, including recently improved genetically encoded Ca2+ and glutamate sensors. With ongoing developments in imaging techniques and genetically encoded probes, optical quantal analysis is a promising strategy for assessing presynaptic function and plasticity in vivo.
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Affiliation(s)
- Zahid Padamsey
- Center for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Rudi Tong
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Nigel Emptage
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
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23
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Manohar S, Ramchander PV, Salvi R, Seigel GM. Synaptic Reorganization Response in the Cochlear Nucleus Following Intense Noise Exposure. Neuroscience 2018; 399:184-198. [PMID: 30593923 DOI: 10.1016/j.neuroscience.2018.12.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 12/13/2018] [Accepted: 12/14/2018] [Indexed: 12/13/2022]
Abstract
The cochlear nucleus, located in the brainstem, receives its afferent auditory input exclusively from the auditory nerve fibers of the ipsilateral cochlea. Noise-induced neurodegenerative changes occurring in the auditory nerve stimulate a cascade of neuroplastic changes in the cochlear nucleus resulting in major changes in synaptic structure and function. To identify some of the key molecular mechanisms mediating this synaptic reorganization, we unilaterally exposed rats to a high-intensity noise that caused significant hearing loss and then measured the resulting changes in a synaptic plasticity gene array targeting neurogenesis and synaptic reorganization. We compared the gene expression patterns in the dorsal cochlear nucleus (DCN) and ventral cochlear nucleus (VCN) on the noise-exposed side versus the unexposed side using a PCR gene array at 2 d (early) and 28 d (late) post-exposure. We discovered a number of differentially expressed genes, particularly those related to synaptogenesis and regeneration. Significant gene expression changes occurred more frequently in the VCN than the DCN and more changes were seen at 28 d versus 2 d post-exposure. We confirmed the PCR findings by in situ hybridization for Brain-derived neurotrophic factor (Bdnf), Homer-1, as well as the glutamate NMDA receptor Grin1, all involved in neurogenesis and plasticity. These results suggest that Bdnf, Homer-1 and Grin1 play important roles in synaptic remodeling and homeostasis in the cochlear nucleus following severe noise-induced afferent degeneration.
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Affiliation(s)
- S Manohar
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States
| | - P V Ramchander
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States
| | - R Salvi
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States.
| | - G M Seigel
- University at Buffalo, Center for Hearing and Deafness, 3435 Main Street, Cary 137, Buffalo, NY 14214, United States
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24
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Foster WJ, Taylor HBC, Padamsey Z, Jeans AF, Galione A, Emptage NJ. Hippocampal mGluR1-dependent long-term potentiation requires NAADP-mediated acidic store Ca 2+ signaling. Sci Signal 2018; 11:11/558/eaat9093. [PMID: 30482851 DOI: 10.1126/scisignal.aat9093] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Acidic organelles, such as endosomes and lysosomes, store Ca2+ that is released in response to intracellular increases in the second messenger nicotinic acid adenine dinucleotide phosphate (NAADP). In neurons, NAADP and Ca2+ signaling contribute to synaptic plasticity, a process of activity-dependent long-term potentiation (LTP) [or, alternatively, long-term depression (LTD)] of synaptic strength and neuronal transmission that is critical for neuronal function and memory formation. We explored the function of and mechanisms regulating acidic Ca2+ store signaling in murine hippocampal neurons. We found that metabotropic glutamate receptor 1 (mGluR1) was coupled to NAADP signaling that elicited Ca2+ release from acidic stores. In turn, this released Ca2+-mediated mGluR1-dependent LTP by transiently inhibiting SK-type K+ channels, possibly through the activation of protein phosphatase 2A. Genetically removing two-pore channels (TPCs), which are endolysosomal-specific ion channels, switched the polarity of plasticity from LTP to LTD, indicating the importance of specific receptor store coupling and providing mechanistic insight into how mGluR1 can produce both synaptic potentiation and synaptic depression.
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Affiliation(s)
- William J Foster
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| | - Henry B C Taylor
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Zahid Padamsey
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Alexander F Jeans
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
| | - Nigel J Emptage
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK.
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25
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Wiegert JS, Pulin M, Gee CE, Oertner TG. The fate of hippocampal synapses depends on the sequence of plasticity-inducing events. eLife 2018; 7:39151. [PMID: 30311904 PMCID: PMC6205809 DOI: 10.7554/elife.39151] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/11/2018] [Indexed: 01/31/2023] Open
Abstract
Synapses change their strength in response to specific activity patterns. This functional plasticity is assumed to be the brain’s primary mechanism for information storage. We used optogenetic stimulation of rat hippocampal slice cultures to induce long-term potentiation (LTP), long-term depression (LTD), or both forms of plasticity in sequence. Two-photon imaging of spine calcium signals allowed us to identify stimulated synapses and to follow their fate for the next 7 days. We found that plasticity-inducing protocols affected the synapse’s chance for survival: LTP increased synaptic stability, LTD destabilized synapses, and the effect of the last stimulation protocol was dominant over earlier stimulations. Interestingly, most potentiated synapses were resistant to depression-inducing protocols delivered 24 hr later. Our findings suggest that activity-dependent changes in the transmission strength of individual synapses are transient, but have long-lasting consequences for synaptic lifetime.
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Affiliation(s)
- J Simon Wiegert
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mauro Pulin
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christine Elizabeth Gee
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas G Oertner
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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26
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NMDA Receptors Containing GluN2B/2C/2D Subunits Mediate an Increase in Glutamate Release at Hippocampal CA3–CA1 Synapses. Mol Neurobiol 2018; 56:1694-1706. [DOI: 10.1007/s12035-018-1187-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 06/07/2018] [Indexed: 12/19/2022]
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