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Xie RG, Xu GY, Wu SX, Luo C. Presynaptic glutamate receptors in nociception. Pharmacol Ther 2023; 251:108539. [PMID: 37783347 DOI: 10.1016/j.pharmthera.2023.108539] [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: 05/26/2023] [Revised: 08/19/2023] [Accepted: 09/25/2023] [Indexed: 10/04/2023]
Abstract
Chronic pain is a frequent, distressing and poorly understood health problem. Plasticity of synaptic transmission in the nociceptive pathways after inflammation or injury is assumed to be an important cellular basis for chronic, pathological pain. Glutamate serves as the main excitatory neurotransmitter at key synapses in the somatosensory nociceptive pathways, in which it acts on both ionotropic and metabotropic glutamate receptors. Although conventionally postsynaptic, compelling anatomical and physiological evidence demonstrates the presence of presynaptic glutamate receptors in the nociceptive pathways. Presynaptic glutamate receptors play crucial roles in nociceptive synaptic transmission and plasticity. They modulate presynaptic neurotransmitter release and synaptic plasticity, which in turn regulates pain sensitization. In this review, we summarize the latest understanding of the expression of presynaptic glutamate receptors in the nociceptive pathways, and how they contribute to nociceptive information processing and pain hypersensitivity associated with inflammation / injury. We uncover the cellular and molecular mechanisms of presynaptic glutamate receptors in shaping synaptic transmission and plasticity to mediate pain chronicity, which may provide therapeutic approaches for treatment of chronic pain.
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Affiliation(s)
- Rou-Gang Xie
- Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China.
| | - Guang-Yin Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou 215123, China
| | - Sheng-Xi Wu
- Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China.
| | - Ceng Luo
- Department of Neurobiology, Fourth Military Medical University, Xi'an 710032, China.
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Wang Z, Yao Y, Tao Y, Fan P, Yu Y, Xie K, Wang G. Spinal microRNA-134-5p targets glutamate receptor ionotropic kainate 3 to modulate opioid induced hyperalgesia in mice. Mol Pain 2023; 19:17448069231178271. [PMID: 37247385 DOI: 10.1177/17448069231178271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023] Open
Abstract
Background: Fentanyl and its analogs are extensively used for pain relief. However, their paradoxically pronociceptive effects often lead to increased opioids consumption and risk of chronic pain. Compared to other synthetic opioids, remifentanil has been strongly linked to acute opioid hyperalgesia after exposure [remifentanil-induced hyperalgesia (RIH)]. The epigenetic regulation of microRNAs (miRNAs) on targeted mRNAs has emerged as an important pathogenesis in pain. The current research aimed at exploring the significance and contributions of miR-134-5p to the development of RIH. Methods: Both the antinociceptive and pronociceptive effects of two commonly used opioids were assessed, and miRNA expression profiles in the spinal dorsal horn (SDH) of mice acutely exposed to remifentanil and remifentanil equianalgesic dose (RED) sufentanil were screened. Next, the candidate miRNA level, cellular distribution, and function were examined by qPCR, fluorescent in situ hybridization (FISH) and Argonaute-2 immunoprecipitation. Furthermore, bioinformatics analysis, luciferase assays, miRNA overexpression, behavioral tests, golgi staining, electron microscopy, whole-cell patch-clamp recording, and immunoblotting were employed to investigate the potential targets and mechanisms underlying RIH. Results: Remifentanil induced significant pronociceptive effects and a distinct miRNA-profile from sufentanil when compared to saline controls. Among top 30 differentially expressed miRNAs spectrum, spinal miR-134-5p was dramatically downregulated in RIH mice but remained comparative in mice subjected to sufentanil. Moreover, Glutamate Receptor Ionotropic Kainate 3 (Grik3) was a target of miR-134-5p. The overexpression of miR-134-5p attenuated the hyperalgesic phenotype, excessive dendritic spine remodeling, excitatory synaptic structural plasticity, and Kainate receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in SDH resulting from remifentanil exposure. Besides, intrathecal injection of selective KA-R antagonist was able to reverse the GRIK3 membrane trafficking and relieved RIH. Conclusion: The miR-134-5p contributes to remifentanil-induced pronociceptive features via directly targeting Grik3 to modulate dendritic spine morphology and synaptic plasticity in spinal neurons.
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Affiliation(s)
- Zhen Wang
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Yao Yao
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, China
| | - Yuzhu Tao
- Department of Anesthesiology, Tianjin Huanhu Hospital, Tianjin, China
| | - Peixin Fan
- Department of Animal and Dairy Science, Mississippi State University, Starkville, MS, USA
- Institute for Genomics, Biocomputing & Biotechnology, Mississippi State University, Starkville, MS, USA
| | - Yonghao Yu
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
| | - Keliang Xie
- Department of Critical Care Medicine, Tianjin Medical University General Hospital, Tianjin, China
| | - Guolin Wang
- Department of Anesthesiology, Tianjin Research Institute of Anesthesiology, Tianjin Medical University General Hospital, Tianjin, China
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3
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Watkins JC, Evans RH, Bayés À, Booker SA, Gibb A, Mabb AM, Mayer M, Mellor JR, Molnár E, Niu L, Ortega A, Pankratov Y, Ramos-Vicente D, Rodríguez-Campuzano A, Rodríguez-Moreno A, Wang LY, Wang YT, Wollmuth L, Wyllie DJA, Zhuo M, Frenguelli BG. 21st century excitatory amino acid research: A Q & A with Jeff Watkins and Dick Evans. Neuropharmacology 2021; 198:108743. [PMID: 34363811 DOI: 10.1016/j.neuropharm.2021.108743] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In 1981 Jeff Watkins and Dick Evans wrote what was to become a seminal review on excitatory amino acids (EAAs) and their receptors (Watkins and Evans, 1981). Bringing together various lines of evidence dating back over several decades on: the distribution in the nervous system of putative amino acid neurotransmitters; enzymes involved in their production and metabolism; the uptake and release of amino acids; binding of EAAs to membranes; the pharmacological action of endogenous excitatory amino acids and their synthetic analogues, and notably the actions of antagonists for the excitations caused by both nerve stimulation and exogenous agonists, often using pharmacological tools developed by Jeff and his colleagues, they provided a compelling account for EAAs, especially l-glutamate, as a bona fide neurotransmitter in the nervous system. The rest, as they say, is history, but far from being consigned to history, EAA research is in rude health well into the 21st Century as this series of Special Issues of Neuropharmacology exemplifies. With EAAs and their receptors flourishing across a wide range of disciplines and clinical conditions, we enter into a dialogue with two of the most prominent and influential figures in the early days of EAA research: Jeff Watkins and Dick Evans.
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Affiliation(s)
| | | | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain and Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Sam A Booker
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Alasdair Gibb
- Research Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Angela M Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Mark Mayer
- Bldg 35A, Room 3D-904, 35A Convent Drive, NINDS, NIH, Bethesda, MD, 20892, USA
| | - Jack R Mellor
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Elek Molnár
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK
| | - Li Niu
- Chemistry Department, University at Albany, SUNY, 1400 Washington Ave, Albany, NY, 12222, USA
| | - Arturo Ortega
- Department of Toxicology, Cinvestav, Mexico City, Mexico
| | - Yuriy Pankratov
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - David Ramos-Vicente
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain and Universitat Autònoma de Barcelona, Barcelona, Spain
| | | | | | - Lu-Yang Wang
- Program in Neurosciences & Mental Health, SickKids Research Institute and Department of Physiology, University of Toronto, 555 University Ave, Toronto, Ontario, M5G 1X8, Canada
| | - Yu Tian Wang
- Department of Medicine, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - Lonnie Wollmuth
- Depts. of Neurobiology & Behavior and Biochemistry & Cell Biology, Center for Nervous System Disorders, Stony Brook University, Stony Brook, NY, 11794-5230, USA
| | - David J A Wyllie
- Simons Initiative for the Developing Brain, Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Min Zhuo
- Institute of Brain Research, Qingdao International Academician Park, Qingdao, 266000, China
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4
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Kainate receptors in the developing neuronal networks. Neuropharmacology 2021; 195:108585. [PMID: 33910033 DOI: 10.1016/j.neuropharm.2021.108585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/14/2022]
Abstract
Kainate receptors (KARs) are highly expressed in the immature brain and have unique developmentally regulated functions that may be important in linking neuronal activity to morphogenesis during activity-dependent fine-tuning of the synaptic connectivity. Altered expression of KARs in the developing neural network leads to changes in glutamatergic connectivity and network excitability, which may lead to long-lasting changes in behaviorally relevant circuitries in the brain. Here, we summarize the current knowledge on physiological and morphogenic functions described for different types of KARs at immature neural circuitries, focusing on their roles in modulating synaptic transmission and plasticity as well as circuit maturation in the rodent hippocampus and amygdala. Finally, we discuss the emerging evidence suggesting that malfunction of KARs in the immature brain may contribute to the pathophysiology underlying developmentally originating neurological disorders.
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5
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Mitchell R, Campbell G, Mikolajczak M, McGill K, Mahad D, Fleetwood-Walker SM. A Targeted Mutation Disrupting Mitochondrial Complex IV Function in Primary Afferent Neurons Leads to Pain Hypersensitivity Through P2Y 1 Receptor Activation. Mol Neurobiol 2019; 56:5917-5933. [PMID: 30689196 DOI: 10.1007/s12035-018-1455-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/14/2018] [Indexed: 01/20/2023]
Abstract
As mitochondrial dysfunction is evident in neurodegenerative disorders that are accompanied by pain, we generated inducible mutant mice with disruption of mitochondrial respiratory chain complex IV, by COX10 deletion limited to sensory afferent neurons through the use of an Advillin Cre-reporter. COX10 deletion results in a selective energy-deficiency phenotype with minimal production of reactive oxygen species. Mutant mice showed reduced activity of mitochondrial respiratory chain complex IV in many sensory neurons, increased ADP/ATP ratios in dorsal root ganglia and dorsal spinal cord synaptoneurosomes, as well as impaired mitochondrial membrane potential, in these synaptoneurosome preparations. These changes were accompanied by marked pain hypersensitivity in mechanical and thermal (hot and cold) tests without altered motor function. To address the underlying basis, we measured Ca2+ fluorescence responses of dorsal spinal cord synaptoneurosomes to activation of the GluK1 (kainate) receptor, which we showed to be widely expressed in small but not large nociceptive afferents, and is minimally expressed elsewhere in the spinal cord. Synaptoneurosomes from mutant mice showed greatly increased responses to GluK1 agonist. To explore whether altered nucleotide levels may play a part in this hypersensitivity, we pharmacologically interrogated potential roles of AMP-kinase and ADP-sensitive purinergic receptors. The ADP-sensitive P2Y1 receptor was clearly implicated. Its expression in small nociceptive afferents was increased in mutants, whose in vivo pain hypersensitivity, in mechanical, thermal and cold tests, was reversed by a selective P2Y1 antagonist. Energy depletion and ADP elevation in sensory afferents, due to mitochondrial respiratory chain complex IV deficiency, appear sufficient to induce pain hypersensitivity, by ADP activation of P2Y1 receptors.
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MESH Headings
- Adenosine Diphosphate/metabolism
- Adenosine Monophosphate/metabolism
- Alkyl and Aryl Transferases/metabolism
- Animals
- Behavior, Animal
- Calcium/metabolism
- Cells, Cultured
- Electron Transport Complex IV/genetics
- Electron Transport Complex IV/metabolism
- Fluorescence
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Hypersensitivity/complications
- Hypersensitivity/pathology
- Membrane Proteins/metabolism
- Mice, Inbred C57BL
- Mice, Transgenic
- Mitochondria/drug effects
- Mitochondria/metabolism
- Mutation/genetics
- Neurons, Afferent/drug effects
- Neurons, Afferent/metabolism
- Neurons, Afferent/pathology
- Nociception/drug effects
- Pain/complications
- Pain/pathology
- Phenotype
- Purinergic P2Y Receptor Antagonists/pharmacology
- Receptors, Kainic Acid/metabolism
- Receptors, Purinergic P2Y1/metabolism
- Spinal Cord/pathology
- Synapses/drug effects
- Synapses/metabolism
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Affiliation(s)
- Rory Mitchell
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Graham Campbell
- Centre for Clinical Brain Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Chancellor's Building, Little France, Edinburgh, Edinburgh, EH16 4SB, UK
| | - Marta Mikolajczak
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Katie McGill
- Centre for Clinical Brain Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Chancellor's Building, Little France, Edinburgh, Edinburgh, EH16 4SB, UK
| | - Don Mahad
- Centre for Clinical Brain Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Chancellor's Building, Little France, Edinburgh, Edinburgh, EH16 4SB, UK
| | - Sue M Fleetwood-Walker
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
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6
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Abstract
There is substantial evidence indicating a role for glutamate in migraine. Levels of glutamate are higher in the brain and possibly also in the peripheral circulation in migraine patients, particularly during attacks. Altered blood levels of kynurenines, endogenous modulators of glutamate receptors, have been reported in migraine patients. Population genetic studies implicate genes that are involved with glutamate signaling in migraine, and gene mutations responsible for familial hemiplegic migraine and other familial migraine syndromes may influence glutamate signaling. Animal studies indicate that glutamate plays a key role in pain transmission, central sensitization, and cortical spreading depression. Multiple therapies that target glutamate receptors including magnesium, topiramate, memantine, and ketamine have been reported to have efficacy in the treatment of migraine, although with the exception of topiramate, the evidence for the efficacy of these therapies is not strong. Also, because all of these therapies have other mechanisms of action, it is not possible to conclude that the efficacy of these drugs is entirely due to their effects on glutamate receptors. Further studies are needed to more clearly delineate the possible roles of glutamate and its specific receptor subtypes in migraine and to identify new ways of targeting glutamate for migraine therapy.
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Affiliation(s)
- Jan Hoffmann
- Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246 Hamburg, Germany
| | - Andrew Charles
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles (UCLA), 635 Charles Young Drive, Los Angeles, CA 90095 USA
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7
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Fernández-Montoya J, Avendaño C, Negredo P. The Glutamatergic System in Primary Somatosensory Neurons and Its Involvement in Sensory Input-Dependent Plasticity. Int J Mol Sci 2017; 19:ijms19010069. [PMID: 29280965 PMCID: PMC5796019 DOI: 10.3390/ijms19010069] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 12/19/2017] [Accepted: 12/21/2017] [Indexed: 01/25/2023] Open
Abstract
Glutamate is the most common neurotransmitter in both the central and the peripheral nervous system. Glutamate is present in all types of neurons in sensory ganglia, and is released not only from their peripheral and central axon terminals but also from their cell bodies. Consistently, these neurons express ionotropic and metabotropic receptors, as well as other molecules involved in the synthesis, transport and release of the neurotransmitter. Primary sensory neurons are the first neurons in the sensory channels, which receive information from the periphery, and are thus key players in the sensory transduction and in the transmission of this information to higher centers in the pathway. These neurons are tightly enclosed by satellite glial cells, which also express several ionotropic and metabotropic glutamate receptors, and display increases in intracellular calcium accompanying the release of glutamate. One of the main interests in our group has been the study of the implication of the peripheral nervous system in sensory-dependent plasticity. Recently, we have provided novel evidence in favor of morphological changes in first- and second-order neurons of the trigeminal system after sustained alterations of the sensory input. Moreover, these anatomical changes are paralleled by several molecular changes, among which those related to glutamatergic neurotransmission are particularly relevant. In this review, we will describe the state of the art of the glutamatergic system in sensory ganglia and its involvement in input-dependent plasticity, a fundamental ground for advancing our knowledge of the neural mechanisms of learning and adaptation, reaction to injury, and chronic pain.
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Affiliation(s)
- Julia Fernández-Montoya
- Department of Anatomy, Histology and Neuroscience, Medical School, Autonoma University of Madrid, 28029 Madrid, Spain.
| | - Carlos Avendaño
- Department of Anatomy, Histology and Neuroscience, Medical School, Autonoma University of Madrid, 28029 Madrid, Spain.
| | - Pilar Negredo
- Department of Anatomy, Histology and Neuroscience, Medical School, Autonoma University of Madrid, 28029 Madrid, Spain.
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8
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Abstract
The study of glutamatergic synapses mainly focuses on the memory-related hippocampus. Recent studies in the cortical areas such as the anterior cingulate cortex (ACC) show that excitatory synapses can undergo long-term plastic changes in adult animals. Long-term potentiation (LTP) of cortical synapses may play important roles in chronic pain and anxiety. In addition to NMDA and AMPA receptors, kainate (KA) receptors have been found to play roles in synaptic transmission, regulation and presynaptic forms of LTP. In this brief review, I will summarize the new progress made on KA receptors, and propose that ACC synapses may provide a good synaptic model for understanding cortical mechanism for behavioral anxiety, and its related emotional disorders.
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Affiliation(s)
- Min Zhuo
- Center for Neuron and Disease, Frontier Institutes of Science and Technology, Xi'an Jiaotong University, Xi'an, Shanxi, 710049, China. .,Department of Physiology, Faculty of Medicine, University of Toronto, Medical Science Building, Room #3342, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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9
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Zhuo M. Ionotropic glutamate receptors contribute to pain transmission and chronic pain. Neuropharmacology 2017; 112:228-234. [DOI: 10.1016/j.neuropharm.2016.08.014] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/12/2016] [Accepted: 08/15/2016] [Indexed: 12/31/2022]
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10
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Andreou AP, Holland PR, Lasalandra MP, Goadsby PJ. Modulation of nociceptive dural input to the trigeminocervical complex through GluK1 kainate receptors. Pain 2015; 156:439-450. [PMID: 25679470 DOI: 10.1097/01.j.pain.0000460325.25762.c0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Migraine is a common and disabling neurologic disorder, with important psychiatric comorbidities. Its pathophysiology involves activation of neurons in the trigeminocervical complex (TCC). Kainate receptors carrying the glutamate receptor subunit 5 (GluK1) are present in key brain areas involved in migraine pathophysiology. To study the influence of kainate receptors on trigeminovascular neurotransmission, we determined the presence of GluK1 receptors within the trigeminal ganglion and TCC with immunohistochemistry. We performed in vivo electrophysiologic recordings from TCC neurons and investigated whether local or systemic application of GluK1 receptor antagonists modulated trigeminovascular transmission. Microiontophoretic application of a selective GluK1 receptor antagonist, but not of a nonspecific ionotropic glutamate receptor antagonist, markedly attenuated cell firing in a subpopulation of neurons activated in response to dural stimulation, consistent with selective inhibition of postsynaptic GluK1 receptor-evoked firing seen in all recorded neurons. In contrast, trigeminovascular activation was significantly facilitated in a different neuronal population. The clinically active kainate receptor antagonist LY466195 attenuated trigeminovascular activation in all neurons. In addition, LY466195 demonstrated an N-methyl-d-aspartate receptor-mediated effect. This study demonstrates a differential role of GluK1 receptors in the TCC, antagonism of which can inhibit trigeminovascular activation through postsynaptic mechanisms. Furthermore, the data suggest a novel, possibly presynaptic, modulatory role of trigeminocervical kainate receptors in vivo. Differential activation of kainate receptors suggests unique roles for this receptor in pro- and antinociceptive mechanisms in migraine pathophysiology.
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Affiliation(s)
- Anna P Andreou
- Headache Group, Department of Neurology, University of California, San Francisco, CA, USA Headache Research-Section of Anaesthetics, Pain Medicine and Intensive Care Section, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, UK, Headache Group, Basic and Clinical Neurosciences, King's College London, London, United Kingdom
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11
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Zhuo M. Canadian Association of Neuroscience Review: Cellular and Synaptic Insights into Physiological and Pathological Pain. Can J Neurol Sci 2014; 32:27-36. [PMID: 15825543 DOI: 10.1017/s031716710001684x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neurons and synapses in the central nervous system are plastic, undergoing long-term changes throughout life. Studies of molecular and cellular mechanisms of such changes not only provide important insight into how we learn and store new knowledge in our brains, but they also reveal the mechanisms of pathological changes that occur following injury. The author proposes that during induction, neuronal mechanisms underlying physiological functions, such as learning and memory, may share some common signaling molecules with abnormal or injury-related changes in the brain. Distinct synaptic and neuronal network mechanisms are involved in pathological pain as compared to cognitive learning and memory. Nociceptive information is transmitted and regulated at different levels of the brain, from the spinal cord to the forebrain. Furthermore, N-methyl-D-aspartate receptor-dependent and calcium-calmodulin activated adenylyl cyclases (AC1 and AC8) in the anterior cingulate cortex play important roles in the induction and expression of persistent inflammatory and neuropathic pain. Neuronal activity in the anterior cingulate cortex can also influence nociceptive transmission in the dorsal horn of the spinal cord by activating the endogenous facilitatory system. Our results provide important synaptic and molecular insights into physiological responses to injury.
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Affiliation(s)
- Min Zhuo
- Department of Physiology, Faculty of Medicine, University of Toronto Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada
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12
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Increased response to glutamate in small diameter dorsal root ganglion neurons after sciatic nerve injury. PLoS One 2014; 9:e95491. [PMID: 24748330 PMCID: PMC3991716 DOI: 10.1371/journal.pone.0095491] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 03/26/2014] [Indexed: 12/24/2022] Open
Abstract
Glutamate in the peripheral nervous system is involved in neuropathic pain, yet we know little how nerve injury alters responses to this neurotransmitter in primary sensory neurons. We recorded neuronal responses from the ex-vivo preparations of the dorsal root ganglia (DRG) one week following a chronic constriction injury (CCI) of the sciatic nerve in adult rats. We found that small diameter DRG neurons (<30 µm) exhibited increased excitability that was associated with decreased membrane threshold and rheobase, whereas responses in large diameter neurons (>30 µm) were unaffected. Puff application of either glutamate, or the selective ionotropic glutamate receptor agonists alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainic acid (KA), or the group I metabotropic receptor (mGluR) agonist (S)-3,5-dihydroxyphenylglycine (DHPG), induced larger inward currents in CCI DRGs compared to those from uninjured rats. N-methyl-D-aspartate (NMDA)-induced currents were unchanged. In addition to larger inward currents following CCI, a greater number of neurons responded to glutamate, AMPA, NMDA, and DHPG, but not to KA. Western blot analysis of the DRGs revealed that CCI resulted in a 35% increase in GluA1 and a 60% decrease in GluA2, the AMPA receptor subunits, compared to uninjured controls. mGluR1 receptor expression increased by 60% in the membrane fraction, whereas mGluR5 receptor subunit expression remained unchanged after CCI. These results show that following nerve injury, small diameter DRG neurons, many of which are nociceptive, have increased excitability and an increased response to glutamate that is associated with changes in receptor expression at the neuronal membrane. Our findings provide further evidence that glutamatergic transmission in the periphery plays a role in nociception.
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13
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Martinez-Perez JA, Iyengar S, Shannon HE, Bleakman D, Alt A, Arnold BM, Bell MG, Bleisch TJ, Castaño AM, Del Prado M, Dominguez E, Escribano AM, Filla SA, Ho KH, Hudziak KJ, Jones CK, Mateo A, Mathes BM, Mattiuz EL, Ogden AML, Simmons RMA, Stack DR, Stratford RE, Winter MA, Wu Z, Ornstein PL. GluK1 antagonists from 6-(carboxy)phenyl decahydroisoquinoline derivatives. SAR and evaluation of a prodrug strategy for oral efficacy in pain models. Bioorg Med Chem Lett 2013; 23:6459-62. [DOI: 10.1016/j.bmcl.2013.09.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/13/2013] [Accepted: 09/13/2013] [Indexed: 11/25/2022]
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14
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Caracciolo L, Fumagalli F, Carelli S, Madaschi L, La Via L, Bonini D, Fiorentini C, Barlati S, Gorio A, Barbon A. Kainate receptor RNA editing is markedly altered by acute spinal cord injury. J Mol Neurosci 2013; 51:903-10. [PMID: 23979837 DOI: 10.1007/s12031-013-0098-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 08/12/2013] [Indexed: 11/24/2022]
Abstract
We have previously observed changes in the RNA editing of AMPA receptors after acute spinal cord injury (SCI); this implies that post-transcriptional modifications are capable of affecting the physiological properties of glutamate receptor channels and related signal transduction in this neurodegenerative condition. Here, we report that the editing of the ionotropic KAR is markedly decreased at both GluK1 and GluK2 Q/R sites in the epicenter of the lesion and with distinct magnitude and kinetics also in the caudal and rostral portions of the injured cord. These effects are persistent, being observed as late as 30 days after lesioning. In addition, also the I/V and Y/C sites of GluK2 were severely affected after SCI. These findings add novel information to the relevance of editing of glutamate receptors following acute SCI, thus expanding the recently emerged role of post-transcriptional mechanisms under these experimental conditions.
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Affiliation(s)
- Luca Caracciolo
- Division of Biology and Genetics, Department of Molecular and Translational Medicine and National Institute of Neuroscience, University of Brescia, Viale Europa 11, 25123, Brescia, Italy
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15
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Ionotropic glutamate receptors and voltage-gated Ca²⁺ channels in long-term potentiation of spinal dorsal horn synapses and pain hypersensitivity. Neural Plast 2013; 2013:654257. [PMID: 24224102 PMCID: PMC3808892 DOI: 10.1155/2013/654257] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 08/27/2013] [Accepted: 08/27/2013] [Indexed: 12/18/2022] Open
Abstract
Over the last twenty years of research on cellular mechanisms of pain hypersensitivity, long-term potentiation (LTP) of synaptic transmission in the spinal cord dorsal horn (DH) has emerged as an important contributor to pain pathology. Mechanisms that underlie LTP of spinal DH neurons include changes in the numbers, activity, and properties of ionotropic glutamate receptors (AMPA and NMDA receptors) and of voltage-gated Ca2+ channels. Here, we review the roles and mechanisms of these channels in the induction and expression of spinal DH LTP, and we present this within the framework of the anatomical organization and synaptic circuitry of the spinal DH. Moreover, we compare synaptic plasticity in the spinal DH with classical LTP described for hippocampal synapses.
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16
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Sihra TS, Flores G, Rodríguez-Moreno A. Kainate receptors: multiple roles in neuronal plasticity. Neuroscientist 2013; 20:29-43. [PMID: 23439589 DOI: 10.1177/1073858413478196] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Ionotropic glutamate receptors of the N-methyl-d-aspartate (NMDA)- and AMPA-type, as well as metabotropic glutamate receptors have been extensively invoked in plasticity. Until relatively recently, however, kainate-type receptors (KARs) had been the most elusive to study because of the lack of appropriate pharmacological tools to specifically address their roles. With the development of selective glutamate receptor antagonists, and knockout mice with specific KAR subunits deleted, the functions of KARs in neuromodulation and synaptic transmission, together with their involvement in some types of plasticity, have been extensively probed in the central nervous system. In this review, we summarize the findings related to the roles of KARs in short- and long-term forms of plasticity, primarily in the hippocampus, where KAR function and synaptic plasticity have received avid attention.
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Affiliation(s)
- Talvinder S Sihra
- 1Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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17
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Bhangoo SK, Swanson GT. Kainate receptor signaling in pain pathways. Mol Pharmacol 2012; 83:307-15. [PMID: 23095167 DOI: 10.1124/mol.112.081398] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Receptors and channels that underlie nociceptive signaling constitute potential sites of intervention for treatment of chronic pain states. The kainate receptor family of glutamate-gated ion channels represents one such candidate set of molecules. They have a prominent role in modulation of excitatory signaling between sensory and spinal cord neurons. Kainate receptors are also expressed throughout central pain neuraxis, where their functional contributions to neural integration are less clearly defined. Pharmacological inhibition or genetic ablation of kainate receptor activity reduces pain behaviors in a number of animal models of chronic pain, and small clinical trials have been conducted using several orthosteric antagonists. This review will cover kainate receptor function and participation in pain signaling as well as the pharmacological studies supporting further consideration as potential targets for therapeutic development.
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Affiliation(s)
- Sonia K Bhangoo
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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18
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Samengo I, Currò D, Navarra P, Barrese V, Taglialatela M, Martire M. Molecular and pharmacological evidence for a facilitatory functional role of pre-synaptic GLUK2/3 kainate receptors on GABA release in rat trigeminal caudal nucleus. Eur J Pain 2012; 16:1148-57. [PMID: 22392917 PMCID: PMC3444694 DOI: 10.1002/j.1532-2149.2012.00122.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/22/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND Gamma-aminobutyric acid (GABA) and glutamate (GLU) are involved in nociceptive signals processing in the trigeminal system. In this study, we investigated the influence of excitatory transmission on GABA release in nerve terminals isolated from the rat trigeminal caudal nucleus (TCN). METHODS We utilize biochemical (superfused synaptosomes loaded with [(3) H]GABA) and morphological (immunofluorescence experiments with specific antibody) techniques. RESULTS Our results show that GLU potentiates the release of [(3) H]GABA evoked by 9, 15 and 30 mM [K(+)](e); 15 mM [K(+)](e)-evoked [(3) H]GABA release was also reinforced by domoate and kainate (KA), two naturally occurring GLU-receptor agonists. The enhancement of 15 mM [K(+)](e)-evoked [(3) H]GABA release produced by 100 μM KA was abolished by NBQX, a mixed AMPA/KA receptor antagonist, but was not affected by GYKI52466, a selective AMPA receptor antagonist. ATPA, a selective agonist for KA receptors containing the GLUK1 subunit, had no effect on depolarization-induced [(3) H]GABA release, and UBP310, which selectively antagonizes these same receptors, failed to reverse the KA-induced potentiation of 15 mM [K(+)](e)-evoked [(3) H]GABA release. The KA-induced potentiation was also unaffected by concanavalin A (10 μM), a positive allosteric modulator of GLUK1- and GLUK2-containing KA receptors. Immunofluorescence experiments revealed that GABAergic nerve terminals in the TCN differentially expressed GLUK subunits, with GLUK2/3-positive terminals being twice more abundant than GLUK1-containing synaptosomes. CONCLUSIONS These findings indicate that pre-synaptic KA receptors facilitating GABA release from TCN nerve terminals mainly express GLUK2/GLUK3 subunits, supporting the notion that different types of KA receptors are involved in the various stages of pain transmission.
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Affiliation(s)
- I Samengo
- Institute of Pharmacology, Catholic University of Sacred Heart, Rome, Italy
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19
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Sherwood JL, Amici M, Dargan SL, Culley GR, Fitzjohn SM, Jane DE, Collingridge GL, Lodge D, Bortolotto ZA. Differences in kainate receptor involvement in hippocampal mossy fibre long-term potentiation depending on slice orientation. Neurochem Int 2012; 61:482-9. [PMID: 22564530 DOI: 10.1016/j.neuint.2012.04.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 04/11/2012] [Accepted: 04/22/2012] [Indexed: 10/28/2022]
Abstract
Long-term potentiation (LTP) is a well-established experimental model used to investigate the synaptic basis of learning and memory. LTP at mossy fibre - CA3 synapses in the hippocampus is unusual because it is normally N-methyl-d-aspartate (NMDA) receptor-independent. Instead it seems that the trigger for mossy fibre LTP involves kainate receptors (KARs). Although it is generally accepted that pre-synaptic KARs play an essential role in frequency facilitation and LTP, their subunit composition remains a matter of significant controversy. We have reported previously that both frequency facilitation and LTP can be blocked by selective antagonism of GluK1 (formerly GluR5/Glu(K5))-containing KARs, but other groups have failed to reproduce this effect. Moreover, data from receptor knockout and mRNA expression studies argue against a major role of GluK1, supporting a more central role for GluK2 (formerly GluR6/Glu(K6)). A potential reason underlying the controversy in the pharmacological experiments may reside in differences in the preparations used. Here we show differences in pharmacological sensitivity of synaptic plasticity at mossy fibre - CA3 synapses depend critically on slice orientation. In transverse slices, LTP of fEPSPs was invariably resistant to GluK1-selective antagonists whereas in parasagittal slices LTP was consistently blocked by GluK1-selective antagonists. In addition, there were pronounced differences in the magnitude of frequency facilitation and the sensitivity to the mGlu2/3 receptor agonist DCG-IV. Using anterograde labelling of granule cells we show that slices of both orientations possess intact mossy fibres and both large and small presynaptic boutons. Transverse slices have denser fibre tracts but a smaller proportion of giant mossy fibre boutons. These results further demonstrate a considerable heterogeneity in the functional properties of the mossy fibre projection.
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Affiliation(s)
- John L Sherwood
- MRC Centre for Synaptic Plasticity, School of Physiology & Pharmacology, University of Bristol, BS8 1TD, UK.
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20
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Maihöfner C, DeCol R. Decreased perceptual learning ability in complex regional pain syndrome. Eur J Pain 2012; 11:903-9. [PMID: 17451979 DOI: 10.1016/j.ejpain.2007.03.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2006] [Revised: 02/27/2007] [Accepted: 03/10/2007] [Indexed: 11/19/2022]
Abstract
Recently, several functional imaging studies have shown that sensorimotor cortical representations may be changed in complex regional pain syndromes (CRPS). Therefore, we investigated tactile performance and tactile learning as indirect markers of cortical changes in patients with CRPS type I and controls. Patients had significant higher spatial discrimination thresholds at CRPS-affected extremities compared to both unaffected sides and control subjects. Furthermore, in order to improve tactile spatial acuity we used a Hebbian stimulation protocol of tactile coactivation. This consistently improved tactile acuity, both in controls and patients. However, the gain of performance was significantly lower on the CRPS-affected side implying an impaired perceptual learning ability. Therefore, we provide further support for an involvement of the CNS in CRPS, which may have implications to future neurorehabilitation strategies for this disease.
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Affiliation(s)
- Christian Maihöfner
- Department of Neurology and Institute for Physiology and Experimental Pathophysiology, University of Erlangen-Nuremberg, Schwabachanlage 6, D-91054 Erlangen, Germany.
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21
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Irvine MW, Costa BM, Dlaboga D, Culley GR, Hulse R, Scholefield CL, Atlason P, Fang G, Eaves R, Morley R, Mayo-Martin MB, Amici M, Bortolotto ZA, Donaldson L, Collingridge GL, Molnár E, Monaghan DT, Jane DE. Piperazine-2,3-dicarboxylic acid derivatives as dual antagonists of NMDA and GluK1-containing kainate receptors. J Med Chem 2011; 55:327-41. [PMID: 22111545 DOI: 10.1021/jm201230z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Competitive N-methyl-d-aspartate receptor (NMDAR) antagonists bind to the GluN2 subunit, of which there are four types (GluN2A-D). We report that some N(1)-substituted derivatives of cis-piperazine-2,3-dicarboxylic acid display improved relative affinity for GluN2C and GluN2D versus GluN2A and GluN2B. These derivatives also display subtype selectivity among the more distantly related kainate receptor family. Compounds 18i and (-)-4 were the most potent kainate receptor antagonists, and 18i was selective for GluK1 versus GluK2, GluK3 and AMPA receptors. Modeling studies revealed structural features required for activity at GluK1 subunits and suggested that S674 was vital for antagonist activity. Consistent with this hypothesis, replacing the equivalent residue in GluK3 (alanine) with a serine imparts 18i antagonist activity. Antagonists with dual GluN2D and GluK1 antagonist activity may have beneficial effects in various neurological disorders. Consistent with this idea, antagonist 18i (30 mg/kg ip) showed antinociceptive effects in an animal model of mild nerve injury.
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Affiliation(s)
- Mark W Irvine
- MRC Centre for Synaptic Plasticity, University of Bristol, Medical Sciences Building, University Walk, Bristol, BS8 1TD, U.K
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22
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Joseph DJ, Williams DJ, MacDermott AB. Modulation of neurite outgrowth by activation of calcium-permeable kainate receptors expressed by rat nociceptive-like dorsal root ganglion neurons. Dev Neurobiol 2011; 71:818-35. [PMID: 21557511 PMCID: PMC3973019 DOI: 10.1002/dneu.20906] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Neurite outgrowth is a fundamental step in establishing proper neuronal connections in the developing central nervous system. Dynamic control of outgrowth has been attributed to changes in growth cone Ca2+ levels in response to extracellular cues. Here we have investigated a possible role for Ca2+ permeable kainate (KA) receptors in regulating neurite outgrowth of nociceptive-like dorsal root ganglion (DRG) neurons. To identify KA receptor subunits likely to be involved, we used quantitative RT-PCR on acutely dissociated DRG and dorsal horn neurons. DRG neurons expressed more GluK1, particularly the GluK1b spice variant, than dorsal horn neurons. Conversely, dorsal horn neurons expressed more GluK2, particularly GluK2a, than DRG neurons. Further, an RNA editing assay indicated that the majority of GluK1 and GluK2 mRNA transcripts in DRG were unedited. Imaging Ca2+ transients following application of a KA receptor agonist to DRG and dorsal horn co-cultures revealed increases in intracellular Ca2+ in the growth cones of DRG neurons. In the majority of cases, this increase in Ca2+ was partly or completely blocked by Joro spider toxin (JSTX), an antagonist for Ca2+-permeable AMPA and KA receptors. Treatment of DRG/dorsal horn co-cultures with KA for 18 hours suppressed neurite outgrowth while application of the rapidly desensitizing KA receptor agonist SYM 2081, the competitive AMPA/KA receptor antagonist, CNQX, and JSTX or philanthotoxin enhanced neurite outgrowth and prevented KA effects on neurite outgrowth. Thus, Ca2+ entry through KA receptors at the growth cone of DRG neurons may be an important regulator of neurite outgrowth.
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Affiliation(s)
- Donald J. Joseph
- Program in Neurobiology and Behavior-Department of Neuroscience, Columbia University, New York, NY 10032
| | - Damian J. Williams
- Department of Physiology and Biophysics, Columbia University, New York, NY 10032
| | - Amy B. MacDermott
- Program in Neurobiology and Behavior-Department of Neuroscience, Columbia University, New York, NY 10032
- Department of Physiology and Biophysics, Columbia University, New York, NY 10032
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23
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Nisticò R, Dargan SL, Amici M, Collingridge GL, Bortolotto ZA. Synergistic interactions between kainate and mGlu receptors regulate bouton Ca signalling and mossy fibre LTP. Sci Rep 2011; 1:103. [PMID: 22355621 PMCID: PMC3216588 DOI: 10.1038/srep00103] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 09/07/2011] [Indexed: 12/04/2022] Open
Abstract
It is currently unknown why glutamatergic presynaptic terminals express multiple types of glutamate receptors. We have addressed this question by studying both acute and long-term regulation of mossy fibre function in the hippocampus. We find that inhibition of both mGlu1 and mGlu5 receptors together can block the induction of mossy fibre LTP. Furthermore, mossy fibre LTP can be induced by the pharmacological activation of either mGlu1 or mGlu5 receptors, provided that kainate receptors are also stimulated. Like conventional mossy fibre LTP, chemically-induced mossy fibre LTP (chem-LTPm) depends on Ca2+ release from intracellular stores and the activation of PKA. Similar synergistic interactions between mGlu receptors and kainate receptors were observed at the level of Ca2+ signalling in individual giant mossy fibre boutons. Thus three distinct glutamate receptors interact, in both an AND and OR gate fashion, to regulate both immediate and long-term presynaptic function in the brain.
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Affiliation(s)
- Robert Nisticò
- MRC Centre for Synaptic Plasticity, School of Physiology and Pharmacology, University of Bristol, Bristol, BS8 1TD, United Kingdom
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24
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Metabotropic actions of kainate receptors in dorsal root ganglion cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011. [PMID: 21713668 DOI: 10.1007/978-1-4419-9557-5_7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Kainate receptors are widely distributed in the CNS, but also in the PNS. Dorsal root ganglia are enriched in this subtype of glutamate ionotropic receptors. In addition to their activity as ligand-gated ion channels, kainate receptors exhibit other properties already characterized in other systems, such as hippocampus, i.e., their ability to induce a metabotropic cascade signalling, through G-protein and PKC activation. With a very similar actuation mechanism as formerly described in the CNS, kainate receptors in the DRG also present other differentiated features, such as the Ca(2+) channel blockade and a self-regulation property. The peculiarity of these neurons has served to progress the study of kainate receptors. Nevertheless, many other physiological functions of these receptors remain unclear, as does the related molecular nature of the metabotropic cascade and the involvement of this signalling pathway with sensory transmission of pain.
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25
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Antinociceptive effects of MSVIII-19, a functional antagonist of the GluK1 kainate receptor. Pain 2011; 152:1052-1060. [PMID: 21324591 DOI: 10.1016/j.pain.2011.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 12/16/2010] [Accepted: 01/11/2011] [Indexed: 11/21/2022]
Abstract
The ionotropic glutamate receptor subunit, GluK1 (GluR5), is expressed in many regions of the nervous system related to sensory transmission. Recently, a selective ligand for the GluK1 receptor, MSVIII-19 (8,9-dideoxy-neodysiherbaine), was synthesized as a derivative of dysiherbaine, a toxin isolated from the marine sponge Lendenfeldia chondrodes. MSVIII-19 potently desensitizes GluK1 receptors without channel activation, rendering it useful as a functional antagonist. Given the high selectivity for GluK1 and the proposed role for this glutamate receptor in nociception, we sought to test the analgesic potential of MSVIII-19 in a series of models of inflammatory, neuropathic, and visceral pain in mice. MSVIII-19 delivered intrathecally dose-dependently reduced formalin-induced spontaneous behaviors and reduced thermal hypersensitivity 3 hours after formalin injection and 24 hours after complete Freund's adjuvant-induced inflammation, but had no effect on mechanical sensitivity in the same models. Intrathecal MSVIII-19 significantly reduced both thermal hyperalgesia and mechanical hypersensitivity in the chronic constriction injury model of neuropathic pain, but had no effect in the acetic acid model of visceral pain. Peripheral administration of MSVIII-19 had no analgesic efficacy in any of these models. Finally, intrathecal MSVIII-19 did not alter responses in Tail-flick tests or performance on the accelerating RotaRod. These data suggest that spinal administration of MSVIII-19 reverses hypersensitivity in several models of pain in mice, supporting the clinical potential of GluK1 antagonists for the management of pain.
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26
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Gregus AM, Inra CN, Giordano TP, Costa ACS, Rajadhyaksha AM, Inturrisi CE. Spinal mediators that may contribute selectively to antinociceptive tolerance but not other effects of morphine as revealed by deletion of GluR5. Neuroscience 2010; 169:475-87. [PMID: 20359526 DOI: 10.1016/j.neuroscience.2010.03.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 03/23/2010] [Accepted: 03/23/2010] [Indexed: 12/22/2022]
Abstract
Several groups maintain that morphine tolerance and dependence correlate with increased activity of protein kinases ERK1/2 and P38 MAPK and PKC as well as elevated levels of the neuropeptides dynorphin (DYN), substance P (sP), and calcitonin gene-related peptide (CGRP) in spinal cord dorsal horn (SCDH). They demonstrate that tolerance and dependence can be prevented, and sometimes reversed, by constitutive genetic deletion or pharmacological inhibition of these factors. Recently, we showed that mice with a constitutive deletion of the GluR5 subunit of kainate receptors (GluR5 KO) are not different from wild type (WT) littermates with respect to baseline nociceptive thresholds as well as acute morphine antinociception, morphine physical dependence and conditioned place preference. However, unlike WT, GluR5 KO mice do not develop antinociceptive tolerance following systemic morphine administration. In this report, we examined levels of these mediators in SCDH of WT and GluR5 KO mice following subcutaneous implantation of placebo or morphine pellets. Surprisingly, spinal DYN and CGRP, along with phosphorylated ERK2 (pERK2), P38 (pP38) and PKCgamma (pPKCgamma) are elevated by deletion of GluR5. Additionally, chronic systemic morphine administration increased spinal pERK2, pP38 and pPKCgamma levels in both tolerant WT and non-tolerant GluR5 KO mice. In contrast, while morphine increased spinal DYN and CGRP in WT mice, DYN remained unchanged and CGRP was reduced in GluR5 KO mice. These observations suggest that spinal ERK2, P38 and PKCgamma are likely involved in multiple adaptive responses following systemic morphine administration, whereas DYN and CGRP may contribute selectively to the development of antinociceptive tolerance.
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Affiliation(s)
- A M Gregus
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065, USA
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27
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Andreou AP, Goadsby PJ. Therapeutic potential of novel glutamate receptor antagonists in migraine. Expert Opin Investig Drugs 2009; 18:789-803. [PMID: 19426123 DOI: 10.1517/13543780902913792] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Migraine is a common and disabling neurological disorder. Although the pharmacotherapy of migraine has advanced in parallel with our understanding of the pathophysiology of the disease, there is still a considerable unmet need to find more effective treatments. Migraine pathophysiology involves activation or the perception of activation of the trigeminovascular system. Glutamate, the major excitatory neurotransmitter in the CNS, is implicated in elements of the pathophysiology of the disorder, including trigeminovascular activation, central sensitization and cortical spreading depression. OBJECTIVE The aim of this article is to review the potential use of glutamate receptor antagonists as innovative neuronally targeted treatments of migraine. METHODS A systematic search of peer-reviewed publications was performed in PubMed on glutamate and migraine/trigeminovascular activation, and important references providing an insight into migraine pathophysiology are included. The results of unpublished trials were obtained from presentations at national and international meetings. RESULTS/CONCLUSIONS The preclinical and clinical data argue strongly for a role of glutamatergic receptor activation in migraine. The pharmacology of glutamatergic trigeminovascular responses in brain areas involved in migraine pathophysiology is relevant to the development of new therapies for this disabling condition. Glutamate receptors represent a promising target for a valuable, non-vasoconstrictor, and perhaps more importantly neuronal-specific therapeutic approach to the treatment of migraine.
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Affiliation(s)
- Anna P Andreou
- Headache Group, Department of Neurology, University of California-San Francisco, 1635 Divisadero St, San Francisco, CA 94115, USA
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28
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GLUK1 receptor antagonists and hippocampal mossy fiber function. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 85:13-27. [PMID: 19607958 DOI: 10.1016/s0074-7742(09)85002-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Kainate receptors, one of the three subtypes of ionotropic receptors for the excitatory transmitter l-glutamate, play a variety of functions in the regulation of synaptic activity. Their physiological properties and functional roles have been identified only recently, following the discovery of selective pharmacological tools that allow for isolation of kainate receptor-mediated events. A considerable amount of data indicates that this class of glutamate receptors is located both at the pre- and postsynaptic site, playing a special role in regulating transmission and controlling short- and long-term plasticity. In this review, we summarize some data obtained in our laboratory over the last decade illustrating how various ligands have contributed to our understanding of the physiological role for neuronal kainate receptors. In particular, we show that the GluK1-containing KARs are important for regulating synaptic facilitation and LTP induction at hippocampal mossy fiber synapses.
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Kainate receptors: Pharmacology, function and therapeutic potential. Neuropharmacology 2009; 56:90-113. [DOI: 10.1016/j.neuropharm.2008.08.023] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/04/2008] [Accepted: 08/07/2008] [Indexed: 01/28/2023]
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30
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De R, Maihöfner C. Centrally mediated sensory decline induced by differential C-fiber stimulation. Pain 2008; 138:556-564. [DOI: 10.1016/j.pain.2008.02.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 01/21/2008] [Accepted: 02/04/2008] [Indexed: 11/24/2022]
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Abstract
Disorders of the central nervous system (CNS) are complex disease states that represent a major challenge for modern medicine. Although aetilogy is often unknown, it is established that multiple factors such as defects in genetics and/or epigenetics, the environment as well as imbalance in neurotransmitter receptor systems are all at play in determining an individual's susceptibility to disease. Gene therapy is currently not available and therefore, most conditions are treated with pharmacological agents that modify neurotransmitter receptor signaling. Here, I provide a review of ionotropic glutamate receptors (iGluRs) and the roles they fulfill in numerous CNS disorders. Specifically, I argue that our understanding of iGluRs has reached a critical turning point to permit, for the first time, a comprehensive re-evaluation of their role in the cause of disease. I illustrate this by highlighting how defects in AMPA receptor (AMPAR) trafficking are important to fragile X mental retardation and ectopic expression of kainate receptor (KAR) synapses contributes to the pathology of temporal lobe epilepsy. Finally, I discuss how parallel advances in studies of other neurotransmitter systems may allow pharmacologists to work towards a cure for many CNS disorders rather than developing drugs to treat their symptoms.
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Affiliation(s)
- Derek Bowie
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec, Canada.
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33
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Abstract
The release of transmitters through vesicle exocytosis from nerve terminals is not constant but is subject to modulation by various mechanisms, including prior activity at the synapse and the presence of neurotransmitters or neuromodulators in the synapse. Instantaneous responses of postsynaptic cells to released transmitters are mediated by ionotropic receptors. In contrast to metabotropic receptors, ionotropic receptors mediate the actions of agonists in a transient manner within milliseconds to seconds. Nevertheless, transmitters can control vesicle exocytosis not only via slowly acting metabotropic, but also via fast acting ionotropic receptors located at the presynaptic nerve terminals. In fact, members of the following subfamilies of ionotropic receptors have been found to control transmitter release: ATP P2X, nicotinic acetylcholine, GABA(A), ionotropic glutamate, glycine, 5-HT(3), andvanilloid receptors. As these receptors display greatly diverging structural and functional features, a variety of different mechanisms are involved in the regulation of transmitter release via presynaptic ionotropic receptors. This text gives an overview of presynaptic ionotropic receptors and briefly summarizes the events involved in transmitter release to finally delineate the most important signaling mechanisms that mediate the effects of presynaptic ionotropic receptor activation. Finally, a few examples are presented to exemplify the physiological and pharmacological relevance of presynaptic ionotropic receptors.
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Affiliation(s)
- M M Dorostkar
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitäts-platz 4, Graz, Austria
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34
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Bourane S, Méchaly I, Venteo S, Garces A, Fichard A, Valmier J, Carroll P. A SAGE-based screen for genes expressed in sub-populations of neurons in the mouse dorsal root ganglion. BMC Neurosci 2007; 8:97. [PMID: 18021428 PMCID: PMC2241628 DOI: 10.1186/1471-2202-8-97] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Accepted: 11/19/2007] [Indexed: 01/23/2023] Open
Abstract
Background The different sensory modalities temperature, pain, touch and muscle proprioception are carried by somatosensory neurons of the dorsal root ganglia. Study of this system is hampered by the lack of molecular markers for many of these neuronal sub-types. In order to detect genes expressed in sub-populations of somatosensory neurons, gene profiling was carried out on wild-type and TrkA mutant neonatal dorsal root ganglia (DRG) using SAGE (serial analysis of gene expression) methodology. Thermo-nociceptors constitute up to 80 % of the neurons in the DRG. In TrkA mutant DRGs, the nociceptor sub-class of sensory neurons is lost due to absence of nerve growth factor survival signaling through its receptor TrkA. Thus, comparison of wild-type and TrkA mutants allows the identification of transcripts preferentially expressed in the nociceptor or mechano-proprioceptor subclasses, respectively. Results Our comparison revealed 240 genes differentially expressed between the two tissues (P < 0.01). Some of these genes, CGRP, Scn10a are known markers of sensory neuron sub-types. Several potential markers of sub-populations, Dok4, Crip2 and Grik1/GluR5 were further analyzed by quantitative RT-PCR and double labeling with TrkA,-B,-C, c-ret, parvalbumin and isolectin B4, known markers of DRG neuron sub-types. Expression of Grik1/GluR5 was restricted to the isolectin B4+ nociceptive population, while Dok4 and Crip2 had broader expression profiles. Crip2 expression was however excluded from the proprioceptor sub-population. Conclusion We have identified and characterized the detailed expression patterns of three genes in the developing DRG, placing them in the context of the known major neuronal sub-types defined by molecular markers. Further analysis of differentially expressed genes in this tissue promises to extend our knowledge of the molecular diversity of different cell types and forms the basis for understanding their particular functional specificities.
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35
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Sarchielli P, Di Filippo M, Nardi K, Calabresi P. Sensitization, glutamate, and the link between migraine and fibromyalgia. Curr Pain Headache Rep 2007; 11:343-51. [PMID: 17894924 DOI: 10.1007/s11916-007-0216-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Recent advances have shed insight on the pathophysiologic mechanisms of fibromyalgia and migraine, especially in the chronic form. A growing body of evidence supports the involvement of peripheral and central sensitization disturbances of pain-related processes underlying both disorders. They involve increased glutamate transmission through interaction with its ionotropic and metabotropic receptors. Few studies supporting the implication of this excitatory amino acid in chronic migraine and primary fibromyalgia demonstrated increased levels of glutamate in the cerebrospinal fluid of affected patients. These findings have implications for future therapies directed against glutamate receptors (in particular, N-methyl-D-aspartate receptors). Limited clinical experience in this regard, although promising, does not exclude additional mechanisms contributing to the maintenance of pain, which can be the target of therapeutic approaches in both disorders.
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Affiliation(s)
- Paola Sarchielli
- Neurologic Clinic, Department of Medical and Surgical Specialties and Public Health, University of Perugia, Ospedale Santa Maria della Misericordia, Via Santa Andrea delle Fratte, San Sisto, 06158 Perugia, Italy.
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36
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Kainate receptors are primarily postsynaptic to SP-containing axon terminals in the trigeminal dorsal horn. Brain Res 2007; 1184:149-59. [PMID: 17964552 DOI: 10.1016/j.brainres.2007.09.070] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 09/25/2007] [Accepted: 09/26/2007] [Indexed: 02/05/2023]
Abstract
Kainate receptors (KARs) are involved in the modulation and transmission of nociceptive information from peripheral afferents to neurons in the spinal cord and trigeminal dorsal horns. KARs are found at both pre- and postsynaptic sites in the dorsal horn. We hypothesized that KARs and Substance P (SP), a modulatory neuropeptide that is used as a marker of nociceptive afferents, have a complex interactive relationship. To determine the cellular relationship and connectivity between KARs and SP afferents, we used electron microscopic dual immunocytochemical analysis to examine the ultrastructural localization of KAR subunits GluR5, 6 and 7 (GluR5,6,7) in relation to SP within laminae I and II in the rat trigeminal dorsal horn. KARs were distributed both postsynaptically in dendrites and somata (51% of GluR5,6,7 immunoreactive (-ir) profiles) and presynaptically in axons and axon terminals (45%). We also found GluR5,6,7-ir glial profiles (5%). The majority of SP-ir profiles were presynaptic axons and axon terminals. SP-ir dendritic profiles were rare, yet 23% contained GluR5,6,7 immunoreactivity. GluR5,6,7 and SP were also colocalized at presynaptic sites (18% of GluR5,6,7-ir axons and axon terminals contained SP; while 11% of SP-ir axons and axon terminals contained GluR5,6,7). The most common interaction between KARs and SP we observed was GluR5,6,7-ir dendrites contacted by SP-ir axon terminals; 54% of the dendritic targets of SP-ir axon terminals were GluR5,6,7-ir. These results provide anatomical evidence that KARs primarily mediate nociceptive transmission postsynaptic to SP-containing afferents and may also modulate the presynaptic release of SP and glutamate in trigeminal dorsal horn.
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37
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Weng HR, Chen JH, Pan ZZ, Nie H. Glial glutamate transporter 1 regulates the spatial and temporal coding of glutamatergic synaptic transmission in spinal lamina II neurons. Neuroscience 2007; 149:898-907. [PMID: 17935889 DOI: 10.1016/j.neuroscience.2007.07.063] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2007] [Revised: 06/18/2007] [Accepted: 08/06/2007] [Indexed: 10/22/2022]
Abstract
Glutamatergic synaptic transmission is a dynamic process determined by the amount of glutamate released by presynaptic sites, the clearance of glutamate in the synaptic cleft, and the properties of postsynaptic glutamate receptors. Clearance of glutamate in the synaptic cleft depends on passive diffusion and active uptake by glutamate transporters. In this study, we examined the role of glial glutamate transporter 1 (GLT-1) in spinal sensory processing. Excitatory postsynaptic currents (EPSCs) of substantia gelatinosa neurons recorded from spinal slices of young adult rats were analyzed before and after GLT-1 was pharmacologically blocked by dihydrokainic acid. Inhibition of GLT-1 prolonged the EPSC duration and the EPSC decay phase. The EPSC amplitudes were increased in neurons with weak synaptic input but decreased in neurons with strong synaptic input upon inhibition of GLT-1. We suggest that presynaptic inhibition, desensitization of postsynaptic AMPA receptors, and glutamate "spillover" contributed to the kinetic change of EPSCs induced by the blockade of GLT-1. Thus, GLT-1 is a key component in maintaining the spatial and temporal coding in signal transmission at the glutamatergic synapse in substantia gelatinosa neurons.
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Affiliation(s)
- H-R Weng
- Department of Anesthesiology and Pain Medicine, The University of Texas M. D. Anderson Cancer Center, 1400 Holcombe Boulevard, Unit 42, Houston, TX 77030-4009, USA.
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38
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Wu LJ, Xu H, Ren M, Zhuo M. Genetic and pharmacological studies of GluR5 modulation of inhibitory synaptic transmission in the anterior cingulate cortex of adult mice. Dev Neurobiol 2007; 67:146-57. [PMID: 17443779 DOI: 10.1002/dneu.20331] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the anterior cingulate cortex (ACC), GluR5-containing kainate receptor mediated the small portion of excitatory postsynaptic current. However, little is known about its role in modulation of neurotransmitter release in this brain region. In the present study, we address this question by using selective GluR5 agonist and antagonist, as well as GluR5(-/-) mice. Our results showed that activation of GluR5 induced action potential-dependent GABA release, which is also required for the activation of voltage-dependent calcium channel and Ca(2+) influx. The effect of GluR5 activation is selective to the GABAergic, but not glutamatergic synaptic transmission. Endogenous activation of GluR5 also enhanced GABA release to ACC pyramidal neurons and the corresponding postsynaptic tonic GABA current. Our results suggest the somatodendritic, but not presynaptic GluR5, in modulation of GABA release. The endogenous GluR5 activation and the subsequent tonic GABA current may play an inhibitory role in ACC-related brain functions.
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Affiliation(s)
- Long-Jun Wu
- Department of Physiology, Faculty of Medicine, University of Toronto, Medical Science Building, Toronto, Ontario, Canada M5S 1A8
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39
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Davila NG, Houpt TA, Trombley PQ. Expression and function of kainate receptors in the rat olfactory bulb. Synapse 2007; 61:320-34. [PMID: 17318880 DOI: 10.1002/syn.20376] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Although recent results suggest roles for NMDA and AMPA receptors in odor encoding, little is known about kainate receptors (KARs) in the olfactory bulb (OB). Molecular, immunological, and electrophysiological techniques were used to provide a functional analysis of KARs in the OB. Reverse transcriptase-polymerase chain reaction revealed that the relative level of expression of KAR subunits was GluR5 approximately GluR6 approximately KA2 > KA1 >> GluR7. In situ hybridization data imply that mitral/tufted cells express mostly GluR5 and KA2, whereas interneurons express mostly GluR6 and KA2. Immunohistochemical double-labeling experiments (GluR5/6/7 or GluR5 + synapsin) suggest that KARs are expressed at both synaptic and extrasynaptic loci. This heterogeneous expression of KAR subunits suggests that KARs may play a multitude of roles in odor processing, each tailored to the function of specific OB circuits. A functional analysis, using whole-cell electrophysiology, suggests that one such role is to increase the frequency of glutamate transmission while attenuating the amplitude of individual events, likely via a presynaptic depolarizing mechanism. Such effects would be important to odor processing particularly by OB glomeruli. In these highly compartmentalized structures, an increase in the frequency of glutamate release and the high density of extrasynaptic KARs, activated by spillover, could enhance glomerular synchronization and thus the transfer of more specific sensory information to cortical structures.
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Affiliation(s)
- Nestor G Davila
- Department of Biological Science, Program in Neuroscience, Florida State University, Tallahassee, Florida 32306, USA
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40
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Dolman NP, More JCA, Alt A, Knauss JL, Pentikäinen OT, Glasser CR, Bleakman D, Mayer ML, Collingridge GL, Jane DE. Synthesis and Pharmacological Characterization of N3-Substituted Willardiine Derivatives: Role of the Substituent at the 5-Position of the Uracil Ring in the Development of Highly Potent and Selective GLUK5Kainate Receptor Antagonists. J Med Chem 2007; 50:1558-70. [PMID: 17348638 DOI: 10.1021/jm061041u] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Some N3-substituted analogues of willardiine such as 11 and 13 are selective kainate receptor antagonists. In an attempt to improve the potency and selectivity for kainate receptors, a range of analogues of 11 and 13 were synthesized with 5-substituents on the uracil ring. An X-ray crystal structure of the 5-methyl analogue of 13 bound to GLUK5 revealed that there was allowed volume around the 4- and 5-positions of the thiophene ring, and therefore the 4,5-dibromo and 5-phenyl (67) analogues were synthesized. Compound 67 (ACET) demonstrated low nanomolar antagonist potency on native and recombinant GLUK5-containing kainate receptors (KB values of 7 +/- 1 and 5 +/- 1 nM for antagonism of recombinant human GLUK5 and GLUK5/GLUK2, respectively) but displayed IC50 values >100 microM for antagonism of GLUA2, GLUK6, or GLUK6/GLUK2.
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MESH Headings
- Alanine/analogs & derivatives
- Alanine/chemical synthesis
- Alanine/chemistry
- Alanine/pharmacology
- Animals
- Animals, Newborn
- Binding Sites
- Calcium/metabolism
- Cell Line
- Crystallography, X-Ray
- Humans
- In Vitro Techniques
- Ligands
- Models, Molecular
- Motor Neurons/drug effects
- Motor Neurons/physiology
- Nerve Fibers, Unmyelinated/drug effects
- Nerve Fibers, Unmyelinated/physiology
- Protein Conformation
- Pyrimidinones/chemical synthesis
- Pyrimidinones/chemistry
- Pyrimidinones/pharmacology
- Rats
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/genetics
- Receptors, AMPA/physiology
- Receptors, Kainic Acid/antagonists & inhibitors
- Receptors, Kainic Acid/genetics
- Receptors, Kainic Acid/physiology
- Recombinant Proteins/antagonists & inhibitors
- Recombinant Proteins/genetics
- Spinal Nerve Roots/drug effects
- Spinal Nerve Roots/physiology
- Stereoisomerism
- Structure-Activity Relationship
- Uracil/analogs & derivatives
- Uracil/chemical synthesis
- Uracil/chemistry
- Uracil/pharmacology
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Affiliation(s)
- Nigel P Dolman
- Department of Pharmacology, MRC Centre for Synaptic Plasticity, School of Medical Sciences, University Walk, University of Bristol, Bristol BS8 1TD, United Kingdom
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41
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Wu LJ, Ko SW, Toyoda H, Zhao MG, Xu H, Vadakkan KI, Ren M, Knifed E, Shum F, Quan J, Zhang XH, Zhuo M. Increased anxiety-like behavior and enhanced synaptic efficacy in the amygdala of GluR5 knockout mice. PLoS One 2007; 2:e167. [PMID: 17245443 PMCID: PMC1766473 DOI: 10.1371/journal.pone.0000167] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2006] [Accepted: 12/28/2006] [Indexed: 11/19/2022] Open
Abstract
GABAergic transmission in the amygdala modulates the expression of anxiety. Understanding the interplay between GABAergic transmission and excitatory circuits in the amygdala is, therefore, critical for understanding the neurobiological basis of anxiety. Here, we used a multi-disciplinary approach to demonstrate that GluR5-containing kainate receptors regulate local inhibitory circuits, modulate the excitatory transmission from the basolateral amygdala to the central amygdala, and control behavioral anxiety. Genetic deletion of GluR5 or local injection of a GluR5 antagonist into the basolateral amygdala increases anxiety-like behavior. Activation of GluR5 selectively depolarized inhibitory neurons, thereby increasing GABA release and contributing to tonic GABA current in the basolateral amygdala. The enhanced GABAergic transmission leads to reduced excitatory inputs in the central amygdala. Our results suggest that GluR5 is a key regulator of inhibitory circuits in the amygdala and highlight the potential use of GluR5-specific drugs in the treatment of pathological anxiety.
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Affiliation(s)
- Long-Jun Wu
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Shanelle W. Ko
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Hiroki Toyoda
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Ming-Gao Zhao
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Hui Xu
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Kunjumon I. Vadakkan
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Ming Ren
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Eva Knifed
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Fanny Shum
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Jessica Quan
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Xue-Han Zhang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Min Zhuo
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
- * To whom correspondence should be addressed. E-mail:
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42
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Abstract
Pain is an important survival and protection mechanism for animals. However, chronic/persistent pain may be differentiated from normal physiological pain in that it confers no obvious advantage. An accumulating body of pharmacological, electrophysiological, and behavioral evidence is emerging in support of the notion that glutamate receptors play a crucial role in pain pathways and that modulation of glutamate receptors may have potential for therapeutic utility in several categories of persistent pain, including neuropathic pain resulting from injury and/or disease of central (e.g., spinal cord injury) or peripheral nerves (e.g., diabetic neuropathy, radiculopathy) and inflammatory or joint-related pain (e.g., rheumatoid arthritis, osteoarthritis). This review focuses on the role of glutamate receptors, including both ionotropic (AMPA, NMDA and kainate) and metabotropic (mGlu1-8) receptors in persistent pain states with particular emphasis on their expression patterns in nociceptive pathways and their potential as targets for pharmacological intervention strategies.
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Affiliation(s)
- David Bleakman
- Neuroscience Division, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN 46285, USA.
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43
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Xu H, Wu LJ, Zhao MG, Toyoda H, Vadakkan KI, Jia Y, Pinaud R, Zhuo M. Presynaptic regulation of the inhibitory transmission by GluR5-containing kainate receptors in spinal substantia gelatinosa. Mol Pain 2006; 2:29. [PMID: 16948848 PMCID: PMC1570342 DOI: 10.1186/1744-8069-2-29] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2006] [Accepted: 09/01/2006] [Indexed: 11/29/2022] Open
Abstract
GluR5-containing kainate receptors (KARs) are known to be involved in nociceptive transmission. Our previous work has shown that the activation of presynaptic KARs regulates GABAergic and glycinergic synaptic transmission in cultured dorsal horn neurons. However, the role of GluR5-containing KARs in the modulation of inhibitory transmission in the spinal substantia gelatinosa (SG) in slices remains unknown. In the present study, pharmacological, electrophysiological and genetic methods were used to show that presynaptic GluR5 KARs are involved in the modulation of inhibitory transmission in the SG of spinal slices in vitro. The GluR5 selective agonist, ATPA, facilitated the frequency but not amplitude of spontaneous inhibitory postsynaptic currents (sIPSCs) in SG neurons. ATPA increased sIPSC frequency in all neurons with different firing patterns as delayed, tonic, initial and single spike patterns. The frequency of either GABAergic or glycinergic sIPSCs was significantly increased by ATPA. ATPA could also induce inward currents in all SG neurons recorded. The frequency, but not amplitude, of action potential-independent miniature IPSCs (mIPSCs) was also facilitated by ATPA in a concentration-dependent manner. However, the effect of ATPA on the frequency of either sIPSCs or mIPSCs was abolished in GluR5-/- mice. Deletion of the GluR5 subunit gene had no effect on the frequency or amplitude of mIPSCs in SG neurons. However, GluR5 antagonist LY293558 reversibly inhibited sIPSC and mIPSC frequencies in spinal SG neurons. Taken together, these results suggest that GluR5 KARs, which may be located at presynaptic terminals, contribute to the modulation of inhibitory transmission in the SG. GluR5-containing KARs are thus important for spinal sensory transmission/modulation in the spinal cord.
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Affiliation(s)
- Hui Xu
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Long-Jun Wu
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Ming-Gao Zhao
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Hiroki Toyoda
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Kunjumon I Vadakkan
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Yongheng Jia
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Raphael Pinaud
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Min Zhuo
- Department of Physiology, Faculty of Medicine, University of Toronto, University of Toronto Centre for the Study of Pain, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
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44
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Abstract
Kainate receptors form a family of ionotropic glutamate receptors that appear to play a special role in the regulation of the activity of synaptic networks. This review first describes briefly the molecular and pharmacological properties of native and recombinant kainate receptors. It then attempts to outline the general principles that appear to govern the function of kainate receptors in the activity of synaptic networks under physiological conditions. It subsequently describes the way that kainate receptors are involved in synaptic integration, synaptic plasticity, the regulation of neurotransmitter release and the control of neuronal excitability, and the manner in which they might play an important role in synaptogenesis and synaptic maturation. These functions require the proper subcellular localization of kainate receptors in specific functional domains of the neuron, necessitating complex cellular and molecular trafficking events. We show that our comprehension of these mechanisms is just starting to emerge. Finally, this review presents evidence that implicates kainate receptors in pathophysiological conditions such as epilepsy, excitotoxicity and pain, and that shows that these receptors represent promising therapeutic targets.
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Affiliation(s)
- Paulo Pinheiro
- CNRS UMR 5091, Laboratoire "Physiologie Cellulaire de la Synapse", Bordeaux Neuroscience Institute, University of Bordeaux, 33077 Bordeaux Cedex, France
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45
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Dolman NP, More JCA, Alt A, Knauss JL, Troop HM, Bleakman D, Collingridge GL, Jane DE. Structure-activity relationship studies on N3-substituted willardiine derivatives acting as AMPA or kainate receptor antagonists. J Med Chem 2006; 49:2579-92. [PMID: 16610801 DOI: 10.1021/jm051086f] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N3-substitution of the uracil ring of willardiine with a variety of carboxyalkyl or carboxybenzyl substituents produces AMPA and kainate receptor antagonists. In an attempt to improve the potency and selectivity of these AMPA and kainate receptor antagonists a series of analogues with different terminal acidic groups and interacidic group spacers was synthesized and pharmacologically characterized. (S)-1-(2-Amino-2-carboxyethyl)-3-(2-carboxythiophene-3-ylmethyl)pyrimidine-2,4-dione (43, UBP304) demonstrated high potency and selectivity toward native GLU(K5)-containing kainate receptors (K(D) 0.105 +/- 0.007 microM vs kainate on native GLU(K5); K(D) 71.4 +/- 8.3 microM vs (S)-5-fluorowillardiine on native AMPA receptors). On recombinant human GLU(K5), GLU(K5)/GLU(K6), and GLU(K5)/GLU(K2), K(B) values of 0.12 +/- 0.03, 0.12 +/- 0.01, and 0.18 +/- 0.02 microM, respectively, were obtained for 43. However, 43 displayed no activity on homomeric GLU(K6) or GLU(K7) kainate receptors or homomeric GLU(A1-4) AMPA receptors (IC(50) values > 100 microM). Thus, 43 is a potent and selective GLU(K5) receptor antagonist.
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Affiliation(s)
- Nigel P Dolman
- Department of Pharmacology, MRC Centre for Synaptic Plasticity, School of Medical Sciences, University Walk, University of Bristol, Bristol BS8 1TD, UK
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46
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Peeters PJ, Aerssens J, de Hoogt R, Stanisz A, Göhlmann HW, Hillsley K, Meulemans A, Grundy D, Stead RH, Coulie B. Molecular profiling of murine sensory neurons in the nodose and dorsal root ganglia labeled from the peritoneal cavity. Physiol Genomics 2006; 24:252-63. [PMID: 16303873 DOI: 10.1152/physiolgenomics.00169.2005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Vagal afferent neurons are thought to convey primarily physiological information, whereas spinal afferents transmit noxious signals from the viscera to the central nervous system. To elucidate molecular identities for these different properties, we compared gene expression profiles of neurons located in nodose ganglia (NG) and dorsal root ganglia (DRG) in mice. Intraperitoneal administration of Alexa Fluor-488-conjugated cholera toxin B allowed enrichment for neurons projecting to the viscera. Fluorescent neurons in DRG (from T10 to T13) and NG were isolated using laser-capture microdissection. Gene expression profiles of these afferent neurons, obtained by microarray hybridization, were analyzed using multivariate spectral map analysis, significance analysis of microarrays (SAM) algorithm, and fold-difference filtering. A total of 1,996 genes were differentially expressed in DRG vs. NG, including 41 G protein-coupled receptors and 60 ion channels. Expression profiles obtained on laser-captured neurons were contrasted to those obtained on whole ganglia, demonstrating striking differences and the need for microdissection when studying visceral sensory neurons because of dilution of the signal by somatic sensory neurons. Furthermore, we provide a detailed catalog of all adrenergic and cholinergic, GABA, glutamate, serotonin, and dopamine receptors; voltage-gated potassium, sodium, and calcium channels; and transient receptor potential cation channels present in afferents projecting to the peritoneal cavity. Our genome-wide expression profiling data provide novel insight into molecular signatures that underlie both functional differences and similarities between NG and DRG sensory neurons. Moreover, these findings will offer novel insight into mode of action of pharmacological agents modulating visceral sensation.
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Affiliation(s)
- Pieter J Peeters
- Department of Internal Medicine, Johnson and Johnson Pharmaceutical Research and Development, Beerse, Belgium.
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47
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Davis-Taber RA, Scott VE. Transcriptional profiling of dorsal root ganglia in a neuropathic pain model using microarray and laser capture microdissection. Drug Dev Res 2006. [DOI: 10.1002/ddr.20096] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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48
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Lucifora S, Willcockson HH, Lu CR, Darstein M, Phend KD, Valtschanoff JG, Rustioni A. Presynaptic low- and high-affinity kainate receptors in nociceptive spinal afferents. Pain 2006; 120:97-105. [PMID: 16360275 DOI: 10.1016/j.pain.2005.10.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Revised: 09/26/2005] [Accepted: 10/19/2005] [Indexed: 10/25/2022]
Abstract
Presynaptic ionotropic glutamate receptors are increasingly attributed a role in the modulation of sensory input at the first synapse of dorsal root ganglion (DRG) neurons in the spinal dorsal horn. Central terminals of DRG neurons express AMPA and NMDA receptors whose activation modulates the release of glutamate, the main transmitter at these synapses. Previous work, with an antibody that recognizes all low-affinity kainate receptor subunits (GluR5, 6, 7), provided microscopic evidence of presynaptic kainate receptors in unidentified primary afferent terminals in superficial laminae of the spinal dorsal horn (Hwang SJ, Pagliardini S, Rustioni A, Valtschanoff JG. Presynaptic kainate receptors in primary afferents to the superficial laminae of the rat spinal cord. J Comp Neurol 2001; 436: pp. 275-289). We show here that, although all such subunits may be expressed in these terminals, GluR5 is the subunit most readily detectable at presynaptic sites in sections processed for immunocytochemistry. We also show that the high-affinity kainate receptor subunits KA1 and KA2 are expressed in central terminals of DRG neurons and are co-expressed with low-affinity receptor subunits in the same terminals. Quantitative data show that kainate-expressing DRG neurons are about six times more likely to express the P2X(3) subunit of the purinergic receptor than to express substance P. Thus, nociceptive afferents that express presynaptic kainate receptors are predominantly non-peptidergic, suggesting a role for these receptors in the modulation of neuropathic rather than inflammatory pain.
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Affiliation(s)
- Simona Lucifora
- Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA Cell and Molecular Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA Department of Physiological Sciences, University of Catania, Italy Institute of Anatomy and Cell Biology I, University of Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany
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Youn DH, Voitenko N, Gerber G, Park YK, Galik J, Randić M. Altered long-term synaptic plasticity and kainate-induced Ca2+ transients in the substantia gelatinosa neurons in GLUK6-deficient mice. ACTA ACUST UNITED AC 2005; 142:9-18. [PMID: 16219388 DOI: 10.1016/j.molbrainres.2005.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2005] [Revised: 08/24/2005] [Accepted: 09/05/2005] [Indexed: 11/22/2022]
Abstract
Functional kainate receptors are expressed in the spinal cord substantia gelatinosa region, and their activation contributes to bi-directional regulation of excitatory synaptic transmission at primary afferent synapses with spinal cord substantia gelatinosa neurons. However, no study has reported a role(s) for kainate receptor subtypes in long-term synaptic plasticity phenomena in this region. Using gene-targeted mice lacking glutamate receptor 5 (GLU(K5)) or GLU(K6) subunit, we here show that GLU(K6) subunit, but not GLU(K5) subunit, is involved in the induction of long-term potentiation of excitatory postsynaptic potentials, evoked by two different protocols: (1) high-frequency primary afferent stimulation (100 Hz, 3 s) and (2) low-frequency spike-timing stimulation (1 Hz, 200 pulses). In addition, GLU(K6) subunit plays an important role in the expression of kainate-induced Ca2+ transients in the substantia gelatinosa. On the other hand, genetic deletion of GLU(K5) or GLU(K6) subunit does not prevent the induction of long-term depression. These results indicate that unique expression of kainate receptors subunits is important in regulating spinal synaptic plasticity and thereby processing of sensory information, including pain.
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Affiliation(s)
- Dong-Ho Youn
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, USA
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Dolman NP, Troop HM, More JCA, Alt A, Knauss JL, Nistico R, Jack S, Morley RM, Bortolotto ZA, Roberts PJ, Bleakman D, Collingridge GL, Jane DE. Synthesis and Pharmacology of Willardiine Derivatives Acting as Antagonists of Kainate Receptors. J Med Chem 2005; 48:7867-81. [PMID: 16302825 DOI: 10.1021/jm050584l] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The natural product willardiine (8) is an AMPA receptor agonist while 5-iodowillardiine (10) is a selective kainate receptor agonist. In an attempt to produce antagonists of kainate and AMPA receptors analogues of willardiine with substituents at the N3 position of the uracil ring were synthesized. The N3-4-carboxybenzyl substituted analogue (38c) was found to be equipotent at AMPA and GLUK5-containing kainate receptors in the neonatal rat spinal cord. The N3-2-carboxybenzyl substituted analogue (38a) proved to be a potent and selective GLUK5 subunit containing kainate receptor antagonist when tested on native rat and human recombinant AMPA and kainate receptor subtypes. The GLUK5 kainate receptor antagonist activity was found to reside in the S enantiomer (44a) whereas the R enantiomer (44b) was almost inactive. 5-Iodo substitution of the uracil ring of 44a gave 45, which was found to have enhanced potency and selectivity for GLUK5.
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Affiliation(s)
- Nigel P Dolman
- Department of Pharmacology, MRC Centre for Synaptic Plasticity, School of Medical Sciences, University Walk, University of Bristol, Bristol, BS8 1TD, UK
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