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Kwon KM, Pak JH, Jeon CJ. Immunocytochemical localization of the AMPA glutamate receptor subtype GluR2/3 in the squid optic lobe. Acta Histochem 2022; 124:151941. [PMID: 35963117 DOI: 10.1016/j.acthis.2022.151941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 11/17/2022]
Abstract
As a major excitatory neurotransmitter in the cephalopod visual system, glutamate signaling is facilitated by ionotropic receptors, such as α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPAR). In cephalopods with large and well-developed brains, the optic lobes (OL) mainly process visual inputs and are involved in learning and memory. Although the presence of AMPAR in squid OL has been reported, the organization of specific AMPAR-containing neurons remains unknown. This study aimed to investigate the immunocytochemical localization of the AMPA glutamate receptor subtype 2/3-immunoreactive (GluR2/3-IR) neurons in the OL of Pacific flying squid (Tordarodes pacificus). Morphologically diverse GluR2/3-IR neurons were predominantly located in the tangential zone of the medulla. Medium-to-large GluR2/3-IR neurons were also detected. The distribution patterns and cell morphologies of calcium-binding protein (CBP)-IR neurons, specifically calbindin-D28K (CB)-, calretinin (CR)-, and parvalbumin (PV)-IR neurons, were similar to those of GluR2/3-IR neurons. However, two-color immunofluorescence revealed that GluR2/3-IR neurons did not colocalize with the CBP-IR neurons. Furthermore, the specific localizations and diverse types of GluR2/3-IR neurons that do not express CB, CR, or PV in squid OL were determined. These findings further contribute to the existing data on glutamatergic visual systems and provide new insights for understanding the visual processing mechanisms in cephalopods.
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Affiliation(s)
- Kyung-Min Kwon
- Department of Biology, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, College of Natural Sciences, Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Republic of Korea; Research Institute for Dok-do and Ulleung-do Island, Department of Biology, School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Jae-Hong Pak
- Research Institute for Dok-do and Ulleung-do Island, Department of Biology, School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Chang-Jin Jeon
- Department of Biology, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, College of Natural Sciences, Brain Science and Engineering Institute, Kyungpook National University, Daegu 41566, Republic of Korea; Research Institute for Dok-do and Ulleung-do Island, Department of Biology, School of Life Sciences, Kyungpook National University, Daegu 41566, Republic of Korea.
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Transcriptomic expression of AMPA receptor subunits and their auxiliary proteins in the human brain. Neurosci Lett 2021; 755:135938. [PMID: 33915226 DOI: 10.1016/j.neulet.2021.135938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 11/21/2022]
Abstract
Receptors to glutamate of the AMPA type (AMPARs) serve as the major gates of excitation in the human brain, where they participate in fundamental processes underlying perception, cognition and movement. Due to their central role in brain function, dysregulation of these receptors has been implicated in neuropathological states associated with a large variety of diseases that manifest with abnormal behaviors. The participation of functional abnormalities of AMPARs in brain disorders is strongly supported by genomic, transcriptomic and proteomic studies. Most of these studies have focused on the expression and function of the subunits that make up the channel and define AMPARs (GRIA1-GRIA4), as well of some accessory proteins. However, it is increasingly evident that native AMPARs are composed of a complex array of accessory proteins that regulate their trafficking, localization, kinetics and pharmacology, and a better understanding of the diversity and regional expression of these accessory proteins is largely needed. In this review we will provide an update on the state of current knowledge of AMPA receptors subunits in the context of their accessory proteins at the transcriptome level. We also summarize the regional expression in the human brain and its correlation with the channel forming subunits. Finally, we discuss some of the current limitations of transcriptomic analysis and propose potential ways to overcome them.
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Hadzic M, Jack A, Wahle P. Ionotropic glutamate receptors: Which ones, when, and where in the mammalian neocortex. J Comp Neurol 2016; 525:976-1033. [PMID: 27560295 DOI: 10.1002/cne.24103] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/09/2016] [Accepted: 08/15/2016] [Indexed: 12/14/2022]
Abstract
A multitude of 18 iGluR receptor subunits, many of which are diversified by splicing and RNA editing, localize to >20 excitatory and inhibitory neocortical neuron types defined by physiology, morphology, and transcriptome in addition to various types of glial, endothelial, and blood cells. Here we have compiled the published expression of iGluR subunits in the areas and cell types of developing and adult cortex of rat, mouse, carnivore, bovine, monkey, and human as determined with antibody- and mRNA-based techniques. iGluRs are differentially expressed in the cortical areas and in the species, and all have a unique developmental pattern. Differences are quantitative rather than a mere absence/presence of expression. iGluR are too ubiquitously expressed and of limited use as markers for areas or layers. A focus has been the iGluR profile of cortical interneuron types. For instance, GluK1 and GluN3A are enriched in, but not specific for, interneurons; moreover, the interneurons expressing these subunits belong to different types. Adressing the types is still a major hurdle because type-specific markers are lacking, and the frequently used neuropeptide/CaBP signatures are subject to regulation by age and activity and vary as well between species and areas. RNA-seq reveals almost all subunits in the two morphofunctionally characterized interneuron types of adult cortical layer I, suggesting a fairly broad expression at the RNA level. It remains to be determined whether all proteins are synthesized, to which pre- or postsynaptic subdomains in a given neuron type they localize, and whether all are involved in synaptic transmission. J. Comp. Neurol. 525:976-1033, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Minela Hadzic
- Developmental Neurobiology, Faculty for Biology and Biotechnology ND 6/72, Ruhr University Bochum, 44801, Bochum, Germany
| | - Alexander Jack
- Developmental Neurobiology, Faculty for Biology and Biotechnology ND 6/72, Ruhr University Bochum, 44801, Bochum, Germany
| | - Petra Wahle
- Developmental Neurobiology, Faculty for Biology and Biotechnology ND 6/72, Ruhr University Bochum, 44801, Bochum, Germany
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Inhibitory interneuron classes express complementary AMPA-receptor patterns in macaque primary visual cortex. J Neurosci 2014; 34:6303-15. [PMID: 24790201 DOI: 10.1523/jneurosci.3188-13.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Glutamate receptors mediate excitatory neurotransmission. A very prevalent type of glutamate receptor in the neocortex is the AMPA receptor (AMPAR). AMPARs mediate fast synaptic transmission and their functionality depends on the subunit composition. In primary visual cortex (area V1), the density and subunit composition of AMPARs differ among cortical layers and among cell types. The AMPARs expressed by the different types of inhibitory interneurons, which are crucial for network function, have not yet been characterized systematically. We investigated the distribution of AMPAR subunits in macaque V1 for three distinct subpopulations of inhibitory interneurons: parvalbumin-immunoreactive (PV-IR) interneurons, calbindin-immunoreactive (CB-IR) interneurons, and calretinin-immunoreactive (CR-IR) interneurons. We found that PV-IR cells, which have previously been identified as fast spiking, show high expression of the GluA2 and GluA3 subunits. In contrast, CB-IR and CR-IR cells, which tend to be intermediate spiking, show high expression of the GluA1 and GluA4 subunits. Thus, our data demonstrate that the expression of AMPARs divides inhibitory interneurons in macaque V1 into two categories that are compatible with existing classification methods based on calcium-binding proteins and firing behavior. Moreover, our findings suggest new approaches to target the different inhibitory interneuron classes pharmacologically in vivo.
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Isayama RN, Leite PEC, Lima JPM, Uziel D, Yamasaki EN. Impact of ethanol on the developing GABAergic system. Anat Rec (Hoboken) 2010; 292:1922-39. [PMID: 19943346 DOI: 10.1002/ar.20966] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Alcohol intake during pregnancy has a tremendous impact on the developing brain. Embryonic and early postnatal alcohol exposures have been investigated experimentally to elucidate the fetal alcohol spectrum disorders' (FASD) milieu, and new data have emerged to support a devastating effect on the GABAergic system in the adult and developing nervous system. GABA is a predominantly inhibitory neurotransmitter that during development excites neurons and orchestrates several developmental processes such as proliferation, migration, differentiation, and synaptogenesis. This review summarizes and brings new data on neurodevelopmental aspects of the GABAergic system with FASD in experimental telencephalic models.
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Affiliation(s)
- Ricardo Noboro Isayama
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Newpher TM, Ehlers MD. Glutamate receptor dynamics in dendritic microdomains. Neuron 2008; 58:472-97. [PMID: 18498731 PMCID: PMC2572138 DOI: 10.1016/j.neuron.2008.04.030] [Citation(s) in RCA: 278] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 04/28/2008] [Accepted: 04/30/2008] [Indexed: 01/08/2023]
Abstract
Among diverse factors regulating excitatory synaptic transmission, the abundance of postsynaptic glutamate receptors figures prominently in molecular memory and learning-related synaptic plasticity. To allow for both long-term maintenance of synaptic transmission and acute changes in synaptic strength, the relative rates of glutamate receptor insertion and removal must be tightly regulated. Interactions with scaffolding proteins control the targeting and signaling properties of glutamate receptors within the postsynaptic membrane. In addition, extrasynaptic receptor populations control the equilibrium of receptor exchange at synapses and activate distinct signaling pathways involved in plasticity. Here, we review recent findings that have shaped our current understanding of receptor mobility between synaptic and extrasynaptic compartments at glutamatergic synapses, focusing on AMPA and NMDA receptors. We also examine the cooperative relationship between intracellular trafficking and surface diffusion of glutamate receptors that underlies the expression of learning-related synaptic plasticity.
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Affiliation(s)
- Thomas M. Newpher
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Michael D. Ehlers
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
- Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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King AE, Chung RS, Vickers JC, Dickson TC. Localization of glutamate receptors in developing cortical neurons in culture and relationship to susceptibility to excitotoxicity. J Comp Neurol 2006; 498:277-94. [PMID: 16856139 DOI: 10.1002/cne.21053] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Overactivation of glutamate receptors leading to excitotoxicity has been implicated in the neurodegenerative alterations of a range of central nervous system (CNS) disorders. We have investigated the cell-type-specific changes in glutamate receptor localization in developing cortical neurons in culture, as well as the relationship between glutamate receptor subunit distribution with synapse formation and susceptibility to excitotoxicity. Glutamate receptor subunit clustering was present prior to the formation of synapses. However, different receptor types showed distinctive temporal patterns of subunit clustering, localization to spines, and apposition to presynaptic terminals. N-methyl-D-aspartate (NMDA) receptor subunit immunolabelling was present in puncta along dendrites prior to the formation of synapses, with relatively little localization to spines. Vulnerability to NMDA receptor-mediated excitotoxicity occurred before receptor subunits became localized in apposition to presynaptic terminals. Clustering of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors occurred concurrently with development of vulnerability to excitotoxicity and was related to localization of AMPA receptors at synapses and in spines. Different AMPA receptor subunits demonstrated cell-type-specific localization as well as distribution to spines, dendrites, and extrasynaptic subunit clusters. A subclass of neurons demonstrated substantial perineuronal synaptic innervation, and these neurons expressed relatively high levels of GluR1 and/or GluR4 at receptor puncta, indicating the presence of calcium-permeable AMPA receptors and suggesting alternative synaptic signalling mechanisms and vulnerability to excitotoxicity. These data demonstrate the relationship between glutamate receptor subunit expression and localization with synaptogenesis and development of neuronal susceptibility to excitotoxicity. These data also suggest that excitotoxicity can be mediated through extrasynaptic receptor subunit complexes along dendrites.
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Affiliation(s)
- A E King
- NeuroRepair Group, University of Tasmania, Hobart, Tasmania 7001, Australia
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Telfeian AE, Tseng HC, Baybis M, Crino PB, Dichter MA. Differential expression of GABA and glutamate-receptor subunits and enzymes involved in GABA metabolism between electrophysiologically identified hippocampal CA1 pyramidal cells and interneurons. Epilepsia 2003; 44:143-9. [PMID: 12558566 DOI: 10.1046/j.1528-1157.2003.06102.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE The balance between synaptic excitation and inhibition within the hippocampus is critical for maintaining normal hippocampal function. Even mild reduction in inhibition or enhancement of excitation can produce seizures. Synaptic excitation is produced by pyramidal cells and granule cells, whereas inhibition is produced by a smaller number of interneurons. To understand how two subpopulations of these excitatory and inhibitory neurons are regulated at the molecular level, we analyzed specific mRNA expression profiles for receptors that are significantly involved in synaptic transmission and in the synthesis and storage of the principal inhibitory neurotransmitter, gamma-aminobutyric acid (GABA). Our hypothesis was that differences in gene expression between inhibitory and excitatory neurons in the rat hippocampus might point to specific new targets for seizure pharmacotherapy. METHODS We combined the techniques of (a) whole-cell patch clamping in rat hippocampal slices, (b) biocytin staining for cell identification, (c) single-cell mRNA amplification, and (d) small-scale cDNA microarray analysis to allow us to obtain expression profiles for candidate genes from identified CA1 pyramidal neurons and interneurons. Electrophysiologic and morphologic data and expression profiles were obtained from 12 stratum pyramidale and seven stratum radiatum cells. RESULTS Presumed inhibitory neurons expressed significantly more GAD65, GAD67, vGAT, GABA(A)-receptor alpha3, and N-methyl-d-aspartate (NMDA)-receptor IIB mRNA, and presumed excitatory neurons expressed more GABA(A)-receptor alpha1, and NMDA-receptor I mRNA. CONCLUSIONS Differential expression of candidate neurotransmitter-receptor subunits distinguished CA1 pyramidal neurons from interneurons. These differences may indicate potential new targets for altering the balance of inhibition and excitation in the treatment of epilepsy.
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Affiliation(s)
- Albert E Telfeian
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania 19104, U.S.A
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Hof PR, Duan H, Page TL, Einstein M, Wicinski B, He Y, Erwin JM, Morrison JH. Age-related changes in GluR2 and NMDAR1 glutamate receptor subunit protein immunoreactivity in corticocortically projecting neurons in macaque and patas monkeys. Brain Res 2002; 928:175-86. [PMID: 11844485 DOI: 10.1016/s0006-8993(01)03345-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A distinct subpopulation of neurons forming long corticocortical projections in the association neocortex is highly vulnerable to the degenerative process in Alzheimer's disease. However, the degree to which age-related molecular and morphologic alterations of identifiable neuronal populations reflects early cellular degeneration leading to functional deficits has not yet been fully investigated in the aging brain. We performed an immunohistochemical analysis of neurons forming short and long corticocortical projections in young and old monkeys using antibodies to the GluR2 and NMDAR1 glutamate receptor subunit proteins. Projection neurons differed in their expression of these receptor subunits, as GluR2 was less prevalent than NMDAR1 among retrogradely labeled neurons. Long and short corticocortical pathways in old animals demonstrated a considerable decrease in the proportions of projection neurons containing GluR2 and NMDAR1, an observation that was particularly consistent in the case of GluR2. No age-related differences were observed in distribution of neurofilament protein in either type of projection neurons. These data suggest that cortical neurons furnishing long and short corticocortical projections display consistent neurochemical changes during aging and that a differential decrease in cellular expression of glutamate receptor subunit proteins occurs. The fact that in aging these neurons have lower levels of GluR2 than in young individuals, but comparatively higher levels of NMDAR1 than GluR2, may render them prone to calcium-mediated excitotoxicity, which in humans may be related to the selective vulnerability of such neurons during the course of Alzheimer's disease. Also, it is apparent that age-related neuronal changes are quite subtle and involve subcellular components of the cortical circuits rather than major morphologic alterations.
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Affiliation(s)
- Patrick R Hof
- Kastor Neurobiology of Aging Laboratories, Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, Box 1639, One Gustave L. Levy Place, New York, NY 10029, USA.
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