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Merighi A. The histology, physiology, neurochemistry and circuitry of the substantia gelatinosa Rolandi (lamina II) in mammalian spinal cord. Prog Neurobiol 2018; 169:91-134. [PMID: 29981393 DOI: 10.1016/j.pneurobio.2018.06.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 06/07/2018] [Accepted: 06/30/2018] [Indexed: 02/06/2023]
Abstract
The substantia gelatinosa Rolandi (SGR) was first described about two centuries ago. In the following decades an enormous amount of information has permitted us to understand - at least in part - its role in the initial processing of pain and itch. Here, I will first provide a comprehensive picture of the histology, physiology, and neurochemistry of the normal SGR. Then, I will analytically discuss the SGR circuits that have been directly demonstrated or deductively envisaged in the course of the intensive research on this area of the spinal cord, with particular emphasis on the pathways connecting the primary afferent fibers and the intrinsic neurons. The perspective existence of neurochemically-defined sets of primary afferent neurons giving rise to these circuits will be also discussed, with the proposition that a cross-talk between different subsets of peptidergic fibers may be the structural and functional substrate of additional gating mechanisms in SGR. Finally, I highlight the role played by slow acting high molecular weight modulators in these gating mechanisms.
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Affiliation(s)
- Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Largo Paolo Braccini 2, I-10095 Grugliasco (TO), Italy.
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2
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Peirs C, Patil S, Bouali-Benazzouz R, Artola A, Landry M, Dallel R. Protein kinase C gamma interneurons in the rat medullary dorsal horn: distribution and synaptic inputs to these neurons, and subcellular localization of the enzyme. J Comp Neurol 2014; 522:393-413. [PMID: 23818225 DOI: 10.1002/cne.23407] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 06/21/2013] [Accepted: 06/21/2013] [Indexed: 12/18/2022]
Abstract
The γ isoform of protein kinase C (PKCγ), which is concentrated in interneurons in the inner part of lamina II (IIi ) of the dorsal horn, has been implicated in the expression of tactile allodynia. Lamina IIi PKCγ interneurons were shown to be activated by tactile inputs and to participate in local circuits through which these inputs can reach lamina I, nociceptive output neurons. That such local circuits are gated by glycinergic inhibition and that A- and C-fibers low threshold mechanoreceptors (LTMRs) terminate in lamina IIi raise the general issue of synaptic inputs to lamina IIi PKCγ interneurons. Combining light and electron microscopic immunochemistry in the rat spinal trigeminal nucleus, we show that PKCγ-immunoreactivity is mostly restricted to interneurons in lamina IIi of the medullary dorsal horn, where they constitute 1/3 of total neurons. The majority of synapses on PKCγ-immunoreactive interneurons are asymmetric (likely excitatory). PKCγ-immunoreactive interneurons appear to receive exclusively myelinated primary afferents in type II synaptic glomeruli. Neither large dense core vesicle terminals nor type I synaptic glomeruli, assumed to be the endings of unmyelinated nociceptive terminals, were found on these interneurons. Moreover, there is no vesicular glutamate transporter 3-immunoreactive bouton, specific to C-LTMRs, on PKCγ-immunoreactive interneurons. PKCγ-immunoreactive interneurons contain GABAA ergic and glycinergic receptors. At the subcellular level, PKCγ-immunoreactivity is mostly concentrated on plasma membranes, close to, but not within, postsynaptic densities. That only myelinated primary afferents were found to contact PKCγ-immunoreactive interneurons suggests that myelinated, but not unmyelinated, LTMRs play a critical role in the expression of mechanical allodynia.
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Affiliation(s)
- Cédric Peirs
- Inserm/UdA U1107, Neuro-Dol: Trigeminal Pain and Migraine, Université d'Auvergne, Faculté de Chirurgie Dentaire, Clermont-Ferrand, 63000, France
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3
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Sakamoto H, Kawate T, Li Y, Atsumi S. Neurokinin-1 receptor immunoreactive neuronal elements in the superficial dorsal horn of the chicken spinal cord: with special reference to their relationship with the tachykinin-containing central axon terminals in synaptic glomeruli. Acta Histochem Cytochem 2009; 42:111-9. [PMID: 19759872 PMCID: PMC2742721 DOI: 10.1267/ahc.09012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 05/20/2009] [Indexed: 11/22/2022] Open
Abstract
Synaptic glomeruli that involve tachykinin-containing primary afferent central terminals are numerous in lamina II of the chicken spinal cord. Therefore, a certain amount of noxious information is likely to be modulated in these structures in chickens. In this study, we used immunohistochemistry with confocal and electron microscopy to investigate whether neurokinin-1 receptor (NK-1R)-expressing neuronal elements are in contact with the central primary afferent terminals in synaptic glomeruli of the chicken spinal cord. We also investigated which neuronal elements (axon terminals, dendrites, cell bodies) and which neurons in the spinal cord possess NK-1R, and are possibly influenced by tachykinin in the glomeruli. By confocal microscopy, NK-1R immunoreactivities were seen in a variety of neuronal cell bodies, their dendrites and smaller fibers of unknown origin. Some of the NK-1R immunoreactive profiles also expressed GABA immunoreactivities. A close association was observed between the NK-1R-immunoreactive neurons and tachykinin-immunoreactive axonal varicosities. By electron microscopy, NK-1R immunoreactivity was seen in cell bodies, conventional dendrites and vesicle-containing dendrites in laminae I and II. Among these elements, dendrites and vesicle-containing dendrites made contact with tachykinin-containing central terminals in the synaptic glomeruli. These results indicate that tachykinin-containing central terminals in the chicken spinal cord can modulate second-order neuronal elements in the synaptic glomeruli.
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Affiliation(s)
| | - Toyoko Kawate
- Faculty of Physical Therapy, Health Science University
| | - Yongnan Li
- Basic Science for Clinical Medicine, Division of Medicine, Interdisciplinary Graduate School of Medical and Engineering, University of Yamanashi
| | - Saoko Atsumi
- Basic Science for Clinical Medicine, Division of Medicine, Interdisciplinary Graduate School of Medical and Engineering, University of Yamanashi
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Aita M, Seo K, Fujiwara N, Takagi R, Maeda T. Postnatal changes in the spatial distributions of substance P and neurokinin-1 receptor in the trigeminal subnucleus caudalis of mice. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 155:33-41. [PMID: 15763273 DOI: 10.1016/j.devbrainres.2004.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 12/01/2004] [Accepted: 12/02/2004] [Indexed: 10/25/2022]
Abstract
Nociceptive afferent signals from the orofacial area are transmitted to the trigeminal subnucleus caudalis (Vc) through the release of glutamate and/or substance P (SP). Although nociceptive transmission and/or modulating mechanisms are known to develop during the postnatal period, the specific developmental changes in nociception and/or modulation remain unclear. The present study examined postnatal changes in the spatial relationship between SP and its receptor, the NK1 receptor (NK1R), in the mouse Vc by immunohistochemistry and quantitative analysis. The medulla was removed from C57BL/6N mice (1, 2, 4, and 8 weeks of age) after perfusion and fixation, and cut horizontally at a thickness of 40 mum. The relative densities of SP- and NK1R-immunoreactive areas and their changes with age were assessed statistically. One- and 2-week-old mice showed relatively high densities of SP-positive structures in the marginal layer (Mar) and the deep part of the magnocellular layer (Mag). The SP distribution in the superficial Vc remained unchanged, but the density in the deep Mag gradually decreased with age, resulting in a complete loss after postnatal week 4. The NK1R-immunoreactivity exhibited a similar distribution pattern to that of SP, but the pattern remained unchanged during the postnatal period. Double-immunofluorescence staining for SP and NK1R demonstrated only moderate direct contact of SP-positive structures with NK1R in the superficial area. These separate distributions and the postnatal changes in SP and NK1R suggest the possibility of another nociceptive afferent transmission mechanism, that is, volume transmission, in the Vc other than synapse-mediated transmission.
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Affiliation(s)
- Megumi Aita
- Division of Oral and Maxillofacial Surgery, Department of Oral Health Sciences, Japan
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5
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Xu C, Yaici ED, Conrath M, Blanchard P, Leclerc P, Benoît G, Vergé D, Giuliano F. Galanin and neurokinin-1 receptor immunoreactivity spinal neurons controlling the prostate and the bulbospongiosus muscle identified by transsynaptic labeling in the rat. Neuroscience 2005; 134:1325-41. [PMID: 16054769 DOI: 10.1016/j.neuroscience.2005.06.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 06/01/2005] [Accepted: 06/02/2005] [Indexed: 11/16/2022]
Abstract
Ejaculation requires the coordination of sympathetic, parasympathetic and somatic neural outputs. Timely occurrence of the emission and expulsion of sperm results from an interplay between spinal nuclei innervating the seminal tract and the sexual accessory glands including the prostate on the one hand, and on the other hand perineal striated muscles, particularly the bulbospongiosus muscle. A group of cells essential for ejaculation, located around the central canal and referred to as lumbar spinothalamic neurons have been recently identified. Lumbar spinothalamic neurons are immunoreactive for galanin and neurokinin-1 receptor. In order to investigate the anatomical relationships between lumbar spinothalamic neurons and both the prostate and the bulbospongiosus muscle, pseudorabies virus retrograde tracing technique was used combined with immunohistochemistry. Three to five days after pseudorabies virus injection in the bulbospongiosus muscle or the prostate in male rats, spinal cord sections were processed for double immunofluorescence against pseudorabies virus and galanin or neurokinin-1 receptor. Immunocytochemical experiments against pseudorabies virus and choline acetyltransferase were also performed to discriminate between motoneurons and preganglionic neurons, or interneurons. Spinal sections were examined with confocal laser scanning microscope. Three days after pseudorabies virus injection within the prostate and the bulbospongiosus muscle, sympathetic preganglionic neurons and motoneurons of the dorsomedial nucleus were retrogradely labeled, respectively. Five days after pseudorabies virus injection, transsynaptically labeled choline acetyltransferase-negative neurons were found mainly located in the medial gray surrounding the central canal from L1 to S1. At the L3-L4 level, most of transsynaptically labeled neurons were immunoreactive for galanin and to a lesser extent for neurokinin-1 receptor, strongly suggesting that they could be the lumbar spinothalamic cells. We have thus evidenced connections between these cells and motoneurons of the dorsomedial nucleus and both sympathetic and parasympathetic preganglionic neurons innervating the bulbospongiosus muscle and the prostate, respectively. These anatomical data reinforce the crucial role for lumbar spinothalamic cells in coordinating the spinal control of ejaculation.
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Affiliation(s)
- C Xu
- Groupe de Recherche en Urologie, UPRESS EA 1602, Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France
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6
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Baker SJ, Morris JL, Gibbins IL. Cloning of a C-terminally truncated NK-1 receptor from guinea-pig nervous system. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2003; 111:136-47. [PMID: 12654513 DOI: 10.1016/s0169-328x(03)00002-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In order to examine the possibility that some actions of substance P may be mediated by a variant of the neurokinin-1 (NK-1) receptor, we isolated and sequenced the cDNA encoding a truncated NK-1 receptor from guinea-pig celiac ganglion and brain mRNA by two-step RT-PCR based on the 3'RACE method. The truncated NK-1 receptor sequence corresponded to a splice variant missing the final exon 5, and encoded a 311-amino acid protein that was truncated just after transmembrane domain 7, in an identical position to a truncated variant of the human NK-1 receptor. Thus, the truncated NK-1 receptor lacked the intracellular C-terminus sequence required for the phosphorylation and internalisation of the full-length NK-1 receptor. Using a sensitive one-step semi-quantitative RT-PCR assay, we detected mRNA for both the full length and truncated NK-1 receptors throughout the brain, spinal cord, sensory and autonomic ganglia, and viscera. Truncated NK-1 receptor mRNA was present in lower quantities than mRNA for the full-length NK-1R in all tissues. Highest levels of mRNA for the truncated NK-1 receptor were detected in coeliac ganglion, spinal cord, basal ganglia and hypothalamus. An antiserum to the N-terminus of the NK-1 receptor labelled dendrites of coeliac ganglion neurons that were not labelled with antisera to the C-terminus of the full length NK-1 receptor. These results show that a C-terminally truncated variant of the NK-1 receptor is likely to be widespread in central and peripheral nervous tissue. We predict that this receptor will mediate actions of substance P on neurons where immunohistochemical evidence for a full-length NK-1 receptor is lacking.
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MESH Headings
- Alternative Splicing/genetics
- Amino Acid Sequence/genetics
- Animals
- Base Sequence/genetics
- Central Nervous System/cytology
- Central Nervous System/metabolism
- Cloning, Molecular
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Dendrites/metabolism
- Dendrites/ultrastructure
- Female
- Fluorescent Antibody Technique
- Ganglia, Sympathetic/cytology
- Ganglia, Sympathetic/metabolism
- Guinea Pigs
- Male
- Microscopy, Confocal
- Microtubule-Associated Proteins/metabolism
- Molecular Sequence Data
- Mutation/genetics
- Neurons/cytology
- Neurons/metabolism
- Peripheral Nervous System/cytology
- Peripheral Nervous System/metabolism
- Protein Isoforms/genetics
- Protein Isoforms/isolation & purification
- Protein Structure, Tertiary/genetics
- RNA, Messenger/metabolism
- Receptors, Neurokinin-1/genetics
- Receptors, Neurokinin-1/isolation & purification
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Affiliation(s)
- Sarah J Baker
- Department of Anatomy and Histology, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia
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Richardson MD, Balius AM, Yamaguchi K, Freilich ER, Barak LS, Kwatra MM. Human substance P receptor lacking the C-terminal domain remains competent to desensitize and internalize. J Neurochem 2003; 84:854-63. [PMID: 12562528 DOI: 10.1046/j.1471-4159.2003.01577.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Substance P receptor (SPR) and its naturally occurring splice-variant, lacking the C-terminal tail, are found in brain and spinal cord. Whether C-terminally truncated SPR desensitizes like full-length SPR is controversial. We used a multivaried approach to determine whether human SPR (hSPR) and a C-terminally truncated mutant, hSPRDelta325, differ in their desensitization and internalization. In HEK-293 cells expressing either hSPRDelta325 or hSPR, SP-induced desensitization of the two receptors was similar when measured by inositol triphosphate accumulation or by transient translocation of coexpressed PKCbetaII-GFP to the plasma membrane. Moreover, translocation of beta-arrestin 1 or 2-GFP (betaarr1-GFP or betaarr2-GFP) to the plasma membrane, and receptor internalization were also similar. However, hSPR and hSPRDelta325 differ in their phosphorylation and in their ability to form beta-arrestin-containing endocytic vesicles. Unlike hSPR, hSPRDelta325 is not phosphorylated to a detectable level in intact HEK293 cells, and whereas hSPR forms vesicles containing either betaarr1-GFP or betaarr2-GFP, hSPRDelta325 does not form any vesicles with betaarr1-GFP, and forms fewer vesicles with betaarr2-GFP. We conclude that truncated hSPR undergoes agonist-dependent desensitization and internalization without detectable receptor phosphorylation.
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Affiliation(s)
- Mark D Richardson
- Departments of Anesthesiology and Cell Biology, The Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710, USA
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8
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Salio C, Fischer J, Franzoni MF, Conrath M. Pre- and postsynaptic localizations of the CB1 cannabinoid receptor in the dorsal horn of the rat spinal cord. Neuroscience 2002; 110:755-64. [PMID: 11934482 DOI: 10.1016/s0306-4522(01)00584-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Several lines of evidence show that endogenous and exogenous cannabinoids modulate pain transmission at the spinal level through specific cannabinoid-1 (CB1) receptors. Since anatomical data concerning spinal CB1 receptors are rather contradictory, we studied the cellular and subcellular localizations of the CB1 receptors by immunocytochemistry. Results show a dual pre- and postsynaptic localization of CB1 receptors. Presynaptic receptors are evidenced by the labeling of (1) heterogeneous dorsal root ganglion neurons and (2) axons of Lissauer's tract. Postsynaptic receptors are shown by the labeling of numerous interneurons in the outer part of lamina II. Double immunolabelings show that lamina II outer CB1 neurons, probably islet cells, may also contain GABA or nitric oxide synthase. Numerous CB1-containing neurons in lamina X are also immunostained with anti-nitric oxide synthase (NOS) antibody. Under the electron microscope, CB1 immunoreactivity is exclusively localized postsynaptically in both somatic and dendritic compartments. The absence of labeling on primary afferent axon terminals is discussed and compared to the absence of labeling on terminals or vesicle-containing dendrites of islet cells, where a presynaptic localization was expected according to data of the literature.
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Affiliation(s)
- C Salio
- Départment de Neurobiologie des Signaux Intercellulaires, Institut des Neurosciences, Université Pierre et Marie Curie, Paris, France
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9
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Makeham JM, Goodchild AK, Pilowsky PM. NK1 receptor and the ventral medulla of the rat: bulbospinal and catecholaminergic neurons. Neuroreport 2001; 12:3663-7. [PMID: 11726770 DOI: 10.1097/00001756-200112040-00012] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Bulbospinal C1 neurons are sympathoexcitatory and excited by substance P. However the substance P receptor (NK1 receptor), has been reported to be absent from the somata of C1 neurons. In this study, using double and triple labelling immunofluorescence and retrograde tracing, we provide evidence that the NK1 receptor is present on 5.3% of C1 neurons, and that 4.7% of C1 neurons receive close oppositions from NK1 receptor immunoreactive terminals, indicating a pre-synaptic and post-synaptic site for the action of substance P. These results provide support for the sympathoexcitatory actions of substance P on C1 neurons. We also demonstrate the NK1 receptor on bulbospinal neurons of the ventral respiratory group, in a region overlapping the pre-Bötzinger Complex.
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Affiliation(s)
- J M Makeham
- Hypertension and Stroke Research Laboratory, Department of Physiology, University of Sydney, Australia
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10
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Beaujouan JC, Saffroy M, Torrens Y, Glowinski J. Different subtypes of tachykinin NK(1) receptor binding sites are present in the rat brain. J Neurochem 2000; 75:1015-26. [PMID: 10936182 DOI: 10.1046/j.1471-4159.2000.0751015.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
(2-[(125)I]iodohistidyl(1))Neurokinin A ([(125)I]NKA), which labels "septide-sensitive" but not classic NK(1) binding sites in peripheral tissues, was used to determine whether septide-sensitive binding sites are also present in the rat brain. Binding studies were performed in the presence of SR 48968 (NK(2) antagonist) and senktide (NK(3) agonist) because [(125)I]NKA also labels peripheral NK(2) binding sites and, as shown in this study, central NK(3) binding sites. [(125)I]NKA was found to label not only septide-sensitive binding sites but also a new subtype of NK(1) binding site distinct from classic NK(1) binding sites. Both subtypes of [(125)I]NKA binding sites were sensitive to tachykinin NK(1) antagonists and agonists but also to the endogenous tachykinins NKA, neuropeptide K (NPK), and neuropeptide gamma (NPgamma). However, compounds of the septide family such as substance P(6-11) [SP(6-11)] and propionyl-[Met(O(2))(11)]SP(7-11) and some NK(1) antagonists, GR 82334, RP 67580, and CP 96345, had a much lower affinity for the new NK(1)-sensitive sites than for the septide-sensitive sites. The hypothalamus and colliculi possess only this new subtype of NK(1) site, whereas both types of [(125)I]NKA binding sites were found in the amygdala and some other brain structures. These results not only explain the central effects of septide or SP(6-11), but also those of NKA, NPK, and NPgamma, which can be selectively blocked by NK(1) receptor antagonists.
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Affiliation(s)
- J C Beaujouan
- Chaire de Neuropharmacologie, INSERM U114, Paris, France.
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11
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Sagot MA, Wijkhuisen A, Créminon C, Tymciu S, Frobert Y, Turbica I, Grassi J, Couraud JY, Boquet D. A monoclonal antibody directed against the neurokinin-1 receptor contains a peptide sequence with similar hydropathy and functional properties to substance P, the natural ligand for the receptor. Mol Immunol 2000; 37:423-33. [PMID: 11090877 DOI: 10.1016/s0161-5890(00)00060-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Monoclonal antibody (mAb) PS12, obtained using the complementary peptide methodology, mimics the neuropeptide substance P (SP) in recognizing the SP-binding domain of the neurokinin-1 receptor (NK1R) and eliciting production of polyclonal antibodies cross-reacting with SP with a high affinity (Déry et al., 1997. J. Neuroimmunol. 76, 1-9). The aim of the present study was to investigate which structural features of mAb PS12 might account for this molecular mimicry. Cloning and sequencing of variable regions of both light (VL) and heavy (VH) chains of this 'SP-like' antibody did not indicate any primary sequence homology between SP and any antibody region. Instead, they revealed a striking similarity between the hydropathic profile of SP and that of an 11-amino-acid region in the light chain encompassing the second complementarity determining region (CDR2). When applied to CHO cells expressing the human NK1R, a synthetic extended 17-amino-acid peptide (denoted CDR2L) corresponding to this VL region inhibited the high-affinity binding of radiolabeled SP and antagonized the SP-induced inositol phosphate production. Moreover, a re-examination of the sequences of several antibodies that previously served in the design of CDR-derived bioactive peptides indicated that these antibodies also carried the hydropathic image of the respective ligands that they mimic. In agreement with previous observations on artificial synthetic peptides, our data thus suggest that the molecular mimicry between natural proteins (i.e. antibody and hormone, for example) could be understood on a structural level directly related, at least in part, to hydropathic homology. These results could then guide the search for bioactive paratope-derived peptides of potential pharmacological interest. We also observed inverse hydropathy between multiple CDRs of mAb PS12 (including CDR3H and CDR3L) and the peptide epitope, confirming the importance of hydropathic complementarity in antigen-antibody interactions.
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Affiliation(s)
- M A Sagot
- CEA, Service de Pharmacologie et d'Immunologie, DSV/DRM, Bât. 136, Centre d'Etudes de Saclay, 91191 Gif-sur-Yvette Cedex, France
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12
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Fischer J, Bancila V, Mailly P, Masson J, Hamon M, El Mestikawy S, Conrath M. Immunocytochemical evidence of vesicular localization of the orphan transporter RXT1 in the rat spinal cord. Neuroscience 1999; 92:729-43. [PMID: 10408621 DOI: 10.1016/s0306-4522(99)00017-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Rxt1, a member of the Na+/Cl- orphan transporter family, exhibits numerous features suggesting a role as plasma membrane transporter. Despite numerous attempts, its substrate has not yet been identified, although immunocytochemical studies have shown that Rxt1 distribution generally matches that of glutamate or GABA. In order to further characterize Rxt1, its detailed immunocytochemical distribution in the rat spinal cord and dorsal root ganglia was studied at both light microscope and ultrastructural levels. The widespread distribution of Rxt1 in spinal cord and ganglia cannot be correlated with any known classical or peptidergic transmitter. Rxt1 is expressed in a subpopulation of glutamatergic primary afferent fibers, in large and medium-sized ganglion cells, while small glutamate cells exhibit generally no Rxt1-like immunoreactivity. In the spinal cord, Rxt1-immunoreactive cell body distribution is quite ubiquitous since Rxt1 is expressed in all laminae in various neuronal types like interneurons, some projection neurons and motoneurons. Some of these neurons are cholinergic. At the electron microscope level, the peroxidase labeling was never localized to the plasma membrane, but rather associated with different organelles including the outer membrane of small synaptic vesicles and large granular vesicles. This localization resembles that of vesicular transporters detected with the same method and suggests that Rxt1, in contrast to other Na+/Cl- transporters, is expressed on vesicles. This was confirmed using a pre-embedding silver-intensified colloidal gold method. Indeed, most gold particles appeared to be localized into the axoplasm on synaptic vesicle accumulations; only few gold particles were observed close to the plasma membrane. These results suggest that Rxt1, despite its molecular characteristics predicting a plasma membrane localization, might be a vesicular transporter.
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Affiliation(s)
- J Fischer
- Département de Neurobiologie des Signaux Intercellulaires, Institut des Neurosciences, CNRS UMR 7624, Université Pierre et Marie Curie, Paris, France
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13
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Smith VC, Sagot MA, Couraud JY, Buchan AM. Localization of the neurokinin 1 (NK-1) receptor in the human antrum and duodenum. Neurosci Lett 1998; 253:49-52. [PMID: 9754802 DOI: 10.1016/s0304-3940(98)00618-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A newly available antibody to the neurokinin-1 receptor (NK-1r) has made it possible to determine the distribution of the NK-1r receptor in human tissue. In the present study the distribution of the NK-1r and substance P have been determined in the human antrum and duodenum by immunocytochemistry. The NK-1r was present on myenteric and submucosal neurons and nerve fibers of the gastro-enteric nervous system. In addition, the receptor was present on spindle-shaped cells in the circular muscle layer, endothelial cells and a population of mucosal cells. In the submucosal plexus NK-1r immunoreactive neurons were surrounded by substance P containing fibers. These results indicate an extensive cellular expression of the NK-1r in the human antrum and duodenum.
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Affiliation(s)
- V C Smith
- Department of Physiology, University of British Columbia, Vancouver, Canada
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