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Zheng H, Kim M, Kim C, Kim Y, Cho PS, Lim JY, Lee H, Yun HI, Choi J, Hwang SW. GnRH peripherally modulates nociceptor functions, exacerbating mechanical pain. Front Mol Neurosci 2024; 17:1160435. [PMID: 38783903 PMCID: PMC11111891 DOI: 10.3389/fnmol.2024.1160435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/22/2024] [Indexed: 05/25/2024] Open
Abstract
The function of peripheral nociceptors, the neurons that relay pain signals to the brain, are frequently tuned by local and systemic modulator substances. In this context, neurohormonal effects are emerging as an important modulatory mechanism, but many aspects remain to be elucidated. Here we report that gonadotropin-releasing hormone (GnRH), a brain-specific neurohormone, can aggravate pain by acting on nociceptors in mice. GnRH and GnRHR, the receptor for GnRH, are expressed in a nociceptor subpopulation. Administration of GnRH and its analogue, localized for selectively affecting the peripheral neurons, deteriorated mechanical pain, which was reproducible in neuropathic conditions. Nociceptor function was promoted by GnRH treatment in vitro, which appears to involve specific sensory transient receptor potential ion channels. These data suggest that peripheral GnRH can positively modulate nociceptor activities in its receptor-specific manner, contributing to pain exacerbation. Our study indicates that GnRH plays an important role in neurohormonal pain modulation via a peripheral mechanism.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, Republic of Korea
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2
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Niu M, Zhao F, Chen R, Li P, Bi L. The transient receptor potential channels in rheumatoid arthritis: Need to pay more attention. Front Immunol 2023; 14:1127277. [PMID: 36926330 PMCID: PMC10013686 DOI: 10.3389/fimmu.2023.1127277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 02/06/2023] [Indexed: 03/06/2023] Open
Abstract
Rheumatoid arthritis (RA) is characterized by the augment of vascular permeability, increased inflammatory cells infiltration, dysregulated immune cells activation, pannus formation and unbearable pain hyperalgesia. Ca2+ affect almost every aspect of cellular functions, involving cell migration, signal transduction, proliferation, and apoptosis. Transient receptor potential channels (TRPs) as a type of non-selective permeable cation channels, can regulate Ca2+ entry and intracellular Ca2+ signal in cells including immune cells and neurons. Researches have demonstrated that TRPs in the mechanisms of inflammatory diseases have achieved rapid progress, while the roles of TRPs in RA pathogenesis and pain hyperalgesia are still not well understood. To solve this problem, this review presents the evidence of TRPs on vascular endothelial cells in joint swelling, neutrophils activation and their trans-endothelial migration, as well as their bridging role in the reactive oxygen species/TRPs/Ca2+/peptidyl arginine deiminases networks in accelerating citrullinated proteins formation. It also points out the distinct functions of TRPs subfamilies expressed in the nervous systems of joints in cold hyperalgesia and neuro-inflammation mutually influenced inflammatory pain in RA. Thus, more attention could be paid on the impact of TRPs in RA and TRPs are useful in researches on the molecular mechanisms of anti-inflammation and analgesic therapeutic strategies.
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Affiliation(s)
- Mengwen Niu
- Department of Rheumatology and Immunology, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Feng Zhao
- Department of Rheumatology and Immunology, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Rui Chen
- Department of Cardiology, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Ping Li
- Department of Rheumatology and Immunology, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Liqi Bi
- Department of Rheumatology and Immunology, China-Japan Union Hospital of Jilin University, Changchun, China
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3
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He J, Li B, Han S, Zhang Y, Liu K, Yi S, Liu Y, Xiu M. Drosophila as a Model to Study the Mechanism of Nociception. Front Physiol 2022; 13:854124. [PMID: 35418874 PMCID: PMC8996152 DOI: 10.3389/fphys.2022.854124] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/28/2022] [Indexed: 12/15/2022] Open
Abstract
Nociception refers to the process of encoding and processing noxious stimuli, which allow animals to detect and avoid potentially harmful stimuli. Several types of stimuli can trigger nociceptive sensory transduction, including thermal, noxious chemicals, and harsh mechanical stimulation that depend on the corresponding nociceptors. In view of the high evolutionary conservation of the mechanisms that govern nociception from Drosophila melanogaster to mammals, investigation in the fruit fly Drosophila help us understand how the sensory nervous system works and what happen in nociception. Here, we present an overview of currently identified conserved genetics of nociception, the nociceptive sensory neurons responsible for detecting noxious stimuli, and various assays for evaluating different nociception. Finally, we cover development of anti-pain drug using fly model. These comparisons illustrate the value of using Drosophila as model for uncovering nociception mechanisms, which are essential for identifying new treatment goals and developing novel analgesics that are applicable to human health.
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Affiliation(s)
- Jianzheng He
- Provincial-Level Key Laboratory for Molecular Medicine of Major Diseases and the Prevention and Treatment with Traditional Chinese Medicine Research in Gansu Colleges and University, Gansu University of Chinese Medicine, Lanzhou, China
- College of Basic Medicine, Gansu University of Chinese Medicine, Lanzhou, China
- Key Laboratory for Transfer of Dunhuang Medicine at the Provincial and Ministerial Level, Gansu University of Chinese Medicine, Lanzhou, China
| | - Botong Li
- Provincial-Level Key Laboratory for Molecular Medicine of Major Diseases and the Prevention and Treatment with Traditional Chinese Medicine Research in Gansu Colleges and University, Gansu University of Chinese Medicine, Lanzhou, China
- College of Basic Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Shuzhen Han
- Provincial-Level Key Laboratory for Molecular Medicine of Major Diseases and the Prevention and Treatment with Traditional Chinese Medicine Research in Gansu Colleges and University, Gansu University of Chinese Medicine, Lanzhou, China
- College of Basic Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Yuan Zhang
- Provincial-Level Key Laboratory for Molecular Medicine of Major Diseases and the Prevention and Treatment with Traditional Chinese Medicine Research in Gansu Colleges and University, Gansu University of Chinese Medicine, Lanzhou, China
- College of Basic Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Kai Liu
- College of Integrated Traditional Chinese and Western Medicine, Gansu University of Chinese Medicine, Lanzhou, China
| | - Simeng Yi
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Yongqi Liu
- Provincial-Level Key Laboratory for Molecular Medicine of Major Diseases and the Prevention and Treatment with Traditional Chinese Medicine Research in Gansu Colleges and University, Gansu University of Chinese Medicine, Lanzhou, China
- Key Laboratory for Transfer of Dunhuang Medicine at the Provincial and Ministerial Level, Gansu University of Chinese Medicine, Lanzhou, China
- *Correspondence: Yongqi Liu,
| | - Minghui Xiu
- Provincial-Level Key Laboratory for Molecular Medicine of Major Diseases and the Prevention and Treatment with Traditional Chinese Medicine Research in Gansu Colleges and University, Gansu University of Chinese Medicine, Lanzhou, China
- Key Laboratory for Transfer of Dunhuang Medicine at the Provincial and Ministerial Level, Gansu University of Chinese Medicine, Lanzhou, China
- College of Public Health, Gansu University of Chinese Medicine, Lanzhou, China
- Minghui Xiu,
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Ben Rehouma M, Kfoury T, Hamdi L, Bouchouareb M, Soued M, Benhamou D, Mazoit JX. Acute Visceral Pain in Rats: Vagal Nerve Block Compared to Bupivacaine Administered Intramuscularly. Anesth Analg 2021; 133:1311-1320. [PMID: 34347648 DOI: 10.1213/ane.0000000000005697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Visceral and parietal peritoneum layers have different sensory innervations. Most visceral peritoneum sensory information is conveyed via the vagus nerve to the nucleus of the solitary tract (NTS). We already showed in animal models that intramuscular (i.m.) injection of local anesthetics decreases acute somatic and visceral pain and general inflammation induced by aseptic peritonitis. The goal of the study was to compare the effects of parietal block, i.m. bupivacaine, and vagotomy on spinal cord and NTS stimulation induced by a chemical peritonitis. METHODS We induced peritonitis in rats using carrageenan and measured cellular activation in spinal cord and NTS under the following conditions, that is, a parietal nerve block with bupivacaine, a chemical right vagotomy, and i.m. microspheres loaded with bupivacaine. Proto-oncogene c-Fos (c-Fos), cluster of differentiation protein 11b (CD11b), and tumor necrosis factor alpha (TNF-α) expression in cord and NTS were studied. RESULTS c-Fos activation in the cord was inhibited by nerve block 2 hours after peritoneal insult. Vagotomy and i.m. bupivacaine similarly inhibited c-Fos activation in NTS. Forty-eight hours after peritoneal insult, the number of cells expressing CD11b significantly increased in the cord (P = .010). The median difference in the effect of peritonitis compared to control was 30 cells (CI95, 13.5-55). TNF-α colocalized with CD11b. Vagotomy inhibited this microglial activation in the NTS, but not in the cord. This activation was inhibited by i.m. bupivacaine both in cord and in NTS. The median difference in the effect of i.m. bupivacaine added to peritonitis was 29 cells (80% increase) in the cord and 18 cells (75% increase) in the NTS. Our study underlines the role of the vagus nerve in the transmission of an acute visceral pain message and confirmed that systemic bupivacaine prevents noxious stimuli by inhibiting c-Fos and microglia activation. CONCLUSIONS In rats receiving intraperitoneal carrageenan, i.m. bupivacaine similarly inhibited c-Fos and microglial activation both in cord and in the NTS. Vagal block inhibited activation only in the NTS. Our study underlines the role of the vagus nerve in the transmission of an acute visceral pain message and confirmed that systemic bupivacaine prevents noxious stimuli. This emphasizes the effects of systemic local anesthetics on inflammation and visceral pain.
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Affiliation(s)
- Mouna Ben Rehouma
- From the Laboratoire d'Anesthésie, Paris-Saclay University and INSERM U1195 Faculté de Médecine de Bicêtre, Le Kremlin-Bicêtre, France
- Department of Anesthesiology and Intensive Care Medicine, Hôpital Bichat, Hôpitaux Universitaires Paris-Nord, APHP
| | - Toni Kfoury
- From the Laboratoire d'Anesthésie, Paris-Saclay University and INSERM U1195 Faculté de Médecine de Bicêtre, Le Kremlin-Bicêtre, France
- Hôpital Bicêtre, Hôpitaux Universitaires Paris-Saclay, APHP, Le Kremlin Bicêtre Cedex, France
| | - Leila Hamdi
- From the Laboratoire d'Anesthésie, Paris-Saclay University and INSERM U1195 Faculté de Médecine de Bicêtre, Le Kremlin-Bicêtre, France
| | - Meriem Bouchouareb
- From the Laboratoire d'Anesthésie, Paris-Saclay University and INSERM U1195 Faculté de Médecine de Bicêtre, Le Kremlin-Bicêtre, France
| | - Mickael Soued
- From the Laboratoire d'Anesthésie, Paris-Saclay University and INSERM U1195 Faculté de Médecine de Bicêtre, Le Kremlin-Bicêtre, France
- Department of Anesthesiology, Hôpital Antoine Béclère, Hôpitaux Universitaires Paris-Saclay, APHP, Clamart, France
| | - Dan Benhamou
- From the Laboratoire d'Anesthésie, Paris-Saclay University and INSERM U1195 Faculté de Médecine de Bicêtre, Le Kremlin-Bicêtre, France
- Hôpital Bicêtre, Hôpitaux Universitaires Paris-Saclay, APHP, Le Kremlin Bicêtre Cedex, France
| | - Jean Xavier Mazoit
- From the Laboratoire d'Anesthésie, Paris-Saclay University and INSERM U1195 Faculté de Médecine de Bicêtre, Le Kremlin-Bicêtre, France
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5
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Zheng H, Lim JY, Kim Y, Jung ST, Hwang SW. The role of oxytocin, vasopressin, and their receptors at nociceptors in peripheral pain modulation. Front Neuroendocrinol 2021; 63:100942. [PMID: 34437871 DOI: 10.1016/j.yfrne.2021.100942] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/01/2021] [Accepted: 08/17/2021] [Indexed: 10/20/2022]
Abstract
Oxytocin and vasopressin are neurohypophyseal hormones with sequence similarity and play a central role in bodily homeostatic regulation. Pain is currently understood to be an important phenotype that those two neurohormones strongly downregulate. Nociceptors, the first component of the ascending neural circuit for pain signals, have constantly been shown to be modulated by those peptides. The nociceptor modulation appears to be critical in pain attenuation, which has led to a gradual increase in scientific interest about their physiological processes and also drawn attention to their translational potentials. This review focused on what are recently understood and stay under investigation in the functional modulation of nociceptors by oxytocin and vasopressin. Effort to produce a nociceptor-specific view could help to construct a more systematic picture of the peripheral pain modulation by oxytocin and vasopressin.
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Affiliation(s)
- Haiyan Zheng
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Korea; Department of Physiology, College of Medicine, Korea University, Seoul 02841, Korea
| | - Ji Yeon Lim
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Korea; Department of Physiology, College of Medicine, Korea University, Seoul 02841, Korea
| | - Yerin Kim
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Korea; Department of Physiology, College of Medicine, Korea University, Seoul 02841, Korea
| | - Sang Taek Jung
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Korea
| | - Sun Wook Hwang
- Department of Biomedical Sciences, College of Medicine, Korea University, Seoul 02841, Korea; Department of Physiology, College of Medicine, Korea University, Seoul 02841, Korea.
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6
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Berthézène CD, Rabiller L, Jourdan G, Cousin B, Pénicaud L, Casteilla L, Lorsignol A. Tissue Regeneration: The Dark Side of Opioids. Int J Mol Sci 2021; 22:7336. [PMID: 34298954 PMCID: PMC8307464 DOI: 10.3390/ijms22147336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 12/13/2022] Open
Abstract
Opioids are regarded as among the most effective analgesic drugs and their use for the management of pain is considered standard of care. Despite their systematic administration in the peri-operative period, their impact on tissue repair has been studied mainly in the context of scar healing and is only beginning to be documented in the context of true tissue regeneration. Indeed, in mammals, growing evidence shows that opioids direct tissue repair towards scar healing, with a loss of tissue function, instead of the regenerative process that allows for recovery of both the morphology and function of tissue. Here, we review recent studies that highlight how opioids may prevent a regenerative process by silencing nociceptive nerve activity and a powerful anti-inflammatory effect. These data open up new perspectives for inducing tissue regeneration and argue for opioid-restricted strategies for managing pain associated with tissue injury.
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Affiliation(s)
- Cécile Dromard Berthézène
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Lise Rabiller
- Alan Edwards Center for Research on Pain, Department of Physiology and Cell Information Systems, McGill University, Montreal, QC H3A 0G1, Canada;
| | - Géraldine Jourdan
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Béatrice Cousin
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Luc Pénicaud
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Louis Casteilla
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Anne Lorsignol
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
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7
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Hu W, Peng Y, Sun J, Zhang F, Zhang X, Wang L, Li Q, Zhong Y. Fan-Shaped Body Neurons in the Drosophila Brain Regulate Both Innate and Conditioned Nociceptive Avoidance. Cell Rep 2020; 24:1573-1584. [PMID: 30089267 DOI: 10.1016/j.celrep.2018.07.028] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/29/2018] [Accepted: 07/06/2018] [Indexed: 01/27/2023] Open
Abstract
Multiple brain regions respond to harmful nociceptive stimuli. However, it remains unclear as to whether behavioral avoidance of such stimuli can be modulated within the same or distinct brain networks. Here, we found subgroups of neurons localized within a well-defined brain region capable of mediating both innate and conditioned nociceptive avoidance in Drosophila. Neurons in the ventral, but not the dorsal, of the multiple-layer organized fan-shaped body (FB) are responsive to electric shock (ES). Silencing ES-responsive neurons, but not non-responsive neurons, leads to reduced avoidance of harmful stimuli, including ES and heat shock. Activating these neurons consistently triggers avoidance and can serve as an unconditional stimulus in an aversive classical conditioning task. Among the three groups of responsive neurons identified, two also have reduced activity in ES-conditioned odor avoidance. These results demonstrate that both innate and conditioned nociceptive avoidance might be represented within neurons confined to a single brain region.
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Affiliation(s)
- Wantong Hu
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yiqing Peng
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiameng Sun
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Fang Zhang
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xuchen Zhang
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Lianzhang Wang
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qian Li
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
| | - Yi Zhong
- Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China.
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8
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Jang Y, Kim M, Hwang SW. Molecular mechanisms underlying the actions of arachidonic acid-derived prostaglandins on peripheral nociception. J Neuroinflammation 2020; 17:30. [PMID: 31969159 PMCID: PMC6975075 DOI: 10.1186/s12974-020-1703-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/06/2020] [Indexed: 12/30/2022] Open
Abstract
Arachidonic acid-derived prostaglandins not only contribute to the development of inflammation as intercellular pro-inflammatory mediators, but also promote the excitability of the peripheral somatosensory system, contributing to pain exacerbation. Peripheral tissues undergo many forms of diseases that are frequently accompanied by inflammation. The somatosensory nerves innervating the inflamed areas experience heightened excitability and generate and transmit pain signals. Extensive studies have been carried out to elucidate how prostaglandins play their roles for such signaling at the cellular and molecular levels. Here, we briefly summarize the roles of arachidonic acid-derived prostaglandins, focusing on four prostaglandins and one thromboxane, particularly in terms of their actions on afferent nociceptors. We discuss the biosynthesis of the prostaglandins, their specific action sites, the pathological alteration of the expression levels of related proteins, the neuronal outcomes of receptor stimulation, their correlation with behavioral nociception, and the pharmacological efficacy of their regulators. This overview will help to a better understanding of the pathological roles that prostaglandins play in the somatosensory system and to a finding of critical molecular contributors to normalizing pain.
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Affiliation(s)
- Yongwoo Jang
- Department of Psychiatry and Program in Neuroscience, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA.,Department of Biomedical Engineering, Hanyang University, Seoul, 04763, South Korea
| | - Minseok Kim
- Department of Biomedical Sciences, Korea University, Seoul, 02841, South Korea
| | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea University, Seoul, 02841, South Korea. .,Department of Physiology, College of Medicine, Korea University, Seoul, 02841, South Korea.
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9
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McKay TB, Seyed-Razavi Y, Ghezzi CE, Dieckmann G, Nieland TJF, Cairns DM, Pollard RE, Hamrah P, Kaplan DL. Corneal pain and experimental model development. Prog Retin Eye Res 2019; 71:88-113. [PMID: 30453079 PMCID: PMC6690397 DOI: 10.1016/j.preteyeres.2018.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 11/03/2018] [Accepted: 11/13/2018] [Indexed: 12/13/2022]
Abstract
The cornea is a valuable tissue for studying peripheral sensory nerve structure and regeneration due to its avascularity, transparency, and dense innervation. Somatosensory innervation of the cornea serves to identify changes in environmental stimuli at the ocular surface, thereby promoting barrier function to protect the eye against injury or infection. Due to regulatory demands to screen ocular safety of potential chemical exposure, a need remains to develop functional human tissue models to predict ocular damage and pain using in vitro-based systems to increase throughput and minimize animal use. In this review, we summarize the anatomical and functional roles of corneal innervation in propagation of sensory input, corneal neuropathies associated with pain, and the status of current in vivo and in vitro models. Emphasis is placed on tissue engineering approaches to study the human corneal pain response in vitro with integration of proper cell types, controlled microenvironment, and high-throughput readouts to predict pain induction. Further developments in this field will aid in defining molecular signatures to distinguish acute and chronic pain triggers based on the immune response and epithelial, stromal, and neuronal interactions that occur at the ocular surface that lead to functional outcomes in the brain depending on severity and persistence of the stimulus.
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Affiliation(s)
- Tina B McKay
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA
| | - Yashar Seyed-Razavi
- Center for Translational Ocular Immunology and Cornea Service, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Chiara E Ghezzi
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA
| | - Gabriela Dieckmann
- Center for Translational Ocular Immunology and Cornea Service, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - Thomas J F Nieland
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA
| | - Dana M Cairns
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA
| | - Rachel E Pollard
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA
| | - Pedram Hamrah
- Center for Translational Ocular Immunology and Cornea Service, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, MA, USA
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA.
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10
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Nociceptor Signalling through ion Channel Regulation via GPCRs. Int J Mol Sci 2019; 20:ijms20102488. [PMID: 31137507 PMCID: PMC6566991 DOI: 10.3390/ijms20102488] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 12/23/2022] Open
Abstract
The prime task of nociceptors is the transformation of noxious stimuli into action potentials that are propagated along the neurites of nociceptive neurons from the periphery to the spinal cord. This function of nociceptors relies on the coordinated operation of a variety of ion channels. In this review, we summarize how members of nine different families of ion channels expressed in sensory neurons contribute to nociception. Furthermore, data on 35 different types of G protein coupled receptors are presented, activation of which controls the gating of the aforementioned ion channels. These receptors are not only targeted by more than 20 separate endogenous modulators, but can also be affected by pharmacotherapeutic agents. Thereby, this review provides information on how ion channel modulation via G protein coupled receptors in nociceptors can be exploited to provide improved analgesic therapy.
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11
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Choi G, Yang TJ, Yoo S, Choi SI, Lim JY, Cho PS, Hwang SW. TRPV4-Mediated Anti-nociceptive Effect of Suberanilohydroxamic Acid on Mechanical Pain. Mol Neurobiol 2018; 56:444-453. [PMID: 29707744 DOI: 10.1007/s12035-018-1093-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/19/2018] [Indexed: 11/29/2022]
Abstract
Biological effects of suberanilohydroxamic acid (SAHA) have mainly been observed in the context of tumor suppression via epigenetic mechanisms, but other potential outcomes from its use have also been proposed in different fields such as pain modulation. Here, we tried to understand whether SAHA modulates specific pain modalities by a non-epigenetic unknown mechanism. From 24 h Complete Freund's Adjuvant (CFA)-inflamed hind paws of mice, mechanical and thermal inflammatory pain indices were collected with or without immediate intraplantar injection of SAHA. To examine the action of SAHA on sensory receptor-specific pain, transient receptor potential (TRP) ion channel-mediated pain indices were collected in the same manner of intraplantar treatment. Activities of primarily cultured sensory neurons and heterologous cells transfected with TRP channels were monitored to determine the molecular mechanism underlying the pain-modulating effect of SAHA. As a result, immediate and localized pretreatment with SAHA, avoiding an epigenetic intervention, acutely attenuated mechanical inflammatory pain and receptor-specific pain evoked by injection of a TRP channel agonist in animal models. We show that a component of the mechanisms involves TRPV4 inhibition based on in vitro intracellular Ca2+ imaging and electrophysiological assessments with heterologous expression systems and cultured sensory neurons. Taken together, the present study provides evidence of a novel off-target action and its mechanism of SAHA in its modality-specific anti-nociceptive effect and suggests the utility of this compound for pharmacological modulation of pain.
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Affiliation(s)
- Geunyeol Choi
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, 02841, South Korea
| | - Tae-Jin Yang
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, 02841, South Korea
| | - Sungjae Yoo
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, 02841, South Korea
| | - Seung-In Choi
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, 02841, South Korea
| | - Ji Yeon Lim
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, 02841, South Korea
| | - Pyung Sun Cho
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, 02841, South Korea
| | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul, 02841, South Korea. .,Department of Physiology, Korea University College of Medicine, Seoul, 02841, South Korea.
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12
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Majikina A, Takahashi K, Saito S, Tominaga M, Ohta T. Involvement of nociceptive transient receptor potential channels in repellent action of pulegone. Biochem Pharmacol 2018; 151:89-95. [PMID: 29501584 DOI: 10.1016/j.bcp.2018.02.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 02/26/2018] [Indexed: 11/27/2022]
Abstract
Pulegone, one of avian repellents, is used to prevent the economic loss caused by birds. Chemical repellents often evoke unpleasant sensations and sensory irritation resulting in avoidance under some circumstances. It is recognized that some TRP channels expressing sensory neurons are related to nociception. Here we determined the molecular mechanisms of the repellent action of pulegone using isolated chicken sensory neurons and heterologous expression system. Pulegone increased the intracellular Ca2+ concentration ([Ca2+]i) in chicken sensory neurons. There were two types of neurons exhibiting different sensitivity to pulegone. One was responded to it at low concentrations and the other at high concentrations. Pharmacological analyses revealed that the former was predominantly mediated by TRP melastatin 8 (TRPM8), and the latter by both TRP ankyrin 1 (TRPA1) and TRPM8. An activation of both channels by pulegone was also determined using heterologously expression system. At high concentrations, pulegone suppressed chicken TRPM8 but not chicken TRPA1. The intraplantar injection of pulegone in chicks caused pain-related behaviors that were attenuated by TRPA1 antagonist. These results indicate that pulegone stimulates both TRPM8 and TRPA1 channel in chicken sensory neurons and suppresses the former but not the latter at high concentrations. Together, these data suggest that the molecular target for the repellent action of pulegone in avian species is nociceptive TRPA1.
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Affiliation(s)
- Azusa Majikina
- Department of Veterinary Pharmacology, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Kenji Takahashi
- Department of Veterinary Pharmacology, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Shigeru Saito
- Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, Japan
| | - Makoto Tominaga
- Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, Japan
| | - Toshio Ohta
- Department of Veterinary Pharmacology, Faculty of Agriculture, Tottori University, Tottori, Japan.
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Jang Y, Cho PS, Yang YD, Hwang SW. Nociceptive Roles of TRPM2 Ion Channel in Pathologic Pain. Mol Neurobiol 2018; 55:6589-6600. [PMID: 29327205 DOI: 10.1007/s12035-017-0862-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/21/2017] [Indexed: 12/18/2022]
Abstract
Pain is a protective mechanism that enables us to avoid potentially harmful environments. However, when pathologically persisted and aggravated under severely injured or inflamed conditions, pain often reduces the quality of life and thus is considered as a disease to eliminate. Inflammatory and/or neuropathic mechanisms may exaggerate interactions between damaged tissues and neural pathways for pain mediation. Similar mechanisms also promote the communication among cellular participants in synapses at spinal or higher levels, which may amplify nociceptive firing and subsequent signal transmission, deteriorating the pain sensation. In this pathology, important cellular players are afferent sensory neurons, peripheral immune cells, and spinal glial cells. Arising from damage of injury, overloaded interstitial and intracellular reactive oxygen species (ROS) and intracellular Ca2+ are key messengers in the development and maintenance of pathologic pain. Thus, an ROS-sensitive and Ca2+-permeable ion channel that is highly expressed in the participant cells might play a critical role in the pathogenesis. Transient receptor potential melastatin subtype 2 (TRPM2) is the unique molecule that satisfies all of the requirements: the sensitivity, permeability, and its expressing cells. Notable progress in delineating the role of TRPM2 in pain has been achieved during the past decade. In the present review, we summarize the important findings in the key cellular components that are involved in pathologic pain. This overview will help to understand TRPM2-mediated pain mechanisms and speculate therapeutic strategies by utilizing this updated information.
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Affiliation(s)
- Yongwoo Jang
- Department of Psychiatry and Program in Neuroscience, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA
| | - Pyung Sun Cho
- Department of Biomedical Sciences and Department of Physiology, College of Medicine, Korea University, Seoul, 02841, South Korea
| | - Young Duk Yang
- Department of Pharmacy, College of Pharmacy, CHA University, Gyeonggi, 11160, South Korea.
| | - Sun Wook Hwang
- Department of Biomedical Sciences and Department of Physiology, College of Medicine, Korea University, Seoul, 02841, South Korea.
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14
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Yoo S, Choi SI, Lee S, Song J, Yang C, Bang S, Kim SU, Min KH, Hwang SW. Endogenous TRPV4 Expression of a Hybrid Neuronal Cell Line N18D3 and Its Utilization to Find a Novel Synthetic Ligand. J Mol Neurosci 2017; 63:422-430. [PMID: 29090425 DOI: 10.1007/s12031-017-0993-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/18/2017] [Indexed: 11/24/2022]
Abstract
Primary sensory afferent neurons detect environmental and painful stimuli at their peripheral termini. A group of transient receptor potential ion channels (TRPs) are expressed in these neurons and constitute sensor molecules for the stimuli such as thermal, mechanical, and chemical insults. We examined whether a mouse sensory neuronal line, N18D3, shows the sensory TRP expressions and their functionality. In Ca2+ imaging and electrophysiology with these cells, putative TRPV4-mediated responses were observed. TRPV4-specific sensory modalities including sensitivity to a specific agonist, hypotonicity, or an elevated temperature were reproduced in N18D3 cells. Electrophysiological and pharmacological profiles conformed to those from native TRPV4 of primarily cultured neurons. The TRPV4 expression in N18D3 was also confirmed by RT-PCR and Western blot analyses. Thus, N18D3 cells may represent TRPV4-expressing sensory neurons. Further, using this cell lines, we discovered a novel synthetic TRPV4-specific agonist, MLV-0901. These results suggest that N18D3 is a reliable cell line for functional and pharmacological TRPV4 assays. The chemical information from the novel agonist will contribute to TRPV4-targeting drug design.
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Affiliation(s)
- Sungjae Yoo
- Department of Biomedical Sciences, Korea University College of Medicine, #722 Moonsook Bldg., Inchon-Ro 73, Seongbuk-Gu, Seoul, 02841, South Korea
| | - Seung-In Choi
- Department of Biomedical Sciences, Korea University College of Medicine, #722 Moonsook Bldg., Inchon-Ro 73, Seongbuk-Gu, Seoul, 02841, South Korea
| | - Seul Lee
- College of Pharmacy, Chung-Ang University, Heukseok-Ro 84, Dongjak-Gu, Seoul, 06974, South Korea
| | - Jiho Song
- College of Pharmacy, Chung-Ang University, Heukseok-Ro 84, Dongjak-Gu, Seoul, 06974, South Korea
| | - Chungmi Yang
- Department of Biomedical Sciences, Korea University College of Medicine, #722 Moonsook Bldg., Inchon-Ro 73, Seongbuk-Gu, Seoul, 02841, South Korea
| | - Sangsu Bang
- Department of Biomedical Sciences, Korea University College of Medicine, #722 Moonsook Bldg., Inchon-Ro 73, Seongbuk-Gu, Seoul, 02841, South Korea
| | - Seung Up Kim
- Medical Research Institute, Chung-Ang University School of Medicine, Seoul, 06974, South Korea.,Division of Neurology, Department of Medicine, UBC Hospital, University of British Columbia, Vancouver, BC, Canada
| | - Kyung Hoon Min
- College of Pharmacy, Chung-Ang University, Heukseok-Ro 84, Dongjak-Gu, Seoul, 06974, South Korea.
| | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea University College of Medicine, #722 Moonsook Bldg., Inchon-Ro 73, Seongbuk-Gu, Seoul, 02841, South Korea.
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Choi G, Hwang SW. Modulation of the Activities of Neuronal Ion Channels by Fatty Acid-Derived Pro-Resolvents. Front Physiol 2016; 7:523. [PMID: 27877134 PMCID: PMC5099253 DOI: 10.3389/fphys.2016.00523] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/24/2016] [Indexed: 12/13/2022] Open
Abstract
Progress of inflammation depends on the balance between two biological mechanisms: pro-inflammatory and pro-resolving processes. Many extracellular and intracellular molecular components including cytokines, growth factors, steroids, neurotransmitters, and lipidergic mediators and their receptors contribute to the two processes, generated from cellular participants during inflammation. Fatty acid-derived mediators are crucial in directing the inflammatory phase and orchestrating heterogeneous reactions of participants such as inflamed cells, innate immune cells, vascular components, innervating neurons, etc. As well as activating specific types of receptor molecules, lipidergic mediators can actively control the functions of various ion channels via direct binding and/or signal transduction, thereby altering cellular functions. Lipid mediators can be divided into two classes based on which of the two processes they promote: pro-inflammatory, which includes prostaglandins and leukotrienes, and pro-resolving, which includes lipoxins, resolvins, and maresins. The research on the modulations of neuronal ion channels regarding the actions of the pro-inflammatory class has begun relatively earlier while the focus is currently expanding to cover the ion channel interaction with pro-resolvents. As a result, knowledge of inhibitory mechanisms by the pro-resolvents, historically seldom found for other known endogenous modulators or pro-inflammatory mediators, is accumulating particularly upon sensory neuronal cation channels. Diverse mechanistic explanations at molecular levels are being proposed and refined. Here we overviewed the interactions of lipidergic pro-resolvents with neuronal ion channels and outcomes from the interactions, focusing on transient receptor potential (TRP) ion channels. We also discuss unanswered hypotheses and perspectives regarding their interactions.
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Affiliation(s)
- Geunyeol Choi
- Department of Biomedical Sciences, Korea University Seoul, South Korea
| | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea UniversitySeoul, South Korea; Department of Physiology, Korea University College of MedicineSeoul, South Korea
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16
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Emerging Role of Spinal Cord TRPV1 in Pain Exacerbation. Neural Plast 2016; 2016:5954890. [PMID: 26885404 PMCID: PMC4738952 DOI: 10.1155/2016/5954890] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2015] [Revised: 07/20/2015] [Accepted: 08/12/2015] [Indexed: 12/25/2022] Open
Abstract
TRPV1 is well known as a sensor ion channel that transduces a potentially harmful environment into electrical depolarization of the peripheral terminal of the nociceptive primary afferents. Although TRPV1 is also expressed in central regions of the nervous system, its roles in the area remain unclear. A series of recent reports on the spinal cord synapses have provided evidence that TRPV1 plays an important role in synaptic transmission in the pain pathway. Particularly, in pathologic pain states, TRPV1 in the central terminal of sensory neurons and interneurons is suggested to commonly contribute to pain exacerbation. These observations may lead to insights regarding novel synaptic mechanisms revealing veiled roles of spinal cord TRPV1 and may offer another opportunity to modulate pathological pain by controlling TRPV1. In this review, we introduce historical perspectives of this view and details of the recent promising results. We also focus on extended issues and unsolved problems to fully understand the role of TRPV1 in pathological pain. Together with recent findings, further efforts for fine analysis of TRPV1's plastic roles in pain synapses at different levels in the central nervous system will promote a better understanding of pathologic pain mechanisms and assist in developing novel analgesic strategies.
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Pradier B, Jeub M, Markert A, Mauer D, Tolksdorf K, Van de Putte T, Seuntjens E, Gailus-Durner V, Fuchs H, Hrabě de Angelis M, Huylebroeck D, Beck H, Zimmer A, Rácz I. Smad-interacting protein 1 affects acute and tonic, but not chronic pain. Eur J Pain 2013; 18:249-57. [PMID: 23861142 DOI: 10.1002/j.1532-2149.2013.00366.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2013] [Indexed: 12/18/2022]
Abstract
BACKGROUND Smad-interacting protein 1 (also named Zeb2 and Zfhx1b) is a transcription factor that plays an important role in neuronal development and, when mutated, causes Mowat-Wilson syndrome (MWS). A corresponding mouse model carrying a heterozygous Zeb2 deletion was comprehensively analysed in the German Mouse Clinic. The most prominent phenotype was the reduced pain sensitivity. In this study, we investigated the role of Zeb2 in inflammatory and neuropathic pain. METHODS For this, we tested mutant Zeb2 animals in different models of inflammatory pain like abdominal constriction, formalin and carrageenan test. Furthermore, we studied the pain reactivity of the mice after peripheral nerve ligation. To examine the nociceptive transmission of primary sensory dorsal root ganglia (DRG) neurons, we determined the neuronal activity in the spinal dorsal horn after the formalin test using staining of c-Fos. Next, we characterized the neuronal cell population in the DRGs and in the sciatic nerve to study the effect of the Zeb2 mutation on peripheral nerve morphology. RESULTS The present data show that Zeb2 is involved in the development of primary sensory DRG neurons, especially of C- and Aδ fibres. These alterations contribute to a hypoalgesic phenotype in inflammatory but not in neuropathic pain in these Zeb2(+/-) mice. CONCLUSION Our data suggest that the under-reaction to pain observed in MWS patients results from a reduced responsivity to nociceptive stimulation rather than an inability to communicate discomfort.
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Affiliation(s)
- B Pradier
- Institute of Molecular Psychiatry, University of Bonn Medical Center, Germany
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20
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Ito K, Creemers L. Mechanisms of intervertebral disk degeneration/injury and pain: a review. Global Spine J 2013; 3:145-52. [PMID: 24436865 PMCID: PMC3854582 DOI: 10.1055/s-0033-1347300] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/19/2013] [Indexed: 12/31/2022] Open
Abstract
Degeneration of the intervertebral disk and its treatments are currently intensely investigated topics. Back pain is a condition whose chronic and debilitating nature combined with its prevalence make it a major health issue of substantial socioeconomic importance. Although researchers, and even sometimes clinicians, focus on the degenerated disk as the problem, to most patients, pain is the factor that limits their function and impacts their well-being. The purpose of this review is to delineate the changes associated with disk degeneration and to outline mechanisms by which they could be the source of back pain. Although the healthy disk is only innervated in the external layer of its annulus fibrosus, adjacent structures are plentiful with nociceptive receptors. Stimulation of such structures as a consequence of processes initiated by disk degeneration is explored. The concept of discogenic pain and possible mechanisms such as neoinnervation and solute transport are discussed. Finally, how such pain mechanisms may relate to current and proposed treatment strategies is discussed.
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Affiliation(s)
- Keita Ito
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands,Address for correspondence Prof. Keita Ito, MD, ScD Orthopaedic Biomechanics, GEM-Z 4.115, Department of Biomedical EngineeringP.O. Box 513, 5600 MB EindhovenThe Netherlands
| | - Laura Creemers
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
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Reichling DB, Green PG, Levine JD. The fundamental unit of pain is the cell. Pain 2013; 154 Suppl 1:S2-9. [PMID: 23711480 DOI: 10.1016/j.pain.2013.05.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 04/12/2013] [Accepted: 05/20/2013] [Indexed: 12/22/2022]
Abstract
The molecular/genetic era has seen the discovery of a staggering number of molecules implicated in pain mechanisms [18,35,61,69,96,133,150,202,224]. This has stimulated pharmaceutical and biotechnology companies to invest billions of dollars to develop drugs that enhance or inhibit the function of many these molecules. Unfortunately this effort has provided a remarkably small return on this investment. Inevitably, transformative progress in this field will require a better understanding of the functional links among the ever-growing ranks of "pain molecules," as well as their links with an even larger number of molecules with which they interact. Importantly, all of these molecules exist side-by-side, within a functional unit, the cell, and its adjacent matrix of extracellular molecules. To paraphrase a recent editorial in Science magazine [223], although we live in the Golden age of Genetics, the fundamental unit of biology is still arguably the cell, and the cell is the critical structural and functional setting in which the function of pain-related molecules must be understood. This review summarizes our current understanding of the nociceptor as a cell-biological unit that responds to a variety of extracellular inputs with a complex and highly organized interaction of signaling molecules. We also discuss the insights that this approach is providing into peripheral mechanisms of chronic pain and sex dependence in pain.
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Affiliation(s)
- David B Reichling
- Department of Medicine, Division of Neuroscience, University of California-San Francisco, San Francisco, CA, USA; Department of Oral and Maxillofacial Surgery, Division of Neuroscience, University of California-San Francisco, San Francisco, CA, USA
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22
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Milinkeviciute G, Gentile C, Neely GG. Drosophila as a tool for studying the conserved genetics of pain. Clin Genet 2012; 82:359-66. [PMID: 22880632 DOI: 10.1111/j.1399-0004.2012.01941.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 07/23/2012] [Accepted: 07/23/2012] [Indexed: 11/27/2022]
Abstract
Survival of all animals depends on an accurate representation of the world, and an organism must be capable of prioritizing and responding to potentially hazardous conditions. This ability is dependent on nociception, the sensory process allowing animals to detect and avoid potentially harmful stimuli. Nociception is the sensory process that results in the subjective experience of 'pain' in humans. Because of its vital and broad role in animal biology, pain/nociception is a complex, whole-body physiological process that is under stringent evolutionary pressure. Here, we discuss the utility of Drosophila melanogaster as an emerging model organism for studying the conserved genetics of nociception, particularly with respect to recently developed high-throughput Drosophila 'pain' paradigms.
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Affiliation(s)
- G Milinkeviciute
- Neuroscience Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
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23
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Ryu JJ, Yoo S, Kim KY, Park JS, Bang S, Lee SH, Yang TJ, Cho H, Hwang SW. Laser modulation of heat and capsaicin receptor TRPV1 leads to thermal antinociception. J Dent Res 2010; 89:1455-60. [PMID: 20935279 DOI: 10.1177/0022034510381394] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Er,Cr:YSGG lasers are used clinically in dentistry. The advantages of laser therapy include minimal thermal damage and the alleviation of pain. This study examined whether the Er,Cr:YSGG laser has in vivo and in vitro antinociceptive effects in itself. In capsaicin-evoked acute licking/shaking tests and Hargreaves tests, laser irradiation with an aerated water spray suppressed nociceptive behavior in mice. Laser irradiation attenuated TRPV1 activation by capsaicin in Ca(2+) imaging experiments with TRPV1-overexpressing cells and cultured trigeminal neurons. Therefore, the laser-induced behavioral changes are probably due to the loss of TRPV1 activity. TRPV4 activity was also attenuated, but limited mechanical antinociception by the laser was observed. The laser failed to alter the other receptor functions, which indicates that the antinociceptive effect of the laser is dependent on TRPV1. These results suggest that the Er,Cr:YSGG laser has analgesic effects via TRPV1 inhibition. Such mechanistic approaches may help define the laser-sensitive pain modality and increase its beneficial uses.
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Affiliation(s)
- J-J Ryu
- Department of Dentistry, Korea University College of Medicine, Seoul 136-705, Korea
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24
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Acid-evoked Ca2+ signalling in rat sensory neurones: effects of anoxia and aglycaemia. Pflugers Arch 2010; 459:159-81. [PMID: 19806360 PMCID: PMC2765625 DOI: 10.1007/s00424-009-0715-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Revised: 07/30/2009] [Accepted: 08/14/2009] [Indexed: 12/11/2022]
Abstract
Ischaemia excites sensory neurones (generating pain) and promotes calcitonin gene-related peptide release from nerve endings. Acidosis is thought to play a key role in mediating excitation via the activation of proton-sensitive cation channels. In this study, we investigated the effects of acidosis upon Ca2+ signalling in sensory neurones from rat dorsal root ganglia. Both hypercapnic (pHo 6.8) and metabolic–hypercapnic (pHo 6.2) acidosis caused a biphasic increase in cytosolic calcium concentration ([Ca2+]i). This comprised a brief Ca2+ transient (half-time approximately 30 s) caused by Ca2+ influx followed by a sustained rise in [Ca2+]i due to Ca2+ release from caffeine and cyclopiazonic acid-sensitive internal stores. Acid-evoked Ca2+ influx was unaffected by voltage-gated Ca2+-channel inhibition with nickel and acid sensing ion channel (ASIC) inhibition with amiloride but was blocked by inhibition of transient receptor potential vanilloid receptors (TRPV1) with (E)-3-(4-t-butylphenyl)-N-(2,3-dihydrobenzo[b][1,4] dioxin-6-yl)acrylamide (AMG 9810; 1 μM) and N-(4-tertiarybutylphenyl)-4-(3-cholorphyridin-2-yl) tetrahydropryazine-1(2H)-carbox-amide (BCTC; 1 μM). Combining acidosis with anoxia and aglycaemia increased the amplitude of both phases of Ca2+ elevation and prolonged the Ca2+ transient. The Ca2+ transient evoked by combined acidosis, aglycaemia and anoxia was also substantially blocked by AMG 9810 and BCTC and, to a lesser extent, by amiloride. In summary, the principle mechanisms mediating increase in [Ca2+]i in response to acidosis are a brief Ca2+ influx through TRPV1 followed by sustained Ca2+ release from internal stores. These effects are potentiated by anoxia and aglycaemia, conditions also prevalent in ischaemia. The effects of anoxia and aglycaemia are suggested to be largely due to the inhibition of Ca2+-clearance mechanisms and possible increase in the role of ASICs.
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Xu C, Li G, Gao Y, Liu S, Lin J, Zhang J, Li X, Liu H, Liang S. Effect of puerarin on P2X3 receptor involved in hyperalgesia after burn injury in the rat. Brain Res Bull 2009; 80:341-6. [DOI: 10.1016/j.brainresbull.2009.08.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 08/30/2009] [Accepted: 08/31/2009] [Indexed: 12/16/2022]
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Ambalavanar R, Dessem D. Emerging peripheral receptor targets for deep-tissue craniofacial pain therapies. J Dent Res 2009; 88:201-11. [PMID: 19329451 DOI: 10.1177/0022034508330176] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
While effective therapies are available for some types of craniofacial pain, treatments for deep-tissue craniofacial pain such as temporomandibular disorders are less efficacious. Several ion channels and receptors which are prominent in craniofacial nociceptive mechanisms have been identified on trigeminal primary afferent neurons. Many of these receptors and channels exhibit unusual distributions compared with extracranial regions. For example, expression of the ATP receptor P2X(3) is strongly implicated in nociception and is more abundant on trigeminal primary afferent neurons than analogous extracranial neurons, making them potentially productive targets specifically for craniofacial pain therapies. The initial part of this review therefore focuses on P2X(3) as a potential therapeutic target to treat deep-tissue craniofacial pain. In the trigeminal ganglion, P2X(3) receptors are often co-expressed with the nociceptive neuropeptides CGRP and SP. Therefore, we discuss the role of CGRP and SP in deep-tissue craniofacial pain and suggest that neuropeptide antagonists, which have shown promise for the treatment of migraine, may have wider therapeutic potential, including the treatment of deep-tissue craniofacial pain. P2X(3), TRPV1, and ASIC3 are often co-expressed in trigeminal neurons, implying the formation of functional complexes that allow craniofacial nociceptive neurons to respond synergistically to altered ATP and pH in pain. Future therapeutics for craniofacial pain thus might be more efficacious if targeted at combinations of P2X(3), CGRP, TRPV1, and ASIC3.
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Affiliation(s)
- R Ambalavanar
- Department of Neural and Pain Sciences and Program in Neuroscience, University of Maryland, Baltimore, MD 21201, USA
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Lundeberg T, Lund I. Is There a Role for Acupuncture in Endometriosis Pain, Or ‘endometrialgia’? Acupunct Med 2008; 26:94-110. [DOI: 10.1136/aim.26.2.94] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Endometriosis is a common cause of pelvic pain in women, many of whom suffer a progression of symptoms over their menstrual life. Symptoms may include combinations of abnormal visceral sensations and emotional distress. Endometriosis pain, or ‘endometrialgia’ often has a negative influence on the ability to work, on family relationships and sense of worth. Endometrialgia is often considered to be a homogeneous sensory entity, mediated by a specialised high threshold sensory system, which extends from the periphery through the spinal cord, brain stem and thalamus to the cerebral cortex. However, multiple mechanisms have been detected in the nervous system responsible for the pain including peripheral sensitisation, phenotypic switches, central sensitisation, ectopic excitability, structural reorganisation, decreased inhibition and increased facilitation, all of which may contribute to the pain. Although the causes of endometrialgia can differ (eg inflammatory, neuropathic and functional), they share some characteristics. Endometrialgia may be evoked by a low intensity, normally innocuous stimulus (allodynia), or it may be an exaggerated and prolonged response to a noxious stimulus (hyperalgesia). The pain may also be spontaneous in the absence of any apparent peripheral stimulus. Oestrogens and prostaglandins probably play key modulatory roles in endometriosis and endometrialgia. Consequently many of the current medical treatments for the condition include oral drugs, like non-steroid anti-inflammatory drugs, contraceptives, progestogens, androgenic agents, gonadotrophin releasing hormone analogues, as well as laparoscopic surgical excision of the endometriosis lesions. However, management of pain in women with endometriosis is currently inadequate for many. Possibly acupuncture and cognitive therapy may be used as an adjunct.
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Affiliation(s)
- Thomas Lundeberg
- Foundation for Acupuncture and Alternative Biological Treatment Methods Sabbatsbergs Hospital Stockholm, Sweden
| | - Iréne Lund
- Department of Physiology and Pharmacology Karolinska Institutet Stockholm, Sweden
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