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González-Marrero I, Hernandez-Garcia JA, Gonzalez-Davila E, Carmona-Calero EM, Gonzalez-Toledo JM, Catañeyra-Ruiz L, Henandez-Abad LG, Castañeyra-Perdomo A. Variations of the grid and place cells in the entorhinal cortex and dentate gyrus of 6 individuals aged 56 to 87 years. Neurologia 2024; 39:244-253. [PMID: 37442425 DOI: 10.1016/j.nrleng.2023.07.007] [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: 03/25/2021] [Accepted: 04/27/2021] [Indexed: 07/15/2023] Open
Abstract
INTRODUCTION The relationship between the entorhinal cortex (EC) and the hippocampus has been studied by different authors, who have highlighted the importance of grid cells, place cells, and the trisynaptic circuit in the processes that they regulate: the persistence of spatial, explicit, and recent memory and their possible impairment with ageing. OBJECTIVE We aimed to determine whether older age causes changes in the size and number of grid cells contained in layer III of the EC and in the granular layer of the dentate gyrus (DG) of the hippocampus. METHODS We conducted post-mortem studies of the brains of 6 individuals aged 56-87 years. The brain sections containing the DG and the adjacent EC were stained according to the Klüver-Barrera method, then the ImageJ software was used to measure the individual neuronal area, the total neuronal area, and the number of neurons contained in rectangular areas in layer III of the EC and layer II of the DG. Statistical analysis was subsequently performed. RESULTS We observed an age-related reduction in the cell population of the external pyramidal layer of the EC, and in the number of neurons in the granular layer of the DG. CONCLUSION Our results indicate that ageing causes a decrease in the size and density of grid cells of the EC and place cells of the DG.
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Affiliation(s)
- I González-Marrero
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canarias, Spain
| | - J A Hernandez-Garcia
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canarias, Spain
| | - E Gonzalez-Davila
- Departamento de Matemáticas, Estadística e Investigación Operativa, Universidad de La Laguna, Tenerife, Islas Canarias, Spain
| | - E M Carmona-Calero
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canarias, Spain; Instituto de Investigación y Ciencias, Puerto del Rosario, Fuerteventura, Islas Canarias, Spain
| | - J M Gonzalez-Toledo
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canarias, Spain
| | - L Catañeyra-Ruiz
- Department of Neurological Surgery, Washington University School of Medicine and the St. Louis Children's Hospital, St. Louis, Missouri, United States
| | - L G Henandez-Abad
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canarias, Spain; Instituto de Investigación y Ciencias, Puerto del Rosario, Fuerteventura, Islas Canarias, Spain
| | - A Castañeyra-Perdomo
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canarias, Spain; Instituto de Investigación y Ciencias, Puerto del Rosario, Fuerteventura, Islas Canarias, Spain.
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Asgarihafshejani A, Raveendran VA, Pressey JC, Woodin MA. LTP is Absent in the CA1 Region of the Hippocampus of Male and Female Rett Syndrome Mouse Models. Neuroscience 2024; 537:189-204. [PMID: 38036056 DOI: 10.1016/j.neuroscience.2023.11.028] [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: 08/10/2023] [Revised: 11/12/2023] [Accepted: 11/22/2023] [Indexed: 12/02/2023]
Abstract
Rett syndrome (RTT) is a debilitating neurodevelopmental disorder caused by mutations in the X-linked methyl-CpG-binding protein 2 (MeCP2) gene, resulting in severe deficits in learning and memory. Alterations in synaptic plasticity have been reported in RTT, however most electrophysiological studies have been performed in male mice only, despite the fact that RTT is primarily found in females. In addition, most studies have focused on excitation, despite the emerging evidence for the important role of inhibition in learning and memory. Here, we performed an electrophysiological characterization in the CA1 region of the hippocampus in both males and females of RTT mouse models with a focus on neurogliaform (NGF) interneurons, given that they are the most abundant dendrite-targeting interneuron subtype in the hippocampus. We found that theta-burst stimulation (TBS) failed to induce long-term potentiation (LTP) in either pyramidal neurons or NGF interneurons in male or female RTT mice, with no apparent changes in short-term plasticity (STP). This failure to induce LTP was accompanied by excitation/inhibition (E/I) imbalances and altered excitability, in a sex- and cell-type specific manner. Specifically, NGF interneurons of male RTT mice displayed increased intrinsic excitability, a depolarized resting membrane potential, and decreased E/I balance, while in female RTT mice, the resting membrane potential was depolarized. Understanding the role of NGF interneurons in RTT animal models is crucial for developing targeted treatments to improve cognition in individuals with this disorder.
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Affiliation(s)
| | | | - Jessica C Pressey
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Melanie A Woodin
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.
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Robles-Gómez ÁA, Ordaz B, Lorea-Hernández JJ, Peña-Ortega F. Deleterious and protective effects of epothilone-D alone and in the context of amyloid β- and tau-induced alterations. Front Mol Neurosci 2023; 16:1198299. [PMID: 37900942 PMCID: PMC10603193 DOI: 10.3389/fnmol.2023.1198299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 09/20/2023] [Indexed: 10/31/2023] Open
Abstract
Amyloid-β (Aβ) and hyperphosphorylated tau (P-tau) are Alzheimer's disease (AD) biomarkers that interact in a complex manner to induce most of the cognitive and brain alterations observed in this disease. Since the neuronal cytoskeleton is a common downstream pathological target of tau and Aβ, which mostly lead to augmented microtubule instability, the administration of microtubule stabilizing agents (MSAs) can protect against their pathological actions. However, the effectiveness of MSAs is still uncertain due to their state-dependent negative effects; thus, evaluating their specific actions in different pathological or physiological conditions is required. We evaluated whether epothilone-D (Epo-D), a clinically used MSA, rescues from the functional and behavioral alterations produced by intracerebroventricular injection of Aβ, the presence of P-tau, or their combination in rTg4510 mice. We also explored the side effects of Epo-D. To do so, we evaluated hippocampal-dependent spatial memory with the Hebb-Williams maze, hippocampal CA1 integrity and the intrinsic and synaptic properties of CA1 pyramidal neurons with the patch-clamp technique. Aβ and P-tau mildly impaired memory retrieval, but produced contrasting effects on intrinsic excitability. When Aβ and P-tau were combined, the alterations in excitability and spatial reversal learning (i.e., cognitive flexibility) were exacerbated. Interestingly, Epo-D prevented most of the impairments induced Aβ and P-tau alone and combined. However, Epo-D also exhibited some side effects depending on the prevailing pathological or physiological condition, which should be considered in future preclinical and translational studies. Although we did not perform extensive histopathological evaluations or measured microtubule stability, our findings show that MSAs can rescue the consequences of AD-like conditions but otherwise be harmful if administered at a prodromal stage of the disease.
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Affiliation(s)
- Ángel Abdiel Robles-Gómez
- Instituto de Neurobiología, UNAM Campus Juriquilla, Querétaro, Mexico
- Posgrado en Ciencias Biológicas, UNAM, Ciudad Universitaria, México City, Mexico
| | - Benito Ordaz
- Instituto de Neurobiología, UNAM Campus Juriquilla, Querétaro, Mexico
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Berndt M, Trusel M, Roberts TF, Pfeiffer BE, Volk LJ. Bidirectional synaptic changes in deep and superficial hippocampal neurons following in vivo activity. Neuron 2023; 111:2984-2994.e4. [PMID: 37689058 PMCID: PMC10958998 DOI: 10.1016/j.neuron.2023.08.014] [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] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 07/06/2023] [Accepted: 08/15/2023] [Indexed: 09/11/2023]
Abstract
Neuronal activity during experience is thought to induce plastic changes within the hippocampal network that underlie memory formation, although the extent and details of such changes in vivo remain unclear. Here, we employed a temporally precise marker of neuronal activity, CaMPARI2, to label active CA1 hippocampal neurons in vivo, followed by immediate acute slice preparation and electrophysiological quantification of synaptic properties. Recently active neurons in the superficial sublayer of stratum pyramidale displayed larger post-synaptic responses at excitatory synapses from area CA3, with no change in pre-synaptic release probability. In contrast, in vivo activity correlated with weaker pre- and post-synaptic excitatory weights onto pyramidal cells in the deep sublayer. In vivo activity of deep and superficial neurons within sharp-wave/ripples was bidirectionally changed across experience, consistent with the observed changes in synaptic weights. These findings reveal novel, fundamental mechanisms through which the hippocampal network is modified by experience to store information.
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Affiliation(s)
- Marcus Berndt
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA
| | - Massimo Trusel
- UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA
| | - Todd F Roberts
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA; Peter O'Donnell Brain Institute, Dallas, TX 75390, USA
| | - Brad E Pfeiffer
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA; Peter O'Donnell Brain Institute, Dallas, TX 75390, USA.
| | - Lenora J Volk
- UT Southwestern Medical Center Neuroscience Graduate Program, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Neuroscience, Dallas, TX 75390, USA; UT Southwestern Medical Center Department of Psychiatry, Dallas, TX 75390, USA; Peter O'Donnell Brain Institute, Dallas, TX 75390, USA.
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Vanrobaeys Y, Mukherjee U, Langmack L, Beyer SE, Bahl E, Lin LC, Michaelson JJ, Abel T, Chatterjee S. Mapping the spatial transcriptomic signature of the hippocampus during memory consolidation. Nat Commun 2023; 14:6100. [PMID: 37773230 PMCID: PMC10541893 DOI: 10.1038/s41467-023-41715-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 09/15/2023] [Indexed: 10/01/2023] Open
Abstract
Memory consolidation involves discrete patterns of transcriptional events in the hippocampus. Despite the emergence of single-cell transcriptomic profiling techniques, mapping the transcriptomic signature across subregions of the hippocampus has remained challenging. Here, we utilized unbiased spatial sequencing to delineate transcriptome-wide gene expression changes across subregions of the dorsal hippocampus of male mice following learning. We find that each subregion of the hippocampus exhibits distinct yet overlapping transcriptomic signatures. The CA1 region exhibited increased expression of genes related to transcriptional regulation, while the DG showed upregulation of genes associated with protein folding. Importantly, our approach enabled us to define the transcriptomic signature of learning within two less-defined hippocampal subregions, CA1 stratum radiatum, and oriens. We demonstrated that CA1 subregion-specific expression of a transcription factor subfamily has a critical functional role in the consolidation of long-term memory. This work demonstrates the power of spatial molecular approaches to reveal simultaneous transcriptional events across the hippocampus during memory consolidation.
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Affiliation(s)
- Yann Vanrobaeys
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA, 52242, USA
| | - Utsav Mukherjee
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA, 52242, USA
| | - Lucy Langmack
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Biochemistry and Molecular Biology Graduate Program, University of Iowa, Iowa City, IA, USA
| | - Stacy E Beyer
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Ethan Bahl
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA, 52242, USA
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
| | - Li-Chun Lin
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Jacob J Michaelson
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
| | - Snehajyoti Chatterjee
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA.
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Dupuis JP, Nicole O, Groc L. NMDA receptor functions in health and disease: Old actor, new dimensions. Neuron 2023:S0896-6273(23)00344-6. [PMID: 37236178 DOI: 10.1016/j.neuron.2023.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/06/2023] [Accepted: 05/02/2023] [Indexed: 05/28/2023]
Abstract
N-Methyl-D-aspartate ionotropic glutamate receptors (NMDARs) play key roles in synaptogenesis, synaptic maturation, long-term plasticity, neuronal network activity, and cognition. Mirroring this wide range of instrumental functions, abnormalities in NMDAR-mediated signaling have been associated with numerous neurological and psychiatric disorders. Thus, identifying the molecular mechanisms underpinning the physiological and pathological contributions of NMDAR has been a major area of investigation. Over the past decades, a large body of literature has flourished, revealing that the physiology of ionotropic glutamate receptors cannot be restricted to fluxing ions, and involves additional facets controlling synaptic transmissions in health and disease. Here, we review newly discovered dimensions of postsynaptic NMDAR signaling supporting neural plasticity and cognition, such as the nanoscale organization of NMDAR complexes, their activity-dependent redistributions, and non-ionotropic signaling capacities. We also discuss how dysregulations of these processes may directly contribute to NMDAR-dysfunction-related brain diseases.
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Affiliation(s)
- Julien P Dupuis
- University of Bordeaux, CNRS, IINS, UMR 5297, 33000 Bordeaux, France
| | - Olivier Nicole
- University of Bordeaux, CNRS, IINS, UMR 5297, 33000 Bordeaux, France
| | - Laurent Groc
- University of Bordeaux, CNRS, IINS, UMR 5297, 33000 Bordeaux, France.
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Vanrobeys Y, Mukherjee U, Langmack L, Bahl E, Lin LC, Michaelson JJ, Abel T, Chatterjee S. Mapping the spatial transcriptomic signature of the hippocampus during memory consolidation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524576. [PMID: 36711475 PMCID: PMC9882356 DOI: 10.1101/2023.01.18.524576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Memory consolidation involves discrete patterns of transcriptional events in the hippocampus. Despite the emergence of single-cell transcriptomic profiling techniques, defining learning-responsive gene expression across subregions of the hippocampus has remained challenging. Here, we utilized unbiased spatial sequencing to elucidate transcriptome-wide changes in gene expression in the hippocampus following learning, enabling us to define molecular signatures unique to each hippocampal subregion. We find that each subregion of the hippocampus exhibits distinct yet overlapping transcriptomic signatures. Although the CA1 region exhibited increased expression of genes related to transcriptional regulation, the DG showed upregulation of genes associated with protein folding. We demonstrate the functional relevance of subregion-specific gene expression by genetic manipulation of a transcription factor selectively in the CA1 hippocampal subregion, leading to long-term memory deficits. This work demonstrates the power of using spatial molecular approaches to reveal transcriptional events during memory consolidation.
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Affiliation(s)
- Yann Vanrobeys
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
| | - Utsav Mukherjee
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, USA
| | - Lucy Langmack
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Biochemistry and Molecular Biology Graduate Program, University of Iowa, Iowa City, IA, USA
| | - Ethan Bahl
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA 52242, USA
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
| | - Li-Chun Lin
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Jacob J Michaelson
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
- Department of Psychiatry, University of Iowa, Iowa City, IA, USA
| | - Ted Abel
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
| | - Snehajyoti Chatterjee
- Department of Neuroscience and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA, USA
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Craig CF, Filippone RT, Stavely R, Bornstein JC, Apostolopoulos V, Nurgali K. Neuroinflammation as an etiological trigger for depression comorbid with inflammatory bowel disease. J Neuroinflammation 2022; 19:4. [PMID: 34983592 PMCID: PMC8729103 DOI: 10.1186/s12974-021-02354-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 12/14/2021] [Indexed: 02/06/2023] Open
Abstract
Patients with inflammatory bowel disease (IBD) suffer from depression at higher rates than the general population. An etiological trigger of depressive symptoms is theorised to be inflammation within the central nervous system. It is believed that heightened intestinal inflammation and dysfunction of the enteric nervous system (ENS) contribute to impaired intestinal permeability, which facilitates the translocation of intestinal enterotoxins into the blood circulation. Consequently, these may compromise the immunological and physiological functioning of distant non-intestinal tissues such as the brain. In vivo models of colitis provide evidence of increased blood–brain barrier permeability and enhanced central nervous system (CNS) immune activity triggered by intestinal enterotoxins and blood-borne inflammatory mediators. Understanding the immunological, physiological, and structural changes associated with IBD and neuroinflammation may aid in the development of more tailored and suitable pharmaceutical treatment for IBD-associated depression.
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Affiliation(s)
- Colin F Craig
- Institute for Heath and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, VIC, Australia
| | - Rhiannon T Filippone
- Institute for Heath and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, VIC, Australia
| | - Rhian Stavely
- Institute for Heath and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, VIC, Australia.,Department of Pediatric Surgery, Pediatric Surgery Research Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Joel C Bornstein
- Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Australia
| | - Vasso Apostolopoulos
- Institute for Heath and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, VIC, Australia.,Immunology Program, Australian Institute of Musculoskeletal Science (AIMSS), Melbourne, VIC, Australia
| | - Kulmira Nurgali
- Institute for Heath and Sport, Victoria University, Western Centre for Health, Research and Education, Sunshine Hospital, Melbourne, VIC, Australia. .,Department of Medicine Western Health, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, Australia. .,Regenerative Medicine and Stem Cells Program, Australian Institute of Musculoskeletal Science (AIMSS), Melbourne, VIC, Australia. .,Institute for Health and Sport, Victoria University, Level 4 Research Labs, Western Centre for Health Research and Education, Sunshine Hospital, 176 Furlong Road, St Albans, VIC, 3021, Australia.
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González-Marrero I, Hernandez-Garcia JA, Gonzalez-Davila E, Carmona-Calero EM, Gonzalez-Toledo JM, Castañeyra-Ruiz L, Hernandez-Abad LG, Castañeyra-Perdomo A. Variations of the grid and place cells in the entorhinal cortex and dentate gyrus of 6 individuals aged 56 to 87 years. Neurologia 2021:S0213-4853(21)00118-3. [PMID: 34531045 DOI: 10.1016/j.nrl.2021.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 11/15/2022] Open
Abstract
INTRODUCTION The relationship between the entorhinal cortex and the hippocampus has been studied by different authors, who have highlighted the importance of grid cells, place cells, and the trisynaptic circuit in the processes that they regulate: the persistence of spatial, explicit, and recent memory and their possible impairment with ageing. OBJECTIVE We aimed to determine whether older age causes changes in the size and number of grid cells contained in layer III of the entorhinal cortex and in the granular layer of the dentate gyrus of the hippocampus. METHODS We conducted post-mortem studies of the brains of 6 individuals aged 56-87 years. The brain sections containing the dentate gyrus and the adjacent entorhinal cortex were stained according to the Klüver-Barrera method, then the Image J software was used to measure the individual neuronal area, the total neuronal area, and the number of neurons contained in rectangular areas in layer III of the entorhinal cortex and layer II of the dentate gyrus. Statistical analysis was subsequently performed. RESULTS We observed an age-related reduction in the cell population of the external pyramidal layer of the entorhinal cortex, and in the number of neurons in the granular layer of the dentate gyrus. CONCLUSION Our results indicate that ageing causes a decrease in the size and density of grid cells of the entorhinal cortex and place cells of the dentate gyrus.
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Affiliation(s)
- I González-Marrero
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canaria, España
| | - J A Hernandez-Garcia
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canaria, España
| | - E Gonzalez-Davila
- Departamento de Matemáticas, Estadística e Investigación Operativa, Universidad de La Laguna, Tenerife, Islas Canaria, España
| | - E M Carmona-Calero
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canaria, España; Instituto de Investigación y Ciencias, Puerto del Rosario, Fuerteventura, Islas Canarias, España
| | - J M Gonzalez-Toledo
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canaria, España
| | - L Castañeyra-Ruiz
- Department of Neurological Surgery, Washington University School of Medicine and the St. Louis Children's Hospital, St. Louis, Missouri, Estados Unidos
| | - L G Hernandez-Abad
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canaria, España; Instituto de Investigación y Ciencias, Puerto del Rosario, Fuerteventura, Islas Canarias, España
| | - A Castañeyra-Perdomo
- Unidad de Anatomía y Embriología Humana, Departamento de Ciencias Médicas Básicas, Facultad de Ciencias de la Salud, Universidad de La Laguna, Tenerife, Islas Canaria, España; Instituto de Investigación y Ciencias, Puerto del Rosario, Fuerteventura, Islas Canarias, España.
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10
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Perez JD, Fusco CM, Schuman EM. A Functional Dissection of the mRNA and Locally Synthesized Protein Population in Neuronal Dendrites and Axons. Annu Rev Genet 2021; 55:183-207. [PMID: 34460296 DOI: 10.1146/annurev-genet-030321-054851] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurons are characterized by a complex morphology that enables the generation of subcellular compartments with unique biochemical and biophysical properties, such as dendrites, axons, and synapses. To sustain these different compartments and carry a wide array of elaborate operations, neurons express a diverse repertoire of gene products. Extensive regulation at both the messenger RNA (mRNA) and protein levels allows for the differentiation of subcellular compartments as well as numerous forms of plasticity in response to variable stimuli. Among the multiple mechanisms that control cellular functions, mRNA translation is manipulated by neurons to regulate where and when a protein emerges. Interestingly, transcriptomic and translatomic profiles of both dendrites and axons have revealed that the mRNA population only partially predicts the local protein population and that this relation significantly varies between different gene groups. Here, we describe the space that local translation occupies within the large molecular and regulatory complexity of neurons, in contrast to other modes of regulation. We then discuss the specialized organization of mRNAs within different neuronal compartments, as revealed by profiles of the local transcriptome. Finally, we discuss the features and functional implications of both locally correlated-and anticorrelated-mRNA-protein relations both under baseline conditions and during synaptic plasticity. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Julio D Perez
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Claudia M Fusco
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
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Watkins JC, Evans RH, Bayés À, Booker SA, Gibb A, Mabb AM, Mayer M, Mellor JR, Molnár E, Niu L, Ortega A, Pankratov Y, Ramos-Vicente D, Rodríguez-Campuzano A, Rodríguez-Moreno A, Wang LY, Wang YT, Wollmuth L, Wyllie DJA, Zhuo M, Frenguelli BG. 21st century excitatory amino acid research: A Q & A with Jeff Watkins and Dick Evans. Neuropharmacology 2021; 198:108743. [PMID: 34363811 DOI: 10.1016/j.neuropharm.2021.108743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In 1981 Jeff Watkins and Dick Evans wrote what was to become a seminal review on excitatory amino acids (EAAs) and their receptors (Watkins and Evans, 1981). Bringing together various lines of evidence dating back over several decades on: the distribution in the nervous system of putative amino acid neurotransmitters; enzymes involved in their production and metabolism; the uptake and release of amino acids; binding of EAAs to membranes; the pharmacological action of endogenous excitatory amino acids and their synthetic analogues, and notably the actions of antagonists for the excitations caused by both nerve stimulation and exogenous agonists, often using pharmacological tools developed by Jeff and his colleagues, they provided a compelling account for EAAs, especially l-glutamate, as a bona fide neurotransmitter in the nervous system. The rest, as they say, is history, but far from being consigned to history, EAA research is in rude health well into the 21st Century as this series of Special Issues of Neuropharmacology exemplifies. With EAAs and their receptors flourishing across a wide range of disciplines and clinical conditions, we enter into a dialogue with two of the most prominent and influential figures in the early days of EAA research: Jeff Watkins and Dick Evans.
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Affiliation(s)
| | | | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain and Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Sam A Booker
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Alasdair Gibb
- Research Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Angela M Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Mark Mayer
- Bldg 35A, Room 3D-904, 35A Convent Drive, NINDS, NIH, Bethesda, MD, 20892, USA
| | - Jack R Mellor
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Elek Molnár
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Li Niu
- Chemistry Department, University at Albany, SUNY, 1400 Washington Ave, Albany, NY, 12222, USA
| | - Arturo Ortega
- Department of Toxicology, Cinvestav, Mexico City, Mexico
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - David Ramos-Vicente
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain and Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | | | - Lu-Yang Wang
- Program in Neurosciences & Mental Health, SickKids Research Institute and Department of Physiology, University of Toronto, 555 University Ave, Toronto, Ontario, M5G 1X8, Canada
| | - Yu Tian Wang
- Department of Medicine, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - Lonnie Wollmuth
- Depts. of Neurobiology & Behavior and Biochemistry & Cell Biology, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - David J A Wyllie
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Min Zhuo
- Institute of Brain Research, Qingdao International Academician Park, Qingdao, 266000, China
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12
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Booker SA, Sumera A, Kind PC, Wyllie DJA. Contribution of NMDA Receptors to Synaptic Function in Rat Hippocampal Interneurons. eNeuro 2021; 8:ENEURO.0552-20.2021. [PMID: 34326063 PMCID: PMC8362681 DOI: 10.1523/eneuro.0552-20.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 06/15/2021] [Accepted: 07/03/2021] [Indexed: 12/12/2022] Open
Abstract
The ability of neurons to produce behaviorally relevant activity in the absence of pathology relies on the fine balance of synaptic inhibition to excitation. In the hippocampal CA1 microcircuit, this balance is maintained by a diverse population of inhibitory interneurons that receive largely similar glutamatergic afferents as their target pyramidal cells, with EPSCs generated by both AMPA receptors (AMPARs) and NMDA receptors (NMDARs). In this study, we take advantage of a recently generated GluN2A-null rat model to assess the contribution of GluN2A subunits to glutamatergic synaptic currents in three subclasses of interneuron found in the CA1 region of the hippocampus. For both parvalbumin-positive and somatostatin-positive interneurons, the GluN2A subunit is expressed at glutamatergic synapses and contributes to the EPSC. In contrast, in cholecystokinin (CCK)-positive interneurons, the contribution of GluN2A to the EPSC is negligible. Furthermore, synaptic potentiation at glutamatergic synapses on CCK-positive interneurons does not require the activation of GluN2A-containing NMDARs but does rely on the activation of NMDARs containing GluN2B and GluN2D subunits.
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Affiliation(s)
- Sam A. Booker
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Patrick Wild Centre, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Anna Sumera
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Patrick Wild Centre, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
| | - Peter C. Kind
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Patrick Wild Centre, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
| | - David J. A. Wyllie
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Patrick Wild Centre, University of Edinburgh, Edinburgh EH8 9XD, United Kingdom
- Centre for Brain Development and Repair, Institute for Stem Cell Biology and Regenerative Medicine, Bangalore 560065, India
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13
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Booker SA, Wyllie DJA. NMDA receptor function in inhibitory neurons. Neuropharmacology 2021; 196:108609. [PMID: 34000273 DOI: 10.1016/j.neuropharm.2021.108609] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 12/26/2022]
Abstract
N-methyl-d-aspartate receptors (NMDARs) are present in the majority of brain circuits and play a key role in synaptic information transfer and synaptic plasticity. A key element of many brain circuits are inhibitory GABAergic interneurons that in themselves show diverse and cell-type-specific NMDAR expression and function. Indeed, NMDARs located on interneurons control cellular excitation in a synapse-type specific manner which leads to divergent dendritic integration properties amongst the plethora of interneuron subtypes known to exist. In this review, we explore the documented diversity of NMDAR subunit expression in identified subpopulations of interneurons and assess the NMDAR subtype-specific control of their function. We also highlight where knowledge still needs to be obtained, if a full appreciation is to be gained of roles played by NMDARs in controlling GABAergic modulation of synaptic and circuit function. This article is part of the 'Special Issue on Glutamate Receptors - NMDA receptors'.
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Affiliation(s)
- Sam A Booker
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK; Patrick Wild Centre for Research into Autism, Fragile X Syndrome & Intellectual Disabilities, University of Edinburgh, Edinburgh, EH8 9XD, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
| | - David J A Wyllie
- Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, EH8 9XD, UK; Patrick Wild Centre for Research into Autism, Fragile X Syndrome & Intellectual Disabilities, University of Edinburgh, Edinburgh, EH8 9XD, UK; Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK; Centre for Brain Development and Repair, InStem, Bangalore, 560065, India.
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14
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Riquelme D, Cerda O, Leiva-Salcedo E. TRPM4 Expression During Postnatal Developmental of Mouse CA1 Pyramidal Neurons. Front Neuroanat 2021; 15:643287. [PMID: 33994959 PMCID: PMC8113704 DOI: 10.3389/fnana.2021.643287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/30/2021] [Indexed: 11/13/2022] Open
Abstract
TRPM4 is a non-selective cation channel activated by intracellular calcium and permeable to monovalent cations. This channel participates in the control of neuronal firing, neuronal plasticity, and neuronal death. TRPM4 depolarizes dendritic spines and is critical for the induction of NMDA receptor-dependent long-term potentiation in CA1 pyramidal neurons. Despite its functional importance, no subcellular localization or expression during postnatal development has been described in this area. To examine the localization and expression of TRPM4, we performed duplex immunofluorescence and patch-clamp in brain slices at different postnatal ages in C57BL/6J mice. At P0 we found TRPM4 is expressed with a somatic pattern. At P7, P14, and P35, TRPM4 expression extended from the soma to the apical dendrites but was excluded from the axon initial segment. Patch-clamp recordings showed a TRPM4-like current active at the resting membrane potential from P0, which increased throughout the postnatal development. This current was dependent on intracellular Ca2+ (ICAN) and sensitive to 9-phenanthrol (9-Ph). Inhibiting TRPM4 with 9-Ph hyperpolarized the membrane potential at P14 and P35, with no effect in earlier stages. Together, these results show that TRPM4 is expressed in CA1 pyramidal neurons in the soma and apical dendrites and associated with a TRPM4-like current, which depolarizes the neurons. The expression, localization, and function of TRPM4 throughout postnatal development in the CA1 hippocampal may underlie an important mechanism of control of membrane potential and action potential firing during critical periods of neuronal development, particularly during the establishment of circuits.
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Affiliation(s)
- Denise Riquelme
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
| | - Oscar Cerda
- Programa de Biología Celular y Molecular, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Millennium Nucleus of Ion Channel-Associated Diseases, Santiago, Chile
| | - Elias Leiva-Salcedo
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
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15
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Soltani Zangbar H, Shahabi P, Seyedi Vafaee M, Ghadiri T, Ebrahimi Kalan A, Fallahi S, Ghorbani M, Jafarzadehgharehziaaddin M. Hippocampal neurodegeneration and rhythms mirror each other during acute spinal cord injury in male rats. Brain Res Bull 2021; 172:31-42. [PMID: 33848614 DOI: 10.1016/j.brainresbull.2021.04.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 03/20/2021] [Accepted: 04/07/2021] [Indexed: 12/29/2022]
Abstract
Spinal Cord Injury (SCI), triggers neurodegenerative changes in the spinal cord, and simultaneously alters oscillatory manifestations of motor cortex. However, these disturbances may not be limited to motor areas and other parts such as hippocampus, which is vital in the neurogenesis and cognitive function, may be affected in the neurogenic and oscillatory manners. Addressing this remarkable complication of SCI, we evaluated the hippocampal neurogenesis and rhythms through acute phase of SCI. In the present study, we used 40 male rats (Sham.W1 = 10, SCI.W1 = 10, Sham.W2 = 10, SCI.W2 = 10), and findings revealed that contusive SCI declines hippocampal rhythms (Delta, Theta, Beta, Gamma) power and max-frequency. Also, there was a significant decrease in the DCX + and BrdU + cells of the dentate gyrus; correlated significantly with rhythms power decline. Considering the TUNEL assay analysis, there were significantly greater apoptotic cells, in the CA1, CA3, and DG regions of injured animals. Furthermore, according to the western blotting analysis, the expression of receptors (NMDA, GABAA, Muscarinic1), which are essential in the neurogenesis and generation of rhythms significantly attenuated following SCI. Our study demonstrated that acute SCI, alters the power and max-frequency of hippocampal rhythms parallel with changes in the hippocampal neurogenesis, apoptosis, and receptors expression.
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Affiliation(s)
- Hamid Soltani Zangbar
- Department of Neuroscience and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran; Aging Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Neurosciences Research Centre (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran
| | - Parviz Shahabi
- Aging Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Neurosciences Research Centre (NSRC), Tabriz University of Medical Sciences, Tabriz, Iran; Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Manouchehr Seyedi Vafaee
- Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark; Department of Psychiatry, Odense University Hospital, Odense, Denmark
| | - Tahereh Ghadiri
- Department of Neuroscience and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Abbas Ebrahimi Kalan
- Department of Neuroscience and Cognition, Faculty of Advanced Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Solmaz Fallahi
- Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Meysam Ghorbani
- Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
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16
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Wang M, Foster DJ, Pfeiffer BE. Alternating sequences of future and past behavior encoded within hippocampal theta oscillations. Science 2020; 370:247-250. [PMID: 33033222 PMCID: PMC8594055 DOI: 10.1126/science.abb4151] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 08/21/2020] [Indexed: 08/25/2023]
Abstract
Neural networks display the ability to transform forward-ordered activity patterns into reverse-ordered, retrospective sequences. The mechanisms underlying this transformation remain unknown. We discovered that, during active navigation, rat hippocampal CA1 place cell ensembles are inherently organized to produce independent forward- and reverse-ordered sequences within individual theta oscillations. This finding may provide a circuit-level basis for retrospective evaluation and storage during ongoing behavior. Theta phase procession arose in a minority of place cells, many of which displayed two preferred firing phases in theta oscillations and preferentially participated in reverse replay during subsequent rest. These findings reveal an unexpected aspect of theta-based hippocampal encoding and provide a biological mechanism to support the expression of reverse-ordered sequences.
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Affiliation(s)
- Mengni Wang
- Neuroscience Graduate Program, Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - David J Foster
- Department of Psychology and Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA
| | - Brad E Pfeiffer
- Neuroscience Graduate Program, Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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17
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Distance-dependent regulation of NMDAR nanoscale organization along hippocampal neuron dendrites. Proc Natl Acad Sci U S A 2020; 117:24526-24533. [PMID: 32929031 PMCID: PMC7533699 DOI: 10.1073/pnas.1922477117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hippocampal pyramidal neurons are characterized by a unique arborization subdivided in segregated dendritic domains receiving distinct excitatory synaptic inputs with specific properties and plasticity rules that shape their respective contributions to synaptic integration and action potential firing. Although the basal regulation and plastic range of proximal and distal synapses are known to be different, the composition and nanoscale organization of key synaptic proteins at these inputs remains largely elusive. Here we used superresolution imaging and single nanoparticle tracking in rat hippocampal neurons to unveil the nanoscale topography of native GluN2A- and GluN2B-NMDA receptors (NMDARs)-which play key roles in the use-dependent adaptation of glutamatergic synapses-along the dendritic arbor. We report significant changes in the nanoscale organization of GluN2B-NMDARs between proximal and distal dendritic segments, whereas the topography of GluN2A-NMDARs remains similar along the dendritic tree. Remarkably, the nanoscale organization of GluN2B-NMDARs at proximal segments depends on their interaction with calcium/calmodulin-dependent protein kinase II (CaMKII), which is not the case at distal segments. Collectively, our data reveal that the nanoscale organization of NMDARs changes along dendritic segments in a subtype-specific manner and is shaped by the interplay with CaMKII at proximal dendritic segments, shedding light on our understanding of the functional diversity of hippocampal glutamatergic synapses.
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18
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Soltani Zangbar H, Ghadiri T, Vafaee MS, Ebrahimi Kalan A, Karimipour M, Fallahi S, Ghorbani M, Shahabi P. A potential entanglement between the spinal cord and hippocampus: Theta rhythm correlates with neurogenesis deficiency following spinal cord injury in male rats. J Neurosci Res 2020; 98:2451-2467. [DOI: 10.1002/jnr.24719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 07/02/2020] [Accepted: 08/08/2020] [Indexed: 01/12/2023]
Affiliation(s)
- Hamid Soltani Zangbar
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
- Aging Research Institute Tabriz University of Medical Sciences Tabriz Iran
- Neurosciences Research Center (NSRC) Tabriz University of Medical Sciences Tabriz Iran
| | - Tahereh Ghadiri
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | | | - Abbas Ebrahimi Kalan
- Department of Neuroscience and Cognition Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | - Mohammad Karimipour
- Department of Applied Cell Sciences Faculty of Advanced Medical Sciences Tabriz University of Medical Sciences Tabriz Iran
| | - Solmaz Fallahi
- Department of Physiology Faculty of Medicine Tabriz University of Medical Sciences Tabriz Iran
| | - Meysam Ghorbani
- Department of Physiology Faculty of Medicine Tabriz University of Medical Sciences Tabriz Iran
| | - Parviz Shahabi
- Aging Research Institute Tabriz University of Medical Sciences Tabriz Iran
- Neurosciences Research Center (NSRC) Tabriz University of Medical Sciences Tabriz Iran
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19
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Luo X, Guet-McCreight A, Villette V, Francavilla R, Marino B, Chamberland S, Skinner FK, Topolnik L. Synaptic Mechanisms Underlying the Network State-Dependent Recruitment of VIP-Expressing Interneurons in the CA1 Hippocampus. Cereb Cortex 2020; 30:3667-3685. [PMID: 32080739 DOI: 10.1093/cercor/bhz334] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 12/13/2019] [Indexed: 11/14/2022] Open
Abstract
Disinhibition is a widespread circuit mechanism for information selection and transfer. In the hippocampus, disinhibition of principal cells is provided by the interneuron-specific interneurons that express the vasoactive intestinal polypeptide (VIP-IS) and innervate selectively inhibitory interneurons. By combining optophysiological experiments with computational models, we determined the impact of synaptic inputs onto the network state-dependent recruitment of VIP-IS cells. We found that VIP-IS cells fire spikes in response to both the Schaffer collateral and the temporoammonic pathway activation. Moreover, by integrating their intrinsic and synaptic properties into computational models, we predicted recruitment of these cells between the rising phase and peak of theta oscillation and during ripples. Two-photon Ca2+-imaging in awake mice supported in part the theoretical predictions, revealing a significant speed modulation of VIP-IS cells and their preferential albeit delayed recruitment during theta-run epochs, with estimated firing at the rising phase and peak of the theta cycle. However, it also uncovered that VIP-IS cells are not activated during ripples. Thus, given the preferential theta-modulated firing of VIP-IS cells in awake hippocampus, we postulate that these cells may be important for information gating during spatial navigation and memory encoding.
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Affiliation(s)
- Xiao Luo
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, PQ, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, PQ, Canada
| | - Alexandre Guet-McCreight
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Vincent Villette
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, PQ, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, PQ, Canada.,Institut de Biologie de l'ÉcoleNormale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Ruggiero Francavilla
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, PQ, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, PQ, Canada
| | - Beatrice Marino
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, PQ, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, PQ, Canada
| | - Simon Chamberland
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, PQ, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, PQ, Canada.,New York University Neuroscience Institute, New York, NY, USA
| | - Frances K Skinner
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, ON, Canada
| | - Lisa Topolnik
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, PQ, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, PQ, Canada
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20
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Fehér E, Szatmári I, Dudás T, Zalatnai A, Farkas T, Lőrinczi B, Fülöp F, Vécsei L, Toldi J. Structural Evaluation and Electrophysiological Effects of Some Kynurenic Acid Analogs. Molecules 2019; 24:molecules24193502. [PMID: 31561643 PMCID: PMC6803921 DOI: 10.3390/molecules24193502] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 01/28/2023] Open
Abstract
Kynurenic acid (KYNA), a metabolite of tryptophan, as an excitatory amino acid receptor antagonist is an effective neuroprotective agent in case of excitotoxicity, which is the hallmark of brain ischemia and several neurodegenerative processes. Therefore, kynurenine pathway, KYNA itself, and its derivatives came into the focus of research. During the past fifteen years, our research group has developed several neuroactive KYNA derivatives, some of which proved to be neuroprotective in preclinical studies. In this study, the synthesis of these KYNA derivatives and their evaluation with divergent molecular characteristics are presented together with their most typical effects on the monosynaptic transmission in CA1 region of the hippocampus of the rat. Their effects on the basic neuronal activity (on the field excitatory postsynaptic potentials: fEPSP) were studied in in vitro hippocampal slices in 1 and 200 μM concentrations. KYNA and its derivative 4 in both 1 and 200 μM concentrations proved to be inhibitory, while derivative 8 only in 200 μM decreased the amplitudes of fEPSPs. Derivative 5 facilitated the fEPSPs in 200 μM concentration. This is the first comparative study which evaluates the structural and functional differences of formerly and newly developed KYNA analogs. Considerations on possible relations between molecular structures and their physiological effects are presented.
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Affiliation(s)
- Evelin Fehér
- Department of Neurology, Interdisciplinary Excellence Centre, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary.
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - István Szatmári
- Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
- Stereochemistry Research Group of the Hungarian Academy of Sciences, Eötvös utca 6, H-6720 Szeged, Hungary.
- Institute of Pharmaceutical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
| | - Tamás Dudás
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - Anna Zalatnai
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - Tamás Farkas
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
| | - Bálint Lőrinczi
- Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
- Stereochemistry Research Group of the Hungarian Academy of Sciences, Eötvös utca 6, H-6720 Szeged, Hungary.
| | - Ferenc Fülöp
- Institute of Pharmaceutical Chemistry, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
- Stereochemistry Research Group of the Hungarian Academy of Sciences, Eötvös utca 6, H-6720 Szeged, Hungary.
- Institute of Pharmaceutical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Eötvös u. 6, H-6720 Szeged, Hungary.
| | - László Vécsei
- Department of Neurology, Interdisciplinary Excellence Centre, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Semmelweis u. 6, H-6725 Szeged, Hungary.
- MTA-SZTE Neuroscience Research Group, Semmelweis u. 6, H-6725 Szeged, Hungary.
| | - József Toldi
- Department of Physiology, Anatomy and Neuroscience, University of Szeged, Közép fasor 52, H-6726 Szeged, Hungary.
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21
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Zheng Y, Ma XX, Dong L, Gao Y, Tian L. Effects of single- and hybrid-frequency extremely low-frequency electromagnetic field stimulations on long-term potentiation in the hippocampal Schaffer collateral pathway. Int J Radiat Biol 2019; 95:1319-1325. [PMID: 31140893 DOI: 10.1080/09553002.2019.1625463] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Purpose: To study the different effects of single- and hybrid-frequency magnetic fields on long-term potentiation (LTP) in synaptic plasticity. Materials and methods: Based on the online electromagnetic field stimulation system and field excitatory postsynaptic potentials (fEPSPs) recording system, we applied four different single- and hybrid-frequency magnetic fields with an intensity of 1 mT to the Schaffer collateral (CA1) pathway of rat hippocampal slices in vitro. Results: The amplitude of fEPSPs decreased significantly under both single- and hybrid-frequency magnetic stimulation. Lower single-frequency magnetic stimulation on LTP had a greater regulating effect, while the regulating effect among four different hybrid-frequency extremely low-frequency electromagnetic fields (ELF-EMFs) stimulations on LTP showed no significant differences. Conclusion: Single-frequency magnetic stimulation produces more significant regulatory effects, and the lower the frequency, the more significant the regulatory effect. The effect of hybrid-frequency magnetic stimulation in each group was similar, and there was no significant difference between each group. The 15-Hz single-frequency magnetic stimulation group showed the most significant regulatory effect, but once it was mixed with other higher frequency magnetic stimulation, its regulation effect was significantly weakened.
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Affiliation(s)
- Yu Zheng
- School of Electronics and Information Engineering, Tianjin Polytechnic University , Tianjin , China
| | - Xiao-Xu Ma
- School of Electronics and Information Engineering, Tianjin Polytechnic University , Tianjin , China
| | - Lei Dong
- State Key Laboratory of Precision Measurement Technology and Instruments, Tianjin University , Tianjin , China
| | - Yang Gao
- The School of Information Technology and Electrical Engineering, The University of Queensland , Brisbane , Australia
| | - Lei Tian
- School of Electronics and Information Engineering, Tianjin Polytechnic University , Tianjin , China
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22
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Waataja JJ, Peterson CD, Verma H, Goracke-Postle CJ, Séguéla P, Delpire E, Wilcox GL, Fairbanks CA. Agmatine preferentially antagonizes GluN2B-containing N-methyl-d-aspartate receptors in spinal cord. J Neurophysiol 2019; 121:662-671. [PMID: 30427758 PMCID: PMC6397392 DOI: 10.1152/jn.00172.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 11/12/2018] [Accepted: 11/14/2018] [Indexed: 12/28/2022] Open
Abstract
The role of the N-methyl-d-aspartate receptor (NMDAr) as a contributor to maladaptive neuroplasticity underlying the maintenance of chronic pain is well established. Agmatine, an NMDAr antagonist, has been shown to reverse tactile hypersensitivity in rodent models of neuropathic pain while lacking the side effects characteristic of global NMDAr antagonism, including sedation and motor impairment, indicating a likely subunit specificity of agmatine's NMDAr inhibition. The present study assessed whether agmatine inhibits subunit-specific NMDAr-mediated current in the dorsal horn of mouse spinal cord slices. We isolated NMDAr-mediated excitatory postsynaptic currents (EPSCs) in small lamina II dorsal horn neurons evoked by optogenetic stimulation of Nav1.8-containing nociceptive afferents. We determined that agmatine abbreviated the amplitude, duration, and decay constant of NMDAr-mediated EPSCs similarly to the application of the GluN2B antagonist ifenprodil. In addition, we developed a site-specific knockdown of the GluN2B subunit of the NMDAr. We assessed whether agmatine and ifenprodil were able to inhibit NMDAr-mediated current in the spinal cord dorsal horn of mice lacking the GluN2B subunit of the NMDAr by analysis of electrically evoked EPSCs. In control mouse spinal cord, agmatine and ifenprodil both inhibited amplitude and accelerated the decay kinetics. However, agmatine and ifenprodil failed to attenuate the decay kinetics of NMDAr-mediated EPSCs in the GluN2B-knockdown mouse spinal cord. The present study indicates that agmatine preferentially antagonizes GluN2B-containing NMDArs in mouse dorsal horn neurons. NEW & NOTEWORTHY Our study is the first to report that agmatine preferentially antagonizes the GluN2B receptor subunit of the N-methyl-d-aspartate (NMDA) receptor in spinal cord. The preferential targeting of GluN2B receptor is consistent with the pharmacological profile of agmatine in that it reduces chronic pain without the motor side effects commonly seen with non-subunit-selective NMDA receptor antagonists.
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Affiliation(s)
- Jonathan J Waataja
- Department of Neuroscience, University of Minnesota , Minneapolis, Minnesota
| | - Cristina D Peterson
- Department of Experimental and Clinical Pharmacology, University of Minnesota , Minneapolis, Minnesota
| | - Harsha Verma
- Department of Pharmaceutics, University of Minnesota , Minneapolis, Minnesota
| | | | - Philippe Séguéla
- Department of Neurology and Neurosurgery, McGill University , Montreal, Quebec , Canada
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt School of Medicine , Nashville, Tennessee
| | - George L Wilcox
- Department of Neuroscience, University of Minnesota , Minneapolis, Minnesota
- Department of Pharmacology, University of Minnesota , Minneapolis, Minnesota
- Department of Dermatology, University of Minnesota , Minneapolis, Minnesota
| | - Carolyn A Fairbanks
- Department of Neuroscience, University of Minnesota , Minneapolis, Minnesota
- Department of Experimental and Clinical Pharmacology, University of Minnesota , Minneapolis, Minnesota
- Department of Pharmaceutics, University of Minnesota , Minneapolis, Minnesota
- Department of Pharmacology, University of Minnesota , Minneapolis, Minnesota
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23
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Miller OH, Bruns A, Ben Ammar I, Mueggler T, Hall BJ. Synaptic Regulation of a Thalamocortical Circuit Controls Depression-Related Behavior. Cell Rep 2018; 20:1867-1880. [PMID: 28834750 DOI: 10.1016/j.celrep.2017.08.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 07/08/2017] [Accepted: 07/26/2017] [Indexed: 01/06/2023] Open
Abstract
The NMDA receptor (NMDAR) antagonist ketamine elicits a long-lasting antidepressant response in patients with treatment-resistant depression. Understanding how antagonism of NMDARs alters synapse and circuit function is pivotal to developing circuit-based therapies for depression. Using virally induced gene deletion, ex vivo optogenetic-assisted circuit analysis, and in vivo chemogenetics and fMRI, we assessed the role of NMDARs in the medial prefrontal cortex (mPFC) in controlling depression-related behavior in mice. We demonstrate that post-developmental genetic deletion of the NMDAR subunit GluN2B from pyramidal neurons in the mPFC enhances connectivity between the mPFC and limbic thalamus, but not the ventral hippocampus, and reduces depression-like behavior. Using intersectional chemogenetics, we show that activation of this thalamocortical circuit is sufficient to elicit a decrease in despair-like behavior. Our findings reveal that GluN2B exerts input-specific control of pyramidal neuron innervation and identify a medial dorsal thalamus (MDT)→mPFC circuit that controls depression-like behavior.
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Affiliation(s)
- Oliver H Miller
- Roche Innovation Center Basel, Basel 4070, Switzerland; Tulane Brain Institute, Tulane University, New Orleans, LA 70115, USA
| | - Andreas Bruns
- Roche Innovation Center Basel, Basel 4070, Switzerland
| | - Imen Ben Ammar
- Faculté de Médecine, Université de Strasbourg, Strasbourg 67000, France
| | | | - Benjamin J Hall
- Roche Innovation Center Basel, Basel 4070, Switzerland; Tulane Brain Institute, Tulane University, New Orleans, LA 70115, USA.
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24
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Wang XX, Li YH, Gong HQ, Liang PJ, Zhang PM, Lu QC. The Subiculum: A Potential Site of Ictogenesis in a Neonatal Seizure Model. Front Neurol 2017; 8:147. [PMID: 28473802 PMCID: PMC5397469 DOI: 10.3389/fneur.2017.00147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 03/31/2017] [Indexed: 01/03/2023] Open
Abstract
Studies have reported that the subiculum is one origin of interictal-like discharges in adult patients with temporal lobe epilepsy; however, whether the subiculum represents a site of ictogenesis for neonatal seizures remains unclear. In this study, multi-electrode recording techniques were used to record epileptiform discharges induced by low-Mg2+ or high-K+ artificial cerebrospinal fluid in neonatal mouse hippocampal slices, and the spatiotemporal dynamics of the epileptiform discharges were analyzed. The Na+–K+–2Cl− cotransporter 1 (NKCC1) blocker, bumetanide, was applied to test its effect upon epileptiform discharges in low-Mg2+ model. The effect of N-methyl-d-aspartate receptors (NMDARs) antagonist, d-AP5, upon the epileptiform discharges in high-K+ model was examined. We found that the neonatal subiculum not only relayed epileptiform discharges emanating from the hippocampus proper (HP) but also initiated epileptiform discharges (interictal- and ictal-like discharges) independently. The latency to onset of the first epileptiform discharge initiated in the subiculum was similar to that initiated in the HP. Bumetanide efficiently blocked seizures in the neonatal HP, but was less effectively in suppressing seizures initiated in the subiculum. In high-K+ model, d-AP5 was more effective in blocking seizures initiated in the subiculum than that initiated in the HP. Furthermore, Western blotting analysis showed that NKCC1 expression was lower in the subiculum than that in the HP, whereas the expression of NMDAR subunits, NR2A and NR2B, was higher in the subiculum than that in the HP. Our results revealed that the subiculum was a potential site of ictogenesis in neonatal seizures and possessed similar seizure susceptibility to the HP. GABAergic excitation resulting from NKCC1 may play a less dominant role during ictogenesis in the subiculum than that in the HP. The subicular ictogenesis may be related to the glutamatergic excitation mediated by NMDARs.
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Affiliation(s)
- Xin-Xin Wang
- Department of Neurology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Yong-Hua Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Hai-Qing Gong
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Pei-Ji Liang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Pu-Ming Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Qin-Chi Lu
- Department of Neurology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
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25
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De Rossi P, Harde E, Dupuis JP, Martin L, Chounlamountri N, Bardin M, Watrin C, Benetollo C, Pernet-Gallay K, Luhmann HJ, Honnorat J, Malleret G, Groc L, Acker-Palmer A, Salin PA, Meissirel C. A critical role for VEGF and VEGFR2 in NMDA receptor synaptic function and fear-related behavior. Mol Psychiatry 2016; 21:1768-1780. [PMID: 26728568 PMCID: PMC5116482 DOI: 10.1038/mp.2015.195] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Revised: 10/07/2015] [Accepted: 10/22/2015] [Indexed: 01/17/2023]
Abstract
Vascular endothelial growth factor (VEGF) is known to be required for the action of antidepressant therapies but its impact on brain synaptic function is poorly characterized. Using a combination of electrophysiological, single-molecule imaging and conditional transgenic approaches, we identified the molecular basis of the VEGF effect on synaptic transmission and plasticity. VEGF increases the postsynaptic responses mediated by the N-methyl-D-aspartate type of glutamate receptors (GluNRs) in hippocampal neurons. This is concurrent with the formation of new synapses and with the synaptic recruitment of GluNR expressing the GluN2B subunit (GluNR-2B). VEGF induces a rapid redistribution of GluNR-2B at synaptic sites by increasing the surface dynamics of these receptors within the membrane. Consistently, silencing the expression of the VEGF receptor 2 (VEGFR2) in neural cells impairs hippocampal-dependent synaptic plasticity and consolidation of emotional memory. These findings demonstrated the direct implication of VEGF signaling in neurons via VEGFR2 in proper synaptic function. They highlight the potential of VEGF as a key regulator of GluNR synaptic function and suggest a role for VEGF in new therapeutic approaches targeting GluNR in depression.
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Affiliation(s)
- P De Rossi
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Neurooncology and Neuroinflammation, Lyon Neuroscience Research Center, Lyon, France
| | - E Harde
- Institute of Cell Biology and Neuroscience and BMLS, Goethe University Frankfurt, Frankfurt, Germany,Max Planck Institute for Brain Research, Frankfurt, Germany,Focus Program Translational Neurosciences, University of Mainz, Mainz, Germany
| | - J P Dupuis
- Interdisciplinary Institute for Neuroscience, Unité Mixte de Recherche 5297, Université de Bordeaux, Bordeaux, France,Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, Bordeaux, France
| | - L Martin
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Neurooncology and Neuroinflammation, Lyon Neuroscience Research Center, Lyon, France
| | - N Chounlamountri
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Neurooncology and Neuroinflammation, Lyon Neuroscience Research Center, Lyon, France
| | - M Bardin
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Neurooncology and Neuroinflammation, Lyon Neuroscience Research Center, Lyon, France
| | - C Watrin
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Neurooncology and Neuroinflammation, Lyon Neuroscience Research Center, Lyon, France
| | - C Benetollo
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Functional Neurogenomics and Optogenetics, Lyon Neuroscience Research Center, Lyon, France
| | - K Pernet-Gallay
- Grenoble Institute of Neurosciences, Grenoble, France,INSERM U836, Microscopy and Electron Microscopy Platform, Grenoble, France
| | - H J Luhmann
- Institute of Physiology, University Medical Center, University of Mainz, Mainz, Germany
| | - J Honnorat
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Neuro-Oncology Department, Hospices Civils de Lyon, Hôpital Neurologique, Lyon, France
| | - G Malleret
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Forgetting and Cortical Dynamics, Lyon Neuroscience Research Center, Lyon, France
| | - L Groc
- Interdisciplinary Institute for Neuroscience, Unité Mixte de Recherche 5297, Université de Bordeaux, Bordeaux, France,Interdisciplinary Institute for Neuroscience, UMR 5297, Centre National de la Recherche Scientifique, Bordeaux, France
| | - A Acker-Palmer
- Institute of Cell Biology and Neuroscience and BMLS, Goethe University Frankfurt, Frankfurt, Germany,Max Planck Institute for Brain Research, Frankfurt, Germany,Focus Program Translational Neurosciences, University of Mainz, Mainz, Germany
| | - P A Salin
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Forgetting and Cortical Dynamics, Lyon Neuroscience Research Center, Lyon, France
| | - C Meissirel
- Institut National de la Santé et de la Recherche Médicale, Unité 1028, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5292, Lyon, France,Claude Bernard University Lyon 1, Lyon, France,Neurooncology and Neuroinflammation, Lyon Neuroscience Research Center, Lyon, France,Equipe Neurooncologie et Neuroinflammation, Centre de Recherche en Neurosciences de Lyon, Institut National de la Santé et de la Recherche Médicale, Unité 1028, Faculté de Médecine Laennec, Lyon cedex O8, 69372 Lyon, France. E-mail:
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26
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Xu X, Zheng C, Li N, Shen H, Wang G. The decrease of NMDAR subunit expression and NMDAR EPSC in hippocampus by neonatal exposure to desflurane in mice. Behav Brain Res 2016; 317:82-87. [PMID: 27639321 DOI: 10.1016/j.bbr.2016.09.035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/13/2016] [Accepted: 09/14/2016] [Indexed: 11/29/2022]
Abstract
Desflurane is one of the third generation inhaled anesthetics and can be used in obstetric and pediatric medicine. However, effects of exposure to desflurane on neonatal brain are largely unknown. In this work, 6-day-old C57BL/6J mice were exposed to 1MAC or 1.5MAC desflurane for 2h. When the mice were 28-day-old, the open-field, spontaneous alternation Y-maze and fear conditioning tests were performed to evaluate general activity, working memory and long term memory, respectively. Levels of NMDAR subunits NR1, NR2A, and NR2B expression in hippocampus were evaluated by western blot. NMDAR-mediated excitatory postsynaptic current (EPSC) in mouse hippocampal slice was recorded by whole-cell patch clamp record. Mice exposed to 1.5MAC desflurane had significantly impaired working memory and fear conditioning memory. The protein expression of NMDAR subunits (NR1, NR2B) and NMDAR-mediated EPSC in hippocampus were significantly decreased. However no significant difference was detected between mice exposed to 1.0MAC desflurane and control mice. In conclusion, in an animal model, 6-day-old mice exposed to 1.5MAC desflurane have significant impairments in working memory and contextual fear memory at postnatal day 28, and the decrease of NMDAR subunits expression and NMDAR EPSC in hippocampus may be involved in this process.
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Affiliation(s)
- Xinyu Xu
- Laboratory of Neurobiology in Medicine, School of Biomedical Engineering, Tianjin Medical University, Tianjin 300070, China
| | - Chen Zheng
- Laboratory of Neurobiology in Medicine, School of Biomedical Engineering, Tianjin Medical University, Tianjin 300070, China
| | - Nan Li
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Institute of Anesthesiology, Tianjin 300052, China
| | - Hui Shen
- Laboratory of Neurobiology in Medicine, School of Biomedical Engineering, Tianjin Medical University, Tianjin 300070, China.
| | - Guolin Wang
- Department of Anesthesiology, Tianjin Medical University General Hospital, Tianjin Institute of Anesthesiology, Tianjin 300052, China.
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27
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Deleuze C, Huguenard JR. Two classes of excitatory synaptic responses in rat thalamic reticular neurons. J Neurophysiol 2016; 116:995-1011. [PMID: 27281752 DOI: 10.1152/jn.01121.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Accepted: 06/08/2016] [Indexed: 11/22/2022] Open
Abstract
The thalamic reticular nucleus (nRt), composed of GABAergic cells providing inhibition of relay neurons in the dorsal thalamus, receives excitation from the neocortex and thalamus. The two excitatory pathways promoting feedback or feedforward inhibition of thalamocortical neurons contribute to sensory processing and rhythm generation. While synaptic inhibition within the nRt has been carefully characterized, little is known regarding the biophysics of synaptic excitation. To characterize the functional properties of thalamocortical and corticothalamic connections to the nRt, we recorded minimal electrically evoked excitatory postsynaptic currents from nRt cells in vitro. A hierarchical clustering algorithm distinguished two types of events. Type 1 events had larger amplitudes and faster kinetics, largely mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, whereas type 2 responses had more prominent N-methyl-d-aspartate (NMDA) receptor contribution. Type 1 responses showed subnormal axonal propagation and paired pulse depression, consistent with thalamocortical inputs. Furthermore, responses kinetically similar to type 1 events were evoked by glutamate-mediated activation of thalamic neurons. Type 2 responses, in contrast, likely arise from corticothalamic inputs, with larger NMDA conductance and weak Mg(2+)-dependent block, suggesting that NMDA receptors are critical for the cortical excitation of reticular neurons. The long-lasting action of NMDA receptors would promote reticular cell burst firing and produce powerful inhibitory output to relay neurons proposed to be important in triggering epilepsy. This work provides the first complete voltage-clamp analysis of the kinetics and voltage dependence of AMPA and NMDA responses of thalamocortical and corticothalamic synapses in the nRt and will be critical in optimizing biologically realistic neural network models of thalamocortical circuits relevant to sensory processing and thalamocortical oscillations.
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Affiliation(s)
- Charlotte Deleuze
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California
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28
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Learning-induced synaptic potentiation in implanted neural precursor cell-derived neurons. Sci Rep 2015; 5:17796. [PMID: 26634434 PMCID: PMC4669478 DOI: 10.1038/srep17796] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/05/2015] [Indexed: 12/17/2022] Open
Abstract
Neuronal loss caused by neurodegenerative diseases, traumatic brain injury and stroke results in cognitive dysfunctioning. Implantation of neural stem/precursor cells (NPCs) can improve the brain function by replacing lost neurons. Proper synaptic integration following neuronal differentiation of implanted cells is believed to be a prerequisite for the functional recovery. In the present study, we characterized the functional properties of immortalized neural progenitor HiB5 cells implanted into the rat hippocampus with chemically induced lesion. The implanted HiB5 cells migrated toward CA1 pyramidal layer and differentiated into vGluT1-positive glutamatergic neurons with morphological and electrophysiological properties of endogenous CA1 pyramidal cells. Functional synaptic integration of HiB5 cell-derived neurons was also evidenced by immunohistochemical and electrophysiological data. Lesion-caused memory deficit was significantly recovered after the implantation when assessed by inhibitory avoidance (IA) learning. Remarkably, IA learning preferentially produced long-term potentiation (LTP) at the synapses onto HiB5 cell-derived neurons, which occluded paring protocol-induced LTP ex vivo. We conclude that the implanted HiB5 cell-derived neurons actively participate in learning process through LTP formation, thereby counteracting lesion-mediated memory impairment.
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29
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Zhou C, Sun H, Klein PM, Jensen FE. Neonatal seizures alter NMDA glutamate receptor GluN2A and 3A subunit expression and function in hippocampal CA1 neurons. Front Cell Neurosci 2015; 9:362. [PMID: 26441533 PMCID: PMC4585040 DOI: 10.3389/fncel.2015.00362] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/31/2015] [Indexed: 12/02/2022] Open
Abstract
Neonatal seizures are commonly caused by hypoxic and/or ischemic injury during birth and can lead to long-term epilepsy and cognitive deficits. In a rodent hypoxic seizure (HS) model, we have previously demonstrated a critical role for seizure-induced enhancement of the AMPA subtype of glutamate receptor (GluA) in epileptogenesis and cognitive consequences, in part due to GluA maturational upregulation of expression. Similarly, as the expression and function of the N-Methyl-D-aspartate (NMDA) subtype of glutamate receptor (GluN) is also developmentally controlled, we examined how early life seizures during the critical period of synaptogenesis could modify GluN development and function. In a postnatal day (P)10 rat model of neonatal seizures, we found that seizures could alter GluN2/3 subunit composition of GluNs and physiological function of synaptic GluNs. In hippocampal slices removed from rats within 48–96 h following seizures, the amplitudes of synaptic GluN-mediated evoked excitatory postsynaptic currents (eEPSCs) were elevated in CA1 pyramidal neurons. Moreover, GluN eEPSCs showed a decreased sensitivity to GluN2B selective antagonists and decreased Mg2+ sensitivity at negative holding potentials, indicating a higher proportion of GluN2A and GluN3A subunit function, respectively. These physiological findings were accompanied by a concurrent increase in GluN2A phosphorylation and GluN3A protein. These results suggest that altered GluN function and expression could potentially contribute to future epileptogenesis following neonatal seizures, and may represent potential therapeutic targets for the blockade of future epileptogenesis in the developing brain.
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Affiliation(s)
- Chengwen Zhou
- Department of Neurology, Division of Neuroscience, Boston Children's Hospital Boston, MA, USA ; Program in Neurobiology, Harvard Medical School Boston, MA, USA
| | - Hongyu Sun
- Department of Neurology, Division of Neuroscience, Boston Children's Hospital Boston, MA, USA ; Program in Neurobiology, Harvard Medical School Boston, MA, USA ; Department of Neurology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
| | - Peter M Klein
- Department of Neurology, Division of Neuroscience, Boston Children's Hospital Boston, MA, USA
| | - Frances E Jensen
- Department of Neurology, Division of Neuroscience, Boston Children's Hospital Boston, MA, USA ; Program in Neurobiology, Harvard Medical School Boston, MA, USA ; Department of Neurology, Perelman School of Medicine, University of Pennsylvania Philadelphia, PA, USA
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30
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De Marco García NV, Priya R, Tuncdemir SN, Fishell G, Karayannis T. Sensory inputs control the integration of neurogliaform interneurons into cortical circuits. Nat Neurosci 2015; 18:393-401. [PMID: 25664912 PMCID: PMC4624196 DOI: 10.1038/nn.3946] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/14/2015] [Indexed: 12/12/2022]
Abstract
Neuronal microcircuits in the superficial layers of the mammalian cortex provide the substrate for associative cortical computation. Inhibitory interneurons constitute an essential component of the circuitry and are fundamental to the integration of local and long-range information. Here we report that, during early development, superficially positioned Reelin-expressing neurogliaform interneurons in the mouse somatosensory cortex receive afferent innervation from both cortical and thalamic excitatory sources. Attenuation of ascending sensory, but not intracortical, excitation leads to axo-dendritic morphological defects in these interneurons. Moreover, abrogation of the NMDA receptors through which the thalamic inputs signal results in a similar phenotype, as well as in the selective loss of thalamic and a concomitant increase in intracortical connectivity. These results suggest that thalamic inputs are critical in determining the balance between local and long-range connectivity and are fundamental to the proper integration of Reelin-expressing interneurons into nascent cortical circuits.
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Affiliation(s)
- Natalia V De Marco García
- 1] NYU Neuroscience Institute, New York Langone Medical Center, New York, New York, USA. [2] Department of Neuroscience and Physiology, New York Langone Medical Center, New York, New York, USA. [3] Department of Neural Science, New York University, New York, New York, USA
| | - Rashi Priya
- 1] NYU Neuroscience Institute, New York Langone Medical Center, New York, New York, USA. [2] Department of Neuroscience and Physiology, New York Langone Medical Center, New York, New York, USA. [3] Department of Neural Science, New York University, New York, New York, USA
| | - Sebnem N Tuncdemir
- 1] NYU Neuroscience Institute, New York Langone Medical Center, New York, New York, USA. [2] Department of Neuroscience and Physiology, New York Langone Medical Center, New York, New York, USA. [3] Department of Neural Science, New York University, New York, New York, USA
| | - Gord Fishell
- 1] NYU Neuroscience Institute, New York Langone Medical Center, New York, New York, USA. [2] Department of Neuroscience and Physiology, New York Langone Medical Center, New York, New York, USA. [3] Department of Neural Science, New York University, New York, New York, USA
| | - Theofanis Karayannis
- 1] NYU Neuroscience Institute, New York Langone Medical Center, New York, New York, USA. [2] Department of Neuroscience and Physiology, New York Langone Medical Center, New York, New York, USA. [3] Department of Neural Science, New York University, New York, New York, USA
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31
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mGlu1 receptor-induced LTD of NMDA receptor transmission selectively at Schaffer collateral-CA1 synapses mediates metaplasticity. J Neurosci 2014; 34:12223-9. [PMID: 25186764 DOI: 10.1523/jneurosci.0753-14.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hippocampal CA1 pyramidal neurons receive inputs from entorhinal cortex directly via the temporoammonic (TA) pathway and indirectly via the Schaffer collateral (SC) pathway from CA3. NMDARs at synapses of both pathways are critical for the induction of synaptic plasticity, information processing, and learning and memory. We now demonstrate that, in the rat hippocampus, activity-dependent mGlu1 receptor-mediated LTD (mGlu1-LTD) of NMDAR-mediated transmission (EPSC(NMDA)) at the SC-CA1 input prevents subsequent LTP of AMPAR-mediated transmission. In contrast, there was no activity-dependent mGlu1-LTD of EPSC(NMDA) at the TA-CA1 pathway, or effects on subsequent plasticity of AMPAR-mediated transmission. Therefore, the two major pathways delivering information to CA1 pyramidal neurons are subject to very different plasticity rules.
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Abstract
NMDA receptors are composed of two GluN1 (N1) and two GluN2 (N2) subunits. Constituent N2 subunits control the pharmacological and kinetic characteristics of the receptor. NMDA receptors in hippocampal or cortical neurons are often thought of as diheteromeric, meaning that they contain only one type of N2 subunit. However, triheteromeric receptors with more than one type of N2 subunit also have been reported, and the relative contribution of diheteromeric and triheteromeric NMDA receptors at synapses has been difficult to assess. Because wild-type hippocampal principal neurons express N1, N2A, and N2B, we used cultured hippocampal principal neurons from N2A and N2B knock-out mice as templates for diheteromeric synaptic receptors. However, summation of N1/N2B and N1/N2A EPSCs could not account for the deactivation kinetics of wild-type EPSCs. To make a quantitative estimate of NMDA receptor subtypes at wild-type synapses, we used the deactivation kinetics and the effects of the competitive antagonist NVP-AAM077. Our results indicate that three types of NMDA receptors contribute to wild-type EPSCs, with at least two-thirds being triheteromeric receptors. Functional isolation of synaptic triheteromeric receptors revealed deactivation kinetics and pharmacology that were distinct from either diheteromeric receptor subtype. Because of differences in open probability, synaptic triheteromeric receptors outnumbered N1/N2A receptors by 5.8 to 1 and N1/N2B receptors by 3.2 to 1. Our results suggest that triheteromeric NMDA receptors must either be preferentially assembled or preferentially localized at synapses.
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Xu JY, Zhang J, Chen C. Long-lasting potentiation of hippocampal synaptic transmission by direct cortical input is mediated via endocannabinoids. J Physiol 2012; 590:2305-15. [PMID: 22411015 DOI: 10.1113/jphysiol.2011.223511] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Hippocampal CA1 pyramidal neurons receive sensory inputs from the entorhinal cortex directly through the perforant path (PP) and indirectly through Schaffer collaterals (SC). Direct cortical inputs to CA1 pyramidal neurons through the PP provide instructive signals for hippocampal long-term synaptic plasticity. However, the molecules conveying synaptic signalling in this new form of heterosynaptic plasticity remain unclear. Endocannabinoids, important endogenous signalling mediators, modulate synaptic efficacy primarily through inhibition of GABAergic or glutamatergic synaptic transmission via presynaptically expressed CB1 receptors. Here, we report that pairing of direct and indirect cortical inputs to CA1 pyramidal neurons resulted in a long-lasting potentiation of synaptic responses at SC synapses, but not at the PP. The pairing-potentiated synaptic transmission at the SC was accompanied by a reduced ratio of paired-pulse facilitation (PPR). Enhanced synaptic response at the SC by pairing of PP–SC stimuli is Ca(2+) dependent and requires the presence of functional GABAergic and glutamatergic synaptic transmissions and activation of group I metabotropic glutamate receptors. Pharmacological inhibition or genetic deletion of the CB1 receptor eliminated the pairing-induced long-term synaptic plasticity and decreased PPR at the SC. The potentiation induced by pairing of PP–SC stimuli primarily is the glutamatergic synaptic transmission. While the pairing-induced long-lasting potentiation of synaptic response was blocked by inhibitors for diacylglycerol lipase (DGL), which biosynthesizes 2-AG, inhibition of monoacylglycerol lipase (MAGL), which metabolizes 2-AG, facilitated the potentiation at SC synapses by pairing of weak PP–SC stimuli. Our results suggest that 2-AG functions as a signalling mediator tuning synaptic efficacy at the proximal synapses of hippocampal CA1 pyramidal neurons while direct and indirect cortical inputs to the same neurons are spatiotemporally primed.
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Affiliation(s)
- Jian-Yi Xu
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, 2020 Gravier Street, Suite D, New Orleans, LA 70112, USA
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Zhao YD, Cheng SY, Ou S, Chen PH, Ruan HZ. Functional response of hippocampal CA1 pyramidal cells to neonatal hypoxic-ischemic brain damage. Neurosci Lett 2012; 516:5-8. [PMID: 22402191 DOI: 10.1016/j.neulet.2012.02.067] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 01/11/2012] [Accepted: 02/21/2012] [Indexed: 11/24/2022]
Abstract
Perinatal hypoxic-ischemic (H-I) is a major cause of brain injury in the newborn. The hippocampus is more sensitive to H-I injury than the other brain regions. It is believed that H-I brain damage causes a loss of neurons in the central nervous system. The patterns of neuronal death include apoptosis and necrosis. With regard to the responses of neurons, the neural functional changes should be earlier than the morphologic changes. The aim of the present study is to evaluate the electrophysiological characteristics and the synaptic transmission functions. Seven-day-old Sprague-Dawley rat pups were randomly divided into sham operation and H-I groups. The patch clamp, immunohistochemistry and Western blotting techniques were used to achieve this objective. The results of the study showed a decrease in neuronal excitability and a significant increase in the frequency of spontaneous excitatory postsynaptic currents and the duration of EPSCs in the CA1 pyramidal cells of H-I brain damage rats. The glutamate transporter subtype 1 (GLT-1) expression level of the hippocampal CA1 area in the H-I group was decreased compared with the control. There was no difference in the amplitude of excitatory postsynaptic currents and should be no difference in the expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR), N-methyl-D-aspartate receptor (NMDAR) and synaptophysin between the control and H-I brain injury group. These results revealed that changes of electrophysiological characteristics and synaptic functions occur instantly after H-I brain damage in the hippocampal pyramidal cells of neonatal rats. The failure to eliminate glutamate should be one of the important factors of excitotoxicity injury on hippocampal CA1 pyramidal cells, while neuronal excitation was not increased in the H-I brain injury model.
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Affiliation(s)
- Yan-Dong Zhao
- Department of Neurobiology, College of Basic Medical Sciences, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China
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Perez-Rosello T, Baker JL, Ferrante M, Iyengar S, Ascoli GA, Barrionuevo G. Passive and active shaping of unitary responses from associational/commissural and perforant path synapses in hippocampal CA3 pyramidal cells. J Comput Neurosci 2011; 31:159-82. [PMID: 21207127 DOI: 10.1007/s10827-010-0303-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 10/17/2010] [Accepted: 12/14/2010] [Indexed: 10/18/2022]
Abstract
Although associational/commissural (A/C) and perforant path (PP) inputs to CA3b pyramidal cells play a central role in hippocampal mnemonic functions, the active and passive processes that shape A/C and PP AMPA and NMDA receptor-mediated unitary EPSP/EPSC (AMPA and NMDA uEPSP/uEPSC) have not been fully characterized yet. Here we find no differences in somatic amplitude between A/C and PP for either AMPA or NMDA uEPSPs. However, larger AMPA uEPSCs were evoked from proximal than from distal A/C or PP. Given the space-clamp constraints in CA3 pyramidal cells, these voltage clamp data suggest that the location-independence of A/C and PP AMPA uEPSP amplitudes is achieved in part through the activation of voltage dependent conductances at or near the soma. Moreover, similarity in uEPSC amplitudes for distal A/C and PP points to the additional participation of unclamped active conductances. Indeed, the pharmacological blockade of voltage-dependent conductances eliminates the location-independence of these inputs. In contrast, the location-independence of A/C and PP NMDA uEPSP/uEPSC amplitudes is maintained across all conditions indicating that propagation is not affected by active membrane processes. The location-independence for A/C uEPSP amplitudes may be relevant in the recruitment of CA3 pyramidal cells by other CA3 pyramidal cells. These data also suggest that PP excitation represents a significant input to CA3 pyramidal cells. Implication of the passive data on local synaptic properties is further investigated in the companion paper with a detailed computational model.
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Abstract
Optimal function of neuronal networks requires interplay between rapid forms of Hebbian plasticity and homeostatic mechanisms that adjust the threshold for plasticity, termed metaplasticity. Numerous forms of rapid synapse plasticity have been examined in detail. However, the rules that govern synaptic metaplasticity are much less clear. Here, we demonstrate a local subunit-specific switch in NMDA receptors that alternately primes or prevents potentiation at single synapses. Prolonged suppression of neurotransmitter release enhances NMDA receptor currents, increases the number of functional NMDA receptors containing NR2B, and augments calcium transients at single dendritic spines. This local switch in NMDA receptors requires spontaneous glutamate release but is independent of action potentials. Moreover, single inactivated synapses exhibit a lower induction threshold for both long-term synaptic potentiation and plasticity-induced spine growth. Thus, spontaneous glutamate release adjusts plasticity threshold at single synapses by local regulation of NMDA receptors, providing a novel spatially delimited form of synaptic metaplasticity.
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Affiliation(s)
- Ming-Chia Lee
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
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Xu JY, Chen R, Zhang J, Chen C. Endocannabinoids differentially modulate synaptic plasticity in rat hippocampal CA1 pyramidal neurons. PLoS One 2010; 5:e10306. [PMID: 20421986 PMCID: PMC2858667 DOI: 10.1371/journal.pone.0010306] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 04/01/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hippocampal CA1 pyramidal neurons receive two excitatory glutamatergic synaptic inputs: their most distal dendritic regions in the stratum lacunosum-moleculare (SLM) are innervated by the perforant path (PP), originating from layer III of the entorhinal cortex, while their more proximal regions of the apical dendrites in the stratum radiatum (SR) are innervated by the Schaffer-collaterals (SC), originating from hippocampal CA3 neurons. Endocannabinoids (eCBs) are naturally occurring mediators capable of modulating both GABAergic and glutamatergic synaptic transmission and plasticity via the CB1 receptor. Previous work on eCB modulation of excitatory synapses in the CA1 region largely focuses on the SC pathway. However, little information is available on whether and how eCBs modulate glutamatergic synaptic transmission and plasticity at PP synapses. METHODOLOGY/PRINCIPAL FINDINGS By employing somatic and dendritic patch-clamp recordings, Ca(2+) uncaging, and immunostaining, we demonstrate that there are significant differences in low-frequency stimulation (LFS)- or DHPG-, an agonist of group I metabotropic glutamate receptors (mGluRs), induced long-term depression (LTD) of excitatory synaptic transmission between SC and PP synapses in the same pyramidal neurons. These differences are eliminated by pharmacological inhibition with selective CB1 receptor antagonists or genetic deletion of the CB1 receptor, indicating that these differences likely result from differential modulation via a CB1 receptor-dependent mechanism. We also revealed that depolarization-induced suppression of excitation (DSE), a form of short-term synaptic plasticity, and photolysis of caged Ca(2+)-induced suppression of Excitatory postsynaptic currents (EPSCs) were less at the PP than that at the SC. In addition, application of WIN55212 (WIN) induced a more pronounced inhibition of EPSCs at the SC when compared to that at the PP. CONCLUSIONS/SIGNIFICANCE Our results suggest that CB1 dependent LTD and DSE are differentially expressed at the PP versus SC synapses in the same neurons, which may have an impact on synaptic scaling, integration and plasticity of hippocampal CA1 pyramidal neurons.
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Affiliation(s)
- Jian-Yi Xu
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Rongqing Chen
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Jian Zhang
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Chu Chen
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana, United States of America
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Ashby DM, Habib D, Dringenberg HC, Reynolds JN, Beninger RJ. Subchronic MK-801 treatment and post-weaning social isolation in rats: differential effects on locomotor activity and hippocampal long-term potentiation. Behav Brain Res 2010; 212:64-70. [PMID: 20382186 DOI: 10.1016/j.bbr.2010.03.041] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 03/17/2010] [Accepted: 03/22/2010] [Indexed: 11/30/2022]
Abstract
Subchronic NMDA receptor antagonist treatment and post-weaning social isolation are two animal models of schizophrenia symptoms. However, behavioral and physiological changes following a combination of these two procedures have not been investigated. Thus, we examined effects of a novel, "double hit" model combining these two treatments, comparing them to standard models involving only NMDA antagonist treatment or social isolation. Male, Sprague-Dawley rats were either group-housed or maintained in social isolation (starting at postnatal day [PD] 21 and continuing throughout the study). Each housing condition was further subdivided into two groups, receiving either subchronic treatment with either saline or MK-801 (0.5mg/kg, i.p., 2xday for seven days starting at PD 56). Post-weaning social isolation increased locomotor activity (assessed at PD 70) in response to a novel environment and an acute amphetamine injection, while subchronic MK-801 increased only amphetamine induced locomotor activity. Subsequent electrophysiological experiments (under urethane anesthesia) assessing changes in plasticity of hippocampal synapses showed that subchronic MK-801 treatment resulted in an increase in long-term potentiation in area CA1 in response to high frequency stimulation of the contralateral CA3 area, while housing condition had no effect. No other changes in hippocampal electrophysiology (input-output curves, paired-pulse facilitation) were observed. These data are the first to demonstrate an enhancement in hippocampal long-term plasticity in vivo following subchronic MK-801 administration, an effect that may be related to the well-characterized changes in glutamatergic and GABAergic systems seen after subchronic NMDA receptor blockade. That lack of additive or synergistic effects in the "double hit model" suggests that combining isolation and subchronic MK-801 treatment does not necessarily produce greater behavioral or physiological dysfunction than that seen with either treatment alone.
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Affiliation(s)
- Donovan M Ashby
- Department of Psychology, Queen's University, Kingston, Ontario, K7L 3N6, Canada
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de Asis ED, Nguyen-Vu TDB, Arumugam PU, Chen H, Cassell AM, Andrews RJ, Yang CY, Li J. High efficient electrical stimulation of hippocampal slices with vertically aligned carbon nanofiber microbrush array. Biomed Microdevices 2009; 11:801-8. [PMID: 19291408 PMCID: PMC2708324 DOI: 10.1007/s10544-009-9295-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Long-term neuroprostheses for functional electrical stimulation must efficiently stimulate tissue without electrolyzing water and raising the extracellular pH to toxic levels. Comparison of the stimulation efficiency of tungsten wire electrodes (W wires), platinum microelectrode arrays (PtMEA), as-grown vertically aligned carbon nanofiber microbrush arrays (VACNF MBAs), and polypyrrole coated (PPy-coated) VACNF MBAs in eliciting field potentials in the hippocampus slice indicates that, at low stimulating voltages that preclude the electrolysis of water, only the PPy-coated VACNF MBA is able to stimulate the CA3 to CA1 pathway. Unlike the W wires, PtMEA, as-grown VACNF MBA, and the PPy-coated VACNF MBA elicit only excitatory postsynaptic potentials (EPSPs). Furthermore, the PPy-coated VACNF MBA evokes somatic action potentials in addition to EPSPs. These results highlight the PPy-coated VACNF's advantages in lower electrode impedance, ability to stimulate tissue through a biocompatible chloride flux, and stable vertical alignment in liquid that enables access to spatially confined regions of neuronal cells.
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Affiliation(s)
- Edward D. de Asis
- Departments of Electrical Engineering and Bioengineering, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053 USA
| | - T. D. Barbara Nguyen-Vu
- Department of Molecular Cell Physiology, Stanford University Medical School, Palo Alto, CA 94305, USA
| | - Prabhu U. Arumugam
- ELORET Corporation, NASA Ames Research Center, Moffett Field, CA 94035 USA
| | - Hua Chen
- ELORET Corporation, NASA Ames Research Center, Moffett Field, CA 94035 USA
| | - Alan M. Cassell
- University Affiliated Research Center, University of California, Santa Cruz, Moffett Field, CA 94035 USA
| | | | - Cary Y. Yang
- Center for Nanostructures, Santa Clara University, 500 El Camino Real, Santa Clara, CA 95053 USA
| | - Jun Li
- NASA Ames Research Center, Moffett Field, CA 94035 USA
- Department of Chemistry, Kansas State University, Manhattan, KS 66506–0401 USA
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Zhao MG, Toyoda H, Wang YK, Zhuo M. Enhanced synaptic long-term potentiation in the anterior cingulate cortex of adult wild mice as compared with that in laboratory mice. Mol Brain 2009; 2:11. [PMID: 19445686 PMCID: PMC2694782 DOI: 10.1186/1756-6606-2-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 05/16/2009] [Indexed: 11/20/2022] Open
Abstract
Activation of N-methyl D-aspartate (NMDA) receptor is important for learning, memory and persistent pain. Genetic enhancement of NMDA receptor function by overexpressing NR2B subunit significantly enhances hippocampal long-term potentiation (LTP), behavioral learning as well as persistent pain. Recent studies found that NMDA NR2B subunits can undergo long-term upregulation in the brain under certain conditions including peripheral injury and environmental enrichment. Considering the fact that laboratory grown animals live in an artificial comfort environment, we wondered if NMDA receptor functions and its related LTP would differ in animals living in a natural wild environment. In this report we performed whole-cell patch-clamp recordings from both laboratory wild-type mice and wild mice from a natural environment. We found that LTP was significantly enhanced in the anterior cingulate cortex (ACC) of the wild mice as compared with that of laboratory mice. In parallel, NMDA receptor NR2B/total NMDA receptor mediated EPSC ratio was significantly increased in slices of wild mice. Our findings provide the first evidence that NMDA NR2B receptors play an important role in experience-dependent synaptic potentiation within the ACC in wild mice as previously reported in laboratory mice.
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Affiliation(s)
- Ming-Gao Zhao
- School of Pharmacy, Fourth Military Medical University, 17 Changle West Road, Xi'an 710032, Shaanxi, PR China.
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Subunit- and pathway-specific localization of NMDA receptors and scaffolding proteins at ganglion cell synapses in rat retina. J Neurosci 2009; 29:4274-86. [PMID: 19339621 DOI: 10.1523/jneurosci.5602-08.2009] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Retinal ganglion cells (RGCs) receive excitatory glutamatergic input from ON and OFF bipolar cells in distinct sublaminae of the inner plexiform layer (IPL). AMPA and NMDA receptors (AMPARs and NMDARs) mediate excitatory inputs in both synaptic layers, but specific roles for NMDARs at RGC synapses remain unclear. NMDARs comprise NR1 and NR2 subunits and are anchored by membrane-associated guanylate kinases (MAGUKs), but it is unknown whether particular NR2 subunits associate preferentially with particular NR1 splice variants and MAGUKs. Here, we used postembedding immunogold electron microscopy techniques to examine the subsynaptic localization of NMDAR subunits and MAGUKs at ON and OFF synapses onto rat RGCs. We found that the NR2A subunit, the NR1C2' splice variant, and MAGUKs PSD-95 and PSD-93 are localized to the postsynaptic density (PSD), preferentially at OFF synapses, whereas the NR2B subunit, the NR1C2 splice variant, and the MAGUK SAP102 are localized perisynaptically, with NR2B exhibiting a preference for ON synapses. Consistent with these anatomical data, spontaneous EPSCs (sEPSCs) recorded from OFF cells exhibited an NMDAR component that was insensitive to the NR2B antagonist Ro 25-6981. In ON cells, sEPSCs expressed an NMDAR component, partially sensitive to Ro 25-6981, only when glutamate transport was inhibited, indicating perisynaptic expression of NR2B NMDARs. These results provide the first evidence for preferential association of particular NR1 splice variants, NR2 subunits, and MAGUKs at central synapses and suggest that different NMDAR subtypes may play specific roles at functionally distinct synapses in the retinal circuitry.
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Abstract
Converging evidence suggests that salience-associated modulation of behavior is mediated by the release of monoamines and that monoaminergic activation of D(1)/D(5) receptors is required for normal hippocampal-dependent learning and memory. However, it is not understood how D(1)/D(5) modulation of hippocampal circuits can affect salience-associated learning and memory. We have observed in CA1 pyramidal neurons that D(1)/D(5) receptor activation elicits a bidirectional long-term plasticity of NMDA receptor-mediated synaptic currents with the polarity of plasticity determined by NMDA receptor, NR2A/B subunit composition. This plasticity results in a decrease in the NR2A/NR2B ratio of subunit composition. Synaptic responses mediated by NMDA receptors that include NR2B subunits are potentiated by D(1)/D(5) receptor activation, whereas responses mediated by NMDA receptors that include NR2A subunits are depressed. Furthermore, these bidirectional, subunit-specific effects are mediated by distinctive intracellular signaling mechanisms. Because there is a predominance of NMDA receptors composed of NR2A subunits observed in entorhinal-CA1 inputs and a predominance of NMDA receptors composed of NR2B subunits in CA3-CA1 synapses, potentiation of synaptic NMDA currents predominates in the proximal CA3-CA1 synapses, whereas depression of synaptic NMDA currents predominates in the distal entorhinal-CA1 synapses. Finally, all of these effects are reproduced by the release of endogenous monoamines through activation of D(1)/D(5) receptors. Thus, endogenous D(1)/D(5) activation can (1) decrease the NR2A/NR2B ratio of NMDA receptor subunit composition at glutamatergic synapses, a rejuvenation to a composition similar to developmentally immature synapses, and, (2) in CA1, bias NMDA receptor responsiveness toward the more highly processed trisynaptic CA3-CA1 circuit and away from the direct entorhinal-CA1 input.
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Speed HE, Dobrunz LE. Developmental changes in short-term facilitation are opposite at temporoammonic synapses compared to Schaffer collateral synapses onto CA1 pyramidal cells. Hippocampus 2009; 19:187-204. [PMID: 18777561 DOI: 10.1002/hipo.20496] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
CA1 pyramidal neurons receive two distinct excitatory inputs that are each capable of influencing hippocampal output and learning and memory. The Schaffer collateral (SC) input from CA3 axons onto the more proximal dendrites of CA1 is part of the trisynaptic circuit, which originates in Layer II of the entorhinal cortex (EC). The temporoammonic (TA) pathway to CA1 provides input directly from Layer III of the EC onto the most distal dendrites of CA1 pyramidal cells, and is involved in spatial memory and memory consolidation. We have previously described a developmental decrease in short-term facilitation from juvenile (P13-18) to young adult (P28-42) rats at SC synapses that is due to feedback inhibition via synaptically activated mGluR1 on CA1 interneurons. It is not known how short-term changes in synaptic strength are regulated at TA synapses, nor is it known how short-term plasticity is balanced at SC and TA inputs during development. Here we describe a novel developmental increase in short-term facilitation at TA synapses, which is the opposite of the decrease in facilitation occurring at SC synapses. Although short-term facilitation is much lower at TA synapses when compared with SC synapses in juveniles, short-term plasticity at SC and TA synapses converges at similar levels of paired-pulse facilitation in the young adult rat. However, in young adults CA3-CA1 synapses still exhibit more facilitation than TA-CA1 synapses during physiologically-relevant activity, suggesting that the two pathways are each poised to uniquely modulate CA1 output in an activity-dependent manner. Finally, we show that there is a developmental decrease in the initial release probability at TA synapses that underlies their developmental decrease in facilitation, but no developmental change in release probability at SC synapses. This represents a fundamental difference in the presynaptic function of the two major inputs to CA1, which could alter the flow of information in hippocampus during development.
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Affiliation(s)
- Haley E Speed
- Department of Neurobiology, Civitan International Research Center and Evelyn F McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Coagonist release modulates NMDA receptor subtype contributions at synaptic inputs to retinal ganglion cells. J Neurosci 2009; 29:1469-79. [PMID: 19193893 DOI: 10.1523/jneurosci.4240-08.2009] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
NMDA receptors (NMDARs) are tetrameric protein complexes usually comprising two NR1 and two NR2 subunits. Different combinations of four potential NR2 subunits (NR2A-D) confer diversity in developmental expression, subsynaptic localization, and functional characteristics, including affinity for neurotransmitter. NR2B-containing NMDARs, for example, exhibit relatively high affinity both for glutamate and the coagonist glycine. Although multiple NMDAR subtypes can colocalize at individual synapses, particular subtypes often mediate inputs from distinct functional pathways. In retinal ganglion cells (RGCs), NMDARs contribute to synaptic responses elicited by light stimulus onset ("ON") and offset ("OFF"), but roles for particular NMDAR subtypes, and potential segregation between the ON and OFF pathways, have not been explored. Moreover, elements in the retinal circuitry release two different NMDAR coagonists, glycine and d-serine, but the effects of endogenous coagonist release on the relative contribution of different NMDAR subtypes are unclear. Here, we show that coagonist release within the retina modulates the relative contribution of different NMDARs in the ON pathway of the rat retina. By pharmacologically stimulating functional pathways independently in acute slices and recording synaptic responses in RGCs, we show that ON inputs, but not OFF inputs, are mediated in part by NMDARs exhibiting NR2B-like pharmacology. Furthermore, suppressing release of NMDAR coagonist reduces NMDAR activation at ON synapses and increases the relative contribution of these putative NR2B-containing receptors. These results demonstrate direct evidence for evoked coagonist release onto NMDARs and indicate that modulating coagonist release may regulate the relative activation of different NMDAR subtypes in the ON pathway.
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Surface trafficking of N-methyl-D-aspartate receptors: physiological and pathological perspectives. Neuroscience 2008; 158:4-18. [PMID: 18583064 DOI: 10.1016/j.neuroscience.2008.05.029] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Revised: 05/06/2008] [Accepted: 05/17/2008] [Indexed: 11/20/2022]
Abstract
The N-methyl-D-aspartate receptor (NMDAR) plays a crucial role in shaping the strength of synaptic connections. Over the last decades, extensive studies have defined the cellular and molecular mechanisms by which synaptic NMDARs control the maturation and plasticity of synaptic transmission, and how altered synaptic NMDAR signaling is implicated in neurodegenerative and psychiatric disorders. It is now clear that activation of synaptic or extrasynaptic NMDARs produces different signaling cascades and thus neuronal functions. Our current understanding of NMDAR surface distribution and trafficking is only emerging. Exchange of NMDARs between synaptic and extrasynaptic areas through surface diffusion is a highly dynamic and regulated process. The aim of this review is to describe the identified mechanisms that regulate surface NMDAR behaviors and discuss the impact of this new trafficking pathway on the well-established NMDAR-dependent physiological and pathophysiological processes.
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Hirsch S, Luhmann H. Pathway-specificity in N-methyl-d-aspartate receptor-mediated synaptic inputs onto subplate neurons. Neuroscience 2008; 153:1092-102. [DOI: 10.1016/j.neuroscience.2008.01.068] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2007] [Revised: 01/17/2008] [Accepted: 01/22/2008] [Indexed: 11/17/2022]
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Kajiwara R, Wouterlood FG, Sah A, Boekel AJ, Baks-te Bulte LT, Witter MP. Convergence of entorhinal and CA3 inputs onto pyramidal neurons and interneurons in hippocampal area CA1—An anatomical study in the rat. Hippocampus 2008; 18:266-80. [DOI: 10.1002/hipo.20385] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Longden KD, Willshaw DJ. Asynchronous inputs and NMDA conductances predict excitatory responses in the cortical-cA1 pathway of the hippocampus. NETWORK (BRISTOL, ENGLAND) 2007; 18:299-325. [PMID: 18360937 DOI: 10.1080/09548980701587100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
In the hippocampus, CA1 place cells are driven by a substantial input from CA3. There is a second pathway to CA1 from the entorhinal cortex. The mode of action of cortex on CA1 through this pathway is not known. The pathway supports CA1 place field activity after CA3 has been lesioned, yet stimulation of the pathway in rat slices results in strong feedforward inhibition that prevents pyramidal cell action potentials. We use a detailed conductance-based model of this pathway to simulate the response to cortical stimulation in slice experiments and in vivo spatial exploration. We find that the presence of NMDA conductances enable CA1 pyramidal cells to integrate cortical inputs over a time scale longer than that which is effective in recruiting the inhibitory response that can suppress action potentials. We then show that this asynchronous response mode supports place field formation in response to experimentally constrained spatially modulated cortical activity. Within this model, the inclusion of GABAB conductances and the hyperpolarisation activated current I(h) reduces the strength of the GABAA inputs required to balance the excitatory inputs, and this facilitates place field formation by reducing variability in the inhibitory inputs.
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Affiliation(s)
- Kit D Longden
- Department of Bioengineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
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Nishimura-Akiyoshi S, Niimi K, Nakashiba T, Itohara S. Axonal netrin-Gs transneuronally determine lamina-specific subdendritic segments. Proc Natl Acad Sci U S A 2007; 104:14801-6. [PMID: 17785411 PMCID: PMC1964543 DOI: 10.1073/pnas.0706919104] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2006] [Indexed: 11/18/2022] Open
Abstract
Axons from a distinct group of neurons make contact with dendritic trees of target neurons in clearly segregated and laminated patterns, thereby forming functional units for processing multiple inputs of information in the vertebrate central nervous system. Whether and how dendrites acquire lamina-specific properties corresponding to each pathway is not known. We show here that vertebrate-specific membrane-anchored members of the UNC-6/netrin family, netrin-G1 and -G2, organize the lamina/pathway-specific differentiation of dendrites. Netrin-G1 and -G2 distribute on axons of different pathways and specifically interact with receptors NGL-1 and -2, respectively. In the hippocampus, parietal cortex, and piriform cortex, NGL-1 is concentrated in the dendritic segments corresponding to the lamina-specific termination of netrin-G1-positive axons, and NGL-2 is concentrated in distinct dendritic segments corresponding to the termination of netrin-G2-positive axons. In netrin-G1- and -G2-deficient mice, in which axonal path-finding is normal, the segmental distribution of NGL-1 and -2 is selectively disrupted, and the individual receptors are diffused along the dendrites. These findings indicate that transneuronal interactions of netrin-Gs and their specific receptors provide a molecular basis for the axonal innervation-dependent mechanism of postsynaptic membrane organization, and provide insight into the formation of the laminar structure within the dendrites.
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Affiliation(s)
| | - Kimie Niimi
- Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Brain Science and Life Technology Research Foundation, 1-28-12 Narimasu, Itabashi, Tokyo 175-0094, Japan; and
| | - Toshiaki Nakashiba
- *Laboratory for Behavioral Genetics and
- The Picower Institute for Learning and Memory, RIKEN-MIT Neuroscience Research Center, Massachusetts Institute of Technology, Cambridge, MA 02139
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Sil'kis IG. What are the mechanisms underlying the involvement of different subtypes of NMDA receptors in inducing long-term potentiation and depression in the hippocampus? NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 2007; 37:477-80. [PMID: 17505798 DOI: 10.1007/s11055-007-0038-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 02/27/2006] [Indexed: 10/23/2022]
Abstract
It has been hypothesized that the sign (direction) of modification of the efficiency of synaptic transmission depends on the subtype of N-methyl-D-aspartate (NMDA)-sensitive receptors involved. Activation of NMDA receptors with 2A subunits facilitates the induction of long-term potentiation, while receptors with 2B subunits facilitate the induction of long-term depression. However, experimental data have been obtained which contradict this hypothesis. We suggest an alternative hypothesis to explain currently available data. According to this hypothesis, activation of NMDA receptors containing different subunits can lead both to long-term potentiation and long-term depression, depending on the post-tetanic increase in the postsynaptic Ca(2+) concentration relative to the increase induced by preceding stimulation. Activation of NMDA receptors containing 2B subunits can lead to long-term depression of the excitatory input to pyramidal neurons because of the presence of these receptors on inhibitory interneurons, with induction of long-term potentiation on the interneuron and potentiation of inhibitory transmission between interneurons and pyramidal cells.
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Affiliation(s)
- I G Sil'kis
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia.
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