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Chen X, Gan Y, Au NPB, Ma CHE. Current understanding of the molecular mechanisms of chemotherapy-induced peripheral neuropathy. Front Mol Neurosci 2024; 17:1345811. [PMID: 38660386 PMCID: PMC11039947 DOI: 10.3389/fnmol.2024.1345811] [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: 11/28/2023] [Accepted: 03/25/2024] [Indexed: 04/26/2024] Open
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is the most common off-target adverse effects caused by various chemotherapeutic agents, such as cisplatin, oxaliplatin, paclitaxel, vincristine and bortezomib. CIPN is characterized by a substantial loss of primary afferent sensory axonal fibers leading to sensory disturbances in patients. An estimated of 19-85% of patients developed CIPN during the course of chemotherapy. The lack of preventive measures and limited treatment options often require a dose reduction or even early termination of life-saving chemotherapy, impacting treatment efficacy and patient survival. In this Review, we summarized the current understanding on the pathogenesis of CIPN. One prominent change induced by chemotherapeutic agents involves the disruption of neuronal cytoskeletal architecture and axonal transport dynamics largely influenced by the interference of microtubule stability in peripheral neurons. Due to an ineffective blood-nerve barrier in our peripheral nervous system, exposure to some chemotherapeutic agents causes mitochondrial swelling in peripheral nerves, which lead to the opening of mitochondrial permeability transition pore and cytochrome c release resulting in degeneration of primary afferent sensory fibers. The exacerbated nociceptive signaling and pain transmission in CIPN patients is often linked the increased neuronal excitability largely due to the elevated expression of various ion channels in the dorsal root ganglion neurons. Another important contributing factor of CIPN is the neuroinflammation caused by an increased infiltration of immune cells and production of inflammatory cytokines. In the central nervous system, chemotherapeutic agents also induce neuronal hyperexcitability in the spinal dorsal horn and anterior cingulate cortex leading to the development of central sensitization that causes CIPN. Emerging evidence suggests that the change in the composition and diversity of gut microbiota (dysbiosis) could have direct impact on the development and progression of CIPN. Collectively, all these aspects contribute to the pathogenesis of CIPN. Recent advances in RNA-sequencing offer solid platform for in silico drug screening which enable the identification of novel therapeutic agents or repurpose existing drugs to alleviate CIPN, holding immense promises for enhancing the quality of life for cancer patients who undergo chemotherapy and improve their overall treatment outcomes.
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Affiliation(s)
- Xinyu Chen
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Yumeng Gan
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Ngan Pan Bennett Au
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, United Kingdom
- Institute of Life Sciences and Healthcare, University of Portsmouth, Portsmouth, United Kingdom
| | - Chi Him Eddie Ma
- Department of Neuroscience, Hong Kong Special Administrative Region (HKSAR), City University of Hong Kong, Kowloon, Hong Kong SAR, China
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2
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Allison C, Korey L, John Z S. A novel computational technique for the quantification of temporal summation in healthy individuals. Musculoskelet Sci Pract 2021; 54:102400. [PMID: 34022750 DOI: 10.1016/j.msksp.2021.102400] [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: 02/03/2021] [Revised: 04/12/2021] [Accepted: 05/10/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND The pathophysiology of chronic musculoskeletal pain is linked to the neurophysiologic condition known as central sensitization. Developing reliable, sensitive and clinically feasible techniques for quantifying central sensitization is a timely priority for advancing the field of chronic pain diagnosis and management. OBJECTIVE To compare the sensitivity of the Windup Ratio, a commonly employed Quantitative Sensory Testing (QST) technique, to a novel approach, the Sumsquare method, for detecting changes in experimentally induced central sensitization. DESIGN Individual, randomized, controlled experimental study. METHODS A total of 37 subjects assigned to experimental (N = 18) and control (N = 19) groups. Central sensitization was experimentally induced in the C5-C6 spinal segments using topical capsaicin (0.075%); controls received a non-sensitizing placebo (Lubriderm). Windup (temporal summation) was assessed using weighted pinpricks (MRC Systems, Heidelberg, Germany) applied within regions of secondary hyperalgesia surrounding the topical capsaicin. A train of 10 stimuli was applied at baseline, 10, 20 and 30 min post-topical application and participants provided numeric pain ratings after each pinprick application. Sumsquare and Windup Ratio outcomes were calculated using the pain rating data. RESULTS Sumsquare outcome was significantly increased at all time points (10, 20, 30 min) post-sensitization (p < 0.05); in contrast, no differences in Windup Ratio from baseline were observed at any time point post-sensitization (p > 0.05). CONCLUSIONS Sumsquare outcome offers greater sensitivity than Windup Ratio for detecting changes in experimentally induced central sensitization. These findings introduce a novel method for assessing changes in central sensitization in patients presenting with chronic musculoskeletal pain hypersensitivity.
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Affiliation(s)
- Clouse Allison
- Human Health and Nutritional Science, University of Guelph, Guelph, Canada
| | - Loi Korey
- Human Health and Nutritional Science, University of Guelph, Guelph, Canada
| | - Srbely John Z
- Human Health and Nutritional Science, University of Guelph, Guelph, Canada.
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3
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Abstract
In terms of antinociceptive action, the main mode of action of magnesium involves its antagonist action at the N-methyl-d-aspartate (NMDA) receptor, which prevents central sensitization and attenuates preexisting pain hypersensitivity. Given the pivotal function of NMDA receptors in pain transduction, magnesium has been investigated in a variety of pain conditions. The oral and parenteral administration of magnesium via the intravenous, intrathecal, or epidural route may alleviate pain and perioperative anesthetic and analgesic requirements. These beneficial effects of magnesium therapy have also been reported in patients with neuropathic pain, such as malignancy-related neurologic symptoms, diabetic neuropathy, postherpetic neuralgia, and chemotherapy-induced peripheral neuropathy. In addition, magnesium treatment is reportedly able to alleviate fibromyalgia, dysmenorrhea, headaches, and acute migraine attacks. Although magnesium plays an evolving role in pain management, better understanding of the mechanism underlying its antinociceptive action and additional clinical studies is required to clarify its role as an adjuvant analgesic.
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4
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Price TJ, Gold MS. From Mechanism to Cure: Renewing the Goal to Eliminate the Disease of Pain. PAIN MEDICINE 2019; 19:1525-1549. [PMID: 29077871 DOI: 10.1093/pm/pnx108] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Objective Persistent pain causes untold misery worldwide and is a leading cause of disability. Despite its astonishing prevalence, pain is undertreated, at least in part because existing therapeutics are ineffective or cause intolerable side effects. In this review, we cover new findings about the neurobiology of pain and argue that all but the most transient forms of pain needed to avoid tissue damage should be approached as a disease where a cure can be the goal of all treatment plans, even if attaining this goal is not yet always possible. Design We reviewed the literature to highlight recent advances in the area of the neurobiology of pain. Results We discuss barriers that are currently hindering the achievement of this goal, as well as the development of new therapeutic strategies. We also discuss innovations in the field that are creating new opportunities to treat and even reverse persistent pain, some of which are in late-phase clinical trials. Conclusion We conclude that the confluence of new basic science discoveries and development of new technologies are creating a path toward pain therapeutics that should offer significant hope of a cure for patients and practitioners alike. Classification of Evidence. Our review points to new areas of inquiry for the pain field to advance the goal of developing new therapeutics to treat chronic pain.
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Affiliation(s)
- Theodore J Price
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, Dallas, Texas
| | - Michael S Gold
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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5
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Inhibition of cytochrome P450c17 reduces spinal astrocyte activation in a mouse model of neuropathic pain via regulation of p38 MAPK phosphorylation. Biomed Pharmacother 2019; 118:109299. [PMID: 31387001 DOI: 10.1016/j.biopha.2019.109299] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/25/2019] [Accepted: 07/31/2019] [Indexed: 01/23/2023] Open
Abstract
We have recently demonstrated that the neurosteroid-metabolizing enzyme, cytochrome P450c17 is increased in spinal astrocytes contributing to the development of mechanical allodynia in chronic constriction injury (CCI)-induced neuropathic mice. However, the mechanisms by which spinal P450c17 modulates pathological changes in astrocytes remain unclear. In this study we investigated whether P450c17 modulates astrocyte activation and whether this process is mediated by spinal p38 mitogen-activated protein kinase phosphorylation ultimately leading to the development of mechanical allodynia in CCI mice. Sciatic nerve injury induced a significant increase in glial fibrillary acidic protein (GFAP) expression in the superficial dorsal horn (SDH, laminae I-II) and nucleus proprius (NP, laminae III-IV) regions of the spinal cord dorsal horn. Repeated daily (from days 0-3 post-surgery) intrathecal administration of the P450c17 inhibitor, ketoconazole (10 nmol) significantly inhibited the CCI-induced increase in GFAP-immunoreactivity, but had no effect on the CCI-induced increase in Iba-1-immunoreactivity. In addition, intrathecal administration of ketoconazole significantly inhibited the CCI-induced increase in p38 phosphorylation, while the levels of ERK and JNK phosphorylation remained unchanged. The CCI-induced development of mechanical allodynia was attenuated by administration of either ketoconazole (10 nmol) or the p38 MAPK inhibitor, SB203580 (5 nmol). Administration of a sub-effective dose of SB203580 (0.5 nmol) potentiated the pharmacological effect of ketoconazole (1 nmol) on spinal GFAP-immunostaining, as well as, the development of mechanical allodynia following CCI. Collectively these data suggest that spinal P450c17 activates astrocytes via p38 phosphorylation, ultimately leading to the development of mechanical allodynia in a model of peripheral neuropathy.
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6
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Grandhi RK, Abd-Elsayed A. Post-operative Pain Management in Spine Surgery. TEXTBOOK OF NEUROANESTHESIA AND NEUROCRITICAL CARE 2019:447-455. [DOI: 10.1007/978-981-13-3387-3_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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7
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Woolf CJ. Pain amplification-A perspective on the how, why, when, and where of central sensitization. ACTA ACUST UNITED AC 2018. [DOI: 10.1111/jabr.12124] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Clifford J. Woolf
- FM Kirby Neurobiology Center; Boston Children's Hospital; Boston MA USA
- Department of Neurobiology; Harvard Medical School; Boston MA USA
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8
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Lee WH, Carey LM, Li LL, Xu Z, Lai YY, Courtney MJ, Hohmann AG. ZLc002, a putative small-molecule inhibitor of nNOS interaction with NOS1AP, suppresses inflammatory nociception and chemotherapy-induced neuropathic pain and synergizes with paclitaxel to reduce tumor cell viability. Mol Pain 2018; 14:1744806918801224. [PMID: 30157705 PMCID: PMC6144507 DOI: 10.1177/1744806918801224] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/16/2018] [Accepted: 08/14/2018] [Indexed: 01/03/2023] Open
Abstract
Elevated N-methyl-D-aspartate receptor activity contributes to central sensitization. Our laboratories and others recently reported that disrupting protein-protein interactions downstream of N-methyl-D-aspartate receptors suppresses pain. Specifically, disrupting binding between the enzyme neuronal nitric oxide synthase and either its upstream (postsynaptic density 95 kDa, PSD95) or downstream (e.g. nitric oxide synthase 1 adaptor protein, NOS1AP) protein partners suppressed inflammatory and/or neuropathic pain. However, the lack of a small-molecule neuronal nitric oxide synthase-NOS1AP inhibitor has hindered efforts to validate the therapeutic utility of disrupting the neuronal nitric oxide synthase-NOS1AP interface as an analgesic strategy. We, therefore, evaluated the ability of a putative small-molecule neuronal nitric oxide synthase-NOS1AP inhibitor ZLc002 to disrupt binding between neuronal nitric oxide synthase and NOS1AP using ex vivo, in vitro, and purified recombinant systems and asked whether ZLc002 would suppress inflammatory and neuropathic pain in vivo. In vitro, ZLc002 reduced co-immunoprecipitation of full-length NOS1AP and neuronal nitric oxide synthase in cultured neurons and in HEK293T cells co-expressing full-length neuronal nitric oxide synthase and NOS1AP. However, using a cell-free biochemical binding assay, ZLc002 failed to disrupt the in vitro binding between His-neuronal nitric oxide synthase1-299 and glutathione S-transferase-NOS1AP400-506, protein sequences containing the required binding domains for this protein-protein interaction, suggesting an indirect mode of action in intact cells. ZLc002 (4-10 mg/kg i.p.) suppressed formalin-evoked inflammatory pain in rats and reduced Fos protein-like immunoreactivity in the lumbar spinal dorsal horn. ZLc002 also suppressed mechanical and cold allodynia in a mouse model of paclitaxel-induced neuropathic pain. Anti-allodynic efficacy was sustained for at least four days of once daily repeated dosing. ZLc002 also synergized with paclitaxel when administered in combination to reduce breast (4T1) or ovarian (HeyA8) tumor cell line viability but did not alter tumor cell viability without paclitaxel. Our results verify that ZLc002 disrupts neuronal nitric oxide synthase-NOS1AP interaction in intact cells and demonstrate, for the first time, that systemic administration of a putative small-molecule inhibitor of neuronal nitric oxide synthase-NOS1AP suppresses inflammatory and neuropathic pain.
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Affiliation(s)
- Wan-Hung Lee
- Biochemistry Interdisciplinary Graduate Program, Molecular and
Cellular Biochemistry Department,
Indiana
University, Bloomington, IN, USA
| | - Lawrence M Carey
- Program in Neuroscience,
Indiana
University, Bloomington, IN, USA
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
| | - Li-Li Li
- Neuronal Signalling Lab, Turku Centre for Biotechnology,
University of Turku; Åbo Academy University, Turku, Finland
- Turku Centre for Biotechnology and Institute of Biomedicine,
Screening Unit, University of Turku, Turku, Finland
| | - Zhili Xu
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
| | - Yvonne Y Lai
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
- Anagin, Inc., Indianapolis, IN, USA
| | - Michael J Courtney
- Neuronal Signalling Lab, Turku Centre for Biotechnology,
University of Turku; Åbo Academy University, Turku, Finland
- Turku Centre for Biotechnology and Institute of Biomedicine,
Screening Unit, University of Turku, Turku, Finland
- Turku Brain and Mind Center, Turku, Finland
| | - Andrea G Hohmann
- Biochemistry Interdisciplinary Graduate Program, Molecular and
Cellular Biochemistry Department,
Indiana
University, Bloomington, IN, USA
- Program in Neuroscience,
Indiana
University, Bloomington, IN, USA
- Department of Psychological and Brain Sciences, Indiana
University, Bloomington, IN, USA
- Gill Center for Biomolecular Science, Bloomington, IN, USA
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9
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Cioffi CL. Modulation of Glycine-Mediated Spinal Neurotransmission for the Treatment of Chronic Pain. J Med Chem 2017; 61:2652-2679. [PMID: 28876062 DOI: 10.1021/acs.jmedchem.7b00956] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Chronic pain constitutes a significant and expanding worldwide health crisis. Currently available analgesics poorly serve individuals suffering from chronic pain, and new therapeutic agents that are more effective, safer, and devoid of abuse liabilities are desperately needed. Among the myriad of cellular and molecular processes contributing to chronic pain, spinal disinhibition of pain signaling to higher cortical centers plays a critical role. Accumulating evidence shows that glycinergic inhibitory neurotransmission in the spinal cord dorsal horn gates nociceptive signaling, is essential in maintaining physiological pain sensitivity, and is diminished in pathological pain states. Thus, it is hypothesized that agents capable of enhancing glycinergic tone within the dorsal horn could obtund nociceptor signaling to the brain and serve as analgesics for persistent pain. This Perspective highlights the potential that pharmacotherapies capable of increasing inhibitory spinal glycinergic neurotransmission hold in providing new and transformative analgesic therapies for the treatment of chronic pain.
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Affiliation(s)
- Christopher L Cioffi
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences , Albany College of Pharmacy and Health Sciences , 106 New Scotland Avenue , Albany , New York 12208 United States
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10
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Interactions between the Kynurenine and the Endocannabinoid System with Special Emphasis on Migraine. Int J Mol Sci 2017; 18:ijms18081617. [PMID: 28758944 PMCID: PMC5578009 DOI: 10.3390/ijms18081617] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 07/18/2017] [Accepted: 07/21/2017] [Indexed: 12/15/2022] Open
Abstract
Both the kynurenine and the endocannabinoid systems are involved in several neurological disorders, such as migraine and there are increasing number of reports demonstrating that there are interactions of two systems. Although their cooperation has not yet been implicated in migraine, there are reports suggesting this possibility. Additionally, the individual role of the endocannabinoid and kynurenine system in migraine is reviewed here first, focusing on endocannabinoids, kynurenine metabolites, in particular kynurenic acid. Finally, the function of NMDA and cannabinoid receptors in the trigeminal system-which has a crucial role in the pathomechanisms of migraine-will also be discussed. The interaction of the endocannabinoid and kynurenine system has been demonstrated to be therapeutically relevant in a number of pathological conditions, such as cannabis addiction, psychosis, schizophrenia and epilepsy. Accordingly, the cross-talk of these two systems may imply potential mechanisms related to migraine, and may offer new approaches to manage the treatment of this neurological disorder.
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11
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Nijs J, Loggia ML, Polli A, Moens M, Huysmans E, Goudman L, Meeus M, Vanderweeën L, Ickmans K, Clauw D. Sleep disturbances and severe stress as glial activators: key targets for treating central sensitization in chronic pain patients? Expert Opin Ther Targets 2017; 21:817-826. [DOI: 10.1080/14728222.2017.1353603] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jo Nijs
- Department of physiotherapy, human physiology and anatomy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium
| | - Marco L. Loggia
- MGH/HST A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Andrea Polli
- Department of physiotherapy, human physiology and anatomy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Maarten Moens
- Department of Neurosurgery and Radiology, University Hospital Brussels, Brussels, Belgium
- Department of Manual Therapy, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Eva Huysmans
- Department of physiotherapy, human physiology and anatomy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium
| | - Lisa Goudman
- Department of physiotherapy, human physiology and anatomy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Neurosurgery and Radiology, University Hospital Brussels, Brussels, Belgium
| | - Mira Meeus
- Department of physiotherapy, human physiology and anatomy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Rehabilitation Sciences and Physiotherapy, Ghent University, Ghent, Belgium
- Department of Rehabilitation Sciences and Physiotherapy, University of Antwerp, Antwerp, Belgium
| | - Luc Vanderweeën
- Department of physiotherapy, human physiology and anatomy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Brussels, Belgium
- Private Practice for Spinal Manual Therapy, Schepdaal-Dilbeek, Belgium
| | - Kelly Ickmans
- Department of physiotherapy, human physiology and anatomy, Pain in Motion International Research Group, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Brussels, Belgium
| | - Daniel Clauw
- Chronic Pain and Fatigue Research Center, University of Michigan, Ann Arbor, USA
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12
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Mazzone SB, Undem BJ. Vagal Afferent Innervation of the Airways in Health and Disease. Physiol Rev 2017; 96:975-1024. [PMID: 27279650 DOI: 10.1152/physrev.00039.2015] [Citation(s) in RCA: 339] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Vagal sensory neurons constitute the major afferent supply to the airways and lungs. Subsets of afferents are defined by their embryological origin, molecular profile, neurochemistry, functionality, and anatomical organization, and collectively these nerves are essential for the regulation of respiratory physiology and pulmonary defense through local responses and centrally mediated neural pathways. Mechanical and chemical activation of airway afferents depends on a myriad of ionic and receptor-mediated signaling, much of which has yet to be fully explored. Alterations in the sensitivity and neurochemical phenotype of vagal afferent nerves and/or the neural pathways that they innervate occur in a wide variety of pulmonary diseases, and as such, understanding the mechanisms of vagal sensory function and dysfunction may reveal novel therapeutic targets. In this comprehensive review we discuss historical and state-of-the-art concepts in airway sensory neurobiology and explore mechanisms underlying how vagal sensory pathways become dysfunctional in pathological conditions.
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Affiliation(s)
- Stuart B Mazzone
- School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, Australia; and Department of Medicine, Johns Hopkins University Medical School, Asthma & Allergy Center, Baltimore, Maryland
| | - Bradley J Undem
- School of Biomedical Sciences, The University of Queensland, St Lucia, Brisbane, Australia; and Department of Medicine, Johns Hopkins University Medical School, Asthma & Allergy Center, Baltimore, Maryland
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13
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Iyengar S, Ossipov MH, Johnson KW. The role of calcitonin gene-related peptide in peripheral and central pain mechanisms including migraine. Pain 2017; 158:543-559. [PMID: 28301400 PMCID: PMC5359791 DOI: 10.1097/j.pain.0000000000000831] [Citation(s) in RCA: 347] [Impact Index Per Article: 49.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Revised: 12/09/2016] [Accepted: 12/22/2016] [Indexed: 12/25/2022]
Abstract
Calcitonin gene-related peptide (CGRP) is a 37-amino acid peptide found primarily in the C and Aδ sensory fibers arising from the dorsal root and trigeminal ganglia, as well as the central nervous system. Calcitonin gene-related peptide was found to play important roles in cardiovascular, digestive, and sensory functions. Although the vasodilatory properties of CGRP are well documented, its somatosensory function regarding modulation of neuronal sensitization and of enhanced pain has received considerable attention recently. Growing evidence indicates that CGRP plays a key role in the development of peripheral sensitization and the associated enhanced pain. Calcitonin gene-related peptide is implicated in the development of neurogenic inflammation and it is upregulated in conditions of inflammatory and neuropathic pain. It is most likely that CGRP facilitates nociceptive transmission and contributes to the development and maintenance of a sensitized, hyperresponsive state not only of the primary afferent sensory neurons but also of the second-order pain transmission neurons within the central nervous system, thus contributing to central sensitization as well. The maintenance of a sensitized neuronal condition is believed to be an important factor underlying migraine. Recent successful clinical studies have shown that blocking the function of CGRP can alleviate migraine. However, the mechanisms through which CGRP may contribute to migraine are still not fully understood. We reviewed the role of CGRP in primary afferents, the dorsal root ganglion, and in the trigeminal system as well as its role in peripheral and central sensitization and its potential contribution to pain processing and to migraine.
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14
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Carey LM, Lee WH, Gutierrez T, Kulkarni PM, Thakur GA, Lai YY, Hohmann AG. Small molecule inhibitors of PSD95-nNOS protein-protein interactions suppress formalin-evoked Fos protein expression and nociceptive behavior in rats. Neuroscience 2017; 349:303-317. [PMID: 28285942 DOI: 10.1016/j.neuroscience.2017.02.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 02/08/2017] [Accepted: 02/27/2017] [Indexed: 11/29/2022]
Abstract
Excessive activation of NMDA receptor (NMDAR) signaling within the spinal dorsal horn contributes to central sensitization and the induction and maintenance of pathological pain states. However, direct antagonism of NMDARs produces undesirable side effects which limit their clinical use. NMDAR activation produces central sensitization, in part, by initiating a signaling cascade that activates the enzyme neuronal nitric oxide synthase (nNOS) and generates the signaling molecule nitric oxide. NMDAR-mediated activation of nNOS requires a scaffolding protein, postsynaptic density protein 95kDa (PSD95), which tethers nNOS to NMDARs. Thus, disrupting the protein-protein interaction between PSD95 and nNOS may inhibit pro-nociceptive signaling mechanisms downstream of NMDARs and suppress central sensitization while sparing unwanted side effects associated with NMDAR antagonists. We examined the impact of small molecule PSD95-nNOS protein-protein interaction inhibitors (ZL006, IC87201) on both nociceptive behavior and formalin-evoked Fos protein expression within the lumbar spinal cord of rats. Comparisons were made with ZL007, an inactive analog of ZL006, and the NMDAR antagonist MK-801. IC87201 and ZL006, but not ZL007, suppressed phase 2 of formalin-evoked pain behavior and decreased the number of formalin-induced Fos-like immunoreactive cells in spinal dorsal horn regions associated with nociceptive processing. MK-801 suppressed Fos protein expression in both dorsal and ventral horns. MK-801 produced motor ataxia in the rotarod test whereas IC87201 and ZL006 failed to do so. ZL006 but not ZL007 suppressed paclitaxel-induced mechanical and cold allodynia in a model of chemotherapy-induced neuropathic pain. Co-immunoprecipitation experiments revealed the presence of the PSD95-nNOS complex in lumbar spinal cord of paclitaxel-treated rats, although ZL006 did not reliably disrupt the complex in all subjects. The present findings validate use of putative small molecule PSD95-nNOS protein-protein interaction inhibitors as novel analgesics and demonstrate, for the first time, that these inhibitors suppress inflammation-evoked neuronal activation at the level of the spinal dorsal horn.
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Affiliation(s)
- Lawrence M Carey
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States; Program in Neuroscience, Indiana University, Bloomington, IN, United States
| | - Wan-Hung Lee
- Interdisciplinary Biochemistry Program, Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN, United States
| | - Tannia Gutierrez
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States
| | - Pushkar M Kulkarni
- Center for Drug Discovery, and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, United States
| | - Ganesh A Thakur
- Center for Drug Discovery, and Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, United States
| | - Yvonne Y Lai
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States; Anagin, Inc., Indianapolis, IN, United States
| | - Andrea G Hohmann
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, United States; Program in Neuroscience, Indiana University, Bloomington, IN, United States; Interdisciplinary Biochemistry Program, Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, IN, United States; Gill Center for Biomolecular Science, Indiana University, Bloomington, IN, United States.
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15
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Fixed spaced stimulation restores adaptive plasticity within the spinal cord: Identifying the eliciting conditions. Physiol Behav 2017; 174:1-9. [PMID: 28238778 DOI: 10.1016/j.physbeh.2017.02.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 02/22/2017] [Indexed: 01/21/2023]
Abstract
Prior work has shown that neurons within the spinal cord are sensitive to temporal relations and that stimulus regularity impacts nociceptive processing and adaptive plasticity. Application of brief (80ms) shocks (180-900) in a variable manner induces a form of maladaptive plasticity that inhibits spinally-mediated learning and enhances nociceptive reactivity. In contrast, an extended exposure (720-900) to stimuli given at regular (fixed spaced) intervals has a restorative effect that counters nociceptive sensitization and enables learning. The present paper explores the stimulus parameters under which this therapeutic effect of fixed spaced stimulation emerges. Spinally transected rats received variably spaced stimulation (180 shocks) to the sciatic nerve at an intensity (40-V) that recruits pain (C) fibers, producing a form of maladaptive plasticity that impairs spinal learning. As previously shown, exposure to 720 fixed spaced shocks had a therapeutic effect that restored adaptive learning. This therapeutic effect was most robust at a lower shock intensity (20V) and was equally strong irrespective of pulse duration (20-80ms). A restorative effect was observed when stimuli were given at a frequency between 0.5 and 5Hz, but not at a higher (50Hz) or lower (0.05Hz) rate. The results are consistent with prior work implicating neural systems related to the central pattern generator that drives stepping behavior. Clinical implications are discussed.
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Babina R, Mohanty PP, Pattnaik M. Effect of thoracic mobilization on respiratory parameters in chronic non-specific low back pain: A randomized controlled trial. J Back Musculoskelet Rehabil 2016; 29:587-95. [PMID: 26966825 DOI: 10.3233/bmr-160679] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Altered respiratory function has been found to be associated with back pain. Limited chest excursion in subjects with chronic low back pain (CLBP) may be due to co-contraction or bracing of erector spinae and abdominal muscles; their flexed spinal posture; and/or their compromised spinal stability resulting from dysfunctional transversus abdominis. OBJECTIVE To check for the effects of thoracic mobilization on respiratory parameters in subjects with chronic non-specific low back pain. METHODS Sixty-two subjects (excluding 11 dropouts) with CLBP of age group 30-60 were randomly allocated to two groups. Both groups received individualized treatment for low back pain (LBP) and HEP (home exercise program) regime of breathing exercises. In addition, group 1 received Maitland's Central postero-anterior vertebral pressure for thoracic spine (T1-T8). Total treatment duration was 10 sessions in 2 weeks (5 sessions/week). RESULTS Results showed significant improvement in respiratory parameters viz. Forced Vital Capacity (FVC), Sustained Maximal Inspiratory Pressure (SMIP) and Chest Wall Expansion (CWE) and Oswestry Disability Index (ODI) in both groups (p< 0.05) at end of 2 weeks of intervention. However, improvement was significantly more in group 1 (p < 0.05) receiving additional thoracic mobilization. CONCLUSION Subjects with non-specific chronic low back pain with or without radiation to lower limbs when treated with thoracic central PA mobilization, in addition to LBP specific treatment and breathing exercises, show an improvement in respiratory parameters and reduction in disability.
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Affiliation(s)
- R Babina
- College of Physiotherapy, MAMC, Haryana, India
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Ziv NY, Tal M, Shavit Y. The transition from naïve to primed nociceptive state: A novel wind-up protocol in mice. Exp Neurol 2015; 275 Pt 1:133-42. [PMID: 26439312 DOI: 10.1016/j.expneurol.2015.09.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 07/05/2015] [Accepted: 09/29/2015] [Indexed: 12/28/2022]
Abstract
Wind-up (WU) is a progressive, frequency-dependent facilitation of spinal cord neurons in response to repetitive nociceptive stimulation of constant intensity. We identified a new WU-associated phenomenon in naïve mice (not exposed to noxious stimulation immediately prior to WU stimulation), which were subjected to a novel experimental protocol composed of three consecutive trains of WU stimulation. The 1st train produced a typical linear 'wind-up' curve as expected following a repeating series of stimuli; in addition, this 1st train sensitized ('primed') the nociceptive system so that the responses to two subsequent trains (inter-train interval of 10 min) were significantly amplified compared with the response to the 1st train. We named this augmented response potentiation-of-windup, or "PoW". The PoW phenomenon appears to be centrally mediated, as the augmented response was suppressed by administration of an NMDA receptor antagonist (MK-801) and by cutting the spinal cord. Furthermore, the PoW protocol is accompanied by enhanced pain behavior. The 'priming' effect of the 1st train could be mimicked by exposure to natural noxious stimuli prior to the PoW protocol. Presumably, the PoW phenomenon has not been previously reported due to a procedural reason: typically, WU protocols have been executed in 'primed' rather than naïve animals, i.e., animals exposed to nociceptive stimulation prior to the actual WU recording. Our findings indicate that the PoW paradigm can distinguish between 'naïve' and 'primed' states, suggesting its use as a tool for the assessment of central sensitization.
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Affiliation(s)
- Nadav Y Ziv
- Department of Medical Neurobiology, Faculty of Medicine, The Hebrew University of Jerusalem, Israel; Department of Psychology, The Hebrew University of Jerusalem, Israel
| | - Michael Tal
- Department of Medical Neurobiology, Faculty of Medicine and Dentistry, The Hebrew University of Jerusalem, Israel; Center for Research on Pain, The Hebrew University of Jerusalem, Israel
| | - Yehuda Shavit
- Department of Psychology, The Hebrew University of Jerusalem, Israel; Center for Research on Pain, The Hebrew University of Jerusalem, Israel.
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Moon JY, Choi SR, Roh DH, Yoon SY, Kwon SG, Choi HS, Kang SY, Han HJ, Kim HW, Beitz AJ, Oh SB, Lee JH. Spinal sigma-1 receptor activation increases the production of D-serine in astrocytes which contributes to the development of mechanical allodynia in a mouse model of neuropathic pain. Pharmacol Res 2015; 100:353-64. [PMID: 26316425 DOI: 10.1016/j.phrs.2015.08.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 08/05/2015] [Accepted: 08/20/2015] [Indexed: 12/21/2022]
Abstract
We have previously demonstrated that activation of the spinal sigma-1 receptor (Sig-1R) plays an important role in the development of mechanical allodynia (MA) via secondary activation of the N-methyl-d-aspartate (NMDA) receptor. Sig-1Rs have been shown to localize to astrocytes, and blockade of Sig-1Rs inhibits the pathologic activation of astrocytes in neuropathic mice. However, the mechanism by which Sig-1R activation in astrocytes modulates NMDA receptors in neurons is currently unknown. d-serine, synthesized from l-serine by serine racemase (Srr) in astrocytes, is an endogenous co-agonist for the NMDA receptor glycine site and can control NMDA receptor activity. Here, we investigated the role of d-serine in the development of MA induced by spinal Sig-1R activation in chronic constriction injury (CCI) mice. The production of d-serine and Srr expression were both significantly increased in the spinal cord dorsal horn post-CCI surgery. Srr and d-serine were only localized to astrocytes in the superficial dorsal horn, while d-serine was also localized to neurons in the deep dorsal horn. Moreover, we found that Srr exists in astrocytes that express Sig-1Rs. The CCI-induced increase in the levels of d-serine and Srr was attenuated by sustained intrathecal treatment with the Sig-1R antagonist, BD-1047 during the induction phase of neuropathic pain. In behavioral experiments, degradation of endogenous d-serine with DAAO, or selective blockade of Srr by LSOS, effectively reduced the development of MA, but not thermal hyperalgesia in CCI mice. Finally, BD-1047 administration inhibited the development of MA and this inhibition was reversed by intrathecal treatment with exogenous d-serine. These findings demonstrate for the first time that the activation of Sig-1Rs increases the expression of Srr and d-serine in astrocytes. The increased production of d-serine induced by CCI ultimately affects dorsal horn neurons that are involved in the development of MA in neuropathic mice.
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Affiliation(s)
- Ji-Young Moon
- KM Fundamental Research Division, Korea Institute of Oriental Medicine, Daejeon 305-811, Republic of Korea
| | - Sheu-Ran Choi
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
| | - Dae-Hyun Roh
- Department of Maxillofacial Tissue Regeneration, Kyung Hee University School of Dentistry, Seoul 130-701, Republic of Korea
| | - Seo-Yeon Yoon
- Pain Cognitive Function Research Center, Department of Brain and Cognitive Sciences College of Natural Sciences, Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul 110-749, Republic of Korea
| | - Soon-Gu Kwon
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
| | - Hoon-Seong Choi
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
| | - Suk-Yun Kang
- KM Fundamental Research Division, Korea Institute of Oriental Medicine, Daejeon 305-811, Republic of Korea
| | - Ho-Jae Han
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea
| | - Hyun-Woo Kim
- Department of Physiology, Institute of Brain Research, Chungnam National University Medical School, Daejeon 301-747, Republic of Korea
| | - Alvin J Beitz
- Department of Veterinary and Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55108, USA
| | - Seog-Bae Oh
- Pain Cognitive Function Research Center, Department of Brain and Cognitive Sciences College of Natural Sciences, Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul 110-749, Republic of Korea
| | - Jang-Hern Lee
- Department of Veterinary Physiology, BK21 PLUS Program for Creative Veterinary Science Research, Research Institute for Veterinary Science and College of Veterinary Medicine, Seoul National University, Seoul 151-742, Republic of Korea.
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Increased CCN2, substance P and tissue fibrosis are associated with sensorimotor declines in a rat model of repetitive overuse injury. J Cell Commun Signal 2015; 9:37-54. [PMID: 25617052 DOI: 10.1007/s12079-015-0263-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 01/14/2015] [Indexed: 01/24/2023] Open
Abstract
Key clinical features of cumulative trauma disorders include pain, muscle weakness, and tissue fibrosis, although the etiology is still under investigation. Here, we characterized the temporal pattern of altered sensorimotor behaviors and inflammatory and fibrogenic processes occurring in forearm muscles and serum of young adult, female rats performing an operant, high repetition high force (HRHF) reaching and grasping task for 6, 12, or 18 weeks. Palmar mechanical sensitivity, cold temperature avoidance and spontaneous behavioral changes increased, while grip strength declined, in 18-week HRHF rats, compared to controls. Flexor digitorum muscles had increased MCP-1 levels after training and increased TNFalpha in 6-week HRHF rats. Serum had increased IL-1beta, IL-10 and IP-10 after training. Yet both muscle and serum inflammation resolved by week 18. In contrast, IFNγ increased at week 18 in both muscle and serum. Given the anti-fibrotic role of IFNγ, and to identify a mechanism for the continued grip strength losses and behavioral sensitivities, we evaluated the fibrogenic proteins CCN2, collagen type I and TGFB1, as well as the nociceptive/fibrogenic peptide substance P. Each increased in and around flexor digitorum muscles and extracellular matrix in the mid-forearm, and in nerves of the forepaw at 18 weeks. CCN2 was also increased in serum at week 18. At a time when inflammation had subsided, increases in fibrogenic proteins correlated with sensorimotor declines. Thus, muscle and nerve fibrosis may be critical components of chronic work-related musculoskeletal disorders. CCN2 and substance P may serve as potential targets for therapeutic intervention, and CCN2 as a serum biomarker of fibrosis progression.
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Kwak KH, Lim DG, Baek WY. N-Acetyl-l-Cysteine Attenuates Ischemia/Reperfusion Injury-Induced Allodynia and N-Methyl-d-Aspartate Receptor Activation in Rats. Curr Ther Res Clin Exp 2014; 72:216-27. [PMID: 24653508 DOI: 10.1016/j.curtheres.2011.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/10/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Although reactive oxygen species (ROS) are believed to be involved in pathogenic mechanisms that underlie complex regional pain syndrome type I (CRPS-I), the role of ROS in the central mechanism of CRPS is not fully understood. OBJECTIVE In this study we investigated whether ROS scavenger N-acetyl-l-cysteine (NAC) was capable of attenuating mechanical allodynia and whether pain was decreased through modulating N-methyl-d-aspartate (NMDA) receptor activation in a chronic postischemia pain (CPIP) animal model that mimics the symptoms of CRPS-I. METHODS Thirty male Sprague-Dawley rats were randomly allocated to 5 different groups: (1) sham rats and CPIP rats treated with (2) vehicle; (3) NAC 30 mg/kg; (4) NAC 100 mg/kg; and (5) NAC 300 mg/kg intraperitoneally at 15 minutes before reperfusion. CPIP was generated after a 3-hour ischemia/reperfusion injury on the hind limb using a tight fitting O-ring. Then, mechanical paw-withdrawal thresholds to von Frey stimuli were assessed before ischemia (baseline), at 4 hours; 1, 3, and 5 days; and 1, 2, 3, and 4 weeks after reperfusion. Another set of 5 animal groups in the same categories was used to determine phosphorylated NMDA receptor 1 subunit (pNR1) immunoreactivity in the ipsilateral L4/6 spinal cord at 3 days after reperfusion. RESULTS The sham group showed no significant difference in pain thresholds over 4 weeks. With NAC treatment, the pain thresholds measured after reperfusion increased significantly, and this increase lasted 4 weeks after reperfusion compared with the vehicle group (P < 0.01 on the ipsilateral side and P < 0.05 on the contralateral side). The relative density of pNR1 at 3 days after reperfusion in NAC-treated rats decreased significantly compared with that of the vehicle group (all, P < 0.001). The NAC dose was significantly correlated not only with paw-withdrawal threshold (ρ = 0.979; P < 0.001) but also with the relative density of pNR1 (ρ = -0.875; P < 0.001). CONCLUSIONS NAC, administered during the pre-reperfusion period, had a long-term antiallodynic effect through the attenuation of NMDA receptor phosphorylation, leading to central sensitization.
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Affiliation(s)
- Kyung-Hwa Kwak
- Department of Anesthesiology and Pain Medicine, Kyungpook National University School of Medicine, Jung gu, Daegu, Republic of Korea
| | - Dong Gun Lim
- Department of Anesthesiology and Pain Medicine, Kyungpook National University School of Medicine, Jung gu, Daegu, Republic of Korea
| | - Woon Yi Baek
- Department of Anesthesiology and Pain Medicine, Kyungpook National University School of Medicine, Jung gu, Daegu, Republic of Korea
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Stephenson R. The complexity of pain: part 1. No pain without gain: the augmentation of nociception in the CNS. PHYSICAL THERAPY REVIEWS 2013. [DOI: 10.1179/ptr.1999.4.2.105] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Learning from the spinal cord: how the study of spinal cord plasticity informs our view of learning. Neurobiol Learn Mem 2013; 108:155-71. [PMID: 23973905 DOI: 10.1016/j.nlm.2013.08.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 08/01/2013] [Accepted: 08/07/2013] [Indexed: 01/10/2023]
Abstract
The paper reviews research examining whether and how training can induce a lasting change in spinal cord function. A framework for the study of learning, and some essential issues in experimental design, are discussed. A core element involves delayed assessment under common conditions. Research has shown that brain systems can induce a lasting (memory-like) alteration in spinal function. Neurons within the lower (lumbosacral) spinal cord can also adapt when isolated from the brain by means of a thoracic transection. Using traditional learning paradigms, evidence suggests that spinal neurons support habituation and sensitization as well as Pavlovian and instrumental conditioning. At a neurobiological level, spinal systems support phenomena (e.g., long-term potentiation), and involve mechanisms (e.g., NMDA mediated plasticity, protein synthesis) implicated in brain-dependent learning and memory. Spinal learning also induces modulatory effects that alter the capacity for learning. Uncontrollable/unpredictable stimulation disables the capacity for instrumental learning and this effect has been linked to the cytokine tumor necrosis factor (TNF). Predictable/controllable stimulation enables learning and counters the adverse effects of uncontrollable stimulation through a process that depends upon brain-derived neurotrophic factor (BDNF). Finally, uncontrollable, but not controllable, nociceptive stimulation impairs recovery after a contusion injury. A process-oriented approach (neurofunctionalism) is outlined that encourages a broader view of learning phenomena.
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Yan X, Jiang E, Gao M, Weng HR. Endogenous activation of presynaptic NMDA receptors enhances glutamate release from the primary afferents in the spinal dorsal horn in a rat model of neuropathic pain. J Physiol 2013; 591:2001-19. [PMID: 23359671 DOI: 10.1113/jphysiol.2012.250522] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Activation of N-methyl-D-aspartate (NMDA) receptors (NMDARs) is a crucial mechanism underlying the development and maintenance of pain. Traditionally, the role of NMDARs in the pathogenesis of pain is ascribed to their activation and signalling cascades in postsynaptic neurons. In this study, we determined if presynaptic NMDARs in the primary afferent central terminals play a role in synaptic plasticity of the spinal first sensory synapse in a rat model of neuropathic pain induced by spinal nerve ligation. Excitatory postsynaptic currents (EPSCs) were recorded from superficial dorsal horn neurons of spinal slices taken from young adult rats. We showed that increased glutamate release from the primary afferents contributed to the enhanced amplitudes of EPSCs evoked by input from the primary afferents in neuropathic rats. Endogenous activation of presynaptic NMDARs increased glutamate release from the primary afferents in neuropathic rats. Presynaptic NMDARs in neuropathic rats were mainly composed of NR2B receptors. The action of presynaptic NMDARs in neuropathic rats was enhanced by exogenous D-serine and/or NMDA and dependent on activation of protein kinase C. In contrast, glutamate release from the primary afferents in sham-operated rats was not regulated by presynaptic NMDARs. We demonstrated that the lack of NMDAR-mediated regulation of glutamate release in sham-operated rats was not attributable to low extracellular levels of the NMDAR agonist and/or coagonist (D-serine), but rather was due to the insufficient function and/or number of presynaptic NMDARs. This was supported by an increase of NR2B receptor protein expression in both the dorsal root ganglion and spinal dorsal horn ipsilateral to the injury site in neuropathic rats. Hence, suppression of the presynaptic NMDAR activity in the primary sensory afferents is an effective approach to attenuate the enhanced glutamatergic response in the spinal first sensory synapse induced by peripheral nerve injury, and presynaptic NMDARs might be a novel target for the development of analgesics.
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Affiliation(s)
- Xisheng Yan
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, GA 30602, USA
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Morales F, Constandil L, Pelissier T, Hernández A, Laurido C. Antinociceptive interaction of (±)-CPP and propentofylline in monoarthritic rats. Arthritis Res Ther 2012; 14:R196. [PMID: 22920607 PMCID: PMC3580594 DOI: 10.1186/ar4030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 08/14/2012] [Indexed: 12/21/2022] Open
Abstract
Introduction Multiple studies have shown that glial cells of the spinal cord, such as astrocytes and microglia, have close contact with neurons, suggesting the term tripartite synapse. In these synapses, astrocytes surrounding neurons contribute to neuronal excitability and synaptic transmission, thereby increasing nociception and thus the persistence of chronic pain. Conversely, the N-methyl-D-aspartate (NMDA) receptor is crucial in the generation and maintenance of chronic pain. It has multiple sites of modulation. One is the site of recognition of extracellular neurotransmitter (glutamate), which can be blocked by competitive antagonists such as (3-(2-carboxipiperazin-4)1-propyl phosphonic acid), (±)-CPP, resulting in a blockade of the calcium current and thus the intracellular transduction process. In the present study, we investigated whether the potential antinociceptive effect of glial inhibition produced by propentofylline (PPF) can be enhanced when combined with an NMDA-receptor inhibitor such as (±)-CPP. Methods We used Sprague-Dawley monoarthritic rats. The monoarthritis was induced by injection of complete Freund adjuvant in the right tibiotarsal joint. Four weeks later, rats were treated with PPF (1, 10, 30, and 100 μg/10 μl) intrathecally (i.t.) for 10 days, injected once with (±)-CPP (2.5, 5, 12.5, 25, 50, and 100 μg/10 μl, i.t.), or both treatments combined. The antinociceptive effect was evaluated on day 11 for PPF and immediately to (±)-CPP, by assessing the vocalization threshold to mechanical stimulation of the arthritic paw. Results The data indicate that intrathecal administration of increasing concentrations of (±)-CPP or PPF produced a significant dose-dependent antinociceptive effect with respect to monoarthritic rats receiving saline. The linear regression analysis showed that the dose that produces 30% of maximal effect (ED30) for i.t. (±)-CPP was 3.97 μg, and 1.42 μg for i.t. PPF. The administration of the PPF and (±)-CPP combination in fixed proportions of ED30 produced a dose-dependent antinociceptive effect, showing an interaction of the supraadditive type. Conclusions The results suggest that glia inhibitors can synergically potentiate the effect of glutamate blockers for the treatment of chronic inflammatory pain.
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Grau JW, Huie JR, Garraway SM, Hook MA, Crown ED, Baumbauer KM, Lee KH, Hoy KC, Ferguson AR. Impact of behavioral control on the processing of nociceptive stimulation. Front Physiol 2012; 3:262. [PMID: 22934018 PMCID: PMC3429038 DOI: 10.3389/fphys.2012.00262] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/23/2012] [Indexed: 12/24/2022] Open
Abstract
How nociceptive signals are processed within the spinal cord, and whether these signals lead to behavioral signs of neuropathic pain, depends upon their relation to other events and behavior. Our work shows that these relations can have a lasting effect on spinal plasticity, inducing a form of learning that alters the effect of subsequent nociceptive stimuli. The capacity of lower spinal systems to adapt, in the absence of brain input, is examined in spinally transected rats that receive a nociceptive shock to the tibialis anterior muscle of one hind leg. If shock is delivered whenever the leg is extended (controllable stimulation), it induces an increase in flexion duration that minimizes net shock exposure. This learning is not observed in subjects that receive the same amount of shock independent of leg position (uncontrollable stimulation). These two forms of stimulation have a lasting, and divergent, effect on subsequent learning: controllable stimulation enables learning whereas uncontrollable stimulation disables it (learning deficit). Uncontrollable stimulation also enhances mechanical reactivity. We review evidence that training with controllable stimulation engages a brain-derived neurotrophic factor (BDNF)-dependent process that can both prevent and reverse the consequences of uncontrollable shock. We relate these effects to changes in BDNF protein and TrkB signaling. Controllable stimulation is also shown to counter the effects of peripheral inflammation (from intradermal capsaicin). A model is proposed that assumes nociceptive input is gated at an early sensory stage. This gate is sensitive to current environmental relations (between proprioceptive and nociceptive input), allowing stimulation to be classified as controllable or uncontrollable. We further propose that the status of this gate is affected by past experience and that a history of uncontrollable stimulation will promote the development of neuropathic pain.
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Affiliation(s)
- James W Grau
- Cellular and Behavioral Neuroscience, Department of Psychology, Texas A&M University College Station, TX, USA
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Lee DZ, Chung JM, Chung K, Kang MG. Reactive oxygen species (ROS) modulate AMPA receptor phosphorylation and cell-surface localization in concert with pain-related behavior. Pain 2012; 153:1905-1915. [PMID: 22770842 DOI: 10.1016/j.pain.2012.06.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 05/15/2012] [Accepted: 06/01/2012] [Indexed: 10/28/2022]
Abstract
Sensitization of dorsal horn neurons (DHNs) in the spinal cord is dependent on pain-related synaptic plasticity and causes persistent pain. The DHN sensitization is mediated by a signal transduction pathway initiated by the activation of N-methyl-d-aspartate receptors (NMDA-Rs). Recent studies have shown that elevated levels of reactive oxygen species (ROS) and phosphorylation-dependent trafficking of GluA2 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptors (AMPA-Rs) are a part of the signaling pathway for DHN sensitization. However, the relationship between ROS and AMPA-R phosphorylation and trafficking is not known. Thus, this study investigated the effects of ROS scavengers on the phosphorylation and cell-surface localization of GluA1 and GluA2. Intrathecal NMDA- and intradermal capsaicin-induced hyperalgesic mice were used for this study since both pain models share the NMDA-R activation-dependent DHN sensitization in the spinal cord. Our behavioral, biochemical, and immunohistochemical analyses demonstrated that: 1) NMDA-R activation in vivo increased the phosphorylation of AMPA-Rs at GluA1 (S818, S831, and S845) and GluA2 (S880) subunits; 2) NMDA-R activation in vivo increased cell-surface localization of GluA1 but decreased that of GluA2; and 3) reduction of ROS levels by ROS scavengers PBN (N-tert-butyl-α-phenylnitrone) or TEMPOL (4-hydroxy-2, 2, 6, 6-tetramethylpiperidin-1-oxyl) reversed these changes in AMPA-Rs, as well as pain-related behavior. Given that AMPA-R trafficking to the cell surface and synapse is regulated by NMDA-R activation-dependent phosphorylation of GluA1 and GluA2, our study suggests that the ROS-dependent changes in the phosphorylation and cell-surface localization of AMPA-Rs are necessary for DHN sensitization and thus, pain-related behavior. We further suggest that ROS reduction will ameliorate these molecular changes and pain.
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Affiliation(s)
- Daniel Z Lee
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
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Vega-Avelaira D, McKelvey R, Hathway G, Fitzgerald M. The emergence of adolescent onset pain hypersensitivity following neonatal nerve injury. Mol Pain 2012; 8:30. [PMID: 22531549 PMCID: PMC3443028 DOI: 10.1186/1744-8069-8-30] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 04/24/2012] [Indexed: 12/30/2022] Open
Abstract
Background Peripheral nerve injuries can trigger neuropathic pain in adults but cause little or no pain when they are sustained in infancy or early childhood. This is confirmed in rodent models where neonatal nerve injury causes no pain behaviour. However, delayed pain can arise in man some considerable time after nerve damage and to examine this following early life nerve injury we have carried out a longer term follow up of rat pain behaviour into adolescence and adulthood. Results Spared nerve injury (SNI) or sham surgery was performed on 10 day old (P10) rat pups and mechanical nociceptive reflex thresholds were analysed 3, 7, 14, 21, 28, 38 and 44 days post surgery. While mechanical thresholds on the ipsilateral side are not significantly different from controls for the first 2–3 weeks post P10 surgery, after that time period, beginning at 21 days post surgery (P31), the SNI group developed following early life nerve injury significant hypersensitivity compared to the other groups. Ipsilateral mechanical nociceptive threshold was 2-fold below that of the contralateral and sham thresholds at 21 days post surgery (SNI-ipsilateral 28 (±5) g control groups 69 (±9) g, p < 0.001, 3-way ANOVA, n = 6 per group). Importantly, no effect was observed on thermal thresholds. This hypersensivity was accompanied by macrophage, microglial and astrocyte activation in the DRG and dorsal horn, but no significant change in dorsal horn p38 or JNK expression. Preemptive minocycline (daily 40 mg/kg, s.c) did not prevent the effect. Ketamine (20 mg/kg, s.c), on the other hand, produced a dose-dependent reversal of mechanical nociceptive thresholds ipsilateral to the nerve injury such that thresholds return to control levels at the highest doses of 20 mg/Kg. Conclusions We report a novel consequence of early life nerve injury whereby mechanical hypersensitivity only emerges later in life. This delayed adolescent onset in mechanical pain thresholds is accompanied by neuroimmune activation and NMDA dependent central sensitization of spinal nociceptive circuits. This delayed onset in mechanical pain sensitivity may provide clues to understand the long term effects of early injury such as late onset phantom pain and the emergence of complex adolescent chronic pain syndromes.
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Affiliation(s)
- David Vega-Avelaira
- UCL Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London WC1E6BT, UK.
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Wu HC, Chang CH, Peng HY, Chen GD, Lai CY, Hsieh MC, Lin TB. EphrinB2 induces pelvic-urethra reflex potentiation via Src kinase-dependent tyrosine phosphorylation of NR2B. Am J Physiol Renal Physiol 2010; 300:F403-11. [PMID: 21147838 DOI: 10.1152/ajprenal.00520.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, the role of EphB receptor (EphBR) tyrosine kinase and their ephrinB ligands in pain-related neural plasticity at the spinal cord level have been identified. To test whether Src-family tyrosine kinase-dependent glutamatergic N-methyl-d-aspartate receptor NR2B subunit phosphorylation underlies lumbosacral spinal EphBR activation to mediate pelvic-urethra reflex potentiation, we recorded external urethra sphincter electromyogram reflex activity and analyzed protein expression in the lumbosacral (L(6)-S(2)) dorsal horn in response to intrathecal ephrinB2 injections. When compared with vehicle solution, exogenous ephrinB2 (5 μg/rat it)-induced reflex potentiation, in associated with phosphorylation of EphB1/2, Src-family kinase, NR2B Y1336 and Y1472 tyrosine residues. Both intrathecal EphB1 and EphB2 immunoglobulin fusion protein (both 10 μg/rat it) prevented ephrinB2-dependent reflex potentiation, as well as protein phosphorylation. Pretreatment with PP2 (50 μM, 10 μl it), an Src-family kinase antagonist, reversed the reflex potentiation, as well as Src kinase and NR2B phosphorylation. Together, these results suggest the ephrinB2-dependent EphBR activation, which subsequently provokes Src kinase-mediated N-methyl-d-aspartate receptor NR2B phosphorylation in the lumbosacral dorsal horn, is crucial for the induction of spinal reflex potentiation contributing to the development of visceral pain and/or hyperalgesia in the pelvic area.
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Affiliation(s)
- Hsi-Chin Wu
- Department of Urology, China Medical University Hospital, Taichung, Taiwan
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30
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Daulhac L, Maffre V, Mallet C, Etienne M, Privat AM, Kowalski-Chauvel A, Seva C, Fialip J, Eschalier A. Phosphorylation of spinal N-methyl-d-aspartate receptor NR1 subunits by extracellular signal-regulated kinase in dorsal horn neurons and microglia contributes to diabetes-induced painful neuropathy. Eur J Pain 2010; 15:169.e1-169.e12. [PMID: 20594879 DOI: 10.1016/j.ejpain.2010.06.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2010] [Revised: 05/10/2010] [Accepted: 06/01/2010] [Indexed: 01/15/2023]
Abstract
The N-methyl-d-aspartate receptor (NMDAR) contributes to central sensitization in the spinal cord, a phenomenon which comprises various pathophysiological mechanisms responsible for neuropathic pain-like signs in animal models. NMDAR function is modulated by post-translational modifications including phosphorylation, and this is proposed to underlie its involvement in the production of pain hypersensitivity. As in diabetic patients, streptozotocin-induced diabetic rats exhibit or not somatic mechanical hyperalgesia; these rats were named DH and DNH respectively. At three weeks of diabetes, we present evidence that somatic mechanical hyperalgesia was correlated with an enhanced phosphorylation of the NMDAR NR1 subunit (pNR1) in the rat spinal cord. This increase was not found in normal and DNH rats, suggesting that this regulation was specific to hyperalgesia. Double immunofluorescence studies revealed that the numbers of pNR1-immunoreactive neurons and microglial cells were significantly increased in all laminae (I-II and III-VI) of the dorsal horn from DH animals. Western-blots analysis showed no change in NR1 protein levels, whatever the behavioural and glycemic status of the animals. Chronic intrathecal treatment (5μg/rat/day for 7days) by U0126 and MK801, which blocked MEK (an upstream kinase of extracellular signal-regulated protein kinase: ERK) and the NMDAR respectively, simultaneously suppressed somatic mechanical hyperalgesia developed by diabetic rats and decreased pNR1. These results indicate for the first time that increased expression of pNR1 is regulated by ERK and the NMDAR via a feedforward mechanism in spinal neurons and microglia and represents one mechanism involved in central sensitization and somatic mechanical hyperalgesia after diabetes.
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Affiliation(s)
- Laurence Daulhac
- Clermont Université, Université d'Auvergne, Pharmacologie Fondamentale et Clinique de la Douleur, Laboratoire de Pharmacologie, Faculté de Pharmacie, Clermont-Ferrand, France.
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31
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Abstract
Animal models of tissue injury have been used to investigate the mechanisms of pain. Here, we describe a variety of animal models that have been used to mimic acute surgical pain in human subjects, which include the plantar, tail, and gastrocnemius incision models. We also provide discussion on animal models of laparotomy, thoracotomy, visceral pain, and bone injury. Preclinical studies using these models have provided insights into the mechanisms and causes of acute surgical pain as well as the treatment options to control postsurgical pain.
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Affiliation(s)
- Hyangin Kim
- Department of Anesthesia and Critical Care, Massachusetts General Hospital Center for Translational Pain Research, Harvard Medical School, Boston, MA, USA
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33
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Central sensitization: a generator of pain hypersensitivity by central neural plasticity. THE JOURNAL OF PAIN 2009; 10:895-926. [PMID: 19712899 DOI: 10.1016/j.jpain.2009.06.012] [Citation(s) in RCA: 2283] [Impact Index Per Article: 152.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 06/08/2009] [Accepted: 06/08/2009] [Indexed: 02/08/2023]
Abstract
UNLABELLED Central sensitization represents an enhancement in the function of neurons and circuits in nociceptive pathways caused by increases in membrane excitability and synaptic efficacy as well as to reduced inhibition and is a manifestation of the remarkable plasticity of the somatosensory nervous system in response to activity, inflammation, and neural injury. The net effect of central sensitization is to recruit previously subthreshold synaptic inputs to nociceptive neurons, generating an increased or augmented action potential output: a state of facilitation, potentiation, augmentation, or amplification. Central sensitization is responsible for many of the temporal, spatial, and threshold changes in pain sensibility in acute and chronic clinical pain settings and exemplifies the fundamental contribution of the central nervous system to the generation of pain hypersensitivity. Because central sensitization results from changes in the properties of neurons in the central nervous system, the pain is no longer coupled, as acute nociceptive pain is, to the presence, intensity, or duration of noxious peripheral stimuli. Instead, central sensitization produces pain hypersensitivity by changing the sensory response elicited by normal inputs, including those that usually evoke innocuous sensations. PERSPECTIVE In this article, we review the major triggers that initiate and maintain central sensitization in healthy individuals in response to nociceptor input and in patients with inflammatory and neuropathic pain, emphasizing the fundamental contribution and multiple mechanisms of synaptic plasticity caused by changes in the density, nature, and properties of ionotropic and metabotropic glutamate receptors.
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Bordet T, Pruss RM. Targeting neuroprotection as an alternative approach to preventing and treating neuropathic pain. Neurotherapeutics 2009; 6:648-62. [PMID: 19789070 PMCID: PMC5084287 DOI: 10.1016/j.nurt.2009.07.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 07/08/2009] [Indexed: 11/29/2022] Open
Abstract
Neuropathic pain syndromes arise from dysfunction of the nerve itself, through traumatic or nontraumatic injury. Unlike acute pain syndromes, the pain is long-lasting and does not respond to common analgesic therapies. Drugs that disrupt nerve conduction and transmission or central sensitization, currently the only effective treatments, are only modestly effective for a portion of the patients suffering from neuropathic pain and come with the cost of serious adverse effects. Neurodegeneration, as a reaction to nerve trauma or chronic metabolic or chemical intoxication, appears to be an underlying cause of neuropathic pain. Identifying mechanisms of neurodegeneration and designing neuroprotective therapies is an ambitious goal toward treating or even preventing the development of these disabling disorders.
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Affiliation(s)
- Thierry Bordet
- Trophos, Parc Scientifique de Luminy, Luminy Biotech Entreprises, Case 931, 13288 Marseille Cedex 9, France
| | - Rebecca M. Pruss
- Trophos, Parc Scientifique de Luminy, Luminy Biotech Entreprises, Case 931, 13288 Marseille Cedex 9, France
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Zhou Q, Price DD, Caudle RM, Verne GN. Spinal NMDA NR1 subunit expression following transient TNBS colitis. Brain Res 2009; 1279:109-20. [PMID: 19406112 DOI: 10.1016/j.brainres.2009.04.038] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 04/15/2009] [Accepted: 04/16/2009] [Indexed: 12/20/2022]
Abstract
BACKGROUND N-methyl-D-aspartic acid (NMDA) receptors play an important role in the development of hypersensitivity to visceral and somatic stimuli following inflammation or tissue injury. Our objective was to investigate the role of NMDA NR1 receptors in the spinal cord (T10-L1; L4-S1) of a subset of rats that remain hypersensitive following the histological resolution of TNBS-induced colitis compared to saline treated rats and rats that had recovered both behaviorally and histologically. We hypothesized that NMDA NR1 subunit expression mediates hypersensitivity following transient TNBS colitis. METHODS Male Sprague-Dawley rats (150 g-250 g) received 20 mg/rat intracolonic trinitrobenzene sulfonic acid (TNBS) in 50% ethanol or saline. Animals underwent nociceptive visceral/somatic pain testing 16 weeks after resolution of TNBS colitis. Animals were sacrificed and their spinal cords (T10-L1; L4-S1) were retrieved and 2-dimensional polyacrylamide gel electrophoresis and immunohistocytochemistry techniques were used to investigate spinal-NMDA receptor expression. RESULTS NR1(001) was the only NMDA NR1 receptor subunit that was expressed in recovered and control rats, whereas hypersensitive animals expressed NR1(011) and NR1(111) as well as NR1(001) subunits. Immunohistochemistry analysis demonstrated increased expression of NMDA NR1-N1, C1, and C2-plus expression in laminae I and II of the spinal cord (T10-L1; L4-S1) in hypersensitive rats but not in recovered/control rats. CONCLUSIONS Selective increases in the expression of the NMDA NR1 splice variants occur in hypersensitive rats following resolution of TNBS colitis. This suggests that the NMDA NR1 receptor plays an important role in the development of neuronal plasticity and central sensitization. The recombination of NR1 splice variants may serve as a key functional protein that maintains hypersensitivity following resolution of TNBS colitis.
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Affiliation(s)
- Qiqi Zhou
- Department of Medicine, Ohio State University, Columbus, Ohio 43210, USA
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36
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Garcia-Larrea L, Magnin M. Physiopathologie de la douleur neuropathique : revue des modèles expérimentaux et des mécanismes proposés. Presse Med 2008; 37:315-40. [DOI: 10.1016/j.lpm.2007.07.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 07/02/2007] [Indexed: 01/22/2023] Open
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Zhou Q, Nicholas Verne G. NMDA Receptors and Colitis: Basic Science and Clinical Implications. ACTA ACUST UNITED AC 2008; 10:33-43. [PMID: 20574552 DOI: 10.3727/154296108783994013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During the last decade, research focusing primarily on alterations in the peripheral and central nervous system has improved our understanding of the pathophysiological mechanisms of chronic visceral pain. These studies have demonstrated significant physiological changes following injury to the viscera in the firing patterns of both primary afferent neurons that transmit nociceptive information from the viscera and in central neurons that process the nociceptive information. A number of receptors, neurotransmitters, cytokines, and second messenger systems in these neurons have been implicated in the enhancement of visceral nociception. N-methyl-d-aspartic acid (NMDA) receptors play an important role in chronic visceral pain and hypersensitivity that is present in the setting of colonic inflammation. NMDA receptors are found in the peripheral nervous system as well as the central terminal of primary afferent neurons and have been shown to play an important role in regulating the release of nociceptive neurotransmitters. Recent work has demonstrated the presence of NMDA receptors in the enteric nervous system. In this article, we will discuss more recent evidence of the role of NMDA receptors in visceral pain associated with colitis.
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Affiliation(s)
- Qiqi Zhou
- Department of Medicine, University of Florida Colleges of Medicine, Gainesville, FL, USA
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38
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Washburn SN, Maultsby ML, Puga DA, Grau JW. Opioid regulation of spinal cord plasticity: evidence the kappa-2 opioid receptor agonist GR89696 inhibits learning within the rat spinal cord. Neurobiol Learn Mem 2007; 89:1-16. [PMID: 17983769 DOI: 10.1016/j.nlm.2007.09.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Revised: 09/27/2007] [Accepted: 09/30/2007] [Indexed: 11/17/2022]
Abstract
Spinal cord neurons can support a simple form of instrumental learning. In this paradigm, rats completely transected at the second thoracic vertebra learn to minimize shock exposure by maintaining a hindlimb in a flexed position. Prior exposure to uncontrollable shock (shock independent of leg position) disrupts this learning. This learning deficit lasts for at least 24h and depends on the NMDA receptor. Intrathecal application of an opioid antagonist blocks the expression, but not the induction, of the learning deficit. A comparison of selective opioid antagonists implicated the kappa-opioid receptor. The present experiments further explore how opioids affect spinal instrumental learning using selective opioid agonists. Male Sprague-Dawley rats were given an intrathecal injection (30 nmol) of a kappa-1 (U69593), a kappa-2 (GR89696), a mu (DAMGO), or a delta opioid receptor agonist (DPDPE) 10 min prior to instrumental testing. Only the kappa-2 opioid receptor agonist GR89696 inhibited acquisition (Experiment 1). GR89696 inhibited learning in a dose-dependent fashion (Experiment 2), but had no effect on instrumental performance in previously trained subjects (Experiment 3). Pretreatment with an opioid antagonist (naltrexone) blocked the GR89696-induced learning deficit (Experiment 4). Administration of GR89696 did not produce a lasting impairment (Experiment 5) and a moderate dose of GR89696 (6 nmol) reduced the adverse consequences of uncontrollable nociceptive stimulation (Experiment 6). The results suggest that a kappa-2 opioid agonist inhibits neural modifications within the spinal cord.
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MESH Headings
- Adaptation, Physiological/drug effects
- Animals
- Association Learning/drug effects
- Association Learning/physiology
- Benzeneacetamides/pharmacology
- Conditioning, Operant/drug effects
- Conditioning, Operant/physiology
- Dose-Response Relationship, Drug
- Enkephalin, Ala(2)-MePhe(4)-Gly(5)-/pharmacology
- Enkephalin, D-Penicillamine (2,5)-/pharmacology
- Male
- Neuronal Plasticity/drug effects
- Neuronal Plasticity/physiology
- Neurons/drug effects
- Neurons/metabolism
- Neurotransmitter Agents/pharmacology
- Piperazines/pharmacology
- Pyrrolidines/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Opioid, kappa/agonists
- Receptors, Opioid, kappa/metabolism
- Spinal Cord/cytology
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Spinal Cord Injuries/metabolism
- Thoracic Vertebrae
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Affiliation(s)
- Stephanie N Washburn
- Texas A&M University, Psychology Department, Mailstop 4235, College Station, TX 77843-4235, USA
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39
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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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40
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Gao X, Kim HK, Mo Chung J, Chung K. Reactive oxygen species (ROS) are involved in enhancement of NMDA-receptor phosphorylation in animal models of pain. Pain 2007; 131:262-271. [PMID: 17317010 PMCID: PMC2048490 DOI: 10.1016/j.pain.2007.01.011] [Citation(s) in RCA: 199] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 11/29/2006] [Accepted: 01/10/2007] [Indexed: 12/24/2022]
Abstract
Recent studies indicate that reactive oxygen species (ROS) play an important role in neuropathic pain, predominantly through spinal mechanisms. Since the data suggest that ROS are involved in central sensitization, the present study examines the levels of activated N-methyl-d-aspartate (NMDA) receptors in the dorsal horn before and after removal of ROS with a ROS scavenger, phenyl-N-t-butyl nitrone (PBN), in animal models of pain. Tight ligation of the L5 spinal nerve was used for the neuropathic pain model and intradermal injection of capsaicin was used for the inflammatory pain model. Foot withdrawal thresholds to von Frey stimuli to the paw were measured as pain indicators. The number of neurons showing immunoreactivity to phosphorylated NMDA-receptor subunit 1 (pNR1) and the total amount of pNR1 proteins in the spinal cord were determined using immunohistochemical and Western blotting techniques, respectively. Hyperalgesia and increased pNR1 expression were observed in both neuropathic and capsaicin-treated rats. A systemic injection of PBN (100 mg/kg, i.p.) dramatically reduced hyperalgesia and blocked the enhancement of spinal pNR1 in both pain models within 1h after PBN treatment. The data suggest that ROS are involved in NMDA-receptor activation, an essential step in central sensitization, and thus contribute to neuropathic and capsaicin-induced pain.
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Affiliation(s)
- Xiu Gao
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555-1069, USA
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41
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Osuka K, Watanabe Y, Usuda N, Atsuzawa K, Aoshima C, Yamauchi K, Takayasu M, Yoshida J. Phosphorylation of neuronal nitric oxide synthase at Ser847 in the nucleus intermediolateralis after spinal cord injury in mice. Neuroscience 2007; 145:241-7. [PMID: 17258865 DOI: 10.1016/j.neuroscience.2006.10.034] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 10/05/2006] [Accepted: 10/26/2006] [Indexed: 11/24/2022]
Abstract
We previously demonstrated that Ca2+/calmodulin (CaM)-dependent protein kinase IIalpha (CaM-KIIalpha) can phosphorylate neuronal nitric oxide synthase (nNOS) at Ser847 and attenuate NOS activity in neuronal cells. In the present study we focused on chronological alteration in levels and cellular location of nNOS, phosphorylated (p)-Ser847-nNOS (NP847), CaM-KII and p-Thr286-CaM-KIIalpha following spinal cord injury (SCI) in mice. Western blot analysis showed nNOS to be significantly phosphorylated at Ser847 from 3 h after SCI, peaking at 24 h and gradually decreasing thereafter, and CaM-KII to be colocalized with nNOS after SCI. Immunohistochemical analysis revealed that SCI causes an increase in both NP847 and p-Thr286-CaM-KIIalpha in the nucleus intermediolateralis. These findings suggest that SCI induces p-Thr286-CaM-KIIalpha, which phosphorylates the nNOS at Ser847 in the nucleus intermediolateralis where NO is thought to play a role as a neurotransmitter in autonomic preganglionic neurons. Thus, the NP847 signaling pathway might be involved in the autonomic failure which occurs immediately after SCI.
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Affiliation(s)
- K Osuka
- Department of Neurosurgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, 466-8550, Japan
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Grau JW, Crown ED, Ferguson AR, Washburn SN, Hook MA, Miranda RC. Instrumental learning within the spinal cord: underlying mechanisms and implications for recovery after injury. ACTA ACUST UNITED AC 2007; 5:191-239. [PMID: 17099112 DOI: 10.1177/1534582306289738] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Using spinally transected rats, research has shown that neurons within the L4-S2 spinal cord are sensitive to response-outcome (instrumental) relations. This learning depends on a form of N-methyl-D-aspartate (NMDA)-mediated plasticity. Instrumental training enables subsequent learning, and this effect has been linked to the expression of brain-derived neurotrophic factor. Rats given uncontrollable stimulation later exhibit impaired instrumental learning, and this deficit lasts up to 48 hr. The induction of the deficit can be blocked by prior training with controllable shock, the concurrent presentation of a tonic stimulus that induces antinociception, or pretreatment with an NMDA or gamma-aminobutyric acid-A antagonist. The expression of the deficit depends on a kappa opioid. Uncontrollable stimulation enhances mechanical reactivity (allodynia), and treatments that induce allodynia (e.g., inflammation) inhibit learning. In intact animals, descending serotonergic neurons exert a protective effect that blocks the adverse consequences of uncontrollable stimulation. Uncontrollable, but not controllable, stimulation impairs the recovery of function after a contusion injury.
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Affiliation(s)
- James W Grau
- Department of Psychology, Texas A&M University, College Station, TX 77843-4235, USA.
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Abstract
The processing and interpretation of pain signals is a complex process that entails excitation of peripheral nerves, local interactions within the spinal dorsal horn, and the activation of ascending and descending circuits that comprise a loop from the spinal cord to supraspinal structures and finally exciting nociceptive inputs at the spinal level. Although the "circuits" described here appear to be part of normal pain processing, the system demonstrates a remarkable ability to undergo neuroplastic transformations when nociceptive inputs are extended over time, and such adaptations function as a pronociceptive positive feedback loop. Manipulations directed to disrupt any of the nodes of this pain facilitatory loop may effectively disrupt the maintenance of the sensitized pain state and diminish or abolish neuropathic pain. Understanding the ascending and descending pain facilitatory circuits may provide for the design of rational therapies that do not interfere with normal sensory processing.
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Affiliation(s)
- Todd W Vanderah
- Department of Pharmacology, University of Arizona, College of Medicine, 1501 N. Campbell Avenue, Tucson, AZ 85724, USA.
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44
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Sah DY, Porreca F, Ossipov MH. Modulation of neurotrophic growth factors as a therapeutic strategy for neuropathic pain. Drug Dev Res 2006. [DOI: 10.1002/ddr.20102] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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45
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Karlsson GA, Preuss CV, Chaitoff KA, Maher TJ, Ally A. Medullary monoamines and NMDA-receptor regulation of cardiovascular responses during peripheral nociceptive stimuli. Neurosci Res 2006; 55:316-26. [PMID: 16684576 DOI: 10.1016/j.neures.2006.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 03/27/2006] [Accepted: 04/04/2006] [Indexed: 10/24/2022]
Abstract
We have previously reported that AMPA-receptor blockade within the rostral ventrolateral medulla (RVLM) attenuates cardiovascular responses and extracellular concentrations of glutamate during mechanical, but not during thermal stimulation [Gray, T., Lewis III, E., Maher, T.J., Ally, A., 2001. AMPA-receptor blockade within the RVLM modulates cardiovascular responses via glutamate during peripheral stimuli. Pharmacol. Res. 43, 47-54]. In this study, we examined the role of NMDA-receptor blockade within the RVLM on cardiovascular responses and release of biogenic monoamines (serotonin [5HT], dopamine [DA], and norepinephrine [NE]) during both mechanical and thermal nociception using anesthetized Sprague-Dawley rats. Both mechanical and thermal stimulation have been shown to activate peripheral Adelta and C-fiber polymodal nociceptors. Noxious mechanical stimuli were induced by applying a pinch to alternate hindpaw for 5s while the noxious thermal stimuli involved immersion of the metatarsus of alternate hindpaw in a water bath at a temperature of 52 degrees C for 5 s. Mechanical stimulation increased mean arterial pressure (MAP), heart rate (HR), extracellular fluid 5HT, and DA concentrations (n=10). However, extracellular levels of NE were decreased within the RVLM. Furthermore, NMDA-receptor blockade with a competitive antagonist, AP-7 (200 nM), within the RVLM attenuated the cardiovascular responses and changes in 5HT and DA, but had no effect on NE levels. The thermal stimulation elicited similar increases in MAP and HR, however, extracellular levels of 5HT or DA did not change. Concentrations of NE were decreased during a thermal stimulation similar to the levels observed following mechanical stimuli. In contrast to mechanical stimuli, bilateral administration of AP-7 (200-1 mM) into the RVLM had no effect on cardiovascular responses, 5HT, DA or NE concentrations during a thermal stimulation. These results show that NMDA receptors within the RVLM most likely play a role in modulating cardiovascular responses by altering 5HT and DA concentrations within the RVLM during mechanical but not thermal nociception. Overall, the present study delineates the NMDA-receptor mediated central integrative mechanisms within the RVLM that coordinate processing of sensory impulses arising from peripheral noxious stimulation.
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Affiliation(s)
- Gudbjorn A Karlsson
- Department of Pharmaceutical Sciences, Lloyd L. Gregory School of Pharmacy, Palm Beach Atlantic University, West Palm Beach, FL 33416, and Emergency Department, Inland Hospital, Waterville, ME 04910, USA
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Ferguson AR, Crown ED, Grau JW. Nociceptive plasticity inhibits adaptive learning in the spinal cord. Neuroscience 2006; 141:421-31. [PMID: 16678969 DOI: 10.1016/j.neuroscience.2006.03.029] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2005] [Revised: 03/08/2006] [Accepted: 03/18/2006] [Indexed: 11/29/2022]
Abstract
Spinal plasticity is known to play a role in central neurogenic pain. Over the last 100 years researchers have found that the spinal cord is also capable of supporting other forms of plasticity including several forms of learning. To study instrumental (response-outcome) learning in the spinal cord, we use a preparation in which spinally transected rats are given shock to the hind leg when the leg is extended. The spinal cord rapidly learns to hold the leg in a flexed position when given this controllable shock. However, if shock is independent of leg position (uncontrollable shock), subjects fail to learn. Uncontrollable shock also impairs future learning. As little as 6 min of uncontrollable shock to either the leg or the tail generates a learning deficit that lasts up to 48 h. Recent data suggest links between the learning deficit and the sensitization of pain circuits associated with inflammation or injury (central sensitization). Here, we explored whether central sensitization and the spinal learning deficit share pharmacological and behavioral features. Central sensitization enhances reactivity to mechanical stimulation (allodynia) and depends on the N-methyl-d-aspartate receptor (NMDAR). The uncontrollable shock stimulus that generates a learning deficit produced a tactile allodynia (Exp. 1) and administration of the NMDAR antagonist MK-801 blocked induction of the learning deficit (Exp. 2). Finally, a treatment known to induce central sensitization, intradermal carrageenan, produced a spinal learning deficit (Exp. 3). The findings suggest that the induction of central sensitization inhibits selective response modifications.
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Affiliation(s)
- A R Ferguson
- Department of Neuroscience, The Ohio State University, 333 West 10th Avenue, Columbus, OH 43210, USA.
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Vera-Portocarrero LP, Zhang ET, Ossipov MH, Xie JY, King T, Lai J, Porreca F. Descending facilitation from the rostral ventromedial medulla maintains nerve injury-induced central sensitization. Neuroscience 2006; 140:1311-20. [PMID: 16650614 DOI: 10.1016/j.neuroscience.2006.03.016] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2005] [Revised: 03/06/2006] [Accepted: 03/12/2006] [Indexed: 11/20/2022]
Abstract
Nerve injury can produce hypersensitivity to noxious and normally innocuous stimulation. Injury-induced central (i.e. spinal) sensitization is thought to arise from enhanced afferent input to the spinal cord and to be critical for expression of behavioral hypersensitivity. Descending facilitatory influences from the rostral ventromedial medulla have been suggested to also be critical for the maintenance, though not the initiation, of experimental neuropathic pain. The possibility that descending facilitation from the rostral ventromedial medulla is required for the maintenance of central sensitization was examined by determining whether ablation of mu-opioid receptor-expressing cells within the rostral ventromedial medulla prevented the enhanced expression of repetitive touch-evoked FOS within the spinal cord of animals with spinal nerve ligation injury as well as nerve injury-induced behavioral hypersensitivity. Rats received a single microinjection of vehicle, saporin, dermorphin or dermorphin-saporin into the rostral ventromedial medulla and 28 days later, underwent either sham or spinal nerve ligation procedures. Animals receiving rostral ventromedial medulla pretreatment with vehicle, dermorphin or saporin that were subjected to spinal nerve ligation demonstrated both thermal and tactile hypersensitivity, and showed significantly increased expression of touch-evoked FOS in the dorsal horn ipsilateral to nerve injury compared with sham-operated controls at days 3, 5 or 10 post-spinal nerve ligation. In contrast, nerve-injured animals pretreated with dermorphin-saporin showed enhanced behaviors and touch-evoked FOS expression in the spinal dorsal horn at day 3, but not days 5 and 10, post-spinal nerve ligation when compared with sham-operated controls. These results indicate the presence of nerve injury-induced behavioral hypersensitivity associated with nerve injury-induced central sensitization. Further, the results demonstrate the novel concept that once initiated, maintenance of nerve injury-induced central sensitization in the spinal dorsal horn requires descending pain facilitation mechanisms arising from the rostral ventromedial medulla.
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Affiliation(s)
- L P Vera-Portocarrero
- Department of Pharmacology, University of Arizona, Health Sciences Center, 1501 North Campbell Avenue, Tucson, AZ 85724, USA
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Petrenko AB, Yamakura T, Askalany AR, Kohno T, Sakimura K, Baba H. Effects of ketamine on acute somatic nociception in wild-type and N-methyl-d-aspartate (NMDA) receptor ɛ1 subunit knockout mice. Neuropharmacology 2006; 50:741-7. [PMID: 16427663 DOI: 10.1016/j.neuropharm.2005.11.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Revised: 11/14/2005] [Accepted: 11/29/2005] [Indexed: 10/25/2022]
Abstract
Although the properties of ketamine appear to be well characterized, there is a lot of ambiguity in the literature regarding its analgesic effects. After careful selection of proper experimental conditions and drug doses, we systematically characterized the effects of systemic ketamine on acute somatic nociception in mice and examined the role of the NMDA receptor epsilon1 subunit in mediating its analgesia. Intraperitoneal administration of ketamine was not analgesic in any of the phasic pain assays (thermal, mechanical, electrical) applied to C57BL/6 (wild-type) and NMDA receptor epsilon1 subunit knockout (mutant) mice. Surprisingly, rather than being analgesic for thermal nociception, ketamine showed pronociceptive properties in case of low-intensity heat stimulation in wild-type mice. In the formalin test (tonic pain), ketamine significantly reduced phase 2 nociceptive behavior in both wild-type and mutant mice. These data indicate that in wild-type mice ketamine has no analgesic effect on phasic pain in normal somatic tissues, but alleviates tonic pain after inflammation. Such analgesic spectrum of ketamine can be fully explained by its NMDA receptor antagonist properties. The results for the mutant mice suggest that the epsilon1 subunit of the NMDA receptor does not mediate the analgesic effects of ketamine in tonic pain.
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Affiliation(s)
- Andrey B Petrenko
- Division of Anesthesiology, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi 1-757, Niigata 951-8510, Japan
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Zhou Q, Caudle RM, Price DD, Del Valle-Pinero AY, Verne GN. Selective up-regulation of NMDA-NR1 receptor expression in myenteric plexus after TNBS induced colitis in rats. Mol Pain 2006; 2:3. [PMID: 16417630 PMCID: PMC1402265 DOI: 10.1186/1744-8069-2-3] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Accepted: 01/17/2006] [Indexed: 01/11/2023] Open
Abstract
Background N-methyl-D-aspartic acid (NMDA) spinal cord receptors play an important role in the development of hyperalgesia following inflammation. It is unclear, however, if changes in NMDA subunit receptor gene expression in the colonic myenteric plexus are associated with colonic inflammation. We investigated regulation of NMDA-NR1 receptor gene expression in TNBS induced colitis in rats. Male Sprague-Dawley rats (150 g–250 g) were treated with 20 mg trinitrobenzene sulfonic acid (TNBS) diluted in 50% ethanol. The agents were delivered with a 24 gauge catheter inserted into the lumen of the colon. The animals were sacrificed at 2, 7, 14, 21, and 28 days after induction of the colitis, their descending colon was retrieved for reverse transcription-polymerase chain reaction; a subset of animals' distal colon was used for two-dimensional (2-D) western analysis and immunocytochemistry. Results NR1-exon 5 (N1) and NR1-exon 21 (C1) appeared 14, 21 and 28 days after TNBS treatment. NR1 pan mRNA was up-regulated at 14, 21, and 28 days. The NR1-exon 22 (C2) mRNA did not show significant changes. Using 2-D western analysis, untreated control rats were found to express only NR1001 whereas TNBS treated rats expressed NR1001, NR1011, and NR1111. Immunocytochemistry demonstrated NR1-N1 and NR1-C1 to be present in the myenteric plexus of TNBS treated rats. Conclusion These results suggest a role for colonic myenteric plexus NMDA receptors in the development of neuronal plasticity and visceral hypersensitivity in the colon. Up-regulation of NMDA receptor subunits may reflect part of the basis for chronic visceral hypersensitivity in conditions such as post-infectious irritable bowel syndrome.
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Affiliation(s)
- QiQi Zhou
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Robert M Caudle
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, FL 32610, USA
- Department of Neuroscience, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | - Donald D Price
- Department of Oral and Maxillofacial Surgery, University of Florida College of Dentistry, Gainesville, FL 32610, USA
- Department of Neuroscience, University of Florida College of Dentistry, Gainesville, FL 32610, USA
| | | | - G Nicholas Verne
- Department of Medicine, University of Florida College of Medicine, Gainesville, FL 32610, USA
- North Florida/South Georgia VA Health System, USA
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