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Burmeister AR, Johnson MB, Chauhan VS, Moerdyk-Schauwecker MJ, Young AD, Cooley ID, Martinez AN, Ramesh G, Philipp MT, Marriott I. Human microglia and astrocytes constitutively express the neurokinin-1 receptor and functionally respond to substance P. J Neuroinflammation 2017; 14:245. [PMID: 29237453 PMCID: PMC5729418 DOI: 10.1186/s12974-017-1012-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/23/2017] [Indexed: 12/30/2022] Open
Abstract
Background The tachykinin substance P (SP) is recognized to exacerbate inflammation at peripheral sites via its target receptor, neurokinin 1 receptor (NK-1R), expressed by leukocytes. More recently, SP/NK-1R interactions have been associated with severe neuroinflammation and neuronal damage. We have previously demonstrated that NK-1R antagonists can limit neuroinflammatory damage in a mouse model of bacterial meningitis. Furthermore, we have since shown that these agents can attenuate bacteria-induced neuronal and glial inflammatory mediator production in nonhuman primate (NHP) brain explants and isolated neuronal cells, and following in vivo infection. Methods In the present study, we have assessed the ability of NHP brain explants, primary human microglia and astrocytes, and immortalized human glial cell lines to express NK-1R isoforms. We have utilized RT-PCR, immunoblot analysis, immunofluorescent microscopy, and/or flow cytometric analysis, to quantify NK-1R expression in each, at rest, or following bacterial challenge. Furthermore, we have assessed the ability of human microglia to respond to SP by immunoblot analysis of NF-kB nuclear translocation and determined the ability of this neuropeptide to augment inflammatory cytokine release and neurotoxic mediator production by human astrocytes using an ELISA and a neuronal cell toxicity assay, respectively. Results We demonstrate that human microglial and astrocytic cells as well as NHP brain tissue constitutively express robust levels of the full-length NK-1R isoform. In addition, we demonstrate that the expression of NK-1R by human astrocytes can be further elevated following exposure to disparate bacterial pathogens or their components. Importantly, we have demonstrated that NK-1R is functional in both human microglia and astrocytes and show that SP can augment the inflammatory and/or neurotoxic immune responses of glial cells to disparate and clinically relevant bacterial pathogens. Conclusions The robust constitutive and functional expression of the full-length NK-1R isoform by human microglia and astrocytes, and the ability of SP to augment inflammatory signaling pathways and mediator production by these cells, support the contention that SP/NK-1R interactions play a significant role in the damaging neuroinflammation associated with conditions such as bacterial meningitis.
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Affiliation(s)
- Amanda R Burmeister
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - M Brittany Johnson
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - Vinita S Chauhan
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - Megan J Moerdyk-Schauwecker
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - Ada D Young
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - Ian D Cooley
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA
| | - Alejandra N Martinez
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Covington, LA, USA
| | - Geeta Ramesh
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Covington, LA, USA
| | - Mario T Philipp
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Covington, LA, USA
| | - Ian Marriott
- Department of Biological Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC, 28223, USA.
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Johnson MB, Young AD, Marriott I. The Therapeutic Potential of Targeting Substance P/NK-1R Interactions in Inflammatory CNS Disorders. Front Cell Neurosci 2017; 10:296. [PMID: 28101005 PMCID: PMC5209380 DOI: 10.3389/fncel.2016.00296] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 12/13/2016] [Indexed: 12/27/2022] Open
Abstract
The inflammatory responses of resident central nervous system (CNS) cells are now known to play a critical role in the initiation and progression of an array of infectious and sterile neuroinflammatory disorders such as meningitis, encephalitis, Parkinson's disease, Alzheimer's disease and multiple sclerosis (MS). Regulating glial inflammatory responses in a timely manner is therefore critical in preserving normal CNS functions. The neuropeptide substance P is produced at high levels within the CNS and its selective receptor, the neurokinin 1 receptor (NK-1R), is abundantly expressed by neurons and is present on glial cell types including microglia and astrocytes. In addition to its functions as a neurotransmitter in the perception of pain and its essential role in gut motility, this tachykinin is widely recognized to exacerbate inflammation at peripheral sites including the skin, gastrointestinal tract and the lungs. Recently, a number of studies have identified a role for substance P and NK-1R interactions in neuroinflammation and described the ability of this neuropeptide to alter the immune functions of activated microglia and astrocytes. In this review article, we describe the expression of substance P and its receptor by resident CNS cells, and we discuss the ability of this neuropeptide to exacerbate the inflammatory responses of glia and immune cells that are recruited to the brain during neurodegenerative diseases. In addition, we discuss the available data indicating that the NK-1R-mediated augmentation of such responses appears to be detrimental during microbial infection and some sterile neurodegenerative disorders, and propose the repurposed use of NK-1R antagonists, of a type that are currently approved as anti-emetic and anti-anxiolytic agents, as an adjunct therapy to ameliorate the inflammatory CNS damage in these conditions.
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Affiliation(s)
- M Brittany Johnson
- Department of Biological Sciences, The University of North Carolina at Charlotte Charlotte, NC, USA
| | - Ada D Young
- Department of Biological Sciences, The University of North Carolina at Charlotte Charlotte, NC, USA
| | - Ian Marriott
- Department of Biological Sciences, The University of North Carolina at Charlotte Charlotte, NC, USA
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Hamity MV, Walder RY, Hammond DL. Increased neuronal expression of neurokinin-1 receptor and stimulus-evoked internalization of the receptor in the rostral ventromedial medulla of the rat after peripheral inflammatory injury. J Comp Neurol 2015; 522:3037-51. [PMID: 24639151 DOI: 10.1002/cne.23564] [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: 10/24/2013] [Revised: 01/31/2014] [Accepted: 02/18/2014] [Indexed: 12/28/2022]
Abstract
This study examined possible mechanisms by which Substance P (Sub P) assumes a pronociceptive role in the rostral ventromedial medulla (RVM) under conditions of peripheral inflammatory injury, in this case produced by intraplantar (ipl) injection of complete Freund's adjuvant (CFA). In saline- and CFA-treated rats, neurokinin-1 receptor (NK1R) immunoreactivity was localized to neurons in the RVM. Four days after ipl injection of CFA, the number of NK1R-immunoreactive neurons in the RVM was increased by 30%, and there was a concomitant increase in NK1R-immunoreactive processes in CFA-treated rats. Although NK1R immunoreactivity was increased, tachykinin-1 receptor (Tacr1) mRNA was not increased in the RVM of CFA-treated rats. To assess changes in Sub P release, the number of RVM neurons that exhibited NK1R internalization was examined in saline- and CFA-treated rats following noxious heat stimulation of the hind paws. Only CFA-treated rats that experienced noxious heat stimulation exhibited a significant increase in the number of neurons showing NK1R internalization. These data suggest that tonic Sub P release is not increased as a simple consequence of peripheral inflammation, but that phasic or evoked release of Sub P in the RVM is increased in response to noxious peripheral stimulation in a persistent inflammatory state. These data support the proposal that an upregulation of the NK1R in the RVM, as well as enhanced release of Sub P following noxious stimulation, underlie the pronociceptive role of Sub P under conditions of persistent inflammatory injury.
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Affiliation(s)
- Marta V Hamity
- Department of Anesthesia, University of Iowa, Iowa City, Iowa, 52242
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4
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Nicotra L, Loram LC, Watkins LR, Hutchinson MR. Toll-like receptors in chronic pain. Exp Neurol 2011; 234:316-29. [PMID: 22001158 DOI: 10.1016/j.expneurol.2011.09.038] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Revised: 09/26/2011] [Accepted: 09/30/2011] [Indexed: 12/16/2022]
Abstract
Proinflammatory central immune signaling contributes significantly to the initiation and maintenance of heightened pain states. Recent discoveries have implicated the innate immune system, pattern recognition Toll-like receptors in triggering these proinflammatory central immune signaling events. These exciting developments have been complemented by the discovery of neuronal expression of Toll-like receptors, suggesting pain pathways can be activated directly by the detection of pathogen associated molecular patterns or danger associated molecular patterns. This review will examine the evidence to date implicating Toll-like receptors and their associated signaling components in heightened pain states. In addition, insights into the impact Toll-like receptors have on priming central immune signaling systems for heightened pain states will be discussed. The influence possible sex differences in Toll-like receptor signaling have for female pain and the recognition of small molecule xenobiotics by Toll-like receptors will also be reviewed.
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Affiliation(s)
- Lauren Nicotra
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, South Australia, 5005, Australia
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5
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Anatomically specific patterns of glial activation in the periaqueductal gray of the sub-population of rats showing pain and disability following chronic constriction injury of the sciatic nerve. Neuroscience 2010; 166:1167-84. [PMID: 20109535 DOI: 10.1016/j.neuroscience.2010.01.045] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 01/07/2010] [Accepted: 01/21/2010] [Indexed: 11/21/2022]
Abstract
Neuropathic pain conditions for which treatment is sought are characterized by complex behavioural disturbances, as well as "pain." Recent studies using chronic constriction injury of the sciatic nerve have shown that rats develop three distinct patterns of disability characterized by changes in social-interactions and sleep-wake cycle behaviours post-injury: (i) Persistent Disability, (ii) Transient Disability and (iii) No Disability. These patterns occur despite all rats showing identical levels of allodynia and hyperalgesia (i.e., pain). In rats, social-interactions and sleep-wake cycle behaviours are regulated in part, by neural networks, which converge on the periaqueductal grey (PAG). We sought therefore to identify neural adaptations in the PAG, 6 days following chronic constriction injury (CCI), the time at which rats in which disabilities persist are first distinguished from those without disabilities (i.e., No Disability and Transient Disability). GeneChips, RT-PCR and Western blotting revealed the select up-regulation in translation and transcription of glial fibrillary acidic protein (GFAP) and Vimentin in rats with Persistent Disability. Significant increases in GFAP immunoreactivity were localized histologically to the lateral and caudal ventrolateral columns of the PAG. This anatomically specific pattern of increased GFAP suggests activation of astrocytes by select neural pathways, which likely include afferents of both spinal and nucleus of the solitary tract (NTS) origin. The PAG columns in which astrocytes are activated play significant roles in modulating both social-interactions and the sleep-wake cycle. It is possible therefore that the persistent disabilities seen in a subgroup of CCI rats are in part a functional consequence of this specific pattern of astrocyte activation.
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GUO CHANGJIANG, DOUGLAS STEVEND, GAO ZHIYONG, WOLF BRYANA, GRINSPAN JUDITH, LAI JIANPING, RIEDEL ERIC, HO WENZHE. Interleukin-1beta upregulates functional expression of neurokinin-1 receptor (NK-1R) via NF-kappaB in astrocytes. Glia 2005; 48:259-66. [PMID: 15390113 PMCID: PMC4016813 DOI: 10.1002/glia.20079] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cytokines and neuropeptides are modulators of neuroimmunoregulation in the central nervous system (CNS). The interaction of these modulators may have important implications in CNS diseases. We investigated whether interleukin-1beta (IL-1beta) modulates the expression of neurokinin-1 receptor (NK-1R), the primary receptor for substance P (SP), a potent neuropeptide in the CNS. IL-1beta upregulated NK-1R expression in human astroglioma cells (U87 MG) and primary rat astrocytes at both mRNA and protein levels. IL-1beta treatment of U87 MG cells and primary rat astrocytes led to an increase in cytosolic Ca(2+) in response to SP stimulation, indicating that IL-1beta-induced NK-1R is functional. CP-96,345, a specific non-peptide NK-1R antagonist, inhibited SP-induced rise of [Ca(2+)](i) in the astroglioma cells. Investigation of the mechanism responsible for IL-1beta action revealed that IL-1beta has the ability of activating nuclear factor-kappab (NF-kappaB). Caffeic acid phenethyl ester (CAPE), a specific inhibitor of NF-kappaB activation, not only abrogated IL-1beta-induced NF-kappaB promoter activation, but also blocked IL-1beta-mediated induction of NK-1R gene expression. These findings provide additional evidence that there is a biological interaction between IL-1beta and the neuropeptide SP in the CNS, which may have important implications in the inflammatory diseases in the CNS.
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Affiliation(s)
- CHANG-JIANG GUO
- Division of Allergy and Immunology, Department of Pediatrics, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - STEVEN D. DOUGLAS
- Division of Allergy and Immunology, Department of Pediatrics, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - ZHIYONG GAO
- Departments of Pathology and Laboratory Medicine, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - BRYAN A. WOLF
- Departments of Pathology and Laboratory Medicine, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - JUDITH GRINSPAN
- Neurology and Neurology Research, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - JIAN-PING LAI
- Division of Allergy and Immunology, Department of Pediatrics, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - ERIC RIEDEL
- Division of Allergy and Immunology, Department of Pediatrics, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
| | - WEN-ZHE HO
- Division of Allergy and Immunology, Department of Pediatrics, Joseph Stokes Jr. Research Institute of Children’s Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania
- Correspondence to: Wen-Zhe Ho, Division of Allergy-Immunology, Children’s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, Philadelphia, PA 19104.
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Scotti Campos L. Evidence for astrocyte heterogeneity: a distinct subpopulation of protoplasmic-like glial cells is detected in transgenic mice expressing Lmo1-lacZ. Glia 2003; 43:195-207. [PMID: 12898699 DOI: 10.1002/glia.10254] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The adult mammalian central nervous system (CNS) contains a large number of different cell types, which arise from the ventricular (VZ) and subventricular zones during embryonic development. In this study, we used a transgenic mouse expressing Lmo1-LacZ from a randomly inserted promoter/reporter gene construct to identify a glial subpopulation. LMO1 is an LIM domain-containing protein, thought to act in protein-protein interactions. We found first that in the adult transgenic CNS, beta-galactosidase (beta-gal) was expressed in a specific subpopulation of protoplasmic-like cells, which did not express detectable levels of glial fibrilary acidic protein unless a lesion was produced. Secondly, during development, beta-gal(+) cells were found arising from discrete regions of the VZ. Taken together, these results identify a subpopulation of protoplasmic glial cells in the adult CNS and suggest that they arise from a restricted VZ region during CNS development.
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8
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Rasley A, Bost KL, Olson JK, Miller SD, Marriott I. Expression of functional NK-1 receptors in murine microglia. Glia 2002; 37:258-67. [PMID: 11857684 DOI: 10.1002/glia.10034] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Cells of myeloid origin such as microglia have the potential to contribute significantly to the development of inflammatory responses in the CNS. The ability of the neuropeptide substance P to augment proinflammatory responses by other myeloid cell types such as macrophages and dendritic cells is well recognized. In the present study, we demonstrate the presence of mRNA encoding NK-1 (substance P) receptors in murine microglia cell lines. Importantly, we have utilized specific antibodies developed by our laboratory to detect the expression of the NK-1 receptor protein in murine microglia cell lines by Western blot analysis and flow cytometry. Furthermore, we have investigated the presence of this receptor on primary murine microglia and report the presence of authentic NK-1 receptors as determined by Western blot analysis and flow cytometry. In addition, we demonstrate that NK-1 receptors expressed on microglia are functional as demonstrated by the ability of nanomolar concentrations of substance P to initiate activation of the transcriptional activator, NF-kappaB. Given the weight of evidence supporting the role of substance P--substance P receptor interactions in the initiation of optimal proinflammatory responses by myeloid cells, the demonstration of authentic and functional NK-1 receptors in microglia identifies this neuropeptide as a potentially important contributor to CNS inflammatory responses during disease states.
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Affiliation(s)
- Amy Rasley
- Department of Biology, University of North Carolina at Charlotte, Charlotte, North Carolina 28223, USA
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9
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Uezono Y, Nakamura E, Ueda Y, Shibuya I, Ueta Y, Yokoo H, Yanagita T, Toyohira Y, Kobayashi H, Yanagihara N, Wada A. Production of cAMP by adrenomedullin in human oligodendroglial cell line KG1C: comparison with calcitonin gene-related peptide and amylin. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2001; 97:59-69. [PMID: 11744163 DOI: 10.1016/s0169-328x(01)00288-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The actions and the presence of adrenomedullin (AM) were investigated in cultured human oligodendroglial cell line KG1C. AM and AM mRNA were detected in KG1C cells by immunohistochemistry and RT-PCR. mRNAs for calcitonin receptor-like receptor (CRLR) and receptor-activity-modifying proteins (RAMPs) 1, 2 and 3 but not for calcitonin receptors were detected in the cells, while mRNAs for CRLR, calcitonin receptors and all RAMPs were detected in the human cerebellum. Application of AM resulted in time- and concentration-dependent increases in the cAMP level of KG1C cells. Calcitonin gene-related peptide (CGRP) and amylin, peptides structurally related to AM, also increased cAMP. The potencies for the cAMP production of the three peptides were CGRP > or =AM >> amylin with EC(50) of 8, 18, 90 nM, respectively. The responses induced by AM were strongly inhibited by the CGRP(1) receptor antagonist human CGRP(8-37), and inhibited also by the AM receptor antagonist human AM(22-52). In contrast, the responses induced by CGRP or amylin were inhibited only by CGRP(8-37) and not by AM(22-52). The responses induced by all three peptides were unaffected by the amylin receptor antagonist human amylin(8-37). The CGRP(2) receptor agonist human [Cys(Acm)(2,7)]CGRP significantly increased the cAMP level but the increase was smaller than that caused by CGRP. This increase in cAMP was unaffected by CGRP(8-37), AM(22-52) or by amylin(8-37). These results suggest that in KG1C cells, AM increases cAMP through AM and CGRP(1) receptors, whereas CGRP does so through CGRP(1) and CGRP(2) receptors, and amylin exerts its effects through CGRP(1) receptors. Collectively, these findings imply that AM released from oligodendroglial cells may play a role in the regulation of oligodendrocytes via autocrine/paracrine through AM receptors and CGRP(1) receptors.
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Affiliation(s)
- Y Uezono
- Department of Pharmacology, Miyazaki Medical College, 5200 Kihara, 889-1692, Kiyotake, Japan.
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10
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Abstract
Pain is classically viewed as being mediated solely by neurons, as are other sensory phenomena. The discovery that spinal cord glia (microglia and astrocytes) amplify pain requires a change in this view. These glia express characteristics in common with immune cells in that they respond to viruses and bacteria, releasing proinflammatory cytokines, which create pathological pain. These spinal cord glia also become activated by certain sensory signals arriving from the periphery. Similar to spinal infection, these signals cause release of proinflammatory cytokines, thus creating pathological pain. Taken together, these findings suggest a new, dramatically different approach to pain control, as all clinical therapies are focused exclusively on altering neuronal, rather than glial, function.
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Affiliation(s)
- L R Watkins
- Dept of Psychology & the Center for Neurosciences, University of Colorado at, Boulder, CO, USA.
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Affiliation(s)
- M S Rao
- Department of Neurobiology and Anatomy, University of Utah Medical School, Salt Lake City 84132, USA.
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Horie M, Miyashita T, Watabe K, Takeda Y, Kawamura K, Kawano H. Immunohistochemical localization of substance P receptors in the midline glia of the developing rat medulla oblongata with special reference to the formation of raphe nuclei. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2000; 121:197-207. [PMID: 10876032 DOI: 10.1016/s0165-3806(00)00048-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Immunohistochemical localization of the substance P receptor (SPR) was examined in the developing rat medulla oblongata, with special reference to the development of substance P (SP)-immunoreactive neurons which form the medullary raphe nuclei. During development, SPR immunoreactivity was detected in cells lying lateral to the medullary midline from embryonic day 13 (E13) to postnatal day 5 (P5). The SPR-positive cell bodies were located close to the fourth ventricle, and bore long processes extending to the ventral pial surface. This SPR immunoreactivity co-localized with staining for monoclonal antibody 1D11, a specific marker of immature astrocytes. Substance P (SP)-immunoreactive neurons were first detected at E14 in the ventrolateral part of the medulla. By E16 their number had increased and they were arrayed in two rows closely parallel to the SPR-immunoreactive processes of non-neuronal cells. By P1, two separate SP-immunoreactive cell clusters could be recognized at the midline, representing dorsally the nascent raphe pallidus and ventrally the raphe obscurus. In addition, many SP-immunoreactive fibers traveled rostrocaudally in the medulla oblongata, juxtaposed to the midline sheets of SPR-immunoreactive long processes. SPR-immunoreactive processes at the midline were also immunoreactive for S-100, a glia-specific calcium-binding protein that is known to promote axonal growth of raphe neurons. These results suggest that SPR-expressing immature glial cells at the medullary midline are involved in the development of SP-immunoreactive raphe neurons, both in the formation of the medullary raphe nuclei and in axon guidance and growth.
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Affiliation(s)
- M Horie
- Department of Developmental Morphology, Tokyo Metropolitan Institute for Neuroscience, 183-8526, Fuchu, Japan
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Dirig DM, Yaksh TL. In vitro prostanoid release from spinal cord following peripheral inflammation: effects of substance P, NMDA and capsaicin. Br J Pharmacol 1999; 126:1333-40. [PMID: 10217526 PMCID: PMC1565904 DOI: 10.1038/sj.bjp.0702427] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. Spinal prostanoids are implicated in the development of thermal hyperalgesia after peripheral injury, but the specific prostanoid species that are involved are presently unknown. The current study used an in vitro spinal superfusion model to investigate the effect of substance P (SP), N-methyl-d-aspartate (NMDA), and capsaicin on multiple prostanoid release from dorsal spinal cord of naive rats as well as rats that underwent peripheral injury and inflammation (knee joint kaolin/carrageenan). 2. In naive rat spinal cords, PGE2 and 6-keto-PGF1alpha, but not TxB2, levels were increased after inclusion of SP, NMDA, or capsaicin in the perfusion medium. 3. Basal PGE2 levels from spinal cords of animals that underwent 5-72 h of peripheral inflammation were elevated relative to age-matched naive cohorts. The time course of this increase in basal PGE2 levels coincided with peripheral inflammation, as assessed by knee joint circumference. Basal 6-keto-PGF1alpha levels were not elevated after injury. 4. From this inflammation-evoked increase in basal PGE2 levels, SP and capsaicin significantly increased spinal PGE2 release in a dose-dependent fashion. Capsaicin-evoked increases were blocked dose-dependently by inclusion of S(+) ibuprofen in the capsaicin-containing perfusate. 5. These data suggest a role for spinal PGE2 and NK-1 receptor activation in the development of hyperalgesia after injury and demonstrate that this relationship is upregulated in response to peripheral tissue injury and inflammation.
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Affiliation(s)
- David M Dirig
- Department of Pharmacology, University of California San Diego, 9500 Gilman Drive, Mail Code 0818 La Jolla, California 92093-0818, U.S.A
| | - Tony L Yaksh
- Department of Pharmacology, University of California San Diego, 9500 Gilman Drive, Mail Code 0818 La Jolla, California 92093-0818, U.S.A
- Department of Anesthesiology, University of California San Diego, 9500 Gilman Drive, Mail Code 0818 La Jolla, California 92093-0818, U.S.A
- Author for correspondence:
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Barnea A, Aguila-Mansilla N, Bigio EH, Worby C, Roberts J. Evidence for regulated expression of neuropeptide Y gene by rat and human cultured astrocytes. REGULATORY PEPTIDES 1998; 75-76:293-300. [PMID: 9802422 DOI: 10.1016/s0167-0115(98)00081-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A series of studies from our laboratory have established that fetal rat and human neuropeptide Y (NPY) cortical neurons in aggregate cultures are differentially regulated. In a preliminary study we found that primary astrocytes produce substantial amounts of immunoreactive (IR) NPY. We addressed the question: Is astrocyte production of NPY-IR a regulated process? The effects of brain-derived neurotrophic factor (BDNF, 50 ng/ml), basic fibroblast growth factor (bFGF), substance P (1 microM), forskolin (10 microM), or phorbol 12-myristate-13-acetate (PMA, 20 nM) on NPY-IR production was tested on rat and human primary astrocyte cultures. Of these agents, PMA and bFGF markedly induced NPY-IR production by rat as well as human astrocytes, forskolin induced NPY-IR production by human but not rat astrocytes, and neither BDNF nor substance P induced NPY-IR production by rat or human astrocytes. The molecular size of PMA-induced NPY-IR was found to be consistent with that of proNPY. Moreover, PMA induced the accumulation of mRNA corresponding in size to the neuronal NPY-mRNA. Immunocytochemical analysis of human post-mortem neocortex revealed co-existence of NPY-IR with astrocyte markers. These results indicate that cultured astrocytes express NPY gene in a regulated manner and they support our proposition that in situ reactive astrocytes may express NPY gene under some physiological/pathological conditions.
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Affiliation(s)
- A Barnea
- Department of Obstetrics and Gynecology, The University of Texas Southwestern Medical Center at Dallas, 75235-9032, USA.
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15
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Barbaresi P. Immunocytochemical localization of substance P receptor in rat periaqueductal gray matter: a light and electron microscopic study. J Comp Neurol 1998; 398:473-90. [PMID: 9717704 DOI: 10.1002/(sici)1096-9861(19980907)398:4<473::aid-cne2>3.0.co;2-#] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The distribution of substance P receptor (SPR) protein in the rat periaqueductal gray matter (PAG) was investigated with a polyclonal antibody in the four subdivisions obtained by cytochrome-oxidase histochemistry (Co-hi). At light microscopic analysis, immunoreactivity appeared particularly dense in the dorsal subdivision of the PAG, was less intense in the other subdivisions, and formed several longitudinally organized columns. SPR-like immunoreactivity (SP(R-i)) was localized mostly to cell bodies and dendrites of small and medium-sized neurons, which constituted about 6% of the total neuronal population of the PAG. At the electron microscopic level, SP(R-i) could be observed on postsynaptic as well as on nonsynaptic regions of both cell bodies and dendrites. A small proportion of axons (4.2%) and axon terminals (5.3%) showed SP(R-i), the majority of labeled axon terminals, amounting to about 70% of synapsing elements, formed asymmetric synapses with dendrites. Rare astroglial processes displaying SP(R-i) were also observed scattered throughout the neuropil of all PAG subdivisions. Our observations suggest that 1) also in the PAG, SP may act in a diffuse, nonsynaptic manner, probably on targets that are distant from its sites of release; and 2) SP may modulate excitatory neurotransmission acting presynaptically on those labeled axons that form asymmetric synapses.
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Affiliation(s)
- P Barbaresi
- Institute of Human Physiology, University of Ancona, Italy.
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16
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Abstract
Glial cells respond to various electrical, mechanical, and chemical stimuli, including neurotransmitters, neuromodulators, and hormones, with an increase in intracellular Ca2+ concentration ([Ca2+]i). The increases exhibit a variety of temporal and spatial patterns. These [Ca2+]i responses result from the coordinated activity of a number of molecular cascades responsible for Ca2+ movement into or out of the cytoplasm either by way of the extracellular space or intracellular stores. Transplasmalemmal Ca2+ movements may be controlled by several types of voltage- and ligand-gated Ca(2+)-permeable channels as well as Ca2+ pumps and a Na+/Ca2+ exchanger. In addition, glial cells express various metabotropic receptors coupled to intracellular Ca2+ stores through the intracellular messenger inositol 1,4,5-triphosphate. The interplay of different molecular cascades enables the development of agonist-specific patterns of Ca2+ responses. Such agonist specificity may provide a means for intracellular and intercellular information coding. Calcium signals can traverse gap junctions between glial cells without decrement. These waves can serve as a substrate for integration of glial activity. By controlling gap junction conductance, Ca2+ waves may define the limits of functional glial networks. Neuronal activity can trigger [Ca2+]i signals in apposed glial cells, and moreover, there is some evidence that glial [Ca2+]i waves can affect neurons. Glial Ca2+ signaling can be regarded as a form of glial excitability.
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Affiliation(s)
- A Verkhratsky
- Department of Cellular Neurosciences, Max-Delbrück Center for Molecular Medicine, Berlin-Buch, Germany
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17
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Palma C, Minghetti L, Astolfi M, Ambrosini E, Silberstein FC, Manzini S, Levi G, Aloisi F. Functional characterization of substance P receptors on cultured human spinal cord astrocytes: synergism of substance P with cytokines in inducing interleukin-6 and prostaglandin E2 production. Glia 1997; 21:183-93. [PMID: 9336233 DOI: 10.1002/(sici)1098-1136(199710)21:2<183::aid-glia2>3.0.co;2-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Following brain injury, astrocytes express receptors for cytokines and neuropeptides and secrete several regulatory mediators that have a well established role in inflammation, immunity, and tissue development or repair. To elucidate the role of substance P (SP), a neurotransmitter peptide of the tachykinin family, in inducing astrocyte secretory activities, we have examined the expression of SP receptors and the functional consequences of their activation in cultured astrocytes from the human embryonic brain or spinal cord. Radioligand binding studies revealed that only one type of SP receptors, the high affinity NK-1 receptor, was present on human astrocytes and that spinal cord astrocytes expressed about 6 times as many SP binding sites as brain astrocytes. Following SP treatment, a substantial inositol phosphate formation was observed in spinal cord astrocytes only. Stimulation of spinal cord astrocytes with SP alone did not induce secretion of cytokines [interleukin-6 (IL-6), granulocyte-macrophage-CSF, macrophage chemoattractant protein-1 or leukemia inhibitory factor] or prostaglandin E2 (PGE2). Interestingly, however, SP selectively potentiated the inducing effect of IL-1beta on IL-6 and PGE2 secretion by spinal cord astrocytes without affecting the IL-1-beta-evoked secretion of other cytokines. SP also enhanced the small inducing effect of tumor necrosis factor-alpha (TNF-alpha) on IL-6 and PGE2 secretion and that of transforming growth factor-beta on PGE2 secretion. These results suggest that SP can enhance immunoregulatory and neurotrophic astroglial functions mediated by IL-6 and PGE2 by acting in concert with a set of cytokines whose cerebral expression has been reported during development and in a variety of diseases.
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Affiliation(s)
- C Palma
- Department of Pharmacology, Menarini Ricerche, Pomezia, Italy
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18
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Simpson PB, Mehotra S, Lange GD, Russell JT. High density distribution of endoplasmic reticulum proteins and mitochondria at specialized Ca2+ release sites in oligodendrocyte processes. J Biol Chem 1997; 272:22654-61. [PMID: 9278423 DOI: 10.1074/jbc.272.36.22654] [Citation(s) in RCA: 139] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In oligodendrocyte processes, methacholine-evoked Ca2+ waves propagate via regions of specialized Ca2+ release kinetics (wave amplification sites) at which the amplitude and rate of rise of local Ca2+ signals are markedly higher than in surrounding areas (Simpson, P. B., and Russell, J. T. (1996) J. Biol. Chem. 271, 33493-33501). In the present study we have examined the effects of other phosphoinositide-coupled agonists on Ca2+ in these cells, and the structural specializations underlying regenerative wave amplification sites. Both bradykinin and norepinephrine evoke Ca2+ waves, which initiate at the same loci and propagate through the cell body and multiple processes via identical wave amplification sites. Antibodies against type 2 inositol 1,4,5-trisphosphate receptors (InsP3R2) and calreticulin identify expression of these proteins in oligodendrocyte membranes in Western blots. Immunocytochemistry followed by high resolution fluorescence microscopy revealed that both InsP3R2 and calreticulin are expressed in high intensity patches along processes. Cross-correlation analysis of the profiles of local Ca2+ release kinetics during a Ca2+ wave and immunofluorescence for these proteins along cellular processes showed that the domains of high endoplasmic reticulum protein expression correspond closely to wave amplification sites. Staining cells with the mitochondrial dye, MitoTracker(R), showed that mitochondria are only found in intimate association with these sites possessing high density endoplasmic reticulum proteins, and they remain in the same locations over relatively long periods of time. It appears, therefore, that multiple specializations are found at domains of elevated Ca2+ release in oligodendrocyte processes, including high levels of calreticulin, InsP3R2 Ca2+ release channels, and mitochondria.
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Affiliation(s)
- P B Simpson
- Laboratory of Cellular and Molecular Neurophysiology, NICHD, National Institutes of Health, Bethesda, Maryland 20892-4995, USA
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19
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Abstract
The syntax of neuronal-glial or axonal-glial interaction is frequently communicated through transient changes in internal calcium (Cai). We examined mechanisms for Cai signaling and intercellular propagation of Cai responses in cultured oligodendrocytes (OLGs) derived from adult spinal cord (SC), postnatal day 21 (P21) SC, and P21 brain. We found that (1) cultured OLGs exhibited a heterogeneous response to norepinephrine, carbachol, ATP, histamine, and glutamate; (2) receptor-mediated Cai increases were derived from both Ca2+ influx and intracellular Ca2+ release; (3) the percentage of responders to neuroligands varied as a function of cell origin; (4) cultured OLGs exhibited a thapsigargin-sensitive, but not a caffeine-sensitive, intracellular Ca2+ pool; and (5) gap junctional contacts between OLGs permitted limited intercellular propagation of mechanically stimulated Cai responses. Receptor-mediated Cai signaling appears to occur not only in cultured OLGs but also in acutely dissociated OLGs. The heterogeneity in Cai responses as a function of cell origin may reflect the existence of OLG subsets or differences in the maturation stage of OLGs.
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Affiliation(s)
- M Takeda
- Department of Neurology, University of Chicago, Illinois 60637, USA
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20
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Smith KE, Fried SG, Durkin MM, Gustafson EL, Borden LA, Branchek TA, Weinshank RL. Molecular cloning of an orphan transporter. A new member of the neurotransmitter transporter family. FEBS Lett 1995; 357:86-92. [PMID: 8001687 DOI: 10.1016/0014-5793(94)01328-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A complementary DNA clone predicted to encode a novel transporter was isolated from rat brain and the localization of its mRNA was examined. The cDNA, designated rB21a, predicts a protein with 12 putative transmembrane domains that exhibits significant sequence homology with neurotransmitter transporters. Expression studies have not yet identified the endogenous substrate for this transporter, but the presence of rB21a mRNA within the leptomeninges of the brain suggests the transporter may regulate CSF levels of its substrate. The cloning of rB21a provides the means to determine its physiological functions and the potential to design novel, transporter-based therapeutic agents for neurological and psychiatric disorders.
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Affiliation(s)
- K E Smith
- Synaptic Pharmaceutical Corporation, Paramus, NJ 07652
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21
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Too HP, Marriott DR, Wilkin GP. Preprotachykinin-A and substance P receptor (NK1) gene expression in rat astrocytes in vitro. Neurosci Lett 1994; 182:185-7. [PMID: 7536313 DOI: 10.1016/0304-3940(94)90793-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The presence of mRNA transcripts coding for preprotachykinin-A and the substance P receptor in cultured astrocytes is demonstrated by a combination of reverse transcription/polymerase chain reaction (PCR) and Southern blotting. These findings showed that astrocytes in culture are capable of synthesing both the precursor of substance P (preprotachykinin-A) and the cognate receptor, substance P receptor (NK1). The simultaneous presence of both the ligand (substance P) and the receptor (NK1) may indicate an autocrine nature of astrocyte communication.
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Affiliation(s)
- H P Too
- Department of Biochemistry, National University of Singapore, Kent Ridge Crescent
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22
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Tatsuno I, Arimura A. Pituitary adenylate cyclase-activating polypeptide (PACAP) mobilizes intracellular free calcium in cultured rat type-2, but not type-1, astrocytes. Brain Res 1994; 662:1-10. [PMID: 7859060 DOI: 10.1016/0006-8993(94)90790-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We investigated the effects of pituitary adenylate cyclase-activating polypeptide (PACAP38) on cytosolic free calcium ([Ca2+]i) at a single cell level in both type-1 and type-2 cultured rat astrocytes using a calcium-sensitive fluorescent dye, fura-2. Type-1 astrocytes were relatively silent during the 20 min observation of baseline [Ca2+]i and PACAP38 did not alter [Ca2+]i in type-1 astrocytes at concentrations up to 1 microM. In contrast, type-2 astrocytes could be divided into three subtypes (silent type, randomly-firing type and oscillatory type) based on the observation of baseline [Ca2+]i. Of 166 type-2 astrocytes tested, 145 (87.4%) were the silent type (stable basal [Ca2+]i levels) and 13 (7.8%) were the randomly-firing type (random increases in [Ca2+]i). PACAP38 could stimulate [Ca2+]i in subpopulations of all three subtypes. In the silent type-2 astrocytes (4 experiments with 255 cells/experiment), 54.4 +/- 3.6% of the total number responded to PACAP38. The half maximal concentration (ED50) of PACAP38 was 2.89 +/- 1.89 nM. Removing Ca2+ from the superfusion media did not alter the PACAP38-induced increase of [Ca2+]i. Neither 1-30 microM of forskolin nor 1-10 mM of dibutyryl cyclic AMP increased [Ca2+]i in the same type-2 astrocytes which responded to PACAP38. These findings suggest that PACAP increases [Ca2+]i in type-2, not type-1, rat astrocytes by mobilizing Ca2+ from intracellular stores, and that this action is not linked to activation of the cyclic AMP second messenger system.
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Affiliation(s)
- I Tatsuno
- US-Japan Biomedical Research Laboratories, Tulane University Hebert Center, Belle Chasse, LA 70037
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23
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Butt AM, Colquhoun K, Tutton M, Berry M. Three-dimensional morphology of astrocytes and oligodendrocytes in the intact mouse optic nerve. JOURNAL OF NEUROCYTOLOGY 1994; 23:469-85. [PMID: 7527074 DOI: 10.1007/bf01184071] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The three-dimensional morphology of astrocytes and oligodendrocytes was analysed in the isolated intact mature mouse optic nerve, by correlating laser scanning confocal microscopy and camera lucida drawings of single cells, dye-filled with lysinated rhodamine dextran or horseradish peroxidase, respectively. These techniques enabled the entire process field of single dye-filled cells to be visualized in all planes and resolved the fine details of glial morphology. Morphometric analysis showed that the processes of all astrocytes had branches ending at the pial surface, on blood vessels, and freely in the nerve; branches ending in the nerve were described to end at nodes of Ranvier in the accompanying paper. Astrocytes were classified into a single morphological population in which each cell subserved multiple functions. The results of this study do not support the contention that astrocytes can be subdivided into two morphological and functional subtypes, namely type-1 and type-2, which have process ending either at the glia limitans or at nodes, respectively. Three-dimensional analysis of oligodendrocyte units, defined as the oligodendrocyte, its processes and the axons it ensheaths, showed the provision of single myelin segments for an average of 19 nearby axons (range 12-35) with a mean internodal length of 138 microns (range 50-350 microns). Mouse optic nerve oligodendrocytes were a homogeneous population and were markedly similar to those in the rat optic nerve. The results of our analysis of oligodendrocyte morphology are consistent with the view that the number and internodal length of myelin sheaths supported by a single oligodendrocyte are related to the diameter of the ensheathed axons.
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Affiliation(s)
- A M Butt
- Sherrington School of Physiology, UMDS, Guy's Hospital, London, UK
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24
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Bordey A, Feltz P, Trouslard J. Mobilization of intracellular calcium by substance P in a human astrocytoma cell line (U-373 MG). Glia 1994; 11:277-83. [PMID: 7525479 DOI: 10.1002/glia.440110309] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Variations in intracellular free calcium concentration (delta[Ca2+]i) were measured in intact and isolated human astrocytoma cells (U373 MG) loaded with fura-2 acetoxymethylester. Microperfusion of 50 nM substance P (SP), applied for 1 s, increased [Ca2+]i by 351 nM from a stable basal level of [Ca2+]i of 26 nM. The peak delta[Ca2+]i induced by SP was dose dependent with a threshold of 10(-3) nM, an ED50 of 1.3 nM and a maximal effect for concentrations of SP greater than 100 nM. The NK1 receptor agonist, [Sar9Met(O2)11]SP, mimicked the effect of SP, while the NK2 and NK3 selective receptor agonists, [N1(10)]NKA(4-10) and senktide, respectively, had no effect. The delta[Ca2+]i induced by SP was unaffected by 100 microM cadmium or by removal of extracellular calcium ions. Caffeine up to 30 mM had no effect on [Ca2+]i. In contrast, thapsigargin increased resting [Ca2+]i by 92 nM and reduced the delta[Ca2+]i induced by SP. A pertussis treatment (500 ng/ml-24 h) did not modify the delta[Ca2+]i induced by SP. We conclude that SP, acting on a NK1 receptor, mobilizes cytosolic calcium from an intracellular calcium pool which can be partially depleted by thapsigargin.
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Affiliation(s)
- A Bordey
- Institut de Physiologie (URA 1446 CNRS), Université Louis Pasteur, Strasbourg, France
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25
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Medrano S, Gruenstein E, Dimlich RV. Substance P receptors on human astrocytoma cells are linked to glycogen breakdown. Neurosci Lett 1994; 167:14-8. [PMID: 7513838 DOI: 10.1016/0304-3940(94)91017-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this study we report that substance P stimulated [3H]glycogen breakdown and elevation of intracellular Ca2+ concentration in the human astrocytoma cell line UC-11MG. Both effects were dose dependent, and completely blocked by CP-96,345 suggesting the involvement of an NK1 receptor. Our previous studies indicated that norepinephrine and histamine stimulate glycogenolysis via cAMP and Ca2+ respectively. Combined stimulation with substance P and norepinephrine or histamine resulted in additive effects suggesting that there is no interaction between these neurotransmitters in regulating glycogenolysis in these cells. These results confirm that UC-11MG cells are a useful model system to investigate the functional role of neurotransmitter receptors in astroglial cells.
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Affiliation(s)
- S Medrano
- Department of Emergency Medicine, University of Cincinnati, College of Medicine, OH 45267
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26
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Mullens L, Marriott DR, Young KA, Tannahill L, Lightman SL, Wilkin GP. Up-regulation of lipocortin-1 and its mRNA in reactive astrocytes in kainate-lesioned rat cerebellum. J Neuroimmunol 1994; 50:25-33. [PMID: 8300854 DOI: 10.1016/0165-5728(94)90211-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have used a combined molecular and immunocytochemical approach to examine the expression of lipocortin-1 (LC-1) in kainate-lesioned rat cerebellum. Using immunocytochemistry, Western and Northern blotting, we have shown upregulation of LC-1 mRNA and expression of LC-1 localised specifically to reactive astrocytes. These studies suggest that reactive astrocytes are a major synthetic compartment for the expression of LC-1. The well-reported immuno-suppressive effects of lipocortin(s), suggests that reactive astrocytes could serve to negatively modulate inflammatory reactions in the central nervous system.
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Affiliation(s)
- L Mullens
- Department of Medicine, Charing Cross & Westminster Medical School, London, UK
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27
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Stephens GJ, Marriott DR, Djamgoz MB, Wilkin GP. Electrophysiological and biochemical evidence for bradykinin receptors on cultured rat cortical oligodendrocytes. Neurosci Lett 1993; 153:223-6. [PMID: 8392156 DOI: 10.1016/0304-3940(93)90327-h] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The effects of the neuropeptide bradykinin (Bk) were examined on antigenically-identified rat cortical oligodendrocytes. Bk significantly increased the incorporation of [3H]myo-inositol into phospholipids, indicating the turnover of phosphatidyl inositol (PI). Ca2+ flux analysis experiments confirmed that this effect was accompanied by an increase in intracellular Ca2+. Using the whole-cell patch clamp technique, Bk was shown to induce an inward current associated with a decrease in membrane conductance, indicating a closure of ion channels. The reversal potential of the current was close to the potassium equilibrium potential, consistent with an effect on a K+ conductance in these cells. These results show that oligodendrocytes possess Bk receptors that may be of functional relevance.
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Affiliation(s)
- G J Stephens
- Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, UK
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