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Caccavano AP, Kimmel S, Vlachos A, Mahadevan V, Kim JH, Vargish G, Chittajallu R, London E, Yuan X, Hunt S, Eldridge MAG, Cummins AC, Hines BE, Plotnikova A, Mohanty A, Averbeck BB, Zaghloul K, Dimidschstein J, Fishell G, Pelkey KA, McBain CJ. Divergent opioid-mediated suppression of inhibition between hippocampus and neocortex across species and development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576455. [PMID: 38313283 PMCID: PMC10836073 DOI: 10.1101/2024.01.20.576455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2024]
Abstract
Opioid receptors within the CNS regulate pain sensation and mood and are key targets for drugs of abuse. Within the adult rodent hippocampus (HPC), μ-opioid receptor agonists suppress inhibitory parvalbumin-expressing interneurons (PV-INs), thus disinhibiting the circuit. However, it is uncertain if this disinhibitory motif is conserved in other cortical regions, species, or across development. We observed that PV-IN mediated inhibition is robustly suppressed by opioids in HPC but not neocortex in mice and nonhuman primates, with spontaneous inhibitory tone in resected human tissue also following a consistent dichotomy. This hippocampal disinhibitory motif was established in early development when immature PV-INs and opioids already influence primordial network rhythmogenesis. Acute opioid-mediated modulation was partially occluded with morphine pretreatment, with implications for the effects of opioids on hippocampal network activity during circuit maturation as well as learning and memory. Together, these findings demonstrate that PV-INs exhibit a divergence in opioid sensitivity across brain regions that is remarkably conserved across evolution and highlights the underappreciated role of opioids acting through immature PV-INs in shaping hippocampal development.
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Affiliation(s)
- Adam P Caccavano
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Sarah Kimmel
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Anna Vlachos
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Vivek Mahadevan
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - June Hoan Kim
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Geoffrey Vargish
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Ramesh Chittajallu
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Edra London
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Xiaoqing Yuan
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Steven Hunt
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | | | - Alex C Cummins
- National Institute of Mental Health (NIMH), NIH, Bethesda, MD, USA
| | - Brendan E Hines
- National Institute of Mental Health (NIMH), NIH, Bethesda, MD, USA
| | - Anya Plotnikova
- National Institute of Mental Health (NIMH), NIH, Bethesda, MD, USA
| | - Arya Mohanty
- National Institute of Mental Health (NIMH), NIH, Bethesda, MD, USA
| | - Bruno B Averbeck
- National Institute of Mental Health (NIMH), NIH, Bethesda, MD, USA
| | - Kareem Zaghloul
- National Institute of Neurological Disorders and Stroke (NINDS) Intramural Research Program, NIH Bethesda, MD, USA
| | - Jordane Dimidschstein
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Gord Fishell
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA, USA
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Kenneth A Pelkey
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Chris J McBain
- Section on Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD, USA
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2
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Margolis EB, Moulton MG, Lambeth PS, O'Meara MJ. The life and times of endogenous opioid peptides: Updated understanding of synthesis, spatiotemporal dynamics, and the clinical impact in alcohol use disorder. Neuropharmacology 2023; 225:109376. [PMID: 36516892 PMCID: PMC10548835 DOI: 10.1016/j.neuropharm.2022.109376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 12/03/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022]
Abstract
The opioid G-protein coupled receptors (GPCRs) strongly modulate many of the central nervous system structures that contribute to neurological and psychiatric disorders including pain, major depressive disorder, and substance use disorders. To better treat these and related diseases, it is essential to understand the signaling of their endogenous ligands. In this review, we focus on what is known and unknown about the regulation of the over two dozen endogenous peptides with high affinity for one or more of the opioid receptors. We briefly describe which peptides are produced, with a particular focus on the recently proposed possible synthesis pathways for the endomorphins. Next, we describe examples of endogenous opioid peptide expression organization in several neural circuits and how they appear to be released from specific neural compartments that vary across brain regions. We discuss current knowledge regarding the strength of neural activity required to drive endogenous opioid peptide release, clues about how far peptides diffuse from release sites, and their extracellular lifetime after release. Finally, as a translational example, we discuss the mechanisms of action of naltrexone (NTX), which is used clinically to treat alcohol use disorder. NTX is a synthetic morphine analog that non-specifically antagonizes the action of most endogenous opioid peptides developed in the 1960s and FDA approved in the 1980s. We review recent studies clarifying the precise endogenous activity that NTX prevents. Together, the works described here highlight the challenges and opportunities the complex opioid system presents as a therapeutic target.
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Affiliation(s)
- Elyssa B Margolis
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, CA, USA; Neuroscience Graduate Program, University of California, San Francisco, CA, USA.
| | - Madelyn G Moulton
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, CA, USA
| | - Philip S Lambeth
- UCSF Weill Institute for Neurosciences, Department of Neurology, University of California, San Francisco, CA, USA
| | - Matthew J O'Meara
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
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3
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Enkephalin release from VIP interneurons in the hippocampal CA2/3a region mediates heterosynaptic plasticity and social memory. Mol Psychiatry 2022; 27:2879-2900. [PMID: 33990774 PMCID: PMC8590711 DOI: 10.1038/s41380-021-01124-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 03/23/2021] [Accepted: 04/13/2021] [Indexed: 12/22/2022]
Abstract
The hippocampus contains a diverse array of inhibitory interneurons that gate information flow through local cortico-hippocampal circuits to regulate memory storage. Although most studies of interneurons have focused on their role in fast synaptic inhibition mediated by GABA release, different classes of interneurons express unique sets of neuropeptides, many of which have been shown to exert powerful effects on neuronal function and memory when applied pharmacologically. However, relatively little is known about whether and how release of endogenous neuropeptides from inhibitory cells contributes to their behavioral role in regulating memory formation. Here we report that vasoactive intestinal peptide (VIP)-expressing interneurons participate in social memory storage by enhancing information transfer from hippocampal CA3 pyramidal neurons to CA2 pyramidal neurons. Notably, this action depends on release of the neuropeptide enkephalin from VIP neurons, causing long-term depression of feedforward inhibition onto CA2 pyramidal cells. Moreover, VIP neuron activity in the CA2 region is increased selectively during exploration of a novel conspecific. Our findings, thus, enhance our appreciation of how GABAergic neurons can regulate synaptic plasticity and mnemonic behavior by demonstrating that such actions can be mediated by release of a specific neuropeptide, rather than through classic fast inhibitory transmission.
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Lehr AB, Kumar A, Tetzlaff C, Hafting T, Fyhn M, Stöber TM. CA2 beyond social memory: Evidence for a fundamental role in hippocampal information processing. Neurosci Biobehav Rev 2021; 126:398-412. [PMID: 33775693 DOI: 10.1016/j.neubiorev.2021.03.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 03/16/2021] [Accepted: 03/18/2021] [Indexed: 01/16/2023]
Abstract
Hippocampal region CA2 has received increased attention due to its importance in social recognition memory. While its specific function remains to be identified, there are indications that CA2 plays a major role in a variety of situations, widely extending beyond social memory. In this targeted review, we highlight lines of research which have begun to converge on a more fundamental role for CA2 in hippocampus-dependent memory processing. We discuss recent proposals that speak to the computations CA2 may perform within the hippocampal circuit.
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Affiliation(s)
- Andrew B Lehr
- Department of Computational Neuroscience, University of Göttingen, Germany; Bernstein Center for Computational Neuroscience, University of Göttingen, Germany; Department of Computational Physiology, Simula Research Laboratory, Lysaker, Norway; Centre for Integrative Neuroplasticity, University of Oslo, Norway.
| | - Arvind Kumar
- Department of Computational Science and Technology, KTH Royal Institute of Technology, Sweden
| | - Christian Tetzlaff
- Department of Computational Neuroscience, University of Göttingen, Germany; Bernstein Center for Computational Neuroscience, University of Göttingen, Germany
| | - Torkel Hafting
- Centre for Integrative Neuroplasticity, University of Oslo, Norway; Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Marianne Fyhn
- Centre for Integrative Neuroplasticity, University of Oslo, Norway; Department of Biosciences, University of Oslo, Norway
| | - Tristan M Stöber
- Department of Computational Physiology, Simula Research Laboratory, Lysaker, Norway; Centre for Integrative Neuroplasticity, University of Oslo, Norway; Department of Informatics, University of Oslo, Norway.
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Johnson MA, Contoreggi NH, Kogan JF, Bryson M, Rubin BR, Gray JD, Kreek MJ, McEwen BS, Milner TA. Chronic stress differentially alters mRNA expression of opioid peptides and receptors in the dorsal hippocampus of female and male rats. J Comp Neurol 2021; 529:2636-2657. [PMID: 33483980 DOI: 10.1002/cne.25115] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 02/06/2023]
Abstract
Chronic immobilization stress (CIS) results in sex-dependent changes in opioid peptide levels and receptor subcellular distributions within the rat dorsal hippocampus, which are paralleled with an inability for males to acquire conditioned place preference (CPP) to oxycodone. Here, RNAScope in situ hybridization was used to determine the expression of hippocampal opioid peptides and receptors in unstressed (US) and CIS estrus female and male adult (∼2.5 months old ) Sprague Dawley rats. In all groups, dentate granule cells expressed PENK and PDYN; additionally, numerous interneurons expressed PENK. OPRD1 and OPRM1 were primarily expressed in interneurons, and to a lesser extent, in pyramidal and granule cells. OPRK1-was expressed in sparsely distributed interneurons. There were few baseline sex differences: US females compared to US males had more PENK-expressing and fewer OPRD1-expressing granule cells and more OPRM1-expressing CA3b interneurons. Several expression differences emerged after CIS. Both CIS females and males compared to their US counterparts had elevated: (1) PENK-expressing dentate granule cells and interneurons in CA1 and CA2/3a; (2) OPRD1 probe number and cell expression in CA1, CA2/3a and CA3b and the dentate gyrus; and (3) OPRK1-expressing interneurons in the dentate hilus. Also, CIS males compared to US males had elevated: (1) PDYN expression in granule cells; (2) OPRD1 probe and interneuron expression in CA2/3a; (3) OPRM1 in granule cells; and (4) OPRK1 interneuron expression in CA2/3a. The sex-specific changes in hippocampal opioid gene expression may impact network properties and synaptic plasticity processes that may contribute to the attenuation of oxycodone CPP in CIS males.
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Affiliation(s)
- Megan A Johnson
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York, USA
| | - Natalina H Contoreggi
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York, USA
| | - Joshua F Kogan
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York, USA
| | - Matthew Bryson
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York, USA
| | - Batsheva R Rubin
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York, USA
| | - Jason D Gray
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York, USA
| | - Mary Jeanne Kreek
- The Laboratory of the Biology of Addictive Diseases, The Rockefeller University, New York, New York, USA
| | - Bruce S McEwen
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York, USA
| | - Teresa A Milner
- Feil Family Brain and Mind Research Institute, Weill Cornell Medicine, New York, New York, USA.,Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, New York, USA
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Semilunar Granule Cells Are the Primary Source of the Perisomatic Excitatory Innervation onto Parvalbumin-Expressing Interneurons in the Dentate Gyrus. eNeuro 2020; 7:ENEURO.0323-19.2020. [PMID: 32571963 PMCID: PMC7340841 DOI: 10.1523/eneuro.0323-19.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 05/29/2020] [Accepted: 06/02/2020] [Indexed: 11/21/2022] Open
Abstract
We analyzed the origin and relevance of the perisomatic excitatory inputs on the parvalbumin interneurons of the granule cell layer in mouse. Confocal analysis of the glutamatergic innervation showed that it represents ∼50% of the perisomatic synapses that parvalbumin cells receive. This excitatory input may originate from granule cell collaterals, the mossy cells, or even supramammillary nucleus. First, we assessed the input from the mossy cells on parvalbumin interneurons. Axon terminals of mossy cells were visualized by their calretinin content. Using multicolor confocal microscopy, we observed that less than 10% of perisomatic excitatory innervation of parvalbumin cells could originate from mossy cells. Correlative light and electron microscopy revealed that innervation from mossy cells, although present, was indeed infrequent, except for those parvalbumin cells whose somata were located in the inner molecular layer. Second, we investigated the potential input from supramammillary nucleus on parvalbumin cell somata using anterograde tracing or immunocytochemistry against vesicular glutamate transporter 2 (VGLUT2) and found only occasional contacts. Third, we intracellularly filled dentate granule cells in acute slice preparations using whole-cell recording and examined whether their axon collaterals target parvalbumin interneurons. We found that typical granule cells do not innervate the perisomatic region of these GABAergic cells. In sharp contrast, semilunar granule cells (SGCs), a scarce granule cell subtype often contacted the parvalbumin cell soma and proximal dendrites. Our data, therefore, show that perisomatic excitatory drive of parvalbumin interneurons in the granular layer of the dentate gyrus is abundant and originates primarily from SGCs.
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7
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Guet-McCreight A, Skinner FK, Topolnik L. Common Principles in Functional Organization of VIP/Calretinin Cell-Driven Disinhibitory Circuits Across Cortical Areas. Front Neural Circuits 2020; 14:32. [PMID: 32581726 PMCID: PMC7296096 DOI: 10.3389/fncir.2020.00032] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 05/04/2020] [Indexed: 12/21/2022] Open
Abstract
In the brain, there is a vast diversity of different structures, circuitries, cell types, and cellular genetic expression profiles. While this large diversity can often occlude a clear understanding of how the brain works, careful analyses of analogous studies performed across different brain areas can hint at commonalities in neuronal organization. This in turn can yield a fundamental understanding of necessary circuitry components that are crucial for how information is processed across the brain. In this review, we outline recent in vivo and in vitro studies that have been performed in different cortical areas to characterize the vasoactive intestinal polypeptide (VIP)- and/or calretinin (CR)-expressing cells that specialize in inhibiting GABAergic interneurons. In doing so, we make the case that, across cortical structures, interneuron-specific cells commonly specialize in the synaptic disinhibition of excitatory neurons, which can ungate the integration and plasticity of external inputs onto excitatory neurons. In line with this, activation of interneuron- specific cells enhances animal performance across a variety of behavioral tasks that involve learning, memory formation, and sensory discrimination, and may represent a key target for therapeutic interventions under different pathological conditions. As such, interneuron-specific cells across different cortical structures are an essential network component for information processing and normal brain function.
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Affiliation(s)
- Alexandre Guet-McCreight
- Krembil Brain Institute - Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Frances K Skinner
- Krembil Brain Institute - Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada.,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Lisa Topolnik
- Department of Biochemistry, Microbiology and Bio-informatics, Laval University, Québec, QC, Canada.,Neuroscience Axis, CHU de Québec Research Center (CHUL), Québec, QC, Canada
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8
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Katona L, Hartwich K, Tomioka R, Somogyi J, Roberts JDB, Wagner K, Joshi A, Klausberger T, Rockland KS, Somogyi P. Synaptic organisation and behaviour-dependent activity of mGluR8a-innervated GABAergic trilaminar cells projecting from the hippocampus to the subiculum. Brain Struct Funct 2020; 225:705-734. [PMID: 32016558 PMCID: PMC7046583 DOI: 10.1007/s00429-020-02029-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 01/16/2020] [Indexed: 02/07/2023]
Abstract
In the hippocampal CA1 area, the GABAergic trilaminar cells have their axon distributed locally in three layers and also innervate the subiculum. Trilaminar cells have a high level of somato-dendritic muscarinic M2 acetylcholine receptor, lack somatostatin expression and their presynaptic inputs are enriched in mGluR8a. But the origin of their inputs and their behaviour-dependent activity remain to be characterised. Here we demonstrate that (1) GABAergic neurons with the molecular features of trilaminar cells are present in CA1 and CA3 in both rats and mice. (2) Trilaminar cells receive mGluR8a-enriched GABAergic inputs, e.g. from the medial septum, which are probably susceptible to hetero-synaptic modulation of neurotransmitter release by group III mGluRs. (3) An electron microscopic analysis identifies trilaminar cell output synapses with specialised postsynaptic densities and a strong bias towards interneurons as targets, including parvalbumin-expressing cells in the CA1 area. (4) Recordings in freely moving rats revealed the network state-dependent segregation of trilaminar cell activity, with reduced firing during movement, but substantial increase in activity with prolonged burst firing (> 200 Hz) during slow wave sleep. We predict that the behaviour-dependent temporal dynamics of trilaminar cell firing are regulated by their specialised inhibitory inputs. Trilaminar cells might support glutamatergic principal cells by disinhibition and mediate the binding of neuronal assemblies between the hippocampus and the subiculum via the transient inhibition of local interneurons.
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Affiliation(s)
- Linda Katona
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
| | - Katja Hartwich
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Ryohei Tomioka
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Laboratory for Cortical Organization and Systematics, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
- Department of Morphological Neural Science, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Jozsef Somogyi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - J David B Roberts
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Kristina Wagner
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Abhilasha Joshi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
- Department of Physiology, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA, USA
| | - Thomas Klausberger
- Center for Brain Research, Division of Cognitive Neurobiology, Medical University of Vienna, 1090, Vienna, Austria
| | - Kathleen S Rockland
- Laboratory for Cortical Organization and Systematics, RIKEN Brain Science Institute, Wako, Saitama, 351-0198, Japan
- Department of Anatomy and Neurobiology, Boston University School of Medicine, 72 East Concord St., Boston, MA, 02118, USA
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK.
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Affiliation(s)
- Marlene A Wilson
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
- Columbia VA Health Care System, Columbia, SC, United States
| | - Alexander J McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, United States
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10
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Zhang Y, Ahmed S, Neagu G, Wang Y, Li Z, Wen J, Liu C, Vreugdenhil M. μ-Opioid receptor activation modulates CA3-to-CA1 gamma oscillation phase-coupling. IBRO Rep 2019; 6:122-131. [PMID: 30834352 PMCID: PMC6384309 DOI: 10.1016/j.ibror.2019.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/07/2019] [Indexed: 12/03/2022] Open
Abstract
CA3 gamma oscillation (γ) drives CA1 gamma and suppresses CA1 intrinsic fast γ. μ-opioid receptor (MOR) activation reduces γ frequency in CA3 and CA1. MOR activation in CA1 phase-uncouples CA1 γ from CA3 γ. Uncoupling is not due to CA3 γ deceleration by MOR activation.
In the intact brain, hippocampal area CA1 alternates between low-frequency gamma oscillations (γ), phase-locked to low-frequency γ in CA3, and high-frequency γ, phase-locked to γ in the medial entorhinal cortex. In hippocampal slices, γ in CA1 is phase-locked to CA3 low-frequency γ. However, when Schaffer collaterals are cut, CA1 can generate its own high-frequency γ. Here we test whether (un)coupling of CA1 γ from CA3 γ can be caused by μ-opioid receptor (MOR) modulation. In CA1 minislices isolated from rat ventral hippocampus slices, MOR activation by DAMGO reduced the dominant frequency of intrinsic fast γ, induced by carbachol. In intact slices, DAMGO strongly reduced the dominant frequency of CA3 slow γ, but did not affect γ power consistently. DAMGO suppressed the phase coupling of CA1 γ to CA3 slow γ and increased the power of CA1 intrinsic fast γ, but not in the presence of the MOR antagonist CTAP. The benzodiazepine zolpidem and local application of DAMGO to CA3 both mimicked the reduction in dominant frequency of CA3 slow γ, but did not reduce the phase coupling. Local application of DAMGO to CA1 reduced phase coupling. These results suggest that MOR-expressing CA1 interneurons, feed-forwardly activated by Schaffer collaterals, are responsible for the phase coupling between CA3 γ and CA1 γ. Modulating their activity may switch the CA1 network between low-frequency γ and high-frequency γ, controlling the information flow between CA1 and CA3 or medial entorhinal cortex respectively.
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Key Words
- CA1, Cornu ammonis area 1
- CA3, Cornu ammonis area 3
- CTAP, D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2
- DAMGO, [D-Ala2, NMe-Phe4, Gly-ol5]-enkephalin
- EPSC, Excitatory post-synaptic current
- ERP, Event-related potential
- Gamma
- Hippocampus
- IPSC, Inhibitory post-synaptic current
- Interneuron
- MEC, Medial entorhinal cortex
- MOR, μ opioid receptor
- Oscillation
- PING, pyramidal-interneuron-network gamma
- PLV, phase-locking value
- PV+, parvalbumin-expressing
- Phase-coupling
- TTX, tetrodotoxin
- aCSF, artificial cerebrospinal fluid
- s.e.m., Standard error of the mean
- γ, gamma frequency oscillation
- θ, theta frequency oscillation
- μ-Opioid
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Affiliation(s)
- Yujiao Zhang
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Sanya Ahmed
- Department of Neuroscience, College of Medical and Dental Sciences, University of Birmingham, Vincent Drive, Birmingham, B15 2TT, United Kingdom
| | - Georgiana Neagu
- Department of Neuroscience, College of Medical and Dental Sciences, University of Birmingham, Vincent Drive, Birmingham, B15 2TT, United Kingdom
| | - Yali Wang
- Department of Neurobiology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Zhenyi Li
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Jianbin Wen
- Department of Neurobiology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Chunjie Liu
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China
| | - Martin Vreugdenhil
- Department of Psychology, Xinxiang Medical University, Jinsui Avenue, Xinxiang, 453003, PR China.,Department of Neuroscience, College of Medical and Dental Sciences, University of Birmingham, Vincent Drive, Birmingham, B15 2TT, United Kingdom.,Department of Life Science, School of Health Sciences, Birmingham City University, Westbourne Road, Birmingham, B15 3TN, United Kingdom
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11
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Harris KD, Hochgerner H, Skene NG, Magno L, Katona L, Bengtsson Gonzales C, Somogyi P, Kessaris N, Linnarsson S, Hjerling-Leffler J. Classes and continua of hippocampal CA1 inhibitory neurons revealed by single-cell transcriptomics. PLoS Biol 2018; 16:e2006387. [PMID: 29912866 PMCID: PMC6029811 DOI: 10.1371/journal.pbio.2006387] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 07/03/2018] [Accepted: 05/22/2018] [Indexed: 01/19/2023] Open
Abstract
Understanding any brain circuit will require a categorization of its constituent neurons. In hippocampal area CA1, at least 23 classes of GABAergic neuron have been proposed to date. However, this list may be incomplete; additionally, it is unclear whether discrete classes are sufficient to describe the diversity of cortical inhibitory neurons or whether continuous modes of variability are also required. We studied the transcriptomes of 3,663 CA1 inhibitory cells, revealing 10 major GABAergic groups that divided into 49 fine-scale clusters. All previously described and several novel cell classes were identified, with three previously described classes unexpectedly found to be identical. A division into discrete classes, however, was not sufficient to describe the diversity of these cells, as continuous variation also occurred between and within classes. Latent factor analysis revealed that a single continuous variable could predict the expression levels of several genes, which correlated similarly with it across multiple cell types. Analysis of the genes correlating with this variable suggested it reflects a range from metabolically highly active faster-spiking cells that proximally target pyramidal cells to slower-spiking cells targeting distal dendrites or interneurons. These results elucidate the complexity of inhibitory neurons in one of the simplest cortical structures and show that characterizing these cells requires continuous modes of variation as well as discrete cell classes.
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Affiliation(s)
- Kenneth D. Harris
- University College London Institute of Neurology, London, United Kingdom
- University College London Department of Neuroscience, Physiology and Pharmacology, London, United Kingdom
| | - Hannah Hochgerner
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Nathan G. Skene
- University College London Institute of Neurology, London, United Kingdom
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Lorenza Magno
- University College London Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Linda Katona
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Carolina Bengtsson Gonzales
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Peter Somogyi
- Department of Pharmacology, University of Oxford, Oxford, United Kingdom
| | - Nicoletta Kessaris
- University College London Wolfson Institute for Biomedical Research, London, United Kingdom
| | - Sten Linnarsson
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Jens Hjerling-Leffler
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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Fukumoto K, Tamada K, Toya T, Nishino T, Yanagawa Y, Takumi T. Identification of genes regulating GABAergic interneuron maturation. Neurosci Res 2017; 134:18-29. [PMID: 29203264 DOI: 10.1016/j.neures.2017.11.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 11/29/2017] [Accepted: 11/30/2017] [Indexed: 10/18/2022]
Abstract
During embryonic development, GABAergic interneurons, a main inhibitory component in the cerebral cortex, migrate tangentially from the ganglionic eminence (GE) to cerebral cortex. After reaching the cerebral cortex, they start to extend their neurites for constructing local neuronal circuits around the neonatal stage. Aberrations in migration or neurite outgrowth are implicated in neurological and psychiatric disorders such as epilepsy, schizophrenia and autism. Previous studies revealed that in the early phase of cortical development the neural population migrates tangentially from the GE in the telencephalon and several genes have been characterized as regulators of migration and specification of GABAergic interneurons. However, much less is known about the molecular mechanisms of GABAergic interneurons-specific maturation at later stages of development. Here, we performed genome-wide screening to identify genes related to the later stage by flow cytometry based-microarray (FACS-array) and identified 247 genes expressed in cortical GABAergic interneurons. Among them, Dgkg, a member of diacylglycerol kinase family, was further analyzed. Correlational analysis revealed that Dgkg is dominantly expressed in somatostatin (SST)-expressing GABAergic interneurons. The functional study of Dgkg using GE neurons indicated alteration in neurite outgrowth of GABAergic neurons. This study shows a new functional role for Dgkg in GABAergic interneurons as well as the identification of other candidate genes for their maturation.
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Affiliation(s)
- Keita Fukumoto
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan
| | - Kota Tamada
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan; Osaka Bioscience Institute, Suita, Osaka 565-0874, Japan
| | - Tsuyoshi Toya
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Department of Pharmacology, Faculty of Pharmacy, Keio University, Minato, Tokyo 105-8512, Japan
| | - Tasuku Nishino
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Faculty of Life and Environmental Sciences, Prefectural University of Hiroshima, Shobara, Hiroshima 727-0023, Japan
| | - Yuchio Yanagawa
- Department of Genetics and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Gunma 371-8511, Japan
| | - Toru Takumi
- RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Graduate School of Biomedical Sciences, Hiroshima University, Minami, Hiroshima 734-8553, Japan; Osaka Bioscience Institute, Suita, Osaka 565-0874, Japan.
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13
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Leroy F, Brann DH, Meira T, Siegelbaum SA. Input-Timing-Dependent Plasticity in the Hippocampal CA2 Region and Its Potential Role in Social Memory. Neuron 2017; 95:1089-1102.e5. [PMID: 28823730 DOI: 10.1016/j.neuron.2017.07.036] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 05/26/2017] [Accepted: 07/28/2017] [Indexed: 02/01/2023]
Abstract
Input-timing-dependent plasticity (ITDP) is a circuit-based synaptic learning rule by which paired activation of entorhinal cortical (EC) and Schaffer collateral (SC) inputs to hippocampal CA1 pyramidal neurons (PNs) produces a long-term enhancement of SC excitation. We now find that paired stimulation of EC and SC inputs also induces ITDP of SC excitation of CA2 PNs. However, whereas CA1 ITDP results from long-term depression of feedforward inhibition (iLTD) as a result of activation of CB1 endocannabinoid receptors on cholecystokinin-expressing interneurons, CA2 ITDP results from iLTD through activation of δ-opioid receptors on parvalbumin-expressing interneurons. Furthermore, whereas CA1 ITDP has been previously linked to enhanced specificity of contextual memory, we find that CA2 ITDP is associated with enhanced social memory. Thus, ITDP may provide a general synaptic learning rule for distinct forms of hippocampal-dependent memory mediated by distinct hippocampal regions.
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Affiliation(s)
- Felix Leroy
- Department of Neuroscience, Kavli Institute of Brain Science, Columbia University Medical Center, 1051 Riverside Drive, New York, NY, USA.
| | - David H Brann
- Department of Neuroscience, Kavli Institute of Brain Science, Columbia University Medical Center, 1051 Riverside Drive, New York, NY, USA
| | - Torcato Meira
- Department of Neuroscience, Kavli Institute of Brain Science, Columbia University Medical Center, 1051 Riverside Drive, New York, NY, USA; Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's, PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Steven A Siegelbaum
- Department of Neuroscience, Kavli Institute of Brain Science, Columbia University Medical Center, 1051 Riverside Drive, New York, NY, USA.
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Nasrallah K, Piskorowski RA, Chevaleyre V. Bi-directional interplay between proximal and distal inputs to CA2 pyramidal neurons. Neurobiol Learn Mem 2017; 138:173-181. [DOI: 10.1016/j.nlm.2016.06.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/22/2016] [Accepted: 06/25/2016] [Indexed: 10/21/2022]
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15
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Zhang J, McDonald AJ. Light and electron microscopic analysis of enkephalin-like immunoreactivity in the basolateral amygdala, including evidence for convergence of enkephalin-containing axon terminals and norepinephrine transporter-containing axon terminals onto common targets. Brain Res 2016; 1636:62-73. [PMID: 26835559 DOI: 10.1016/j.brainres.2016.01.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/20/2016] [Accepted: 01/25/2016] [Indexed: 12/21/2022]
Abstract
Modulatory interactions of opioids and norepinephrine (NE) in the anterior subdivision of the basolateral nucleus of the amygdala (BLa) are critical for the consolidation of memories of emotionally arousing experiences. Although there have been several studies of the noradrenergic system in the amygdalar basolateral nuclear complex (BLC), little is known about the chemical neuroanatomy of opioid systems in this region. To address this knowledge gap the present study first examined the distribution of met-enkephalin-like immunoreactivity (ENK-ir) in the BLC at the light microscopic level, and then utilized dual-labeling immunocytochemistry combined with electron microscopy to investigate the extent of convergence of NE and ENK terminals onto common structures in the BLa. Antibodies to ENK and the norepinephrine transporter (NET) were used in these studies. Light microscopic examination revealed that a subpopulation of small nonpyramidal neurons expressed ENK-ir in all nuclei of the BLC. In addition, the somata of some pyramidal cells exhibited light to moderate ENK-ir. ENK+ axon terminals were also observed. Ultrastructural analysis confined to the BLa revealed that most ENK+ axon terminals formed asymmetrical synapses that mainly contacted spines and shafts of thin dendrites. ENK+ terminals forming symmetrical synapses mainly contacted dendritic shafts. Approximately 20% of NET+ terminals contacted a structure that was also contacted by an ENK+ terminal and 6% of NET+ terminals contacted an ENK+ terminal. These findings suggest that ENK and NE terminals in the BLa may interact by targeting common dendrites and by direct interactions between the two types of terminals.
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Affiliation(s)
- Jingyi Zhang
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, United States
| | - Alexander J McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, United States.
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16
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Francavilla R, Luo X, Magnin E, Tyan L, Topolnik L. Coordination of dendritic inhibition through local disinhibitory circuits. Front Synaptic Neurosci 2015; 7:5. [PMID: 25767448 PMCID: PMC4341546 DOI: 10.3389/fnsyn.2015.00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 02/11/2015] [Indexed: 11/13/2022] Open
Abstract
It has been recognized for some time that different subtypes of cortical inhibitory interneurons innervate specific dendritic domains of principal cells and release GABA at particular times during behaviorally relevant network oscillations. However, the lack of basic information on how the activity of interneurons can be controlled by GABA released in particular behavioral states has hindered our understanding of the rules that govern the spatio-temporal organization and function of dendritic inhibition. Similar to principal cells, any given interneuron may receive several functionally distinct inhibitory inputs that target its specific subcellular domains. We recently found that local circuitry of the so-called interneuron-specific (IS) interneurons is responsible for dendritic inhibition of different subtypes of hippocampal interneurons with a great impact on cell output. Here, we will review the properties and the specificity of connections of IS interneurons in the CA1 hippocampus and neocortex, and discuss their possible role in the activity-dependent regulation of dendritic inhibition received by pyramidal neurons.
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Affiliation(s)
- Ruggiero Francavilla
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval; Axis of Cellular and Molecular Neuroscience, IUSMQ Québec, PQ, Canada
| | - Xiao Luo
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval; Axis of Cellular and Molecular Neuroscience, IUSMQ Québec, PQ, Canada
| | - Elise Magnin
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval; Axis of Cellular and Molecular Neuroscience, IUSMQ Québec, PQ, Canada
| | - Leonid Tyan
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval; Axis of Cellular and Molecular Neuroscience, IUSMQ Québec, PQ, Canada
| | - Lisa Topolnik
- Department of Biochemistry, Microbiology and Bio-informatics, Université Laval; Axis of Cellular and Molecular Neuroscience, IUSMQ Québec, PQ, Canada
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17
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Ford GK, Moriarty O, Okine BN, Tully E, Mulcahy A, Harhen B, Finn DP. Involvement of the endocannabinoid system in attentional modulation of nociceptive behaviour in rats. Eur J Pain 2014; 19:1177-85. [PMID: 25504741 DOI: 10.1002/ejp.646] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2014] [Indexed: 12/11/2022]
Abstract
BACKGROUND Distraction is used clinically to relieve and manage pain. It is hypothesized that pain demands attention and that exposure to another attention-demanding stimulus causes withdrawal of attention away from painful stimuli, thereby reducing perceived pain. We have recently developed a rat model that provides an opportunity to investigate the neurobiological mechanisms mediating distraction-induced analgesia, as these mechanisms are, at present, poorly understood. Given the well-described role of the endogenous cannabinoid (endocannabinoid; EC) system in the modulation of pain and attentional processing, the present study investigated its role in distraction-induced antinociception in rats. METHODS Animals received the CB1 receptor antagonist/inverse agonist, rimonabant or vehicle intraperitoneally, 30 min prior to behavioural evaluation. Formalin-evoked nociceptive behaviour was measured in the presence or absence of a novel-object distractor. Liquid chromatography-tandem mass spectrometry was used to determine the levels of the endogenous cannabinoids anandamide and 2-arachidonoylglycerol (2-AG) in the ventral hippocampus (vHip). RESULTS Exposure to a novel object distractor significantly reduced formalin-evoked nociceptive behaviour. The novel object-induced reduction in nociceptive behaviour was attenuated by rimonabant. Novel object exposure was also associated with increased tissue levels of anandamide and 2-AG in the vHip. CONCLUSIONS These data suggest that the reduction in formalin-evoked nociceptive behaviour that occurs as a result of exposure to a novel object may be mediated by engagement of the EC system, in particular in the vHip. The results provide evidence that the EC system may be an important neural substrate subserving attentional modulation of pain.
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Affiliation(s)
- G K Ford
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway.,NCBES Neuroscience Centre, National University of Ireland, Galway.,Centre for Pain Research, National University of Ireland, Galway
| | - O Moriarty
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway.,NCBES Neuroscience Centre, National University of Ireland, Galway.,Centre for Pain Research, National University of Ireland, Galway
| | - B N Okine
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway.,NCBES Neuroscience Centre, National University of Ireland, Galway.,Centre for Pain Research, National University of Ireland, Galway
| | - E Tully
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway
| | - A Mulcahy
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway
| | - B Harhen
- NCBES Neuroscience Centre, National University of Ireland, Galway.,Centre for Pain Research, National University of Ireland, Galway
| | - D P Finn
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway.,NCBES Neuroscience Centre, National University of Ireland, Galway.,Centre for Pain Research, National University of Ireland, Galway
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18
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Hernández-González S, Ballestín R, López-Hidalgo R, Gilabert-Juan J, Blasco-Ibáñez JM, Crespo C, Nácher J, Varea E. Altered distribution of hippocampal interneurons in the murine Down Syndrome model Ts65Dn. Neurochem Res 2014; 40:151-64. [PMID: 25399236 DOI: 10.1007/s11064-014-1479-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 12/30/2022]
Abstract
Down Syndrome, with an incidence of one in 800 live births, is the most common genetic alteration producing intellectual disability. We have used the Ts65Dn model, that mimics some of the alterations observed in Down Syndrome. This genetic alteration induces an imbalance between excitation and inhibition that has been suggested as responsible for the cognitive impairment present in this syndrome. The hippocampus has a crucial role in memory processing and is an important area to analyze this imbalance. In this report we have analysed, in the hippocampus of Ts65Dn mice, the expression of synaptic markers: synaptophysin, vesicular glutamate transporter-1 and isoform 67 of the glutamic acid decarboxylase; and of different subtypes of inhibitory neurons (Calbindin D-28k, parvalbumin, calretinin, NPY, CCK, VIP and somatostatin). We have observed alterations in the inhibitory neuropil in the hippocampus of Ts65Dn mice. There was an excess of inhibitory puncta and a reduction of the excitatory ones. In agreement with this observation, we have observed an increase in the number of inhibitory neurons in CA1 and CA3, mainly interneurons expressing calbindin, calretinin, NPY and VIP, whereas parvalbumin cell numbers were not affected. These alterations in the number of interneurons, but especially the alterations in the proportion of the different types, may influence the normal function of inhibitory circuits and underlie the cognitive deficits observed in DS.
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Affiliation(s)
- Samuel Hernández-González
- Neurobiology Unit, Program in Basic and Applied Neurosciences, Cell Biology Department, Universitat de València, Dr. Moliner, 50, 46100, Burjassot, Spain
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19
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Delta-opioid receptors mediate unique plasticity onto parvalbumin-expressing interneurons in area CA2 of the hippocampus. J Neurosci 2013; 33:14567-78. [PMID: 24005307 DOI: 10.1523/jneurosci.0649-13.2013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Inhibition is critical for controlling information transfer in the brain. However, the understanding of the plasticity and particular function of different interneuron subtypes is just emerging. Using acute hippocampal slices prepared from adult mice, we report that in area CA2 of the hippocampus, a powerful inhibitory transmission is acting as a gate to prevent CA3 inputs from driving CA2 neurons. Furthermore, this inhibition is highly plastic, and undergoes a long-term depression following high-frequency 10 Hz or theta-burst induction protocols. We describe a novel form of long-term depression at parvalbumin-expressing (PV+) interneuron synapses that is dependent on delta-opioid receptor (DOR) activation. Additionally, PV+ interneuron transmission is persistently depressed by DOR activation in area CA2 but only transiently depressed in area CA1. These results provide evidence for a differential temporal modulation of PV+ synapses between two adjacent cortical circuits, and highlight a new function of PV+ cells in controlling information transfer.
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20
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Giannopoulos P, Papatheodoropoulos C. Effects of μ-opioid receptor modulation on the hippocampal network activity of sharp wave and ripples. Br J Pharmacol 2013; 168:1146-64. [PMID: 23043226 DOI: 10.1111/j.1476-5381.2012.02240.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 08/30/2012] [Accepted: 09/17/2012] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE Hippocampus-dependent memory involves the activity of sharp wave ripples (SWRs), which are thought to participate in the process of memory consolidation. The hippocampus contains high levels of endogenous opioids and of μ-opioid receptors (MORs). Here, we have assessed the role of MOR agonists in the modulation of SWRs. EXPERIMENTAL APPROACH Using recordings of extracellular potentials from the CA1 field of rat hippocampal slices, we examined the pharmacological actions of morphine, DAMGO and fentanyl on SWRs and on network excitability and paired-pulse inhibition. KEY RESULTS All three MOR agonists (1 nM-10 μM) significantly increased the amplitude of sharp waves and the occurrence of SWR sequences, but reduced the initiation of episodes of SWRs. Fentanyl was most potent in producing these effects and morphine the least. Interestingly, although SWRs were reduced by relatively high concentrations (≥100 nM) of all agonists, they were significantly enhanced by very low concentrations of morphine (5-10 nM). Morphine and DAMGO at moderate-to-high concentrations increased network excitability and reduced inhibition. Furthermore, DAMGO suppressed inhibition more readily than it increased excitation, whereas morphine suppressed inhibition only at high concentrations. These drug effects were reversed by the MOR antagonists naloxone and CTOP. CONCLUSIONS AND IMPLICATIONS We found that the SWRs were significantly modulated by three MOR agonists and that the SWRs were very sensitive to subtle changes in the excitation/inhibition balance induced by MOR agonists. Such modulation might underlie the effects of these agonists on hippocampus-dependent memory.
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Affiliation(s)
- Panagiotis Giannopoulos
- Specialist Community Addictions Service, Unit 5, The Valley Centre, Gordon Road High Wycombe, Buckinghamshire, HP13 6EQ, UK.
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21
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Chamberland S, Topolnik L. Inhibitory control of hippocampal inhibitory neurons. Front Neurosci 2012; 6:165. [PMID: 23162426 PMCID: PMC3496901 DOI: 10.3389/fnins.2012.00165] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 10/24/2012] [Indexed: 11/13/2022] Open
Abstract
Information processing within neuronal networks is determined by a dynamic partnership between principal neurons and local circuit inhibitory interneurons. The population of GABAergic interneurons is extremely heterogeneous and comprises, in many brain regions, cells with divergent morphological and physiological properties, distinct molecular expression profiles, and highly specialized functions. GABAergic interneurons have been studied extensively during the past two decades, especially in the hippocampus, which is a relatively simple cortical structure. Different types of hippocampal inhibitory interneurons control spike initiation [e.g., axo-axonic and basket cells (BCs)] and synaptic integration (e.g., bistratified and oriens–lacunosum moleculare interneurons) within pyramidal neurons and synchronize local network activity, providing a means for functional segregation of neuronal ensembles and proper routing of hippocampal information. Thus, it is thought that, at least in the hippocampus, GABAergic inhibitory interneurons represent critical regulating elements at all stages of information processing, from synaptic integration and spike generation to large-scale network activity. However, this raises an important question: if inhibitory interneurons are fundamental for network computations, what are the mechanisms that control the activity of the interneurons themselves? Given the essential role of synaptic inhibition in the regulation of neuronal activity, it would be logical to expect that specific inhibitory mechanisms have evolved to control the operation of interneurons. Here, we review the mechanisms of synaptic inhibition of interneurons and discuss their role in the operation of hippocampal inhibitory circuits.
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Affiliation(s)
- Simon Chamberland
- Axis of Cellular and Molecular Neuroscience, IUSMQ, Department of Biochemistry, Microbiology and Bio-informatics, Université Laval Québec, QC, Canada
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22
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Ford GK, Kieran S, Dolan K, Harhen B, Finn DP. A role for the ventral hippocampal endocannabinoid system in fear-conditioned analgesia and fear responding in the presence of nociceptive tone in rats. Pain 2011; 152:2495-2504. [PMID: 21864979 DOI: 10.1016/j.pain.2011.07.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2011] [Revised: 06/14/2011] [Accepted: 07/20/2011] [Indexed: 02/02/2023]
Abstract
The endogenous cannabinoid (endocannabinoid) system plays an important role in fear-conditioned analgesia (FCA) and expression and extinction of conditioned fear. The hippocampus has an established role in both pain and conditioned fear and is a substrate for endocannabinoid activity. This study aimed to investigate the role of the endocannabinoid system in the ventral hippocampus (vHip) in FCA and in fear responding in the presence of nociceptive tone. Fear-conditioned rats displayed significantly increased freezing and 22-kHz ultrasonic vocalisation and a reduction in formalin-evoked nociceptive behaviour (ie, FCA) upon re-exposure to a context previously paired with footshock. Tissue levels of the endocannabinoids, anandamide, and 2-arachidonoylglycerol, as well as the fatty acid amide, palmitoylethanolamide, were significantly higher in the vHip of fear-conditioned rats compared with non-fear-conditioned controls. URB597 (inhibitor of fatty acid amide hydrolase [FAAH]), administered bilaterally into the vHip, significantly enhanced FCA during the entire trial and increased fear responding in formalin-treated rats early in the trial. The URB597-induced enhancement of FCA was blocked by intra-vHip administration of the cannabinoid(1) (CB(1)) receptor antagonist/inverse agonist rimonabant. Intra-vHip rimonabant alone had no effect on the expression of FCA, and URB597 did not significantly alter formalin-evoked nociceptive behaviour in non-fear-conditioned rats. These data suggest an important role for the endocannabinoid system in the vHip in FCA, whereby levels of 2-arachidonoylglycerol and the FAAH substrates palmitoylethanolamide and anandamide are increased in rats expressing FCA, and pharmacological inhibition of FAAH in the vHip enhances this form of endogenous analgesia via a CB(1) receptor-dependent mechanism.
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Affiliation(s)
- Gemma K Ford
- Pharmacology and Therapeutics, School of Medicine, National University of Ireland, Galway, Ireland National Centre for Biomedical Engineering Science (NCBES), Neuroscience Cluster, National University of Ireland, Galway, Ireland Centre for Pain Research, National University of Ireland, Galway, Ireland
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23
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McQuiston AR. Mu opioid receptor activation normalizes temporo-ammonic pathway driven inhibition in hippocampal CA1. Neuropharmacology 2010; 60:472-9. [PMID: 21056047 DOI: 10.1016/j.neuropharm.2010.10.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 10/26/2010] [Accepted: 10/29/2010] [Indexed: 11/24/2022]
Abstract
The hippocampus of the mammalian brain is important for the formation of long-term memories. Hippocampal-dependent learning can be affected by a number of neurotransmitters including the activation of μ-opioid receptors (MOR). It has been shown that MOR activation can alter synaptic plasticity and network oscillations in the hippocampus, both of which are thought to be important for the encoding of information and formation of memories. One hippocampal oscillation that has been correlated with learning and memory formation is the 4-10 Hz theta rhythm. During theta rhythms, inputs to hippocampal CA1 from CA3 (Schaffer collaterals, SC) and the entorhinal cortex (perforant path) can integrate at different times within an individual theta cycle. Consequently, when excitatory inputs in the stratum lacunosum-moleculare (the temporo-ammonic pathway (TA), which includes the perforant path) are stimulated approximately one theta period before SC inputs, the TA can indirectly inhibit SC inputs. This inhibition is due to the activation of postsynaptic GABA(B) receptors on CA1 pyramidal neurons. Importantly, MOR activation has been shown to suppress GABA(B) inhibitory postsynaptic potentials in CA1 pyramidal neurons. Therefore, we examined how MOR activation affects the integration between TA inputs and SC inputs in hippocampal CA1. To do this we used voltage-sensitive dye imaging and whole cell patch clamping from acute hippocampal slices taken from young adult rats. Here we show that MOR activation has no effect on the integration between TA and SC inputs when activation of the TA precedes SC by less than one half of a theta cycle (<75 ms). However, MOR activation completely blocked the inhibitory action of TA on SC inputs when TA stimulation occurred approximately one theta cycle before SC activation (>150 ms). This MOR suppression of TA driven inhibition occurred in both the SC input layer of hippocampal CA1 (stratum radiatum) and the output layer of CA1 pyramidal neurons (stratum pyramidale). Thus MOR activation can have profound effects on the temporal integration between two primary excitatory pathways to hippocampal CA1 and subsequently the resultant output from CA1 pyramidal neurons. These data provide important information for understanding how acute or chronic MOR activation may affect the integration of activity within hippocampal CA1 during theta rhythm.
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Affiliation(s)
- A Rory McQuiston
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Box 980709, Richmond, VA 23298, USA.
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Expression of COUP-TFII nuclear receptor in restricted GABAergic neuronal populations in the adult rat hippocampus. J Neurosci 2010; 30:1595-609. [PMID: 20130170 DOI: 10.1523/jneurosci.4199-09.2010] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The COUP-TFII nuclear receptor, also known as NR2F2, is expressed in the developing ventral telencephalon and modulates the tangential migration of a set of subpallial neuronal progenitors during forebrain development. Little information is available about its expression patterns in the adult brain. We have identified the cell populations expressing COUP-TFII and the contribution of some of them to network activity in vivo. Expression of COUP-TFII by hippocampal pyramidal and dentate granule cells, as well as neurons in the neocortex, formed a gradient increasing from undetectable in the dorsal to very strong in the ventral sectors. In the dorsal hippocampal CA1 area, COUP-TFII was restricted to GABAergic interneurons and expressed in several, largely nonoverlapping neuronal populations. Immunoreactivity was present in calretinin-, neuronal nitric oxide synthase-, and reelin-expressing cells, as well as in subsets of cholecystokinin- or calbindin-expressing or radiatum-retrohippocampally projecting GABAergic cells, but not in parvalbumin- and/or somatostatin-expressing interneurons. In vivo recording and juxtacellular labeling of COUP-TFII-expressing cells revealed neurogliaform cells, basket cells in stratum radiatum and tachykinin-expressing radiatum dentate innervating interneurons, identified by their axodendritic distributions. They showed cell type-selective phase-locked firing to the theta rhythm but no activation during sharp wave/ripple oscillations. These basket cells in stratum radiatum and neurogliaform cells fired at the peak of theta oscillations detected extracellularly in stratum pyramidale, unlike previously reported ivy cells, which fired at the trough. The characterization of COUP-TFII-expressing neurons suggests that this developmentally important transcription factor plays cell type-specific role(s) in the adult hippocampus.
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Jinno S. Structural organization of long-range GABAergic projection system of the hippocampus. Front Neuroanat 2009; 3:13. [PMID: 19649167 PMCID: PMC2718779 DOI: 10.3389/neuro.05.013.2009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 07/03/2009] [Indexed: 01/17/2023] Open
Abstract
GABA is a key mediator of neural activity in the mammalian central nervous system, and a diverse set of GABAergic neurons utilize GABA as a transmitter. It has been widely accepted that GABAergic neurons typically serve as interneurons while glutamatergic principal cells send excitatory signals to remote areas. In general, glutamatergic projection neurons monosynaptically innervate both principal cells and local GABAergic interneurons in each target area, and these GABAergic cells play a vital role in modulation of the activity of principal cells. The formation and recall of sensory, motor and cognitive representations require coordinated fast communication among multiple areas of the cerebral cortex, which are thought to be mostly mediated by glutamatergic neurons. However, there is an increasing body of evidence showing that specific subpopulations of cortical GABAergic neurons send long-range axonal projections to subcortical and other cortical areas. In particular, a variety of GABAergic neurons in the hippocampus project to neighboring and remote areas. Using anatomical, molecular and electrophysiological approaches, several types of GABAergic projection neurons have been shown to exist in the hippocampus. The target areas of these cells are the subiculum and other retrohippocampal areas, the medial septum and the contralateral dentate gyrus. The long-range GABAergic projection system of the hippocampus may serve to coordinate precisely the multiple activity patterns of widespread cortical cell assemblies in different brain states and among multiple functionally related areas.
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Affiliation(s)
- Shozo Jinno
- Department of Anatomy and Neurobiology, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan
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Favaroni Mendes LA, Menescal-de-Oliveira L. Role of cholinergic, opioidergic and GABAergic neurotransmission of the dorsal hippocampus in the modulation of nociception in guinea pigs. Life Sci 2008; 83:644-50. [DOI: 10.1016/j.lfs.2008.09.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Revised: 07/31/2008] [Accepted: 09/04/2008] [Indexed: 10/21/2022]
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Rhythmically active enkephalin-expressing GABAergic cells in the CA1 area of the hippocampus project to the subiculum and preferentially innervate interneurons. J Neurosci 2008; 28:10017-22. [PMID: 18829959 DOI: 10.1523/jneurosci.2052-08.2008] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Enkephalins (ENKs) are endogenous opioids that regulate synaptic excitability of GABAergic networks in the cerebral cortex. Using retrograde tracer injections in the subiculum, we identified a hippocampal population of ENK-expressing projection neurons. In situ hybridization for GAD shows that ENK-expressing cells are a small GABAergic subpopulation. Furthermore, by extracellular recording and juxtacellular labeling in vivo, we identified an ENK-expressing cell in stratum radiatum of the CA1 area by its complete axodendritic arborization and characteristic spike timing during network oscillations. The somatodendritic membrane was immunopositive for mGluR1alpha, and there was both a rich local axon in CA1 and subicular-projecting branches. The boutons showed cell-type- and layer-specific innervation, i.e., interneurons were the main targets in the alveus, both interneurons and pyramidal cell dendrites were innervated in the other layers, and interneurons were exclusive targets in the subiculum. Parvalbumin-, but not somatostatin-, calbindin-, or cholecystokinin-expressing interneurons were preferred synaptic targets. During network activity, the juxtacellularly labeled ENK-expressing cell was phase modulated throughout theta oscillations, but silenced during sharp-wave/ripple episodes. After these episodes the interneuron exhibited rebound activity of high-frequency spike bursts, presumably causing peptide release. The ENK-expressing interneurons innervating parvalbumin-positive interneurons might contribute to the organization of the sharp-wave/ripple episodes by decreased firing during and rebound activity after the ripple episodes, as well as to the coordination of activity between the CA1 and subicular areas during network oscillations.
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Abstract
Somatic inhibition, which is critical for determining the spike output of principal cells, is mediated by two physiologically distinct classes of GABAergic interneurons called basket cells. In the hippocampus, despite both targeting the somatic membrane of CA1 pyramidal cells, these two classes of basket cells are active at different times. Differential modulation of these two types of basket cells could hence be important for regulating the activity patterns of CA1 pyramidal cells at very specific periods during ongoing activity. Indeed, cannabinoids selectively suppress the output of one class of basket cell. Whether opioids, another major modulator of inhibition in the hippocampus, also selectively suppress somatic inhibition is not known. Here, we show that basket cells are selectively modulated by either opioids or cannabinoids, but not both. We also find that basket cells are integrated into specific inhibitory subnetworks that are themselves under differential control of opioids and cannabinoids. Furthermore, because the two interneuron types are activated at different times, opioids and cannabinoids suppress different epochs of inhibition. This cell-type specific sensitivity to neuromodulators allows for a fine control of the temporal structure of hippocampal activity.
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Quiñones-Hinojosa A, Sanai N, Soriano-Navarro M, Gonzalez-Perez O, Mirzadeh Z, Gil-Perotin S, Romero-Rodriguez R, Berger MS, Garcia-Verdugo JM, Alvarez-Buylla A. Cellular composition and cytoarchitecture of the adult human subventricular zone: a niche of neural stem cells. J Comp Neurol 2006; 494:415-34. [PMID: 16320258 DOI: 10.1002/cne.20798] [Citation(s) in RCA: 401] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The lateral wall of the lateral ventricle in the human brain contains neural stem cells throughout adult life. We conducted a cytoarchitectural and ultrastructural study in complete postmortem brains (n = 7) and in postmortem (n = 42) and intraoperative tissue (n = 43) samples of the lateral walls of the human lateral ventricles. With varying thickness and cell densities, four layers were observed throughout the lateral ventricular wall: a monolayer of ependymal cells (Layer I), a hypocellular gap (Layer II), a ribbon of cells (Layer III) composed of astrocytes, and a transitional zone (Layer IV) into the brain parenchyma. Unlike rodents and nonhuman primates, adult human glial fibrillary acidic protein (GFAP)+ subventricular zone (SVZ) astrocytes are separated from the ependyma by the hypocellular gap. Some astrocytes as well as a few GFAP-cells in Layer II in the SVZ of the anterior horn and the body of the lateral ventricle appear to proliferate based on proliferating cell nuclear antigen (PCNA) and Ki67 staining. However, compared to rodents, the adult human SVZ appears to be devoid of chain migration or large numbers of newly formed young neurons. It was only in the anterior SVZ that we found examples of elongated Tuj1+ cells with migratory morphology. We provide ultrastructural criteria to identify the different cells types in the human SVZ including three distinct types of astrocytes and a group of displaced ependymal cells between Layers II and III. Ultrastructural analysis of this layer revealed a remarkable network of astrocytic and ependymal processes. This work provides a basic description of the organization of the adult human SVZ.
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Affiliation(s)
- Alfredo Quiñones-Hinojosa
- Department of Neurological Surgery, Brain Tumor Research Center, Developmental Stem Cell Biology Program, University of California, San Francisco, San Francisco, California 94143-0112, USA.
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Solbrig MV, Adrian R, Baratta J, Lauterborn JC, Koob GF. Kappa opioid control of seizures produced by a virus in an animal model. ACTA ACUST UNITED AC 2006; 129:642-54. [PMID: 16399805 DOI: 10.1093/brain/awl008] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Epilepsy remains a major medical problem of unknown aetiology. Potentially, viruses can be environmental triggers for development of seizures in genetically vulnerable individuals. An estimated half of encephalitis patients experience seizures and approximately 4% develop status epilepticus. Epilepsy vulnerability has been associated with a dynorphin promoter region polymorphism or low dynorphin expression genotype, in man. In animals, the dynorphin system in the hippocampus is known to regulate excitability. The present study was designed to test the hypothesis that reduced dynorphin expression in the dentate gyrus of hippocampus due to periadolescent virus exposure leads to epileptic responses. Encephalitis produced by the neurotropic Borna disease virus in the rat caused epileptic responses and dynorphin to disappear via dentate granule cell loss, failed neurogenesis and poor survival of new neurons. Kappa opioid (dynorphin) agonists prevented the behavioural and electroencephalographic seizures produced by convulsant compounds, and these effects were associated with an absence of dynorphin from the dentate gyrus granule cell layer and upregulation of enkephalin in CA1 interneurons, thus reproducing a neurochemical marker of epilepsy, namely low dynorphin tone. A key role for kappa opioids in anticonvulsant protection provides a framework for exploration of viral and other insults that increase seizure vulnerability and may provide insights into potential interventions for treatment of epilepsy.
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MESH Headings
- 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer/therapeutic use
- Animals
- Blotting, Northern
- Borna Disease/complications
- Borna Disease/metabolism
- Borna Disease/pathology
- Cell Survival
- Disease Models, Animal
- Dynorphins/metabolism
- Dynorphins/physiology
- Electroencephalography
- Encephalitis, Viral/complications
- Encephalitis, Viral/metabolism
- Encephalitis, Viral/pathology
- Enkephalins/metabolism
- Hippocampus/metabolism
- Male
- Naloxone
- Narcotic Antagonists
- Neurons/pathology
- Rats
- Rats, Inbred Lew
- Receptors, Opioid, kappa/agonists
- Seizures/chemically induced
- Seizures/metabolism
- Seizures/prevention & control
- Seizures/virology
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Affiliation(s)
- Marylou V Solbrig
- Department of Neurology, University of California-Irvine, Irvine, CA 92697-4292, USA.
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Romo-Parra H, Aceves J, Gutiérrez R. Tonic modulation of inhibition by dopamine D4 receptors in the rat hippocampus. Hippocampus 2005; 15:254-9. [PMID: 15476261 DOI: 10.1002/hipo.20049] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Dopaminergic pathways have been recognized to play a critical role in cognition and emotion. Dopamine D2 and D4 receptors are the target for most common antipsychotics and their activation, particularly those in the medial temporal lobe structures, has been associated with their beneficial actions. The entorhinal cortex, which is the cortical area most consistently and severely affected in schizophrenia constitutes the main input to the hippocampus. Since the D4 receptor is highly concentrated in the hippocampus, and the effects of the selective activation of D4 receptors on the input/output function of the hippocampal formation are poorly understood, we sought to investigate the role of these receptors in the synaptic transmission and paired-pulse inhibition from the perforant path to area CA1 and the dentate gyrus. The D4 receptor antagonist, clozapine, translated paired-pulse inhibition into paired-pulse potentiation in both perforant path targets. By contrast, the D2/D3 antagonist quinpirole had no effect. The blockade of the D2/3 receptors with sulpiride, and of D1/5 receptors with SCH-23390, has no effect on paired-pulse inhibition, suggesting that these receptors are not involved in feedforward inhibition in these hippocampal areas. Interestingly, the perfusion of the D4 selective antagonist, L-745,870 (Patel et al., 1997: J Pharmacol Exp Ther 283:636-647) during the blockade of D2/3 and D1/5 receptors produces a reversible decrease in paired-pulse inhibition in CA1, but not in the DG. Our results show that endogenous DA tonically modulates feedforward inhibition in area CA1 and the dentate gyrus through the activation of D4 receptors located in the interneuronal population of these hippocampal regions. Since activation of the D4 receptor inhibits GABA release and GABAergic synaptic transmission, we suggest that the perforant path stimulates interneurons that have the D4 receptor and that, in turn, contact other interneurons that synapse onto pyramidal cells. (c) 2004 Wiley-Liss, Inc.
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Affiliation(s)
- Héctor Romo-Parra
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados, México, México
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Rodriguez A, Whitson J, Granger R. Derivation and analysis of basic computational operations of thalamocortical circuits. J Cogn Neurosci 2004; 16:856-77. [PMID: 15200713 DOI: 10.1162/089892904970690] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Shared anatomical and physiological features of primary, secondary, tertiary, polysensory, and associational neocortical areas are used to formulate a novel extended hypothesis of thalamocortical circuit operation. A simplified anatomically based model of topographically and nontopographically projecting ("core" and "matrix") thalamic nuclei, and their differential connections with superficial, middle, and deep neocortical laminae, is described. Synapses in the model are activated and potentiated according to physiologically based rules. Features incorporated into the models include differential time courses of excitatory versus inhibitory postsynaptic potentials, differential axonal arborization of pyramidal cells versus interneurons, and different laminar afferent and projection patterns. Observation of the model's responses to static and time-varying inputs indicates that topographic "core" circuits operate to organize stored memories into natural similarity-based hierarchies, whereas diffuse "matrix" circuits give rise to efficient storage of time-varying input into retrievable sequence chains. Examination of these operations shows their relationships with well-studied algorithms for related functions, including categorization via hierarchical clustering, and sequential storage via hash- or scatter-storage. Analysis demonstrates that the derived thalamocortical algorithms exhibit desirable efficiency, scaling, and space and time cost characteristics. Implications of the hypotheses for central issues of perceptual reaction times and memory capacity are discussed. It is conjectured that the derived functions are fundamental building blocks recurrent throughout the neocortex, which, through combination, gives rise to powerful perceptual, motor, and cognitive mechanisms.
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Gracia-Llanes FJ, Crespo C, Blasco-Ibáñez JM, Marqués-Marí AI, Martínez-Guijarro FJ. VIP-containing deep short-axon cells of the olfactory bulb innervate interneurons different from granule cells. Eur J Neurosci 2003; 18:1751-63. [PMID: 14622210 DOI: 10.1046/j.1460-9568.2003.02895.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
This study investigates the targets of the population of vasoactive intestinal polypeptide (VIP)-containing deep short-axon cells of the rat olfactory bulb (OB), combining single- and double-immunocytochemical approaches under light and electron microscopy. It has been assumed that deep short-axon cells innervate granule cells in the mammalian OB, but their synaptic connectivity has not been demonstrated to date. Our results indicate that, instead of the accepted scheme of the bulbar circuitry, VIP-containing deep short-axon cells are gamma-aminobutyric acid (GABA)ergic interneurons specialized in the selective innervation of other GABAergic deep short-axon cells. Their axons contact with the perisomatic region and the dendritic portions of subsets of deep short-axon cells that contain VIP, calbindin D-28k and neuropeptide Y. Electron microscopy reveals axo-somatic and axo-dendritic symmetrical synapses from VIP-containing boutons. Taken altogether, our data show that the VIP-containing deep short-axon cells of the rat OB form an interneuronal network that modulates the function of other interneurons different from granule cells. They might be involved indirectly in the inhibition or disinhibition of principal cells or might participate in the generation of oscillatory activity and in the synchronization of populations of interneurons and, then, of principal cells. Present data demonstrate that modulation of the OB by local circuits is more complex than the simple inhibition from periglomerular cells and granule cells, and remark the importance of considering the contribution of other classes of GABAergic interneurons different from periglomerular cells and granule cells to the bulbar circuitry.
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34
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Stumm RK, Zhou C, Schulz S, Höllt V. Neuronal types expressing μ- and δ-opioid receptor mRNA in the rat hippocampal formation. J Comp Neurol 2003; 469:107-18. [PMID: 14689476 DOI: 10.1002/cne.10997] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Opioids are thought to control the excitability of hippocampal principal neurons indirectly by inhibiting GABAergic interneurons. However, direct inhibition of hippocampal principal neurons by opioids has also been reported. To understand better the neuromodulatory role of opioids in rat hippocampal circuits, we analyzed types of micro- and delta-opioid receptor (MOR, DOR)-expressing hippocampal neurons. Most MOR-immunoreactive neurons in the granular and pyramidal cell layers exhibited multipolar morphologies characteristic of GABAergic neurons. Virtually all neurons in the hippocampal formation expressing high MOR mRNA levels cocontained the mRNA for glutamic acid decarboxylase (GAD). Most parvalbumin-, several calretinin-, and several pre-proenkephalin-containing neurons expressed the MOR gene in the hippocampal formation. Expression of high DOR mRNA levels was restricted to GAD-positive neurons in the principal cell layers, oriens layer and hilus. More than 90% of the parvalbumin-positive neurons in the hippocampal formation strongly expressed the DOR gene. Granule cells expressing vesicular glutamate transporter 1 (VGLUT1) mRNA contained very low MOR and DOR transcript levels. In VGLUT1-positive pyramidal cells, weak DOR but no MOR gene expression was detected. Whereas most somatostatinergic hilar neurons were negative for MOR and DOR mRNA, somatostatinergic oriens layer neurons frequently expressed these receptors. Taken together, weak expression of MOR and DOR genes in hippocampal principal cells is in concordance with direct opioid-mediated inhibition of principal cells. However, strong expression of the MOR and DOR genes in the hippocampus is restricted to gamma-aminobutyric acid (GABA)ergic neurons, with DORs being selectively expressed in the parvalbumin- and somatostatin-containing subpopulations. Activation of MOR and/or DOR in parvalbumin- and somatostatin-containing neurons, which provide GABAergic inhibition to the perisomatic and distal dendritic regions of principal cells, respectively, is likely to facilitate principal cell excitation.
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MESH Headings
- Animals
- Gene Expression Regulation/physiology
- Hippocampus/metabolism
- Male
- Neurons/classification
- Neurons/metabolism
- Neurons/physiology
- RNA, Messenger/biosynthesis
- Rats
- Rats, Wistar
- Receptors, Opioid, delta/biosynthesis
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, mu/biosynthesis
- Receptors, Opioid, mu/genetics
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Affiliation(s)
- Ralf K Stumm
- Department of Pharmacology and Toxicology, Otto-von-Guericke University, Leipziger Strasse 44, 39120 Magdeburg, Germany.
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35
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Sil'kis IG. A possible mechanism for the effect of neuromodulators and modifiable inhibition on long-term potentiation and depression of the excitatory inputs to hippocampal principal cells. ACTA ACUST UNITED AC 2003; 33:529-41. [PMID: 14552546 DOI: 10.1023/a:1023960402109] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A postsynaptic mechanism for the influences of various neuromodulators and modifiable disynaptic inhibition on long-term potentiation and depression of the excitatory inputs to granule and pyramidal neurons in the hippocampus is described. According to this mechanism, facilitation of the induction of long-term depression/potentiation at the excitatory input to the inhibitory interneuron induced by the action of a neuromodulator on a receptor bound to a G(i/0)/(Gs or G(q/11)) protein can lead to decreases/increases in GABA release, weakening/strengthening of the inhibitory action on the target cell, and improvement in the conditions for induction of long-term potentiation/depression of the excitatory input to this cell. In the absence of inhibition, the same neuromodulator, activating the same type of receptors on the target cell, would facilitate induction of long-term depression/potentiation in that cell. The resultant effect of the action of the neuromodulator on the target cell depends on the ratio of the "strengths" of the excitatory and inhibitory inputs to the cell, on the presence on the interneuron and the target cell of the same or different types of receptors sensitive to this neurumodulator, and on the concentration of the neurumodulator, because of its different affinities for the receptors through which its differently directed effects on postsynaptic processes are mediated. Predictions based on this mechanism are in agreement with known experimental data.
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Affiliation(s)
- I G Sil'kis
- Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow
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36
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Hoffman AF, Riegel AC, Lupica CR. Functional localization of cannabinoid receptors and endogenous cannabinoid production in distinct neuron populations of the hippocampus. Eur J Neurosci 2003; 18:524-34. [PMID: 12911748 DOI: 10.1046/j.1460-9568.2003.02773.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The possible localization of cannabinoid (CB) receptors to glutamatergic and GABAergic synaptic terminals impinging upon GABAergic interneurons in the CA1 region of the rat hippocampus was examined using the electrophysiological measurement of neurotransmitter release in brain slices. Whereas activation of cannabinoid receptors via the application of the cannabinoid agonist WIN55,212-2 significantly and dose-dependently reduced evoked IPSCs recorded from interneurons possessing somata located in the stratum radiatum (S.R.) and stratum oriens (S.O.) lamellae, evoked glutamatergic EPSCs were unaffected in both neuronal populations. However, in agreement with previous reports, WIN55,212-2 significantly reduced EPSCs recorded from CA1 pyramidal neurons. Additional experiments confirmed that the effects of WIN55,212-2 on IPSCs were presynaptic and that they could be blocked by the CB1 receptor antagonist SR141716A. The involvement of endogenous cannabinoids in the presynaptic inhibition of GABA release was also examined in the interneurons and pyramidal cells using a depolarization-induced suppression of inhibition (DSI) paradigm. DSI was observed in CA1 pyramidal neurons under control conditions, and its incidence was greatly increased by the cholinergic agonist carbachol. However, DSI was not observed in the S.R. or S.O. interneuron populations, in either the presence or absence of carbachol. Whereas DSI was not present in these interneurons, the inhibitory inputs to these cells were modulated by the synthetic cannabinoid WIN55,212-2. These data support the hypothesis that cannabinoid receptors are located on inhibitory, but not excitatory, axon terminals impinging upon hippocampal interneurons, and that CA1 pyramidal neurons, and not interneurons, are capable of generating endogenous cannabinoids during prolonged states of depolarization.
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Affiliation(s)
- Alexander F Hoffman
- Cellular Neurobiology Research Branch, National Institute on Drug Abuse, National Institutes of Health, US Department of Health and Human Services, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA
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Number, density, and surface/cytoplasmic distribution of GABA transporters at presynaptic structures of knock-in mice carrying GABA transporter subtype 1-green fluorescent protein fusions. J Neurosci 2002. [PMID: 12451126 DOI: 10.1523/jneurosci.22-23-10251.2002] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
GABA transporter subtype 1 (GAT1) molecules were counted near GABAergic synapses, to a resolution of approximately 0.5 microm. Fusions between GAT1 and green fluorescent protein (GFP) were tested in heterologous expression systems, and a construct was selected that shows function, expression level, and trafficking similar to that of wild-type (WT) GAT1. A strain of knock-in mice was constructed that expresses this mGAT1-GFP fusion in place of the WT GAT1 gene. The pattern of fluorescence in brain slices agreed with previous immunocytochemical observations. [3H]GABA uptake, synaptic electrophysiology, and subcellular localization of the mGAT1-GFP construct were also compared with WT mice. Quantitative fluorescence microscopy was used to measure the density of mGAT1-GFP at presynaptic structures in CNS preparations from the knock-in mice. Fluorescence measurements were calibrated with transparent beads and gels that have known GFP densities. Surface biotinylation defined the fraction of transporters on the surface versus those in the nearby cytoplasm. The data show that the presynaptic boutons of GABAergic interneurons in cerebellum and hippocampus have a membrane density of 800-1300 GAT1 molecules per square micrometer, and the axons that connect boutons have a linear density of 640 GAT1 molecules per micrometer. A cerebellar basket cell bouton, a pinceau surrounding a Purkinje cell axon, and a cortical chandelier cell cartridge carry 9000, 7.8 million, and 430,000 GAT1 molecules, respectively; 61-63% of these molecules are on the surface membrane. In cultures from hippocampus, the set of fluorescent cells equals the set of GABAergic interneurons. Knock-in mice carrying GFP fusions of membrane proteins provide quantitative data required for understanding the details of synaptic transmission in living neurons.
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Drake CT, Milner TA. Mu opioid receptors are in discrete hippocampal interneuron subpopulations. Hippocampus 2002; 12:119-36. [PMID: 12000113 DOI: 10.1002/hipo.1107] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the rat hippocampal formation, application of mu opioid receptor (MOR) agonists disinhibits principal cells, promoting excitation-dependent processes such as epileptogenesis and long-term potentiation. However, the precise location of MORs in particular inhibitory circuits, has not been determined, and the roles of MORs in endogenous functioning are unclear. To address these issues, the distribution of MOR-like immunoreactivity (-li) was examined in several populations of inhibitory hippocampal neurons in the CA1 region using light and electron microscopy. We found that MOR-li was present in many parvalbumin-containing basket cells, but absent from cholecystokinin-labeled basket cells. MOR-li was also commonly in interneurons containing somatostatin-li or neuropeptide Y-li that resembled the "oriens-lacunosum-moleculare" (O-LM) interneurons innervating pyramidal cell distal dendrites. Finally, MOR-li was in some vasoactive intestinal peptide- or calretinin-containing profiles resembling interneurons that primarily innervate other interneurons. These findings indicate that MOR-containing neurons form a neurochemically and functionally heterogeneous subset of hippocampal GABAergic neurons. MORs are most frequently on interneurons that are specialized to inhibit pyramidal cells, and are on a limited number of interneurons that target other interneurons. Moreover, the distribution of MORs to different neuronal types in several laminae, some relatively far from endogenous opioids, suggests normal functional roles that are different from the actions seen with exogenous agonists such as morphine.
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Affiliation(s)
- Carrie T Drake
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10021, USA.
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Crespo C, Blasco-Ibáñez JM, Marqués-Marí AI, Alonso JR, Briñón JG, Martínez-Guijarro FJ. Vasoactive intestinal polypeptide-containing elements in the olfactory bulb of the hedgehog (Erinaceus europaeus). J Chem Neuroanat 2002; 24:49-63. [PMID: 12084411 DOI: 10.1016/s0891-0618(02)00018-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The distribution of vasoactive intestinal polypeptide (VIP)-immunopositive elements was analyzed in the olfactory bulb (OB) of the Western European hedgehog (Erinaceus europaeus) under light and electron microscopy. The immunoreactivity appeared in an abundant population of periglomerular cells of the glomerular layer, in interneurons of the external plexiform layer, and in a restricted group of deep short-axon cells of the internal plexiform layer, the granule cell layer and the white matter. In the glomerular layer, VIP-containing periglomerular cells constituted a population of non-GABAergic neurons and did not receive synapses from olfactory axons. In the EPL, VIP-immunoreactivity appeared in a morphologically heterogeneous population of GABAergic interneurons, most of them identified as satellite cells and Van Gehuchten cells. These interneurons exerted an abundant and selective innervation of the somata, primary and secondary dendrites of the principal mitral and tufted cells, but did not contact granule cells. Perisomatic innervation of the principal cells followed two different patterns. The first included 'normal' basket-like arrangements of VIP-containing varicosities surrounding the somata of mitral and tufted cells. In the second, a set of satellite cells gave rise to short dendritic shafts that embraced the somata of principal cells in an 'exuberant' basket-like arrangement. These two morphological patterns of perisomatic innervation of principal cells were correlated with a neurochemical specificity of the target. In this sense, the 'exuberant' basket-like structures were always found surrounding a subpopulation of principal cells that did not contain the calcium-binding protein parvalbumin (PV). By contrast, they were never found surrounding the subpopulation of PV-containing principal cells, which only showed 'normal' basket-like structures. This study provides new data on the connectivity and neurochemical features of the hedgehog olfactory bulb and suggests that the olfactory circuits in this species are more complex than those described in other mammals.
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Affiliation(s)
- Carlos Crespo
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Valencia. C/Dr Moliner 50, E-46100 Burjasot, Spain
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Morgane PJ, Mokler DJ, Galler JR. Effects of prenatal protein malnutrition on the hippocampal formation. Neurosci Biobehav Rev 2002; 26:471-83. [PMID: 12204193 DOI: 10.1016/s0149-7634(02)00012-x] [Citation(s) in RCA: 250] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
In this review we have assessed the effects of prenatal protein malnutrition on the hippocampal formation of the developing brain. In investigating this insult in the hippocampal neuronal model we have concentrated on aspects of enhanced inhibition we have shown in our earlier studies. Since this involves particular attention to the GABAergic interneurons we have examined the complex interneuronal networks of the hippocampal formation and their neurotransmitter afferent inputs, particularly the serotonergic system from the midbrain raphé nuclei. A variety of combinations of specialized interneurons are discussed in terms of how malnutrition insults perturb function in these inhibitory and disinhibitory networks. Pathological enhancement of inhibition manifests itself by diminished plasticity, alterations in theta activity and deficits in long-term learning behaviors. Long-term inhibition in select GABA interneuron systems may form a major derangement seen following prenatal protein malnutrition. The focus of this study is to relate enhanced inhibition to the several forms of inhibitory systems present in the hippocampal formation and develop hypotheses as to the primary derangements that may account for pathological inhibition in prenatal malnutrition.
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Affiliation(s)
- Peter J Morgane
- Center for Behavioral Development and Mental Retardation, Boston University School of Medicine, Boston, MA 02118, USA.
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Abstract
The polysialylated form of the neural cell adhesion molecule (PSA-NCAM) continues to be expressed in the adult hippocampus, mainly in a subset of neurons located in the innermost portion of the granule cell layer. PSA-NCAM immunoreactive neurons have also been described outside this layer in humans, where they are severely reduced in schizophrenic brains. Given this important clinical implication, we were interested in finding whether similar neurons existed in the adult rat hippocampus and to characterize their distribution, morphology and phenotype. PSA-NCAM immunocytochemistry reveals labeled neurons in the subiculum, fimbria, alveus, hilus, and stratum oriens, lucidum and radiatum of CA3 and CA1. They are mainly distributed in the ventral hippocampus, and have polygonal or fusiform somata with multipolar or bipolar morphology. These neurons show long straight dendrites, which reach several strata and even enter the fimbria and the alveus. These dendrites are often varicose, appear devoid of excrescences and apparently do not show spines. Most of these neurons display GABA immunoreactivity and further analysis has shown that a subpopulation expresses calretinin, but not somatostatin, neuropeptide Y, parvalbumin, calbindin or NADPH diaphorase. Our study demonstrates that there is an important subpopulation of PSA-NCAM immunoreactive neurons, many of which can be considered interneurons, outside the rat granule cell layer, probably homologous to those described in the human hippocampus. The presence of the polysialylated form of NCAM in these neurons could indicate that they are undergoing continuous remodeling during adulthood and may have an important role in hippocampal structural plasticity.
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Affiliation(s)
- Juan Nacher
- Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, Rockefeller University, York Avenue 1230, New York, NY 10021, USA.
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Miklós IH, Kovács KJ. GABAergic innervation of corticotropin-releasing hormone (CRH)-secreting parvocellular neurons and its plasticity as demonstrated by quantitative immunoelectron microscopy. Neuroscience 2002; 113:581-92. [PMID: 12150778 DOI: 10.1016/s0306-4522(02)00147-1] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
GABA has been identified as an important neurotransmitter in stress-related circuitry mediating inhibitory effects on neurosecretory neurons that comprise the central limb of the hypothalamo-pituitary-adrenocortical axis. Using combinations of pre-embedding immunostaining and postembedding immunogold methods at the ultrastructural level, direct synaptic contacts were revealed between GABA-containing terminals and neurosecretory cells that were immunoreactive for corticotropin-releasing hormone (CRH) in the hypothalamic paraventricular nucleus (PVN). The vast majority of axo-dendritic GABA synapses was symmetric (inhibitory) type, and 46% of all synaptic boutons in the medial parvocellular subdivision of the PVN were immunoreactive to GABA. Using the disector method, an unbiased stereological method on serial ultrathin sections, the total calculated number of synaptic contacts within the medial parvocellular subdivision of the PVN was 55.4 x 10(6)/mm(3). On CRH-positive profiles 20.1 x 10(6) GABAergic synaptic boutons were detected per mm(3) in control, colchicine-treated rats. In the medial parvocellular subdivision, 79% of GABAergic boutons terminated on CRH neurons. Following adrenalectomy, which increases the synthetic and secretory activities of CRH neurons, the number of GABAergic synapses that terminate on CRH-positive profiles was increased by 55%. GABA-containing boutons appeared to be swollen, while the contact surfaces of cellular membranes between GABAergic boutons and CRH-positive profiles were shorter in adrenalectomized animals than in controls. Our data provide ultrastructural evidence for direct inhibitory GABAergic control of stress-related CRH neurons and suggest a pivotal role of GABA-containing inputs in the functional plasticity of parvocellular neurosecretory neurons seen in response to adrenalectomy.
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Affiliation(s)
- I H Miklós
- Laboratory of Molecular Neuroendocrinology, Institute of Experimental Medicine, Szigony u 43 H-1083, Budapest, Hungary
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Blasco-Ibáñez JM, Martínez-Guijarro FJ, Freund TF. Recurrent mossy fibers preferentially innervate parvalbumin-immunoreactive interneurons in the granule cell layer of the rat dentate gyrus. Neuroreport 2000; 11:3219-25. [PMID: 11043552 DOI: 10.1097/00001756-200009280-00034] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Detection of vesicular zinc and immunohistochemistry against markers for different interneuron subsets were combined to study the postsynaptic target selection of zinc-containing recurrent mossy fiber collaterals in the dentate gyrus. Mossy fiber collaterals in the granule cell layer selectively innervated parvalbumin-containing cells, with numerous contacts per cell, whereas the granule cells were avoided. Under the electron microscope, those boutons made asymmetrical contacts on dendrites and somata. These findings suggest that, in addition to the hilar perforant path-associated (HIPP) interneurons, the basket and chandelier cells also receive a powerful feed-back drive from the granule cells, and thereby are able to control population synchrony in the dentate gyrus. On the other hand, the amount of monosynaptic excitatory feed-back among granule cells is shown to be negligible.
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Affiliation(s)
- J M Blasco-Ibáñez
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest
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Drake CT, Milner TA. Mu opioid receptors are in somatodendritic and axonal compartments of GABAergic neurons in rat hippocampal formation. Brain Res 1999; 849:203-15. [PMID: 10592303 DOI: 10.1016/s0006-8993(99)01910-1] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Activation of mu opioid receptors (MORs) has a net excitatory effect in the hippocampal formation through inhibition of gamma-amino butyric acid (GABA)-containing interneurons. To determine the precise subcellular targets of MOR agonists, immunoreactivity against MOR1 and GABA was examined in single sections of the hippocampal formation prepared for dual-labeling electron microscopy. In both the CA1 region of hippocampus and the dentate gyrus, MOR-like immunoreactivity (-li) was present in neuronal somata, dendrites, axons, and axon terminals, as well as a very few glial processes. Axon terminals with MOR-li formed symmetric synapses with principal cell dendrites and somata. Many MOR-labeled profiles of all types also contained GABA-li, and the vast majority possessed the ultrastructural characteristics of interneurons. Additionally, in the dentate gyrus a very small proportion of granule cell dendrites contained MOR-li. MOR-li, identified using immunogold-silver particles, was often affiliated with the extrasynaptic regions of neuronal plasma membranes, consistent with responsiveness to diffusing endogenous neuropeptide ligands. Semiquantitative analysis of the distribution of MOR-li revealed significantly more "presynaptic" (axons and terminals) than "postsynaptic" (somata and dendrites) labeled profiles in most laminae. We conclude that in addition to previously described somatodendritic MOR-li, a substantial amount of MOR-li in hippocampal formation is presynaptic. Furthermore, MORs are almost exclusively in GABAergic interneurons.
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Affiliation(s)
- C T Drake
- Department of Neurology, Division of Neurobiology, Weill Medical College of Cornell University, 411 East 69th Street, New York, NY, USA.
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Doetsch F, García-Verdugo JM, Alvarez-Buylla A. Regeneration of a germinal layer in the adult mammalian brain. Proc Natl Acad Sci U S A 1999; 96:11619-24. [PMID: 10500226 PMCID: PMC18083 DOI: 10.1073/pnas.96.20.11619] [Citation(s) in RCA: 510] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuronal precursors reside in the subventricular zone (SVZ) of adult mammals. This region is composed of a network of chains of migrating neuroblasts ensheathed by astrocytes and juxtaposed by clusters of immature precursors (type C cells). Here we show that after antimitotic treatment with cytosine-beta-D-arabinofuranoside, neuroblasts and type C cells are eliminated but some astrocytes remain. Remarkably, the SVZ network rapidly regenerates. Soon after cytosine-beta-D-arabinofuranoside treatment astrocytes divide. Two days later, type C cells reappear, followed at 4.5 days by migrating neuroblasts. By 10 days the SVZ network is fully regenerated, and the orientation and organization of chains of migrating neuroblasts resemble that of normal mice. This regeneration reveals an unexpected plasticity in the adult central nervous system and should provide a model system to study the early stages of neurogenesis in the adult brain.
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Affiliation(s)
- F Doetsch
- The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA
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Muscarinic receptor activity induces an afterdepolarization in a subpopulation of hippocampal CA1 interneurons. J Neurosci 1999. [PMID: 10407011 DOI: 10.1523/jneurosci.19-14-05703.1999] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cholinergic input to the hippocampus may be involved in important behavioral functions and the pathophysiology of neurodegenerative diseases. Muscarinic receptor activity in interneurons of the hippocampus may play a role in these actions. In this study, we investigated the effects of muscarinic receptor activity on the excitability of different subtypes of interneurons in rat hippocampal CA1. Most interneurons displayed an afterhyperpolarizing potential (AHP) after depolarization by injected current or synaptic stimulation. In the presence of a muscarinic agonist, the AHP of a subset of these interneurons was replaced by an afterdepolarization (ADP), often of sufficient magnitude to evoke action potentials in the absence of further stimulation. The ADP was insensitive to cadmium and low extracellular calcium. It was blocked by low extracellular sodium but not by tetrodotoxin or low concentrations of amiloride. Muscarinic ADPs were sometimes observed in isolation but were often accompanied by depolarizing, hyperpolarizing, or biphasic changes in the membrane potential. Interneurons with muscarinic ADPs were found in all strata of CA1 and did not fall into a single morphological classification. The potential functions of the prolonged action potential output of interneurons produced by the ADP could include changes in hippocampal circuit properties and facilitation of the release of peptide cotransmitters in these interneurons.
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Muscarinic receptor activity has multiple effects on the resting membrane potentials of CA1 hippocampal interneurons. J Neurosci 1999. [PMID: 10407010 DOI: 10.1523/jneurosci.19-14-05693.1999] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Inhibitory interneurons appear to be an important target for the muscarinic actions of cholinergic inputs to the hippocampus. We investigated the effect of muscarinic receptor activity on the membrane potential (V(m)) and currents of rat hippocampal CA1 interneurons using whole-cell recording from visually identified CA1 interneurons. The predominant response observed was a muscarinic depolarization that was detected in interneurons from all layers of CA1. This depolarization was mediated by at least two mechanisms: a reduction in a potassium current and a mechanism that depended on extracellular sodium. Other interneurons responded to muscarinic agonists with a hyperpolarization or a biphasic response (hyperpolarization followed by depolarization). Hyperpolarizations and biphasic responses were found in all layers of CA1 but more frequently in stratum radiatum and stratum lacunosum moleculare. Muscarinic hyperpolarization was caused by the activation of a barium- and cesium-sensitive inwardly rectifying potassium channel. A small number of interneurons, primarily in or bordering the stratum pyramidale, produced slow membrane potential (0.04 Hz) oscillations. Many interneurons did not respond to muscarinic activity at all; half of these were in the stratum oriens. There was no strong correlation between any changes in V(m) response to muscarine and morphology, as determined by reconstruction of the interneurons. It was not possible to predict the morphology or the layer distribution of an interneuron based on the type of muscarinic membrane potential response it had. This lack of correlation between muscarinic function and morphology implies a greater complexity of interneuron function than has been realized previously.
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Doetsch F, Caillé I, Lim DA, García-Verdugo JM, Alvarez-Buylla A. Subventricular zone astrocytes are neural stem cells in the adult mammalian brain. Cell 1999; 97:703-16. [PMID: 10380923 DOI: 10.1016/s0092-8674(00)80783-7] [Citation(s) in RCA: 2927] [Impact Index Per Article: 117.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Neural stem cells reside in the subventricular zone (SVZ) of the adult mammalian brain. This germinal region, which continually generates new neurons destined for the olfactory bulb, is composed of four cell types: migrating neuroblasts, immature precursors, astrocytes, and ependymal cells. Here we show that SVZ astrocytes, and not ependymal cells, remain labeled with proliferation markers after long survivals in adult mice. After elimination of immature precursors and neuroblasts by an antimitotic treatment, SVZ astrocytes divide to generate immature precursors and neuroblasts. Furthermore, in untreated mice, SVZ astrocytes specifically infected with a retrovirus give rise to new neurons in the olfactory bulb. Finally, we show that SVZ astrocytes give rise to cells that grow into multipotent neurospheres in vitro. We conclude that SVZ astrocytes act as neural stem cells in both the normal and regenerating brain.
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Affiliation(s)
- F Doetsch
- The Rockefeller University, New York, New York 10021, USA
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