1
|
McDonald AJ. Functional neuroanatomy of basal forebrain projections to the basolateral amygdala: Transmitters, receptors, and neuronal subpopulations. J Neurosci Res 2024; 102:e25318. [PMID: 38491847 PMCID: PMC10948038 DOI: 10.1002/jnr.25318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/20/2024] [Accepted: 02/23/2024] [Indexed: 03/18/2024]
Abstract
The projections of the basal forebrain (BF) to the hippocampus and neocortex have been extensively studied and shown to be important for higher cognitive functions, including attention, learning, and memory. Much less is known about the BF projections to the basolateral nuclear complex of the amygdala (BNC), although the cholinergic innervation of this region by the BF is actually far more robust than that of cortical areas. This review will focus on light and electron microscopic tract-tracing and immunohistochemical (IHC) studies, many of which were published in the last decade, that have analyzed the relationship of BF inputs and their receptors to specific neuronal subtypes in the BNC in order to better understand the anatomical substrates of BF-BNC circuitry. The results indicate that BF inputs to the BNC mainly target the basolateral nucleus of the BNC (BL) and arise from cholinergic, GABAergic, and perhaps glutamatergic BF neurons. Cholinergic inputs mainly target dendrites and spines of pyramidal neurons (PNs) that express muscarinic receptors (MRs). MRs are also expressed by cholinergic axons, as well as cortical and thalamic axons that synapse with PN dendrites and spines. BF GABAergic axons to the BL also express MRs and mainly target BL interneurons that contain parvalbumin. It is suggested that BF-BL circuitry could be very important for generating rhythmic oscillations known to be critical for emotional learning. BF cholinergic inputs to the BNC might also contribute to memory formation by activating M1 receptors located on PN dendritic shafts and spines that also express NMDA receptors.
Collapse
Affiliation(s)
- Alexander Joseph McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| |
Collapse
|
2
|
McDonald AJ. Colocalization of M1 muscarinic cholinergic receptors and NMDA receptors in dendrites and spines of pyramidal neurons of the mouse basolateral amygdala: An ultrastructural analysis. Neurosci Lett 2022; 779:136624. [DOI: 10.1016/j.neulet.2022.136624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 11/26/2022]
|
3
|
Lalo U, Koh W, Lee CJ, Pankratov Y. The tripartite glutamatergic synapse. Neuropharmacology 2021; 199:108758. [PMID: 34433089 DOI: 10.1016/j.neuropharm.2021.108758] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 07/25/2021] [Accepted: 08/20/2021] [Indexed: 12/31/2022]
Abstract
Astroglial cells were long considered as structural and metabolic supporting cells are which do not directly participate in information processing in the brain. Discoveries of responsiveness of astrocytes to synaptically-released glutamate and their capability to release agonists of glutamate receptors awakened extensive studies of glia-neuron communications and led to the revolutionary changes in our understanding of brain cellular networks. Nowadays, astrocytes are widely acknowledged as inseparable element of glutamatergic synapses and role for glutamatergic astrocyte-neuron interactions in the brain computation is emerging. Astroglial glutamate receptors, in particular of NMDA, mGluR3 and mGluR5 types, can activate a variety of molecular cascades leading astroglial-driven modulation of extracellular levels of glutamate and activity of neuronal glutamate receptors. Their preferential location to the astroglial perisynaptic processes facilitates interaction of astrocytes with individual excitatory synapses. Bi-directional glutamatergic communication between astrocytes and neurons underpins a complex, spatially-distributed modulation of synaptic signalling thus contributing to the enrichment of information processing by the neuronal networks. Still, further research is needed to bridge the substantial gaps in our understanding of mechanisms and physiological relevance of astrocyte-neuron glutamatergic interactions, in particular ability of astrocytes directly activate neuronal glutamate receptors by releasing glutamate and, arguably, d-Serine. An emerging roles for aberrant changes in glutamatergic astroglial signalling, both neuroprotective and pathogenic, in neurological and neurodegenerative diseases also require further investigation. This article is part of the special Issue on 'Glutamate Receptors - The Glutamatergic Synapse'.
Collapse
Affiliation(s)
- Ulyana Lalo
- School of Life Sciences, Immanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Wuhyun Koh
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, South Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Institute for Basic Science, Daejeon, 34126, South Korea
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, United Kingdom.
| |
Collapse
|
4
|
Shelkar GP, Liu J, Dravid SM. Astrocytic NMDA Receptors in the Basolateral Amygdala Contribute to Facilitation of Fear Extinction. Int J Neuropsychopharmacol 2021; 24:907-919. [PMID: 34363482 PMCID: PMC8598288 DOI: 10.1093/ijnp/pyab055] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Enhancement of N-methyl-D-aspartate (NMDA) receptor function using glycine-site agonist D-cycloserine is known to facilitate fear extinction, providing a means to augment cognitive behavioral therapy in anxiety disorders. A novel class of glycine-site agonists has recently been identified, and we have found that the prototype, AICP, is more effective than D-cycloserine in modulating neuronal function. METHODS Using novel glycine-site agonist AICP, local infusion studies, and genetic models, we elucidated the role of GluN2C-containing receptors in fear extinction. RESULTS We tested the effect of intracerebroventricular injection of AICP on fear extinction and found a robust facilitation of fear extinction. This effect was dependent on GluN2C subunit, consistent with superagonist action of AICP at GluN2C-containing receptors. Local infusion studies in wild-type and GluN2C knockout mice suggested that AICP produces its effect via GluN2C-containing receptors in the basolateral amygdala (BLA). Furthermore, consistent with astrocytic expression of GluN2C subunit in the amygdala, we found that AICP did not facilitate fear extinction in mice with conditional deletion of obligatory GluN1 subunit from astrocytes. Importantly, chemogenetic activation of astrocytes in the basolateral amygdala facilitated fear extinction. Acutely, AICP was found to facilitate excitatory neurotransmission in the BLA via presynaptic GluN2C-dependent mechanism. Immunohistochemical studies suggest that AICP-mediated facilitation of fear extinction involves synaptic insertion of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor GluA1 subunit. CONCLUSION These results identify a unique role of astrocytic NMDA receptors composed of GluN2C subunit in extinction of conditioned fear memory and demonstrate that further development of recently identified superagonists of GluN2C-containing receptors may have utility for anxiety disorders.
Collapse
Affiliation(s)
- Gajanan P Shelkar
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, Nebraska, USA,Correspondence: Gajanan P. Shelkar, PhD, Department of Pharmacology and Neuroscience, Creighton University, School of Medicine, 2500 California Plaza, Omaha, NE 68178, USA ()
| | - Jinxu Liu
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, Nebraska, USA
| | - Shashank M Dravid
- Department of Pharmacology and Neuroscience, Creighton University School of Medicine, Omaha, Nebraska, USA
| |
Collapse
|
5
|
Gurma M, Yang YM, Wang LY. Developmental plasticity of NMDA receptors at the calyx of Held synapse. Neuropharmacology 2021; 196:108697. [PMID: 34242682 DOI: 10.1016/j.neuropharm.2021.108697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/11/2021] [Accepted: 06/12/2021] [Indexed: 11/25/2022]
Abstract
Excitatory synaptic transmission is largely mediated by glutamate receptors in central synapses, such as the calyx of Held synapse in the auditory brainstem. This synapse is best known for undergoing extensive morphological and functional changes throughout early development and thereby has served as a prominent model system to study presynaptic mechanisms of neurotransmitter release. However, the pivotal roles of N-methyl-d-aspartate receptors (NMDARs) in gating acute forms of activity-dependent, persistent plasticity in vitro and chronic developmental remodeling in vivo are hardly noted. This article will provide a retrospective review of key experimental evidence to conceptualize the impact of a transient abundance of NMDARs during the early postnatal stage on the functionality of fast-spiking central synapses while raising a series of outstanding questions that are of general significance for understanding the developing brain in health and diseases. This article is part of the special Issue on "Glutamate Receptors - NMDA receptors".
Collapse
Affiliation(s)
- Maria Gurma
- Program in Neurosciences & Mental Health, SickKids Research Institute, 555 University Ave, Toronto, Ontario M5G 1X8, Canada; Department of Physiology, University of Toronto, 1 Kings Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Yi-Mei Yang
- Department of Biomedical Sciences, University of Minnesota, Duluth MN, 55812, USA
| | - Lu-Yang Wang
- Program in Neurosciences & Mental Health, SickKids Research Institute, 555 University Ave, Toronto, Ontario M5G 1X8, Canada; Department of Physiology, University of Toronto, 1 Kings Circle, Toronto, Ontario, M5S 1A8, Canada.
| |
Collapse
|
6
|
McDonald AJ, Mott DD. Neuronal localization of m1 muscarinic receptor immunoreactivity in the monkey basolateral amygdala. J Comp Neurol 2021; 529:2450-2463. [PMID: 33410202 PMCID: PMC8113068 DOI: 10.1002/cne.25104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/17/2020] [Accepted: 01/01/2021] [Indexed: 11/11/2022]
Abstract
The basolateral nuclear complex (BNC) of the amygdala plays an important role in the generation of emotional/motivational behavior and the consolidation of emotional memories. Activation of M1 cholinergic receptors (M1Rs) in the BNC is critical for memory consolidation. Previous receptor binding studies in the monkey amygdala demonstrated that the BNC has a high density of M1Rs, but did not have sufficient resolution to identify which neurons in the BNC expressed them. This was accomplished in the present immunohistochemical investigation using an antibody for the m1 receptor (m1R). Analysis of m1Rs in the monkey BNC using immunoperoxidase techniques revealed that their expression was very dense in the BNC, and suggested that virtually all of the pyramidal projection neurons (PNs) in all of the BNC nuclei were m1R-immunoreactive (m1R+). This was confirmed with dual-labeling immunofluorescence using staining for calcium/calmodulin-dependent protein kinase II (CaMK) as a marker for BNC PNs. However, additional dual-labeling studies indicated that one-third of inhibitory interneurons (INs) expressing glutamic acid decarboxylase (GAD) were also m1R+. Moreover, the finding that 60% of parvalbumin (PV) immunoreactive neurons were m1R+ indicated that this IN subpopulation was the main GAD+ subpopulation exhibiting m1R expression. The cholinergic innervation of the amygdala is greatly reduced in Alzheimer's disease and there is currently considerable interest in developing selective M1R positive allosteric modulators (PAMs) to treat the symptoms. The results of the present study indicate that M1Rs in both PNs and INs in the primate BNC would be targeted by M1R PAMs.
Collapse
Affiliation(s)
- Alexander Joseph McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - David D Mott
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| |
Collapse
|
7
|
Wang X, Yang Z, Fang S, Zhang Y, Guo J, Gou L. Declining Levels of Specialized Synaptic Surface Proteins in nNOS-Expressing Interneurons in Mice Treated Prenatally with Valproic Acid. Neurochem Res 2021; 46:1794-1800. [PMID: 33876374 DOI: 10.1007/s11064-021-03326-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 03/12/2021] [Accepted: 04/09/2021] [Indexed: 11/27/2022]
Abstract
Autism spectrum disorder (ASD) is a heterogeneous group of neurodevelopmental disorder characterized by impaired social interaction, and repetitive or restricted interests and behaviors. Membrane proteins are a significant part of the proteins in cell and play key functions in synaptic transmission. We have recently shown that neuronal nitric oxide synthase (nNOS) expression was reduced in the basolateral amygdala (BLA) of mice following postnatal valproic acid (VPA) exposure. In the current study, we utilized a label-free proteomics approach to identify and quantify surface protein expression in nNOS-positive interneurons between VPA-treated and control mice. Western blot was used to confirm the expression of selected membrane proteins. Our proteomics data revealed differentially expressed surface proteins in nNOS interneurons, e.g. Narp, AMPA-type glutamate (AMPA) receptor subunit GluA4 and Protein kinase C gamma (PKCγ), which were validated by Western blotting in mice treated with VPA. This work will pave the way for further elucidation of the mechanisms of these differentially membrane proteins in nNOS interneurons-medicated ASD.
Collapse
Affiliation(s)
- Xiaona Wang
- Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Engineering Research Center of Childhood Neurodevelopment, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China.
| | - Zhigang Yang
- Department of Neurology, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China
| | - Shuanfeng Fang
- Healthcare Department, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China
| | - Yaodong Zhang
- Henan Provincial Key Laboratory of Children's Genetics and Metabolic Diseases, Henan Engineering Research Center of Childhood Neurodevelopment, Children's Hospital Affiliated to Zhengzhou University, 33 Longhu Outer Circle Dong Road, Zhengzhou, 450018, Henan, China
| | - Jisheng Guo
- School of Basic Medical Sciences, Yantai Campus of Binzhou Medical University, 346 Guanhai Road, Laishan District, Yantai City, 264003, Shandong, China
| | - Lingshan Gou
- Center for Genetic Medicine, Xuzhou Maternity and Child Health Care Hospital, Xuzhou, China
| |
Collapse
|
8
|
Lim D, Semyanov A, Genazzani A, Verkhratsky A. Calcium signaling in neuroglia. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 362:1-53. [PMID: 34253292 DOI: 10.1016/bs.ircmb.2021.01.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glial cells exploit calcium (Ca2+) signals to perceive the information about the activity of the nervous tissue and the tissue environment to translate this information into an array of homeostatic, signaling and defensive reactions. Astrocytes, the best studied glial cells, use several Ca2+ signaling generation pathways that include Ca2+ entry through plasma membrane, release from endoplasmic reticulum (ER) and from mitochondria. Activation of metabotropic receptors on the plasma membrane of glial cells is coupled to an enzymatic cascade in which a second messenger, InsP3 is generated thus activating intracellular Ca2+ release channels in the ER endomembrane. Astrocytes also possess store-operated Ca2+ entry and express several ligand-gated Ca2+ channels. In vivo astrocytes generate heterogeneous Ca2+ signals, which are short and frequent in distal processes, but large and relatively rare in soma. In response to neuronal activity intracellular and inter-cellular astrocytic Ca2+ waves can be produced. Astrocytic Ca2+ signals are involved in secretion, they regulate ion transport across cell membranes, and are contributing to cell morphological plasticity. Therefore, astrocytic Ca2+ signals are linked to fundamental functions of the central nervous system ranging from synaptic transmission to behavior. In oligodendrocytes, Ca2+ signals are generated by plasmalemmal Ca2+ influx, or by release from intracellular stores, or by combination of both. Microglial cells exploit Ca2+ permeable ionotropic purinergic receptors and transient receptor potential channels as well as ER Ca2+ release. In this contribution, basic morphology of glial cells, glial Ca2+ signaling toolkit, intracellular Ca2+ signals and Ca2+-regulated functions are discussed with focus on astrocytes.
Collapse
Affiliation(s)
- Dmitry Lim
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy.
| | - Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia
| | - Armando Genazzani
- Department of Pharmaceutical Sciences, Università del Piemonte Orientale, Novara, Italy
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Achucarro Centre for Neuroscience, IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
| |
Collapse
|
9
|
Wang GH, Chou P, Hsueh SW, Yang YC, Kuo CC. Glutamate transmission rather than cellular pacemaking propels excitatory-inhibitory resonance for ictogenesis in amygdala. Neurobiol Dis 2020; 148:105188. [PMID: 33221531 DOI: 10.1016/j.nbd.2020.105188] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 10/20/2020] [Accepted: 11/17/2020] [Indexed: 12/16/2022] Open
Abstract
Epileptic seizures are automatic, excessive, and synchronized neuronal activities originating from many brain regions especially the amygdala, the allocortices and neocortices. This may reflect a shared principle for network organization and signaling in these telencephalic structures. In theory, the automaticity of epileptic discharges may stem from spontaneously active "oscillator" neurons equipped with intrinsic pacemaking conductances, or from a group of synaptically-connected collaborating "resonator" neurons. In the basolateral amygdalar (BLA) network of pyramidal-inhibitory (PN-IN) neuronal resonators, we demonstrated that rhythmogenic currents are provided by glutamatergic rather than the classic intrinsic or cellular pacemaking conductances (namely the h currents). The excitatory output of glutamatergic neurons such as PNs presumably propels a novel network-based "relay burst mode" of discharges especially in INs, which precondition PNs into a state prone to burst discharges and thus further glutamate release. Also, selective activation of unilateral PNs, but never INs, readily drives bilateral BLA networks into reverberating discharges which are fully synchronized with the behavioral manifestations of seizures (e.g. muscle contractions). Seizures originating in BLA and/or the other structures with similar PN-IN networks thus could be viewed as glutamate-triggered erroneous network oscillations that are normally responsible for information relay.
Collapse
Affiliation(s)
- Guan-Hsun Wang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; School of Medicine, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Department of Medical Education, Chang Gung Memorial Hospital, Linkou Medical Center, Tao-Yuan, Taiwan
| | - Ping Chou
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Shu-Wei Hsueh
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Ya-Chin Yang
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan; Neuroscience Research Center, Chang Gung Memorial Hospital, Linkou Medical Center, Tao-Yuan, Taiwan.
| | - Chung-Chin Kuo
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.
| |
Collapse
|
10
|
McDonald AJ, Jones GC, Mott DD. Diverse glutamatergic inputs target spines expressing M1 muscarinic receptors in the basolateral amygdala: An ultrastructural analysis. Brain Res 2019; 1722:146349. [PMID: 31348911 PMCID: PMC6755062 DOI: 10.1016/j.brainres.2019.146349] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/21/2019] [Accepted: 07/22/2019] [Indexed: 11/19/2022]
Abstract
Although it is known that acetylcholine acting through M1 muscarinic receptors (M1Rs) is essential for memory consolidation in the anterior basolateral nucleus of the amygdala (BLa), virtually nothing is known about the circuits involved. In the hippocampus M1R activation facilitates long-term potentiation (LTP) by potentiating NMDA glutamate receptor (NMDAR) currents. The majority of NMDAR+ profiles in the BLa are spines. Since about half of dendritic spines of BLa pyramidal neurons (PNs) receiving glutamatergic inputs are M1R-immunoreactive (M1R+) it is possible that the role of M1Rs in BLa mnemonic functions also involves potentiation of NMDAR currents in spines. However, the finding that only about half of BLa spines are M1R+ suggests that this proposed mechanism may only apply to a subset of glutamatergic inputs. As a first step in the identification of differential glutamatergic inputs to M1R+ spines in the BLa, the present electron microscopic study used antibodies to two different vesicular glutamate transporter proteins (VGluTs) to label two different subsets of glutamatergic inputs to M1R+ spines. These inputs are largely complimentary with VGluT1+ inputs arising mainly from cortical structures and the basolateral nucleus, and VGluT2+ inputs arising mainly from the thalamus. It was found that about one-half of the spines that were postsynaptic to VGluT1+ or VGluT2+ terminals were M1R+. In addition, a subset of the VGluT1+ or VGluT2+ axon terminals were M1R+, including those that synapsed with M1R+ spines. These results suggest that acetylcholine can modulate glutamatergic inputs to BLa spines by presynaptic as well as postsynaptic M1R-mediated mechanisms.
Collapse
Affiliation(s)
- Alexander J McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA.
| | - Grace C Jones
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| | - David D Mott
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC, USA
| |
Collapse
|
11
|
Tolou-Dabbaghian B, Delphi L, Rezayof A. Blockade of NMDA Receptors and Nitric Oxide Synthesis Potentiated Morphine-Induced Anti-Allodynia via Attenuating Pain-Related Amygdala pCREB/CREB Signaling Pathway. THE JOURNAL OF PAIN 2019; 20:885-897. [DOI: 10.1016/j.jpain.2019.01.329] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 11/30/2018] [Accepted: 01/11/2019] [Indexed: 01/26/2023]
|
12
|
Verkhratsky A, Chvátal A. NMDA Receptors in Astrocytes. Neurochem Res 2019; 45:122-133. [DOI: 10.1007/s11064-019-02750-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 01/22/2019] [Accepted: 02/05/2019] [Indexed: 12/12/2022]
|
13
|
Skowrońska K, Obara-Michlewska M, Zielińska M, Albrecht J. NMDA Receptors in Astrocytes: In Search for Roles in Neurotransmission and Astrocytic Homeostasis. Int J Mol Sci 2019; 20:ijms20020309. [PMID: 30646531 PMCID: PMC6358855 DOI: 10.3390/ijms20020309] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 12/15/2022] Open
Abstract
Studies of the last two decades have demonstrated the presence in astrocytic cell membranes of N-methyl-d-aspartate (NMDA) receptors (NMDARs), albeit their apparently low abundance makes demonstration of their presence and function more difficult than of other glutamate (Glu) receptor classes residing in astrocytes. Activation of astrocytic NMDARs directly in brain slices and in acutely isolated or cultured astrocytes evokes intracellular calcium increase, by mutually unexclusive ionotropic and metabotropic mechanisms. However, other than one report on the contribution of astrocyte-located NMDARs to astrocyte-dependent modulation of presynaptic strength in the hippocampus, there is no sound evidence for the significant role of astrocytic NMDARs in astrocytic-neuronal interaction in neurotransmission, as yet. Durable exposure of astrocytic and neuronal co-cultures to NMDA has been reported to upregulate astrocytic synthesis of glutathione, and in this way to increase the antioxidative capacity of neurons. On the other hand, overexposure to NMDA decreases, by an as yet unknown mechanism, the ability of cultured astrocytes to express glutamine synthetase (GS), aquaporin-4 (AQP4), and the inward rectifying potassium channel Kir4.1, the three astroglia-specific proteins critical for homeostatic function of astrocytes. The beneficial or detrimental effects of astrocytic NMDAR stimulation revealed in the in vitro studies remain to be proven in the in vivo setting.
Collapse
Affiliation(s)
- Katarzyna Skowrońska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
| | - Marta Obara-Michlewska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
| | - Magdalena Zielińska
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
| | - Jan Albrecht
- Department of Neurotoxicology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 5 Pawińskiego Str., 02-106 Warsaw, Poland.
| |
Collapse
|
14
|
Santiago AN, Lim KY, Opendak M, Sullivan RM, Aoki C. Early life trauma increases threat response of peri-weaning rats, reduction of axo-somatic synapses formed by parvalbumin cells and perineuronal net in the basolateral nucleus of amygdala. J Comp Neurol 2018; 526:2647-2664. [PMID: 30136731 DOI: 10.1002/cne.24522] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 07/20/2018] [Accepted: 08/03/2018] [Indexed: 01/17/2023]
Abstract
Early life trauma is a risk factor for life-long disorders related to emotional processing, but knowledge underlying its enduring effect is incomplete. This study was motivated by the hypothesis that early life trauma increases amygdala-dependent threat responses via reduction in inhibition by parvalbumin (PV) interneurons and perineuronal nets (PNN) supporting PV cells, thus increasing excitability of the basolateral amygdala (BLA). From postnatal day (PN) 8-12, rat pups of both sexes were reared under normal bedding or under insufficient nest-building materials to induce maternal-to-infant maltreatment trauma (Scarcity-Adversity Model, SAM). At weaning age of PN23, the SAM group exhibited increased threat responses to predator odor. The SAM-induced increase in threat response was recapitulated in normally reared PN22-23 rats that were unilaterally depleted of PNN in the BLA by the enzymes, chondroitinase-ABC plus hyaluronidase at PN19-20. Light and electron microscopic analysis of the BLA revealed that anterior-to-mid levels of SAM group's BLAs exhibited decreased PNN intensity and decreased axo-somatic synapses between PV-to-principal pyramidal-like neurons and PV-to-PV. PV and PNN densities (cells/mm2 ) in the BLA of both control (CON) and SAM groups were still low at PN12 and SAM delayed the ontogenetic rise of PV intensity and PNN density. Moreover, PV cell density in the anterior-to-mid BLA correlated negatively with threat response of CON animals, but not for SAM animals. Thus, reduction of PNN-supported, PV-mediated somatic inhibition of pyramidal cells provides a mechanistic support for the enduring effect of early life maltreatment manifested as increasing innate threat response at weaning.
Collapse
Affiliation(s)
- Adrienne N Santiago
- Center for Neural Science, New York University, New York, New York.,Emotional Brain Institute, Nathan Kline Institute, New York University School of Medicine, New York, New York.,Department of Child and Adolescent Psychiatry, NYU School of Medicine, New York, New York
| | - Kayla Y Lim
- Center for Neural Science, New York University, New York, New York
| | - Maya Opendak
- Emotional Brain Institute, Nathan Kline Institute, New York University School of Medicine, New York, New York.,Department of Child and Adolescent Psychiatry, NYU School of Medicine, New York, New York
| | - Regina M Sullivan
- Emotional Brain Institute, Nathan Kline Institute, New York University School of Medicine, New York, New York.,Department of Child and Adolescent Psychiatry, NYU School of Medicine, New York, New York
| | - Chiye Aoki
- Center for Neural Science, New York University, New York, New York
| |
Collapse
|
15
|
Oshima-Takago T, Takago H. NMDA receptor-dependent presynaptic inhibition at the calyx of Held synapse of rat pups. Open Biol 2018; 7:rsob.170032. [PMID: 28747405 PMCID: PMC5541344 DOI: 10.1098/rsob.170032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 07/04/2017] [Indexed: 12/26/2022] Open
Abstract
N-Methyl-d-aspartate receptors (NMDARs) play diverse roles in synaptic transmission, synaptic plasticity, neuronal development and neurological diseases. In addition to their postsynaptic expression, NMDARs are also expressed in presynaptic terminals at some central synapses, and their activation modulates transmitter release. However, the regulatory mechanisms of NMDAR-dependent synaptic transmission remain largely unknown. In the present study, we demonstrated that activation of NMDARs in a nerve terminal at a central glutamatergic synapse inhibits presynaptic Ca2+ currents (ICa) in a GluN2C/2D subunit-dependent manner, thereby decreasing nerve-evoked excitatory postsynaptic currents. Neither presynaptically loaded fast Ca2+ chelator BAPTA nor non-hydrolysable GTP analogue GTPγS affected NMDAR-mediated ICa inhibition. In the presence of a glutamate uptake blocker, the decline in ICa amplitude evoked by repetitive depolarizing pulses at 20 Hz was attenuated by an NMDAR competitive antagonist, suggesting that endogenous glutamate has a potential to activate presynaptic NMDARs. Moreover, NMDA-induced inward currents at a negative holding potential (−80 mV) were abolished by intra-terminal loading of the NMDAR open channel blocker MK-801, indicating functional expression of presynaptic NMDARs. We conclude that presynaptic NMDARs can attenuate glutamate release by inhibiting voltage-gated Ca2+ channels at a relay synapse in the immature rat auditory brainstem.
Collapse
Affiliation(s)
- Tomoko Oshima-Takago
- Department of Rehabilitation for Sensory Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama 359-8555, Japan.,Department of Neurophysiology, University of Tokyo Graduate School of Medicine, Tokyo 113-0033, Japan
| | - Hideki Takago
- Department of Rehabilitation for Sensory Functions, Research Institute, National Rehabilitation Center for Persons with Disabilities, Saitama 359-8555, Japan .,Department of Neurophysiology, University of Tokyo Graduate School of Medicine, Tokyo 113-0033, Japan.,Department of Otolaryngology, Tokyo Medical and Dental University Graduate School, Tokyo 113-8510, Japan
| |
Collapse
|
16
|
Ravikrishnan A, Gandhi PJ, Shelkar GP, Liu J, Pavuluri R, Dravid SM. Region-specific Expression of NMDA Receptor GluN2C Subunit in Parvalbumin-Positive Neurons and Astrocytes: Analysis of GluN2C Expression using a Novel Reporter Model. Neuroscience 2018; 380:49-62. [PMID: 29559384 DOI: 10.1016/j.neuroscience.2018.03.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 02/26/2018] [Accepted: 03/09/2018] [Indexed: 12/12/2022]
Abstract
Hypofunction of NMDA receptors in parvalbumin (PV)-positive interneurons has been proposed as a potential mechanism for cortical abnormalities and symptoms in schizophrenia. GluN2C-containing receptors have been linked to this hypothesis due to the higher affinity of psychotomimetic doses of ketamine for GluN1/2C receptors. However, the precise cell-type expression of GluN2C subunit remains unknown. We describe the expression of the GluN2C subunit using a novel EGFP reporter model. We observed EGFP(GluN2C) localization in PV-positive neurons in the nucleus reticularis of the thalamus, globus pallidus externa and interna, ventral pallidum and substantia nigra. In contrast, EGFP(GluN2C)-expressing cells did not co-localize with PV-positive neurons in the cortex, striatum, hippocampus or amygdala. Instead, EGFP(GluN2C) expression in these regions co-localized with an astrocytic marker. We confirmed functional expression of GluN2C-containing receptors in the PV-neurons in substantia nigra and cortical astrocytes using electrophysiology. GluN2C was found to be enriched in several first-order and higher order thalamic nuclei. Interestingly, we found that a previous GluN2C β-gal reporter model excluded expression from PV-neurons and certain thalamic nuclei but exhibited expression in the retrosplenial cortex. GluN2C's unique distribution in neuronal and non-neuronal cells in a brain region-specific manner raises interesting questions regarding the role of GluN2C-containing receptors in the central nervous system.
Collapse
Affiliation(s)
| | - Pauravi J Gandhi
- Department of Pharmacology, Creighton University, Omaha, NE 68178, USA
| | - Gajanan P Shelkar
- Department of Pharmacology, Creighton University, Omaha, NE 68178, USA
| | - Jinxu Liu
- Department of Pharmacology, Creighton University, Omaha, NE 68178, USA
| | | | - Shashank M Dravid
- Department of Pharmacology, Creighton University, Omaha, NE 68178, USA.
| |
Collapse
|
17
|
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
Collapse
Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| |
Collapse
|
18
|
Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 888] [Impact Index Per Article: 148.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
Collapse
Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| |
Collapse
|
19
|
Lamprecht R. The Role of Actin Cytoskeleton in Memory Formation in Amygdala. Front Mol Neurosci 2016; 9:23. [PMID: 27065800 PMCID: PMC4815361 DOI: 10.3389/fnmol.2016.00023] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/21/2016] [Indexed: 11/13/2022] Open
Abstract
The central, lateral and basolateral amygdala (BLA) nuclei are essential for the formation of long-term memories including emotional and drug-related memories. Studying cellular and molecular mechanisms of memory in amygdala may lead to better understanding of how memory is formed and of fear and addiction-related disorders. A challenge is to identify molecules activated by learning that subserve cellular changes needed for memory formation and maintenance in amygdala. Recent studies show that activation of synaptic receptors during fear and drug-related learning leads to alteration in actin cytoskeleton dynamics and structure in amygdala. Such changes in actin cytoskeleton in amygdala are essential for fear and drug-related memories formation. Moreover, the actin cytoskeleton subserves, after learning, changes in neuronal morphogenesis and glutamate receptors trafficking in amygdala. These cellular events are involved in fear and drug-related memories formation. Actin polymerization is also needed for the maintenance of drug-associated memories in amygdala. Thus, the actin cytoskeleton is a key mediator between receptor activation during learning and cellular changes subserving long-term memory (LTM) in amygdala. The actin cytoskeleton may serve as a target for pharmacological treatment of fear memory associated with fear and anxiety disorders and drug addiction to prevent the debilitating consequences of these diseases.
Collapse
|
20
|
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.
Collapse
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.
| |
Collapse
|
21
|
Bouvier G, Bidoret C, Casado M, Paoletti P. Presynaptic NMDA receptors: Roles and rules. Neuroscience 2015; 311:322-40. [DOI: 10.1016/j.neuroscience.2015.10.033] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/18/2015] [Accepted: 10/19/2015] [Indexed: 01/03/2023]
|
22
|
Ganea DA, Dines M, Basu S, Lamprecht R. The Membrane Proximal Region of AMPA Receptors in Lateral Amygdala is Essential for Fear Memory Formation. Neuropsychopharmacology 2015; 40:2727-35. [PMID: 25915472 PMCID: PMC4864648 DOI: 10.1038/npp.2015.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 03/16/2015] [Accepted: 04/17/2015] [Indexed: 11/09/2022]
Abstract
The membrane proximal region (MPR) of AMPA receptor (AMPAR) is needed for receptor trafficking and synaptic plasticity. However, its roles in long-term memory formation are not known. To assess the possible roles of AMPAR-MPR in rat lateral amygdala (LA) in short- and long-term fear memory formation, we used glutamate receptors (GluAs)-MPR competitive peptides MPR(DD) and MPR(AA). The MPR(DD) peptide is derived from GluA1 MPR and was previously shown to impair synaptic plasticity and to inhibit GluA1 containing AMPAR insertion into the synapse in an activity-dependent manner. The MPR(AA) peptide is derived from GluA2/4 MPR, and this receptor fragment was shown to be essential for GluA4 protein interaction needed for its insertion into the neuronal membrane and synapse. The peptides were linked to a TAT peptide (TAT-MPR(DD) and TAT-MPR(AA)) to facilitate internalization into LA cells. Infusion of the TAT-MPR(DD) peptide into LA 30 min before fear conditioning led to a significant impairment of long-term fear memory formation. Injection of TAT-MPR(DD) peptide into LA 30 min before fear conditioning impaired short-term fear memory formation. The TAT-MPR(DD) peptide had no effect on memory retrieval when injected into LA 30 min before fear memory test. Infusion of the TAT-MPR(AA) peptide into LA 30 min before fear conditioning led to a significant impairment of long-term fear memory formation. In contrast, the TAT-MPR(AA) had no effect on short-term fear memory formation. A TAT-control peptide had no effect on short- or long-term fear memory. These results show that the AMPAR-MPR in LA is needed for fear memory formation and that the MPR region of GluA1 is essential for acquisition of memory, whereas the MPR region of GluA4 is essential for long-term fear memory consolidation.
Collapse
Affiliation(s)
- Dan A Ganea
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Monica Dines
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Sreetama Basu
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel
| | - Raphael Lamprecht
- Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa, Israel,Sagol Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Mount Carmel, Haifa 31905, Israel, Tel: +972 4828 8786, Fax: +972 4824 0339, E-mail:
| |
Collapse
|
23
|
Stensrud MJ, Sogn CJ, Gundersen V. Immunogold characteristics of VGLUT3-positive GABAergic nerve terminals suggest corelease of glutamate. J Comp Neurol 2015; 523:2698-713. [PMID: 26010578 DOI: 10.1002/cne.23811] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 05/18/2015] [Accepted: 05/18/2015] [Indexed: 12/20/2022]
Abstract
There is compelling evidence that glutamate can act as a cotransmitter in the mammalian brain. Interestingly, the third vesicular glutamate transporter (VGLUT3) is primarily found in neurons that were anticipated to be nonglutamatergic. Whereas the function of VGLUT3 in acetylcholinergic and serotoninergic neurons has been elucidated, the role of VGLUT3 in neurons releasing gamma-aminobutyric acid (GABA) is not settled. We have previously shown that VGLUT3 is found together with the vesicular GABA transporter (VIAAT) on synaptic vesicle membranes in the hippocampus. Now we provide novel electron microscopic data from the rat hippocampus suggesting that glutamate is enriched in inhibitory nerve terminals containing VGLUT3 compared to those lacking VGLUT3. The opposite was found for GABA; VGLUT3-positive inhibitory terminals contained lower density of GABA labeling compared to VGLUT3-negative inhibitory terminals. In addition, semiquantitative confocal immunofluorescence showed that N-methyl-D-aspartate (NMDA)-receptor labeling was present more frequently in VGLUT3-positive/VIAAT-positive synapses versus in VGLUT3-negative/VIAAT-positive synapses. Electron microscopic immunogold data further suggest that NMDA receptors are enriched in VGLUT3 containing inhibitory terminals. Our data reveal new chemical characteristics of a subset of GABAergic interneurons in the hippocampus. The analyses suggest that glutamate is coreleased with GABA from hippocampal basket cell-synapses to act on NMDA receptors.
Collapse
Affiliation(s)
- Mats Julius Stensrud
- Department of Anatomy and Healthy Brain Ageing Centre Regional Research Network, Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Carl Johan Sogn
- Department of Anatomy and Healthy Brain Ageing Centre Regional Research Network, Institute of Basic Medical Sciences, University of Oslo, Norway
| | - Vidar Gundersen
- Department of Anatomy and Healthy Brain Ageing Centre Regional Research Network, Institute of Basic Medical Sciences, University of Oslo, Norway.,Department of Neurology, Oslo University Hospital, Rikshospitalet, Oslo, Norway
| |
Collapse
|
24
|
Spuz CA, Tomaszycki ML, Borszcz GS. N-methyl-D-aspartate receptor agonism and antagonism within the amygdaloid central nucleus suppresses pain affect: differential contribution of the ventrolateral periaqueductal gray. THE JOURNAL OF PAIN 2014; 15:1305-18. [PMID: 25261341 DOI: 10.1016/j.jpain.2014.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/07/2014] [Accepted: 09/16/2014] [Indexed: 01/12/2023]
Abstract
UNLABELLED The amygdala contributes to the generation of pain affect, and the amygdaloid central nucleus (CeA) receives nociceptive input that is mediated by glutamatergic neurotransmission. The present study compared the contribution of N-methyl-d-aspartate (NMDA) receptor agonism and antagonism in the CeA to generation of the affective response of rats to an acute noxious stimulus. Vocalizations that occur following a brief tail shock (vocalization afterdischarges) are a validated rodent model of pain affect and were preferentially suppressed, in a dose-dependent manner, by bilateral injection into the CeA of NMDA (.1, .25, .5, or 1 μg/side) or the NMDA receptor antagonist d-(-)-2-amino-5-phosphopentanoic acid (AP5; 1, 2, or 4 μg/side). Vocalizations that occur during tail shock were suppressed to a lesser degree, whereas spinal motor reflexes (tail flick and hind limb movements) were unaffected by injection of NMDA or AP5 into the CeA. Injection of NMDA, but not AP5, into the CeA increased c-Fos immunoreactivity in the ventrolateral periaqueductal gray, and unilateral injection of the μ-opiate receptor antagonist H-d-Phe-Cys-Tyr-d-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP; .25 μg) into ventrolateral periaqueductal gray prevented the antinociception generated by injection of NMDA into the CeA. These findings demonstrate that although NMDA receptor agonism and antagonism in the CeA produce similar suppression of pain behaviors, they do so via different neurobiologic mechanisms. PERSPECTIVE The amygdala contributes to production of the emotional dimension of pain. NMDA receptor agonism and antagonism within the CeA suppressed rats' emotional response to acute painful stimulation. Understanding the neurobiology underlying emotional responses to pain will provide insights into new treatments for pain and its associated affective disorders.
Collapse
Affiliation(s)
- Catherine A Spuz
- Department of Psychology, Behavioral & Cognitive Neuroscience Program, Wayne State University, Detroit, Michigan
| | - Michelle L Tomaszycki
- Department of Psychology, Behavioral & Cognitive Neuroscience Program, Wayne State University, Detroit, Michigan
| | - George S Borszcz
- Department of Psychology, Behavioral & Cognitive Neuroscience Program, Wayne State University, Detroit, Michigan.
| |
Collapse
|
25
|
Hubert GW, Muly EC. Distribution of AMPA receptor subunit glur1 in the bed nucleus of the stria terminalis and effect of stress. Synapse 2014; 68:194-201. [PMID: 24492926 DOI: 10.1002/syn.21729] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 12/21/2013] [Indexed: 12/11/2022]
Abstract
The brain circuitry thought to be involved in stress responses includes several nuclei of the extended amygdala. The bed nucleus of the stria terminalis (BNST) is thought to be involved in the generation of sustained, nonspecific anxiety. Previous behavioral and electrophysiological experiments demonstrate that glutamate systems are involved in anxiety-like behaviors in the BNST. Antagonists for AMPA receptors injected into the BNST decrease anxiety-like behaviors. However, little is known about the role of AMPA receptors and the mechanism by which they act in the establishment of anxiety-like behavior in response to a stressor. We hypothesized that the distribution of AMPA receptors is changed following a paradigm of unpredictable footshock as has been seen in the basolateral amygdala (BLA). We examined the subcellular localization of the GluR1 subunits of the AMPA receptor. We found that the neuropil of the BNST had a lower density of dendritic spines compared to dendritic shafts in the BLA. The majority of elements immunolabeled for GluR1 were dendritic shafts and spines with axonal and glial elements rarely labeled. Compared with controls, no significant effect was observed on days 1, 6, or 14 poststress. However, there was a trend for an increase at 6 and 14 days poststress. These data demonstrate that GluR1 subunits are primarily located on postsynaptic elements in the BNST. Moreover, it was shown that the response of the AMPA GluR1 subunit does not undergo a significant migration into spines from dendrites in response to a stressor as has been demonstrated in the BLA.
Collapse
Affiliation(s)
- George W Hubert
- Department of Psychiatry, Atlanta Veteran's Medical Center, Atlanta, Georgia
| | | |
Collapse
|
26
|
Dzamba D, Honsa P, Anderova M. NMDA Receptors in Glial Cells: Pending Questions. Curr Neuropharmacol 2013; 11:250-62. [PMID: 24179462 PMCID: PMC3648778 DOI: 10.2174/1570159x11311030002] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 01/08/2013] [Accepted: 02/02/2013] [Indexed: 01/28/2023] Open
Abstract
Glutamate receptors of the N-methyl-D-aspartate (NMDA) type are involved in many cognitive processes, including behavior, learning and synaptic plasticity. For a long time NMDA receptors were thought to be the privileged domain of neurons; however, discoveries of the last 25 years have demonstrated their active role in glial cells as well. Despite the large number of studies in the field, there are many unresolved questions connected with NMDA receptors in glia that are still a matter of debate. The main objective of this review is to shed light on these controversies by summarizing results from all relevant works concerning astrocytes, oligodendrocytes and polydendrocytes (also known as NG2 glial cells) in experimental animals, further extended by studies performed on human glia. The results are divided according to the study approach to enable a better comparison of how findings obtained at the mRNA level correspond with protein expression or functionality. Furthermore, special attention is focused on the NMDA receptor subunits present in the particular glial cell types, which give them special characteristics different from those of neurons – for example, the absence of Mg2+ block and decreased Ca2+ permeability. Since glial cells are implicated in important physiological and pathophysiological roles in the central nervous system (CNS), the last part of this review provides an overview of glial NMDA receptors with respect to ischemic brain injury.
Collapse
Affiliation(s)
- David Dzamba
- Department of Cellular Neurophysiology, Institute of Experimental Medicine AS CR, Prague, Czech Republic and Second Medical Faculty, Charles University, Prague, Czech Republic
| | | | | |
Collapse
|
27
|
Muller JF, Mascagni F, Zaric V, McDonald AJ. Muscarinic cholinergic receptor M1 in the rat basolateral amygdala: ultrastructural localization and synaptic relationships to cholinergic axons. J Comp Neurol 2013; 521:1743-59. [PMID: 23559406 DOI: 10.1002/cne.23254] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 09/20/2012] [Accepted: 10/25/2012] [Indexed: 02/02/2023]
Abstract
Muscarinic neurotransmission in the anterior basolateral amygdalar nucleus (BLa) mediated by the M1 receptor (M1R) is critical for memory consolidation. Although knowledge of the subcellular localization of M1R in the BLa would contribute to an understanding of cholinergic mechanisms involved in mnemonic function, there have been no ultrastructural studies of this receptor in the BLa. In the present investigation, immunocytochemistry at the electron microscopic level was used to determine which structures in the BLa express M1R. The innervation of these structures by cholinergic axons expressing the vesicular acetylcholine transporter (VAChT) was also studied. All perikarya of pyramidal neurons were labeled, and about 90% of dendritic shafts and 60% of dendritic spines were M1R+. Some dendrites had spines suggesting that they belonged to pyramidal cells, whereas others had morphological features typical of interneurons. M1R immunoreactivity (M1R-ir) was also seen in axon terminals, most of which formed asymmetrical synapses. The main targets of M1R+ terminals forming asymmetrical synapses were dendritic spines, most of which were M1R+. The main targets of M1R+ terminals forming symmetrical synapses were M1R+ perikarya and dendritic shafts. About three-quarters of VAChT+ cholinergic terminals formed synapses; the main postsynaptic targets were M1R+ dendritic shafts and spines. In some cases M1R-ir was seen near the postsynaptic membrane of these processes, but in other cases it was found outside of the active zone of VAChT+ synapses. These findings suggest that M1R mechanisms in the BLa are complex, involving postsynaptic effects as well as regulating release of neurotransmitters from presynaptic terminals.
Collapse
Affiliation(s)
- Jay F Muller
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina 29208, USA
| | | | | | | |
Collapse
|
28
|
Hubert GW, Li C, Rainnie DG, Muly EC. Effects of stress on AMPA receptor distribution and function in the basolateral amygdala. Brain Struct Funct 2013; 219:1169-79. [PMID: 23644586 DOI: 10.1007/s00429-013-0557-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 04/17/2013] [Indexed: 01/07/2023]
Abstract
Stress is a growing public health concern and can lead to significant disabilities. The neural response to stressors is thought to be dependent on the extended amygdala. The basolateral amygdala (BLA) is responsible for associations of sensory stimuli with emotional valence and is thought to be involved in stress-induced responses. Previous behavioral and electrophysiological experiments demonstrate that, in response to stress, changes occur in glutamatergic neurotransmission within the BLA and, in particular in transmission at AMPA receptors. Given the established role of AMPA receptors in memory and synaptic plasticity, we tested the hypothesis that stress produces alterations in the distribution of these receptors in a way that might account for stress-induced alterations in amygdala circuitry function. We examined the subcellular localization of GluR1 subunits of the AMPA receptor and the electrophysiological characteristics of BLA principal neurons in an animal model of unpredictable stress. Compared to controls, we demonstrated an increase in the ratio of labeled spines to labeled dendritic shafts in the BLA of rats 6 and 14 days post-stress, but not 1 day post-stress. Furthermore, the frequency of mini-EPSCs was increased in stressed animals without a change in general membrane properties, mini-EPSC amplitude, or in paired pulse modulation of glutamate release. Taken together, these data suggest that the shift of GluR1-containing AMPA receptors from dendritic stores into spines may be in part responsible for the persistent behavioral alterations observed following severe stressors.
Collapse
Affiliation(s)
- G W Hubert
- Department of Psychiatry, Atlanta Veteran's Medical Center, Atlanta, GA, USA,
| | | | | | | |
Collapse
|
29
|
Zhang J, Muller JF, McDonald AJ. Noradrenergic innervation of pyramidal cells in the rat basolateral amygdala. Neuroscience 2013; 228:395-408. [PMID: 23103792 PMCID: PMC4586037 DOI: 10.1016/j.neuroscience.2012.10.035] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 10/16/2012] [Accepted: 10/16/2012] [Indexed: 11/26/2022]
Abstract
The basolateral nuclear complex of the amygdala (BLC) receives dense noradrenergic/norepinephrine (NE) inputs from the locus coeruleus that play a key role in modulating emotional memory consolidation. Knowledge of the extent of synapse formation by NE inputs to the BLC, as well as the cell types innervated, would contribute to an understanding of how NE modulates the activity of the BLC. To gain a better understanding of NE circuits in the BLC, dual-label immunohistochemistry was used at the light and electron microscopic levels in the present study to analyze NE axons and their innervation of pyramidal cells in the anterior subdivision of the basolateral amygdalar nucleus (BLa). NE axons and BLa pyramidal cells were labeled using antibodies to the norepinephrine transporter (NET) and Ca(2+)/calmodulin-dependent protein kinase (CaMK), respectively. Dual localization studies using antibodies to NET and dopamine-beta-hydroxylase (DBH) revealed that virtually all NE axons and varicosities expressed both proteins. The BLa exhibited a medium density of NET+ fibers. Ultrastructural analysis of serial section reconstructions of NET+ axons revealed that only about half of NET+ terminals formed synapses. The main postsynaptic targets were small-caliber CAMK+ dendritic shafts and spines of pyramidal cells. A smaller number of NET+ terminals formed synapses with unlabeled cell bodies and dendrites. These findings indicate that the distal dendritic domain of BLa pyramidal cells is the major target of NE terminals in the BLa, and the relatively low synaptic incidence suggests that diffusion from non-synaptic terminals may be important for noradrenergic modulation of the BLa.
Collapse
Affiliation(s)
- Jingyi Zhang
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208
| | - Jay F. Muller
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208
| | - Alexander J. McDonald
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208
| |
Collapse
|
30
|
Delaney AJ, Sedlak PL, Autuori E, Power JM, Sah P. Synaptic NMDA receptors in basolateral amygdala principal neurons are triheteromeric proteins: physiological role of GluN2B subunits. J Neurophysiol 2012; 109:1391-402. [PMID: 23221411 DOI: 10.1152/jn.00176.2012] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
N-methyl-(D)-aspartate (NMDA) receptors are heteromultimeric ion channels that contain an essential GluN1 subunit and two or more GluN2 (GluN2A-GluN2D) subunits. The biophysical properties and physiological roles of synaptic NMDA receptors are dependent on their subunit composition. In the basolateral amygdala (BLA), it has been suggested that the plasticity that underlies fear learning requires activation of heterodimeric receptors composed of GluN1/GluN2B subunits. In this study, we investigated the subunit composition of NMDA receptors present at synapses on principal neurons in the BLA. Purification of the synaptic fraction showed that both GluN2A and GluN2B subunits are present at synapses, and co-immunoprecipitation revealed the presence of receptors containing both GluN2A and GluN2B subunits. The kinetics of NMDA receptor-mediated synaptic currents and pharmacological blockade indicate that heterodimeric GluN1/GluN2B receptors are unlikely to be present at glutamatergic synapses on BLA principal neurons. Selective RNA interference-mediated knockdown of GluN2A subunits converted synaptic receptors to a GluN1/GluN2B phenotype, whereas knockdown of GluN2B subunits had no effect on the kinetics of the synaptically evoked NMDA current. Blockade of GluN1/GluN2B heterodimers with ifenprodil had no effect, but knockdown of GluN2B disrupted the induction of CaMKII-dependent long-term potentiation at these synapses. These results suggest that, on BLA principal neurons, GluN2B subunits are only present as GluN1/GluN2A/GluN2B heterotrimeric NMDA receptors. The GluN2B subunit has little impact on the kinetics of the receptor, but is essential for the recruitment of signaling molecules essential for synaptic plasticity.
Collapse
Affiliation(s)
- Andrew J Delaney
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | | | | | | | | |
Collapse
|
31
|
Synaptic transmission changes in fear memory circuits underlie key features of an animal model of schizophrenia. Behav Brain Res 2012; 227:184-93. [DOI: 10.1016/j.bbr.2011.10.050] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 10/26/2011] [Accepted: 10/31/2011] [Indexed: 12/26/2022]
|
32
|
Nedelescu H, Kelso CM, Lázaro-Muñoz G, Purpura M, Cain CK, Ledoux JE, Aoki C. Endogenous GluR1-containing AMPA receptors translocate to asymmetric synapses in the lateral amygdala during the early phase of fear memory formation: an electron microscopic immunocytochemical study. J Comp Neurol 2011; 518:4723-39. [PMID: 20963825 DOI: 10.1002/cne.22472] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Although glutamate receptor 1 (GluR1)-containing α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate receptors (GluR1-AMPARs) are implicated in synaptic plasticity, it has yet to be demonstrated whether endogenous GluR1-AMPARs undergo activity-dependent trafficking in vivo to synapses to support short-term memory (STM) formation. The paradigm of pavlovian fear conditioning (FC) can be used to address this question, because a discrete region-the lateral amygdala (LA)-has been shown unambiguously to be necessary for the formation of the associative memory between a neutral stimulus (tone [CS]) and a noxious stimulus (foot shock [US]). Acquisition of STM for FC can occur even in the presence of protein synthesis inhibitors, indicating that redistribution of pre-existing molecules to synaptic junctions underlies STM. We employed electron microscopic immunocytochemistry to evaluate alterations in the distribution of endogenous AMPAR subunits at LA synapses during the STM phase of FC. Rats were sacrificed 40 minutes following three CS-US pairings. In the LA of paired animals, relative to naïve animals, the proportion of GluR1-AMPAR-labeled synapses increased 99% at spines and 167% in shafts. In the LA of unpaired rats, for which the CS was never associated with the US, GluR1 immunoreactivity decreased 84% at excitatory shaft synapses. GluR2/3 immunoreactivity at excitatory synapses did not change detectably following paired or unpaired conditioning. Thus, the early phase of FC involves rapid redistribution specifically of the GluR1-AMPARs to the postsynaptic membranes in the LA, together with the rapid translocation of GluR1-AMPARs from remote sites into the spine head cytoplasm, yielding behavior changes that are specific to stimulus contingencies.
Collapse
Affiliation(s)
- Hermina Nedelescu
- Center for Neural Science, New York University, New York, New York 10003, USA
| | | | | | | | | | | | | |
Collapse
|
33
|
Scavone JL, Asan E, Van Bockstaele EJ. Unraveling glutamate-opioid receptor interactions using high-resolution electron microscopy: implications for addiction-related processes. Exp Neurol 2011; 229:207-13. [PMID: 21459090 DOI: 10.1016/j.expneurol.2011.03.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 03/11/2011] [Accepted: 03/21/2011] [Indexed: 11/24/2022]
Abstract
Adaptive responses in glutamate and opioid receptor systems in limbic circuits are emerging as a critical component of the neural plasticity induced by chronic use of abused substances. The present commentary reviews findings from neuroanatomical studies, with superior spatial resolution, that support a cellular basis for prominent interactions of glutamate and opioid receptor systems in preclinical models of drug addiction. The review begins by highlighting the advantages of high-resolution electron microscopic immunohistochemistry for unraveling receptor interactions at the synapse. With an emphasis on a recent publication describing the anatomical relationship between the μ-opioid receptor (MOR) and the AMPA-GluR2 subunit (Beckerman, M. A., and Glass, M. J., 2011. Ultrastructural relationship between the AMPA-GluR2 receptor subunit and the mu-opioid receptor in the mouse central nucleus of the amygdala. Exp Neurol), we review the anatomical evidence for opioid-induced neural plasticity of glutamate receptors in selected brain circuits that are key integrative substrates in the brain's motivational system. The findings stress the importance of glutamate-opioid interactions as important neural mediators of adaptations to chronic use of abused drugs, particularly within the amygdaloid complex.
Collapse
Affiliation(s)
- Jillian L Scavone
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | |
Collapse
|
34
|
Liu Z, Han J, Jia L, Maillet JC, Bai G, Xu L, Jia Z, Zheng Q, Zhang W, Monette R, Merali Z, Zhu Z, Wang W, Ren W, Zhang X. Synaptic neurotransmission depression in ventral tegmental dopamine neurons and cannabinoid-associated addictive learning. PLoS One 2010; 5:e15634. [PMID: 21187978 PMCID: PMC3004941 DOI: 10.1371/journal.pone.0015634] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2010] [Accepted: 11/18/2010] [Indexed: 12/18/2022] Open
Abstract
Drug addiction is an association of compulsive drug use with long-term associative learning/memory. Multiple forms of learning/memory are primarily subserved by activity- or experience-dependent synaptic long-term potentiation (LTP) and long-term depression (LTD). Recent studies suggest LTP expression in locally activated glutamate synapses onto dopamine neurons (local Glu-DA synapses) of the midbrain ventral tegmental area (VTA) following a single or chronic exposure to many drugs of abuse, whereas a single exposure to cannabinoid did not significantly affect synaptic plasticity at these synapses. It is unknown whether chronic exposure of cannabis (marijuana or cannabinoids), the most commonly used illicit drug worldwide, induce LTP or LTD at these synapses. More importantly, whether such alterations in VTA synaptic plasticity causatively contribute to drug addictive behavior has not previously been addressed. Here we show in rats that chronic cannabinoid exposure activates VTA cannabinoid CB1 receptors to induce transient neurotransmission depression at VTA local Glu-DA synapses through activation of NMDA receptors and subsequent endocytosis of AMPA receptor GluR2 subunits. A GluR2-derived peptide blocks cannabinoid-induced VTA synaptic depression and conditioned place preference, i.e., learning to associate drug exposure with environmental cues. These data not only provide the first evidence, to our knowledge, that NMDA receptor-dependent synaptic depression at VTA dopamine circuitry requires GluR2 endocytosis, but also suggest an essential contribution of such synaptic depression to cannabinoid-associated addictive learning, in addition to pointing to novel pharmacological strategies for the treatment of cannabis addiction.
Collapse
Affiliation(s)
- Zhiqiang Liu
- College of Life Sciences, Shaanxi Normal University, Xian, People's Republic of China
- Institute of Mental Health Research and Departments of Psychiatry and Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Jing Han
- College of Life Sciences, Shaanxi Normal University, Xian, People's Republic of China
- Institute of Mental Health Research and Departments of Psychiatry and Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Lintao Jia
- Institute of Mental Health Research and Departments of Psychiatry and Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Jean-Christian Maillet
- Institute of Mental Health Research and Departments of Psychiatry and Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Guang Bai
- Department of Neural and Pain Sciences, Dental School, Program in Neuroscience, University of Maryland, Baltimore, Maryland, United States of America
| | - Lin Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Science, Kunming, People's Republic of China
| | - Zhengping Jia
- Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Qiaohua Zheng
- Institute of Mental Health Research and Departments of Psychiatry and Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Wandong Zhang
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Canada
| | - Robert Monette
- Neurobiology Program, Institute for Biological Sciences, National Research Council of Canada, Ottawa, Canada
| | - Zul Merali
- Institute of Mental Health Research and Departments of Psychiatry and Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Zhou Zhu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Wei Ren
- College of Life Sciences, Shaanxi Normal University, Xian, People's Republic of China
| | - Xia Zhang
- College of Life Sciences, Shaanxi Normal University, Xian, People's Republic of China
- Institute of Mental Health Research and Departments of Psychiatry and Cellular & Molecular Medicine, University of Ottawa, Ottawa, Canada
- * E-mail:
| |
Collapse
|
35
|
Farb CR, Chang W, Ledoux JE. Ultrastructural characterization of noradrenergic axons and Beta-adrenergic receptors in the lateral nucleus of the amygdala. Front Behav Neurosci 2010; 4:162. [PMID: 21048893 PMCID: PMC2967335 DOI: 10.3389/fnbeh.2010.00162] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 08/23/2010] [Indexed: 11/13/2022] Open
Abstract
Norepinephrine (NE) is thought to play a key role in fear and anxiety, but its role in amygdala-dependent Pavlovian fear conditioning, a major model for understanding the neural basis of fear, is poorly understood. The lateral nucleus of the amygdala (LA) is a critical brain region for fear learning and regulating the effects of stress on memory. To understand better the cellular mechanisms of NE and its adrenergic receptors in the LA, we used antibodies directed against dopamine beta-hydroxylase (DβH), the synthetic enzyme for NE, or against two different isoforms of the beta-adrenergic receptors (βARs), one that predominately recognizes neurons (βAR 248) and the other astrocytes (βAR 404), to characterize the microenvironments of DβH and βAR. By electron microscopy, most DβH terminals did not make synapses, but when they did, they formed both asymmetric and symmetric synapses. By light microscopy, βARs were present in both neurons and astrocytes. Confocal microscopy revealed that both excitatory and inhibitory neurons express βAR248. By electron microscopy, βAR 248 was present in neuronal cell bodies, dendritic shafts and spines, and some axon terminals and astrocytes. When in dendrites and spines, βAR 248 was frequently concentrated along plasma membranes and at post-synaptic densities of asymmetric (excitatory) synapses. βAR 404 was expressed predominately in astrocytic cell bodies and processes. These astrocytic processes were frequently interposed between unlabeled terminals or ensheathed asymmetric synapses. Our findings provide a morphological basis for understanding ways in which NE may modulate transmission by acting via synaptic or non-synaptic mechanisms in the LA.
Collapse
Affiliation(s)
- Claudia R Farb
- Center for Neural Science, New York University New York, NY, USA
| | | | | |
Collapse
|
36
|
Ota KT, Monsey MS, Wu MS, Schafe GE. Synaptic plasticity and NO-cGMP-PKG signaling regulate pre- and postsynaptic alterations at rat lateral amygdala synapses following fear conditioning. PLoS One 2010; 5:e11236. [PMID: 20574537 PMCID: PMC2888610 DOI: 10.1371/journal.pone.0011236] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 05/27/2010] [Indexed: 11/18/2022] Open
Abstract
In vertebrate models of synaptic plasticity, signaling via the putative "retrograde messenger" nitric oxide (NO) has been hypothesized to serve as a critical link between functional and structural alterations at pre- and postsynaptic sites. In the present study, we show that auditory Pavlovian fear conditioning is associated with significant and long-lasting increases in the expression of the postsynaptically-localized protein GluR1 and the presynaptically-localized proteins synaptophysin and synapsin in the lateral amygdala (LA) within 24 hrs following training. Further, we show that rats given intra-LA infusion of either the NR2B-selective antagonist Ifenprodil, the NOS inhibitor 7-Ni, or the PKG inhibitor Rp-8-Br-PET-cGMPS exhibit significant decreases in training-induced expression of GluR1, synaptophysin, and synapsin immunoreactivity in the LA, while those rats infused with the PKG activator 8-Br-cGMP exhibit a significant increase in these proteins in the LA. In contrast, rats given intra-LA infusion of the NO scavenger c-PTIO exhibit a significant decrease in synapsin and synaptophysin expression in the LA, but no significant impairment in the expression of GluR1. Finally, we show that intra-LA infusions of the ROCK inhibitor Y-27632 or the CaMKII inhibitor KN-93 impair training-induced expression of GluR1, synapsin, and synaptophysin in the LA. These findings suggest that the NO-cGMP-PKG, Rho/ROCK, and CaMKII signaling pathways regulate fear memory consolidation, in part, by promoting both pre- and post-synaptic alterations at LA synapses. They further suggest that synaptic plasticity in the LA during auditory fear conditioning promotes alterations at presynaptic sites via NO-driven "retrograde signaling".
Collapse
Affiliation(s)
- Kristie T. Ota
- Department of Psychology, Yale University, New Haven, Connecticut, United States of America
| | - Melissa S. Monsey
- Department of Psychology, Yale University, New Haven, Connecticut, United States of America
| | - Melissa S. Wu
- Department of Psychology, Yale University, New Haven, Connecticut, United States of America
| | - Glenn E. Schafe
- Department of Psychology, Yale University, New Haven, Connecticut, United States of America
- Interdepartmental Neuroscience Program, Yale University, New Haven, Connecticut, United States of America
| |
Collapse
|
37
|
Rodríguez-Moreno A, Banerjee A, Paulsen O. Presynaptic NMDA Receptors and Spike Timing-Dependent Depression at Cortical Synapses. Front Synaptic Neurosci 2010; 2:18. [PMID: 21423504 PMCID: PMC3059699 DOI: 10.3389/fnsyn.2010.00018] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/24/2010] [Indexed: 01/23/2023] Open
Abstract
It has recently been discovered that some forms of timing-dependent long-term depression (t-LTD) require presynaptic N-methyl-d-aspartate (NMDA) receptors. In this review, we discuss the evidence for the presence of presynaptic NMDA receptors at cortical synapses and their possible role in the induction of t-LTD. Two basic models emerge for the induction of t-LTD at cortical synapses. In one model, coincident activation of presynaptic NMDA receptors and CB1 receptors mediates t-LTD. In a second model, CB1 receptors are not necessary, and the activation of presynaptic NMDA receptors alone appears to be sufficient for the induction of t-LTD.
Collapse
|
38
|
Pape HC, Pare D. Plastic synaptic networks of the amygdala for the acquisition, expression, and extinction of conditioned fear. Physiol Rev 2010; 90:419-63. [PMID: 20393190 DOI: 10.1152/physrev.00037.2009] [Citation(s) in RCA: 751] [Impact Index Per Article: 53.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The last 10 years have witnessed a surge of interest for the mechanisms underlying the acquisition and extinction of classically conditioned fear responses. In part, this results from the realization that abnormalities in fear learning mechanisms likely participate in the development and/or maintenance of human anxiety disorders. The simplicity and robustness of this learning paradigm, coupled with the fact that the underlying circuitry is evolutionarily well conserved, make it an ideal model to study the basic biology of memory and identify genetic factors and neuronal systems that regulate the normal and pathological expressions of learned fear. Critical advances have been made in determining how modified neuronal functions upon fear acquisition become stabilized during fear memory consolidation and how these processes are controlled in the course of fear memory extinction. With these advances came the realization that activity in remote neuronal networks must be coordinated for these events to take place. In this paper, we review these mechanisms of coordinated network activity and the molecular cascades leading to enduring fear memory, and allowing for their extinction. We will focus on Pavlovian fear conditioning as a model and the amygdala as a key component for the acquisition and extinction of fear responses.
Collapse
Affiliation(s)
- Hans-Christian Pape
- Institute of Physiology, Westfaelische Wilhelms-University, Muenster, Germany; and Rutgers State University, Newark, New Jersey, USA.
| | | |
Collapse
|
39
|
Graebenitz S, Lesting J, Sosulina L, Seidenbecher T, Pape HC. Alteration of NMDA receptor-mediated synaptic interactions in the lateral amygdala associated with seizure activity in a mouse model of chronic temporal lobe epilepsy. Epilepsia 2010; 51:1754-62. [DOI: 10.1111/j.1528-1167.2010.02561.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
40
|
McCool BA, Christian DT, Diaz MR, Läck AK. Glutamate plasticity in the drunken amygdala: the making of an anxious synapse. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2010; 91:205-33. [PMID: 20813244 DOI: 10.1016/s0074-7742(10)91007-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Plasticity at glutamatergic synapses is believed to be the cellular correlate of learning and memory. Classic fear conditioning, for example, is dependent upon NMDA-type glutamate receptor activation in the lateral/basolateral amygdala followed by increased synaptic expression of AMPA-type glutamate receptors. This review provides an extensive comparison between the initiation and expression of glutamatergic plasticity during learning/memory and glutamatergic alterations associated with chronic ethanol exposure and withdrawal. The parallels between these neuro-adaptive processes suggest that long-term ethanol exposure might "chemically condition" amygdala-dependent fear/anxiety via the increased function of pre- and post-synaptic glutamate signaling.
Collapse
Affiliation(s)
- Brian A McCool
- Department of Physiology & Pharmcology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA
| | | | | | | |
Collapse
|
41
|
Aoki C, Kojima N, Sabaliauskas N, Shah L, Ahmed TH, Oakford J, Ahmed T, Yamazaki H, Hanamura K, Shirao T. Drebrin a knockout eliminates the rapid form of homeostatic synaptic plasticity at excitatory synapses of intact adult cerebral cortex. J Comp Neurol 2009; 517:105-21. [PMID: 19711416 DOI: 10.1002/cne.22137] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Homeostatic synaptic plasticity (HSP) is important for maintaining neurons' excitability within the dynamic range and for protecting neurons from unconstrained long-term potentiation that can cause breakdown of synapse specificity (Turrigiano [2008] Cell 135:422-435). Knowledge of the molecular mechanism underlying this phenomenon remains incomplete, especially for the rapid form of HSP. To test whether HSP in adulthood depends on an F-actin binding protein, drebrin A, mice deleted of the adult isoform of drebrin (DAKO) but retaining the embryonic isoform (drebrin E) were generated. HSP was assayed by determining whether the NR2A subunit of N-methyl-D-aspartate receptors (NMDARs) can rise rapidly within spines following the application of an NMDAR antagonist, D-APV, onto the cortical surface. Electron microscopic immunocytochemistry revealed that, as expected, the D-APV treatment of wild-type (WT) mouse cortex increased the proportion of NR2A-immunolabeled spines within 30 minutes relative to basal levels in hemispheres treated with an inactive enantiomer, L-APV. This difference was significant at the postsynaptic membrane and postsynaptic density (i.e., synaptic junction) as well as at nonsynaptic sites within spines and was not accompanied by spine size changes. In contrast, the D-APV treatment of DAKO brains did not augment NR2A labeling within the spine cytoplasm or at the synaptic junction, even though basal levels of NR2A were not significantly different from those of WT cortices. These findings indicate that drebrin A is required for the rapid (<30 minutes) form of HSP at excitatory synapses of adult cortices, whereas drebrin E is sufficient for maintaining basal NR2A levels within spines.
Collapse
Affiliation(s)
- Chiye Aoki
- Center for Neural Science, New York University, New York, New York 10003, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
|
43
|
Muller T, Albrecht D, Gebhardt C. Both NR2A and NR2B subunits of the NMDA receptor are critical for long-term potentiation and long-term depression in the lateral amygdala of horizontal slices of adult mice. Learn Mem 2009; 16:395-405. [DOI: 10.1101/lm.1398709] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
44
|
Wilson YM, Murphy M. A discrete population of neurons in the lateral amygdala is specifically activated by contextual fear conditioning. Learn Mem 2009; 16:357-61. [DOI: 10.1101/lm.1361509] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
45
|
Corlew R, Brasier DJ, Feldman DE, Philpot BD. Presynaptic NMDA receptors: newly appreciated roles in cortical synaptic function and plasticity. Neuroscientist 2009; 14:609-25. [PMID: 19029059 DOI: 10.1177/1073858408322675] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Many aspects of synaptic development, plasticity, and neurotransmission are critically influenced by NMDA-type glutamate receptors (NMDARs). Moreover, dysfunction of NMDARs has been implicated in a broad array of neurological disorders, including schizophrenia, stroke, epilepsy, and neuropathic pain. Classically, NMDARs were thought to be exclusively postsynaptic. However, substantial evidence in the past 10 years demonstrates that NMDARs also exist presynaptically and that presynaptic NMDA receptors (preNMDARs) modulate synapse function and have critical roles in plasticity at many synapses. Here the authors review current knowledge of the role of preNMDARs in synaptic transmission and plasticity, focusing on the neocortex. They discuss the prevalence, function, and development of these receptors, and their potential modification by experience and in brain pathology.
Collapse
Affiliation(s)
- Rebekah Corlew
- Curriculum in Neurobiology, Neuroscience Center, University of North Carolina, Chapel Hill, NC 27599-7545, USA
| | | | | | | |
Collapse
|
46
|
Muller JF, Mascagni F, McDonald AJ. Dopaminergic innervation of pyramidal cells in the rat basolateral amygdala. Brain Struct Funct 2008; 213:275-88. [PMID: 18839210 DOI: 10.1007/s00429-008-0196-y] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Accepted: 09/09/2008] [Indexed: 11/26/2022]
Abstract
Dopaminergic (DA) inputs to the basolateral nuclear complex of the amygdala (BLC) are critical for several important functions, including reward-related learning, drug-stimulus learning, and fear conditioning. Despite the importance of the DA projection to the BLC, very little is known about which neuronal subpopulations are innervated. The present study utilized dual-labeling immunohistochemistry at the electron microscopic level to examine DA inputs to pyramidal cells in the anterior basolateral amygdalar nucleus (BLa) in the rat. DA axon terminals and BLa pyramidal cells were labeled using antibodies to tyrosine hydroxylase (TH) and calcium/calmodulin-dependent protein kinase II (CaMK), respectively. Serial section reconstructions of TH-positive (TH+) terminals were performed to determine the extent to which these axon terminals formed synapses versus non-synaptic appositions in the BLa. Our results demonstrate that at least 77% of TH+ terminals form synapses in the BLa, and that 90% of these synapses are with pyramidal cells. The distal dendritic compartment received the great majority of these synaptic contacts, with CaMK+ distal dendrites and spines receiving one-third and one-half, respectively, of all synaptic inputs to pyramidal cells. Many spines receiving innervation from TH+ terminals also received asymmetrical synaptic inputs from putative excitatory terminals. In addition, TH+ terminals often formed non-synaptic appositions with axon terminals, most of which were putatively excitatory in that they were CaMK+ and/or made asymmetrical synapses. Thus, using CaMK as a marker, the present study demonstrates that pyramidal cells, especially their distal dendritic compartments, are the primary targets of dopaminergic inputs to the basolateral amygdala.
Collapse
Affiliation(s)
- Jay F Muller
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, SC 29208, USA
| | | | | |
Collapse
|
47
|
Pérez de la Mora M, Hernández-Gómez AM, Arizmendi-García Y, Jacobsen KX, Lara-García D, Flores-Gracia C, Crespo-Ramírez M, Gallegos-Cari A, Nuche-Bricaire A, Fuxe K. Role of the amygdaloid cholecystokinin (CCK)/gastrin-2 receptors and terminal networks in the modulation of anxiety in the rat. Effects of CCK-4 and CCK-8S on anxiety-like behaviour and [3H]GABA release. Eur J Neurosci 2008; 26:3614-30. [PMID: 18088282 DOI: 10.1111/j.1460-9568.2007.05963.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The amygdala plays a key role in fear and anxiety. The intercalated islands are clusters of glutamate-responsive GABAergic neurons rich in cholecystokinin (CCK)-2 receptors which control the trafficking of nerve impulses from the cerebral cortex to the central nucleus of amygdala. In this study, the nature of the CCK-glutamate-GABA interactions within the rat rostral amygdala, and their relevance for anxiety, were studied. CCK/gastrin-like immunoreactive nerve terminals were found to be mainly restricted to the paracapsular intercalated islands and the rostrolateral part of the main intercalated island. Behaviourally, the bilateral microinjection of CCK-4 (0.043-4.3 pmol/side) or CCK-8S (4.3 pmol/side) into the rostrolateral amygdala reduced the open-arm exploration in the elevated plus-maze without affecting locomotion. In contrast, neither CCK-4 nor CCK-8S (0.043-4.3 pmol/side) had any effects in the shock-probe burying test as compared with their saline-treated controls. Biochemically, CCK-4 (0.3 and 1.5 microm), unlike CCK-8S, enhanced significantly the K(+)-stimulated release of [(3)H]GABA from amygdala slices. These effects were fully prevented by prior superfusion of the slices with either the selective CCK-2 receptor antagonist CR2945 (3 microm), or 6,7-dinitroquinoxaline-2,3(1H,4H)-dione (DNQX), 10 microm, a glutamatergic (+/-)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate receptor antagonist. It is suggested that CCK modulates glutamate-GABA mechanisms by acting on CCK-2 receptors via volume transmission occurring at the level of the basolateral amygdaloid nucleus and/or by synaptic or perisynaptic volume transmission in the region of the rostrolateral main and paracapsular intercalated islands, resulting in subsequent disinhibition of the central amygdaloid nucleus and anxiety or panic-like behaviour.
Collapse
Affiliation(s)
- Miguel Pérez de la Mora
- Department of Biophysics, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Apartado Postal 70-253, México 04510 DF, México.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
48
|
Walker DL, Davis M. Amygdala infusions of an NR2B-selective or an NR2A-preferring NMDA receptor antagonist differentially influence fear conditioning and expression in the fear-potentiated startle test. Learn Mem 2008; 15:67-74. [PMID: 18230675 PMCID: PMC2216678 DOI: 10.1101/lm.798908] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Accepted: 12/02/2007] [Indexed: 11/24/2022]
Abstract
Within the amygdala, most N-methyl-D-aspartic acid (NMDA) receptors consist of NR1 subunits in combination with either NR2A or NR2B subunits. Because the particular subunit composition greatly influences the receptors' properties, we investigated the contribution of both subtypes to fear conditioning and expression. To do so, we infused the NR1/NR2B receptor antagonist CP101,606 (0.5, 1.5, or 4.5 microg/amygdala) or the NR1/NR2A-preferring antagonist NVP-AAM077 (0.075, 0.25, 0.75, or 2.5 microg/amygdala) into the amygdala prior to either fear conditioning (i.e., light-shock pairings) or fear-potentiated startle testing. CP101,606 nonmonotonically disrupted fear conditioning but did not disrupt fear expression. NVP-AAM077 dose-dependently disrupted fear conditioning as well as fear expression. The results suggest that amygdala NR1/NR2B receptors play a special role in fear memory formation, whereas NR1/NR2A receptors participate more generally in synaptic transmission.
Collapse
Affiliation(s)
- David L Walker
- Department of Psychiatry and Behavioral Sciences, School of Medicine, Emory University, Atlanta, Georgia 30329, USA.
| | | |
Collapse
|
49
|
Kim J, Lee S, Park K, Hong I, Song B, Son G, Park H, Kim WR, Park E, Choe HK, Kim H, Lee C, Sun W, Kim K, Shin KS, Choi S. Amygdala depotentiation and fear extinction. Proc Natl Acad Sci U S A 2007; 104:20955-60. [PMID: 18165656 PMCID: PMC2409248 DOI: 10.1073/pnas.0710548105] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2007] [Indexed: 11/18/2022] Open
Abstract
Auditory fear memory is thought to be maintained by fear conditioning-induced potentiation of synaptic efficacy, which involves enhanced expression of surface AMPA receptor (AMPAR) at excitatory synapses in the lateral amygdala (LA). Depotentiation, reversal of conditioning-induced potentiation, has been proposed as a cellular mechanism for fear extinction; however, a direct link between depotentiation and extinction has not yet been tested. To address this issue, we applied both ex vivo and in vivo approaches to rats in which fear memory had been consolidated. A unique form of depotentiation reversed conditioning-induced potentiation at thalamic input synapses onto the LA (T-LA synapses) ex vivo. Extinction returned the enhanced T-LA synaptic efficacy observed in conditioned rats to baseline and occluded the depotentiation. Consistently, extinction reversed conditioning-induced enhancement of surface expression of AMPAR subunits in LA synaptosomal preparations. A GluR2-derived peptide that blocks regulated AMPAR endocytosis inhibited depotentiation, and microinjection of a cell-permeable form of the peptide into the LA attenuated extinction. Our results are consistent with the use of depotentiation to weaken potentiated synaptic inputs onto the LA during extinction and provide strong evidence that AMPAR removal at excitatory synapses in the LA underlies extinction.
Collapse
Affiliation(s)
- Jeongyeon Kim
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Sukwon Lee
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Kyungjoon Park
- Departments of Biology and Biological and Nanopharmaceutical Sciences, Kyunghee University, Seoul 130-701, Korea
| | - Ingie Hong
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Beomjong Song
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Gihoon Son
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Heewoo Park
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Woon Ryoung Kim
- Department of Anatomy, Division of Brain Korea 21 Biomedical Science, College of Medicine, Korea University, Seoul 136-701, Korea; and
| | - Eunjin Park
- Department of Biological Sciences, College of Natural Sciences, Inha University, 253 Yong-Hyun Dong, Nam-Gu, Inchon 402-751, Korea
| | - Han Kyung Choe
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Hyun Kim
- Department of Anatomy, Division of Brain Korea 21 Biomedical Science, College of Medicine, Korea University, Seoul 136-701, Korea; and
| | - Changjoong Lee
- Department of Biological Sciences, College of Natural Sciences, Inha University, 253 Yong-Hyun Dong, Nam-Gu, Inchon 402-751, Korea
| | - Woong Sun
- Department of Anatomy, Division of Brain Korea 21 Biomedical Science, College of Medicine, Korea University, Seoul 136-701, Korea; and
| | - Kyungjin Kim
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| | - Ki Soon Shin
- Departments of Biology and Biological and Nanopharmaceutical Sciences, Kyunghee University, Seoul 130-701, Korea
| | - Sukwoo Choi
- *School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul 151-742, Korea
| |
Collapse
|
50
|
Berninghausen O, Rahman MA, Silva JP, Davletov B, Hopkins C, Ushkaryov YA. Neurexin Ibeta and neuroligin are localized on opposite membranes in mature central synapses. J Neurochem 2007; 103:1855-63. [PMID: 17868325 PMCID: PMC2517655 DOI: 10.1111/j.1471-4159.2007.04918.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Synaptogenesis requires formation of trans-synaptic complexes between neuronal cell-adhesion receptors. Heterophilic receptor pairs, such as neurexin Ibeta and neuroligin, can mediate distinct intracellular signals and form different cytoplasmic scaffolds in the pre- and post-synaptic neuron, and may be particularly important for synaptogenesis. However, the functions of neurexin and neuroligin depend on their distribution in the synapse. Neuroligin has been experimentally assigned to the post-synaptic membrane, while the localization of neurexin remains unclear. To study the subcellular distribution of neurexin Ibeta and neuroligin in mature cerebrocortical synapses, we have developed a novel method for the physical separation of junctional membranes and their direct analysis by western blotting. Using urea and dithiothreitol, we disrupted trans-synaptic protein links, without dissolving the lipid phase, and fractionated the pre- and post-synaptic membranes. The purity of these fractions was validated by electron microscopy and western blotting using multiple synaptic markers. A quantitative analysis has confirmed that neuroligin is localized strictly in the post-synaptic membrane. We have also demonstrated that neurexin Ibeta is largely (96%) pre-synaptic. Thus, neurexin Ibeta and neuroligin normally form trans-synaptic complexes and can transduce bidirectional signals.
Collapse
Affiliation(s)
- Otto Berninghausen
- Division of Cell and Molecular Biology, Imperial College London, London, UK
| | | | | | | | | | | |
Collapse
|