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Tullis JE, Bayer KU. Induction of LTP mechanisms in dually innervated dendritic spines. Sci Rep 2024; 14:15855. [PMID: 38982271 PMCID: PMC11233660 DOI: 10.1038/s41598-024-66871-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 07/04/2024] [Indexed: 07/11/2024] Open
Abstract
Dendritic spines are the postsynaptic compartments of excitatory synapses, however, a substantial subset of spines additionally receives inhibitory input. In such dually innervated spines (DiSs), excitatory long-term potentiation (LTP) mechanisms are suppressed, but can be enabled by blocking tonic inhibitory GABAB receptor signaling. Here we show that LTP mechanisms at DiSs are also enabled by two other excitatory LTP stimuli. In hippocampal neurons, these chemical LTP (cLTP) stimuli induced robust movement of the Ca2+/calmodulin-dependent protein kinase II (CaMKII) to DiSs. Such synaptic CaMKII accumulation is an essential LTP mechanism at singly innervated spines (SiSs). Indeed, CaMKII accumulation at DiSs was also accompanied by other readouts for successful LTP induction: spine growth and surface insertion of GluA1. Thus, DiSs are capable of the same LTP mechanisms as SiSs, although induction of these mechanism additionally requires either reduced inhibitory signaling or increased excitatory stimulation. This additional regulation may provide further computational control.
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Affiliation(s)
- Jonathan E Tullis
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - K Ulrich Bayer
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
- Program in Neuroscience, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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2
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Wang Z, Hu Q, Tian C, Wang R, Jiao Q, Chen F, Wu T, Wang J, Zhu Y, Liu A, Zhang W, Li J, Shen H. Prophylactic Effects of n-Acethylcysteine on Inflammation-induced Depression-like Behaviors in Mice. Neuroscience 2024; 549:42-54. [PMID: 38729599 DOI: 10.1016/j.neuroscience.2024.05.005] [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: 12/30/2023] [Revised: 04/16/2024] [Accepted: 05/04/2024] [Indexed: 05/12/2024]
Abstract
Depression, affecting individuals worldwide, is a prevalent mental disease, with an increasing incidence. Numerous studies have been conducted on depression, yet its pathogenesis remains elusive. Recent advancements in research indicate that disturbances in synaptic transmission, synaptic plasticity, and reduced neurotrophic factor expression significantly contribute to depression's pathogenesis. In our study, we utilized adult male C57BL/6J mice. Lipopolysaccharide (LPS) can induce both chronic and acute depression-like symptoms in mice, a widely used model for studying depression associated with inflammation. N-acetylcysteine (NAC) exhibits anti-inflammatory and ameliorative effects on depressive symptoms. This study sought to determine whether NAC use could mitigate inflammatory depressive behavior through the enhancement of synaptic transmission, synaptic plasticity, and increasing levels of brain-derived neurotrophic factor (BDNF). In this study, we discovered that in mice modeled with depression-like symptoms, the expression levels of dendrites, BDNF, and miniature excitatory postsynaptic potential (mEPSC) in glutamatergic neurons, as well as the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid glutamate receptors (AMPARs) GluA1 and GluA2 subunits, were significantly decreased. These findings suggest an impairment in the synaptic transmission of glutamatergic neurons. Following treatment with NAC, the previously mentioned levels improved, indicating an enhancement in both synaptic transmission and synaptic plasticity. Our results suggest that NAC exerts a protective effect on mouse models of inflammatory depression, potentially through the enhancement of synaptic transmission and plasticity, as well as the restoration of neurotrophic factor expression. These findings offer vital animal experimental evidence supporting NAC's role in mitigating inflammatory depressive behaviors.
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Affiliation(s)
- Zhenhuan Wang
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Qi Hu
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China; Comprehensive Development Service Center, Tianjin Baodi District Health Commission, Tianjin, China
| | - Chao Tian
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Ruipeng Wang
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Qingyan Jiao
- Department of Sleep Medicine, Tianjin Anding Hospital, Tianjin, China
| | - Feng Chen
- Institute for Translational Neuroscience, the Second Affiliated Hospital of Nantong University, Nantong, Jiangsu Province, China
| | - Tongrui Wu
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Jialiang Wang
- Laboratory of Neurobiology, School of Biomedical Engineering, Tianjin Medical University, Tianjin, China
| | - Yuxuan Zhu
- Laboratory of Neurobiology, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Aili Liu
- Laboratory of Neurobiology, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Wei Zhang
- Tianjin Eye Hospital, Tianjin Eye Institute, Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin, China.
| | - Jie Li
- Institute of Mental Health, Tianjin Anding Hospital, Tianjin, China.
| | - Hui Shen
- Laboratory of Neurobiology, Department of Cell Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.
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Zhu S, Shen Z, Wu X, Han W, Jia B, Lu W, Zhang M. Demixing is a default process for biological condensates formed via phase separation. Science 2024; 384:920-928. [PMID: 38781377 DOI: 10.1126/science.adj7066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 04/15/2024] [Indexed: 05/25/2024]
Abstract
Excitatory and inhibitory synapses do not overlap even when formed on one submicron-sized dendritic protrusion. How excitatory and inhibitory postsynaptic cytomatrices or densities (e/iPSDs) are segregated is not understood. Broadly, why membraneless organelles are naturally segregated in cellular subcompartments is unclear. Using biochemical reconstitutions in vitro and in cells, we demonstrate that ePSDs and iPSDs spontaneously segregate into distinct condensed molecular assemblies through phase separation. Tagging iPSD scaffold gephyrin with a PSD-95 intrabody (dissociation constant ~4 nM) leads to mistargeting of gephyrin to ePSD condensates. Unexpectedly, formation of iPSD condensates forces the intrabody-tagged gephyrin out of ePSD condensates. Thus, instead of diffusion-governed spontaneous mixing, demixing is a default process for biomolecules in condensates. Phase separation can generate biomolecular compartmentalization specificities that cannot occur in dilute solutions.
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Affiliation(s)
- Shihan Zhu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
- School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zeyu Shen
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
- School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Xiandeng Wu
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wenyan Han
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824, USA
| | - Bowen Jia
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wei Lu
- Synapse and Neural Circuit Research Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20824, USA
| | - Mingjie Zhang
- School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
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Cano-Astorga N, Plaza-Alonso S, Turegano-Lopez M, Rodrigo-Rodríguez J, Merchan-Perez A, DeFelipe J. Unambiguous identification of asymmetric and symmetric synapses using volume electron microscopy. Front Neuroanat 2024; 18:1348032. [PMID: 38645671 PMCID: PMC11026665 DOI: 10.3389/fnana.2024.1348032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 03/08/2024] [Indexed: 04/23/2024] Open
Abstract
The brain contains thousands of millions of synapses, exhibiting diverse structural, molecular, and functional characteristics. However, synapses can be classified into two primary morphological types: Gray's type I and type II, corresponding to Colonnier's asymmetric (AS) and symmetric (SS) synapses, respectively. AS and SS have a thick and thin postsynaptic density, respectively. In the cerebral cortex, since most AS are excitatory (glutamatergic), and SS are inhibitory (GABAergic), determining the distribution, size, density, and proportion of the two major cortical types of synapses is critical, not only to better understand synaptic organization in terms of connectivity, but also from a functional perspective. However, several technical challenges complicate the study of synapses. Potassium ferrocyanide has been utilized in recent volume electron microscope studies to enhance electron density in cellular membranes. However, identifying synaptic junctions, especially SS, becomes more challenging as the postsynaptic densities become thinner with increasing concentrations of potassium ferrocyanide. Here we describe a protocol employing Focused Ion Beam Milling and Scanning Electron Microscopy for studying brain tissue. The focus is on the unequivocal identification of AS and SS types. To validate SS observed using this protocol as GABAergic, experiments with immunocytochemistry for the vesicular GABA transporter were conducted on fixed mouse brain tissue sections. This material was processed with different concentrations of potassium ferrocyanide, aiming to determine its optimal concentration. We demonstrate that using a low concentration of potassium ferrocyanide (0.1%) improves membrane visualization while allowing unequivocal identification of synapses as AS or SS.
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Affiliation(s)
- Nicolás Cano-Astorga
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- PhD Program in Neuroscience, Autonoma de Madrid University-Cajal Institute, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Sergio Plaza-Alonso
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Turegano-Lopez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - José Rodrigo-Rodríguez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Angel Merchan-Perez
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
- Departamento de Arquitectura y Tecnología de Sistemas Informáticos, Universidad Politécnica de Madrid, Madrid, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
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Ogelman R, Gomez Wulschner LE, Hoelscher VM, Hwang IW, Chang VN, Oh WC. Serotonin modulates excitatory synapse maturation in the developing prefrontal cortex. Nat Commun 2024; 15:1368. [PMID: 38365905 PMCID: PMC10873381 DOI: 10.1038/s41467-024-45734-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] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 02/02/2024] [Indexed: 02/18/2024] Open
Abstract
Serotonin (5-HT) imbalances in the developing prefrontal cortex (PFC) are linked to long-term behavioral deficits. However, the synaptic mechanisms underlying 5-HT-mediated PFC development are unknown. We found that chemogenetic suppression and enhancement of 5-HT release in the PFC during the first two postnatal weeks decreased and increased the density and strength of excitatory spine synapses, respectively, on prefrontal layer 2/3 pyramidal neurons in mice. 5-HT release on single spines induced structural and functional long-term potentiation (LTP), requiring both 5-HT2A and 5-HT7 receptor signals, in a glutamatergic activity-independent manner. Notably, LTP-inducing 5-HT stimuli increased the long-term survival of newly formed spines ( ≥ 6 h) via 5-HT7 Gαs activation. Chronic treatment of mice with fluoxetine, a selective serotonin-reuptake inhibitor, during the first two weeks, but not the third week of postnatal development, increased the density and strength of excitatory synapses. The effect of fluoxetine on PFC synaptic alterations in vivo was abolished by 5-HT2A and 5-HT7 receptor antagonists. Our data describe a molecular basis of 5-HT-dependent excitatory synaptic plasticity at the level of single spines in the PFC during early postnatal development.
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Affiliation(s)
- Roberto Ogelman
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Luis E Gomez Wulschner
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Victoria M Hoelscher
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - In-Wook Hwang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Victoria N Chang
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Won Chan Oh
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO, 80045, USA.
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Cano-Astorga N, Plaza-Alonso S, DeFelipe J, Alonso-Nanclares L. 3D synaptic organization of layer III of the human anterior cingulate and temporopolar cortex. Cereb Cortex 2023; 33:9691-9708. [PMID: 37455478 PMCID: PMC10472499 DOI: 10.1093/cercor/bhad232] [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: 04/11/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 07/18/2023] Open
Abstract
The human anterior cingulate and temporopolar cortices have been proposed as highly connected nodes involved in high-order cognitive functions, but their synaptic organization is still basically unknown due to the difficulties involved in studying the human brain. Using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) to study the synaptic organization of the human brain obtained with a short post-mortem delay allows excellent results to be obtained. We have used this technology to analyze layer III of the anterior cingulate cortex (Brodmann area 24) and the temporopolar cortex, including the temporal pole (Brodmann area 38 ventral and dorsal) and anterior middle temporal gyrus (Brodmann area 21). Our results, based on 6695 synaptic junctions fully reconstructed in 3D, revealed that Brodmann areas 24, 21 and ventral area 38 showed similar synaptic density and synaptic size, whereas dorsal area 38 displayed the highest synaptic density and the smallest synaptic size. However, the proportion of the different types of synapses (excitatory and inhibitory), the postsynaptic targets, and the shapes of excitatory and inhibitory synapses were similar, regardless of the region examined. These observations indicate that certain aspects of the synaptic organization are rather homogeneous, whereas others show specific variations across cortical regions.
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Affiliation(s)
- Nicolás Cano-Astorga
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce 37, 28002 Madrid, Spain
- PhD Program in Neuroscience, Autonoma de Madrid University - Cajal Institute, 28029 Madrid, Spain
| | - Sergio Plaza-Alonso
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce 37, 28002 Madrid, Spain
| | - Javier DeFelipe
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce 37, 28002 Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Valderrebollo 5, 28031 Madrid, Spain
| | - Lidia Alonso-Nanclares
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica, Universidad Politécnica de Madrid, Pozuelo de Alarcón, 28223 Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Avda. Doctor Arce 37, 28002 Madrid, Spain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ISCIII, Valderrebollo 5, 28031 Madrid, Spain
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Swenson KS, Gomez Wulschner LE, Hoelscher VM, Folts L, Korth KM, Oh WC, Bates EA. Fetal cannabidiol (CBD) exposure alters thermal pain sensitivity, problem-solving, and prefrontal cortex excitability. Mol Psychiatry 2023; 28:3397-3413. [PMID: 37433966 PMCID: PMC10618089 DOI: 10.1038/s41380-023-02130-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 05/13/2023] [Accepted: 06/13/2023] [Indexed: 07/13/2023]
Abstract
Thousands of people suffer from nausea with pregnancy each year. Nausea can be alleviated with cannabidiol (CBD), a primary component of cannabis that is widely available. However, it is unknown how fetal CBD exposure affects embryonic development and postnatal outcomes. CBD binds and activates receptors that are expressed in the fetal brain and are important for brain development, including serotonin receptors (5HT1A), voltage-gated potassium (Kv)7 receptors, and the transient potential vanilloid 1 receptor (TRPV1). Excessive activation of each of these receptors can disrupt neurodevelopment. Here, we test the hypothesis that fetal CBD exposure in mice alters offspring neurodevelopment and postnatal behavior. We administered 50 mg/kg CBD in sunflower oil or sunflower oil alone to pregnant mice from embryonic day 5 through birth. We show that fetal CBD exposure sensitizes adult male offspring to thermal pain through TRPV1. We show that fetal CBD exposure decreases problem-solving behaviors in female CBD-exposed offspring. We demonstrate that fetal CBD exposure increases the minimum current required to elicit action potentials and decreases the number of action potentials in female offspring layer 2/3 prefrontal cortex (PFC) pyramidal neurons. Fetal CBD exposure reduces the amplitude of glutamate uncaging-evoked excitatory post-synaptic currents, consistent with CBD-exposed female problem-solving behavior deficits. Combined, these data show that fetal CBD exposure disrupts neurodevelopment and postnatal behavior in a sex specific manner.
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Affiliation(s)
- Karli S Swenson
- Section of Developmental Biology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Luis E Gomez Wulschner
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Victoria M Hoelscher
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Lillian Folts
- Section of Developmental Biology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Kamryn M Korth
- Section of Developmental Biology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Won Chan Oh
- Department of Pharmacology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Emily Anne Bates
- Section of Developmental Biology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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Kanigowski D, Bogaj K, Barth AL, Urban-Ciecko J. Somatostatin-expressing interneurons modulate neocortical network through GABAb receptors in a synapse-specific manner. Sci Rep 2023; 13:8780. [PMID: 37258641 DOI: 10.1038/s41598-023-35890-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 05/25/2023] [Indexed: 06/02/2023] Open
Abstract
The firing activity of somatostatin-expressing inhibitory neurons (SST-INs) can suppress network activity via both GABAa and GABAb receptors (Rs). Although SST-INs do not receive GABAaR input from other SST-INs, it is possible that SST-IN-released GABA could suppress the activity of SST-INs themselves via GABAbRs, providing a negative feedback loop. Here we characterized the influence of GABAbR modulation on SST-IN activity in layer 2/3 of the somatosensory cortex in mice. We compared this to the effects of GABAbR activation on parvalbumin-expressing interneurons (PV-INs). Using in vitro whole-cell patch clamp recordings, pharmacological and optogenetic manipulations, we found that the firing activity of SST-INs suppresses excitatory drive to themselves via presynaptic GABAbRs. Postsynaptic GABAbRs did not influence SST-IN spontaneous activity or intrinsic excitability. Although GABAbRs at pre- and postsynaptic inputs to PV-INs are modestly activated during cortical network activity in vitro, the spontaneous firing of SST-INs was not the source of GABA driving this GABAbR activation. Thus, SST-IN firing regulates excitatory synaptic strength through presynaptic GABAbRs at connections between pyramidal neurons (Pyr-Pyr) and synapses between pyramidal neurons and SST-INs (Pyr-SST), but not Pyr-PV and PV-Pyr synapses. Our study indicates that two main types of neocortical inhibitory interneurons are differentially modulated by SST-IN-mediated GABA release.
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Affiliation(s)
- Dominik Kanigowski
- Laboratory of Electrophysiology, Nencki Institute of Experimental Biology, Warsaw, 02-093, Poland
| | - Karolina Bogaj
- Laboratory of Electrophysiology, Nencki Institute of Experimental Biology, Warsaw, 02-093, Poland
| | - Alison L Barth
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Joanna Urban-Ciecko
- Laboratory of Electrophysiology, Nencki Institute of Experimental Biology, Warsaw, 02-093, Poland.
- Department of Biological Sciences and Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
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Rasia-Filho AA, Calcagnotto ME, von Bohlen Und Halbach O. Introduction: What Are Dendritic Spines? ADVANCES IN NEUROBIOLOGY 2023; 34:1-68. [PMID: 37962793 DOI: 10.1007/978-3-031-36159-3_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Dendritic spines are cellular specializations that greatly increase the connectivity of neurons and modulate the "weight" of most postsynaptic excitatory potentials. Spines are found in very diverse animal species providing neural networks with a high integrative and computational possibility and plasticity, enabling the perception of sensorial stimuli and the elaboration of a myriad of behavioral displays, including emotional processing, memory, and learning. Humans have trillions of spines in the cerebral cortex, and these spines in a continuum of shapes and sizes can integrate the features that differ our brain from other species. In this chapter, we describe (1) the discovery of these small neuronal protrusions and the search for the biological meaning of dendritic spines; (2) the heterogeneity of shapes and sizes of spines, whose structure and composition are associated with the fine-tuning of synaptic processing in each nervous area, as well as the findings that support the role of dendritic spines in increasing the wiring of neural circuits and their functions; and (3) within the intraspine microenvironment, the integration and activation of signaling biochemical pathways, the compartmentalization of molecules or their spreading outside the spine, and the biophysical properties that can affect parent dendrites. We also provide (4) examples of plasticity involving dendritic spines and neural circuits relevant to species survival and comment on (5) current research advancements and challenges in this exciting research field.
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Affiliation(s)
- Alberto A Rasia-Filho
- Department of Basic Sciences/Physiology and Graduate Program in Biosciences, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, RS, Brazil
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Maria Elisa Calcagnotto
- Graduate Program in Neuroscience, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Department of Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Graduate Program in Biochemistry, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
- Graduate Program in Psychiatry and Behavioral Science, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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