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Merighi A. Brain-Derived Neurotrophic Factor, Nociception, and Pain. Biomolecules 2024; 14:539. [PMID: 38785946 PMCID: PMC11118093 DOI: 10.3390/biom14050539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 05/25/2024] Open
Abstract
This article examines the involvement of the brain-derived neurotrophic factor (BDNF) in the control of nociception and pain. BDNF, a neurotrophin known for its essential role in neuronal survival and plasticity, has garnered significant attention for its potential implications as a modulator of synaptic transmission. This comprehensive review aims to provide insights into the multifaceted interactions between BDNF and pain pathways, encompassing both physiological and pathological pain conditions. I delve into the molecular mechanisms underlying BDNF's involvement in pain processing and discuss potential therapeutic applications of BDNF and its mimetics in managing pain. Furthermore, I highlight recent advancements and challenges in translating BDNF-related research into clinical practice.
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Affiliation(s)
- Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, 10095 Turin, Italy
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Calvo PM, de la Cruz RR, Pastor AM, Alvarez FJ. Preservation of KCC2 expression in axotomized abducens motoneurons and its enhancement by VEGF. Brain Struct Funct 2023; 228:967-984. [PMID: 37005931 PMCID: PMC10428176 DOI: 10.1007/s00429-023-02635-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 03/23/2023] [Indexed: 04/04/2023]
Abstract
The potassium chloride cotransporter 2 (KCC2) is the main Cl- extruder in neurons. Any alteration in KCC2 levels leads to changes in Cl- homeostasis and, consequently, in the polarity and amplitude of inhibitory synaptic potentials mediated by GABA or glycine. Axotomy downregulates KCC2 in many different motoneurons and it is suspected that interruption of muscle-derived factors maintaining motoneuron KCC2 expression is in part responsible. In here, we demonstrate that KCC2 is expressed in all oculomotor nuclei of cat and rat, but while trochlear and oculomotor motoneurons downregulate KCC2 after axotomy, expression is unaltered in abducens motoneurons. Exogenous application of vascular endothelial growth factor (VEGF), a neurotrophic factor expressed in muscle, upregulated KCC2 in axotomized abducens motoneurons above control levels. In parallel, a physiological study using cats chronically implanted with electrodes for recording abducens motoneurons in awake animals, demonstrated that inhibitory inputs related to off-fixations and off-directed saccades in VEGF-treated axotomized abducens motoneurons were significantly higher than in control, but eye-related excitatory signals in the on direction were unchanged. This is the first report of lack of KCC2 regulation in a motoneuron type after injury, proposing a role for VEGF in KCC2 regulation and demonstrating the link between KCC2 and synaptic inhibition in awake, behaving animals.
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Affiliation(s)
- Paula M Calvo
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
- Department of Cell Biology, Emory University, Atlanta, GA, 30322, USA
| | - Rosa R de la Cruz
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
| | - Angel M Pastor
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012, Seville, Spain
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Shi M, Zhou J, Hu R, Xu H, Chen Y, Wu X, Chen B, Ma R. EA participates in pain transition through regulating KCC2 expression by BDNF-TrkB in the spinal cord dorsal horn of male rats. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 13:100115. [PMID: 36875547 PMCID: PMC9982673 DOI: 10.1016/j.ynpai.2023.100115] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
The pathogenesis of chronic pain is complex and poorly treated, seriously affecting the quality of life of patients. Electroacupuncture (EA) relieves pain by preventing the transition of acute pain into chronic pain, but its mechanism of action is still unclear. Here, we aimed to investigate whether EA can inhibit pain transition by increasing KCC2 expression via BDNF-TrkB. We used hyperalgesic priming (HP) model to investigate the potential central mechanisms of EA intervention on pain transition. HP model male rats showed significant and persistent mechanically abnormal pain. Brain derived neurotrophic factor (BDNF) expression and Tropomyosin receptor kinase B (TrkB) phosphorylation were upregulated in the affected spinal cord dorsal horn (SCDH) of HP model rats, accompanied by K+-Cl-- Cotransporter-2 (KCC2) expression was down-regulated. EA significantly increased the mechanical pain threshold in HP model male rats and decreased BDNF and p-TrkB overexpression and upregulated KCC2 expression. Blockade of BDNF with BDNF neutralizing antibody attenuated mechanical abnormal pain in HP rats. Finally, administration of exogenous BDNF by pharmacological methods reversed the EA-induced resistance to abnormal pain. In all, these results suggest that BDNF-TrkB contributes to mechanical abnormal pain in HP model rats and that EA ameliorates mechanical abnormal pain through upregulation of KCC2 by BDNF-TrkB in SCDH. Our study further supports EA as an effective treatment to prevent the transition of acute pain into chronic pain.
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Affiliation(s)
- Mengting Shi
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Jie Zhou
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
- Department of Acupuncture and Moxibustion, Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Rong Hu
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Haipeng Xu
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Yi Chen
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Xingying Wu
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Bowen Chen
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
| | - Ruijie Ma
- The Third School of Clinical Medicine, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, Zhejiang, China
- Department of Acupuncture and Moxibustion, Third Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
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Zhao X, Li X, Guo H, Liu P, Ma M, Wang Y. Resolvin D1 attenuates mechanical allodynia after burn injury: Involvement of spinal glia, p38 mitogen-activated protein kinase, and brain-derived neurotrophic factor/tropomyosin-related kinase B signaling. Mol Pain 2023; 19:17448069231159970. [PMID: 36765459 PMCID: PMC9986910 DOI: 10.1177/17448069231159970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
Resolvin D1 (RvD1) suppresses inflammatory, postoperative, and neuropathic pain. The present study assessed the roles and mechanisms of RvD1 in mechanical allodynia after burn injury. A rat model of burn injury was established for analyses, and RvD1 was injected intraperitoneally. Pain behavior and the expression levels of spinal dorsal horn Iba-1 (microglia marker), GFAP (astrocyte marker), p-p38 mitogen-activated protein kinase (MAPK), brain-derived neurotrophic factor (BDNF), and tropomyosin-related kinase B (TrkB) were detected by behavioral and immunocytochemical assays. The results showed that RvD1 attenuated mechanical allodynia after burn injury, prevented microglial and astroglial activation, and downregulated p-p38 MAPK in microglia and BDNF/TrkB following burn injury. Similarly, inhibition of p38 MAPK and BDNF/TrkB signaling attenuated mechanical allodynia after burn injury. In addition, inhibition of p38 MAPK prevented spinal microglial activation and downregulated BDNF/TrkB following burn injury. Furthermore, inhibition of BDNF/TrkB signaling prevented spinal microglial activation and downregulated p-p38 MAPK within spinal microglia. Taken together, this study demonstrated that RvD1 might attenuate mechanical allodynia after burn injury by inhibiting spinal cord glial activation, microglial p38 MAPK, and BDNF/TrkB signaling in the spinal dorsal horn.
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Affiliation(s)
- Xiaona Zhao
- Department of Anesthesiology, Pain and Perioperative Medicine, 191599The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xinxin Li
- Department of Anesthesiology, Pain and Perioperative Medicine, 191599The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Huiling Guo
- Department of Anesthesiology, Pain and Perioperative Medicine, 191599The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Panmei Liu
- Department of Anesthesiology, Pain and Perioperative Medicine, 191599The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Minyu Ma
- Department of Anesthesiology, Pain and Perioperative Medicine, 191599The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Yanping Wang
- Department of Anesthesiology, Pain and Perioperative Medicine, 191599The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Talifu Z, Pan Y, Gong H, Xu X, Zhang C, Yang D, Gao F, Yu Y, Du L, Li J. The role of KCC2 and NKCC1 in spinal cord injury: From physiology to pathology. Front Physiol 2022; 13:1045520. [PMID: 36589461 PMCID: PMC9799334 DOI: 10.3389/fphys.2022.1045520] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/05/2022] [Indexed: 12/23/2022] Open
Abstract
The balance of ion concentrations inside and outside the cell is an essential homeostatic mechanism in neurons and serves as the basis for a variety of physiological activities. In the central nervous system, NKCC1 and KCC2, members of the SLC12 cation-chloride co-transporter (CCC) family, participate in physiological and pathophysiological processes by regulating intracellular and extracellular chloride ion concentrations, which can further regulate the GABAergic system. Over recent years, studies have shown that NKCC1 and KCC2 are essential for the maintenance of Cl- homeostasis in neural cells. NKCC1 transports Cl- into cells while KCC2 transports Cl- out of cells, thereby regulating chloride balance and neuronal excitability. An imbalance of NKCC1 and KCC2 after spinal cord injury will disrupt CI- homeostasis, resulting in the transformation of GABA neurons from an inhibitory state into an excitatory state, which subsequently alters the spinal cord neural network and leads to conditions such as spasticity and neuropathic pain, among others. Meanwhile, studies have shown that KCC2 is also an essential target for motor function reconstruction after spinal cord injury. This review mainly introduces the physiological structure and function of NKCC1 and KCC2 and discusses their pathophysiological roles after spinal cord injury.
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Affiliation(s)
- Zuliyaer Talifu
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China
| | - Yunzhu Pan
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China
| | - Han Gong
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Xin Xu
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Chunjia Zhang
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Degang Yang
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Feng Gao
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Yan Yu
- School of Rehabilitation, Capital Medical University, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China
| | - Liangjie Du
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,*Correspondence: Liangjie Du, ; Jianjun Li,
| | - Jianjun Li
- School of Rehabilitation, Capital Medical University, Beijing, China,Department of Spinal and Neural Functional Reconstruction, China Rehabilitation Research Center, Beijing, China,Chinese Institute of Rehabilitation Science, Beijing, China,Center of Neural Injury and Repair, Beijing Institute for Brain Disorders, Beijing, China,Beijing Key Laboratory of Neural Injury and Rehabilitation, Beijing, China,School of Rehabilitation Sciences and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China,*Correspondence: Liangjie Du, ; Jianjun Li,
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Hudson KE, Grau JW. Ionic Plasticity: Common Mechanistic Underpinnings of Pathology in Spinal Cord Injury and the Brain. Cells 2022; 11:cells11182910. [PMID: 36139484 PMCID: PMC9496934 DOI: 10.3390/cells11182910] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/12/2022] [Accepted: 09/14/2022] [Indexed: 11/16/2022] Open
Abstract
The neurotransmitter GABA is normally characterized as having an inhibitory effect on neural activity in the adult central nervous system (CNS), which quells over-excitation and limits neural plasticity. Spinal cord injury (SCI) can bring about a modification that weakens the inhibitory effect of GABA in the central gray caudal to injury. This change is linked to the downregulation of the potassium/chloride cotransporter (KCC2) and the consequent rise in intracellular Cl- in the postsynaptic neuron. As the intracellular concentration increases, the inward flow of Cl- through an ionotropic GABA-A receptor is reduced, which decreases its hyperpolarizing (inhibitory) effect, a modulatory effect known as ionic plasticity. The loss of GABA-dependent inhibition enables a state of over-excitation within the spinal cord that fosters aberrant motor activity (spasticity) and chronic pain. A downregulation of KCC2 also contributes to the development of a number of brain-dependent pathologies linked to states of neural over-excitation, including epilepsy, addiction, and developmental disorders, along with other diseases such as hypertension, asthma, and irritable bowel syndrome. Pharmacological treatments that target ionic plasticity have been shown to bring therapeutic benefits.
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Affiliation(s)
- Kelsey E. Hudson
- Neuroscience, Texas A&M University, College Station, TX 77843, USA
- Correspondence:
| | - James W. Grau
- Psychological & Brain Sciences, Texas A&M University, College Station, TX 77843, USA
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Abstract
We aimed to investigate a sexually dimorphic role of calcitonin gene-related peptide (CGRP) in rodent models of pain. Based on findings in migraine where CGRP has a preferential pain-promoting effect in female rodents, we hypothesized that CGRP antagonists and antibodies would attenuate pain sensitization more efficaciously in female than male mice and rats. In hyperalgesic priming induced by activation of interleukin 6 signaling, CGRP receptor antagonists olcegepant and CGRP8-37 both given intrathecally, blocked, and reversed hyperalgesic priming only in females. A monoclonal antibody against CGRP, given systemically, blocked priming specifically in female rodents but failed to reverse it. In the spared nerve injury model, there was a transient effect of both CGRP antagonists, given intrathecally, on mechanical hypersensitivity in female mice only. Consistent with these findings, intrathecally applied CGRP caused a long-lasting, dose-dependent mechanical hypersensitivity in female mice but more transient effects in males. This CGRP-induced mechanical hypersensitivity was reversed by olcegepant and the KCC2 enhancer CLP257, suggesting a role for anionic plasticity in the dorsal horn in the pain-promoting effects of CGRP in females. In spinal dorsal horn slices, CGRP shifted GABAA reversal potentials to significantly more positive values, but, again, only in female mice. Therefore, CGRP may regulate KCC2 expression and/or activity downstream of CGRP receptors specifically in females. However, KCC2 hypofunction promotes mechanical pain hypersensitivity in both sexes because CLP257 alleviated hyperalgesic priming in male and female mice. We conclude that CGRP promotes pain plasticity in female rodents but has a limited impact in males.SIGNIFICANCE STATEMENT The majority of patients impacted by chronic pain are women. Mechanistic studies in rodents are creating a clear picture that molecular events promoting chronic pain are different in male and female animals. We sought to build on evidence showing that CGRP is a more potent and efficacious promoter of headache in female than in male rodents. To test this, we used hyperalgesic priming and the spared nerve injury neuropathic pain models in mice. Our findings show a clear sex dimorphism wherein CGRP promotes pain in female but not male mice, likely via a centrally mediated mechanism of action. Our work suggests that CGRP receptor antagonists could be tested for efficacy in women for a broader variety of pain conditions.
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Sadeghi M, Manaheji H, Zaringhalam J, Haghparast A, Nazemi S, Bahari Z, Noorbakhsh SM. Evaluation of the GABAA Receptor Expression and the Effects of Muscimol on the Activity of Wide Dynamic Range Neurons Following Chronic Constriction Injury of Sciatic Nerve in Rats. Basic Clin Neurosci 2021; 12:651-666. [PMID: 35173919 PMCID: PMC8818116 DOI: 10.32598/bcn.2021.1726.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/05/2020] [Accepted: 08/02/2021] [Indexed: 11/20/2022] Open
Abstract
Introduction The modality of γ-aminobutyric acid type a receptors (GABAA) controls dorsal horn neuronal excitability and inhibits sensory information. This study aimed to investigate the expression of the GABAA receptor and the effects of its agonist muscimol on Wide Dynamic Range (WDR) neuronal activity in the Chronic Constriction Injury (CCI) model of neuropathic pain. Methods Adult male Wistar rats weighing 200 to 250 g were used to induce CCI neuropathy. Fourteen days after surgery, muscimol (0.5, 1, and 2 mg/kg IP) was injected. Then, the behavioral tests were performed. After that, the animals were killed, and the lumbar segments of the spinal cords were collected for Western blot analysis of the GABAA receptor α1 subunit expression. The electrophysiological properties of WDR neurons were studied by single-unit recordings in separate groups 14 days after CCI. Results The outcomes indicated the development of thermal hyperalgesia and mechanical allodynia after neuropathy; nonetheless, the expression of the GABAA receptor α1 subunit did not change significantly. Moreover, the evoked responses of the WDR neurons to electrical, mechanical, and thermal stimuli increased considerably. Fourteen days after CCI, muscimol administration decreased thermal hyperalgesia, mechanical allodynia, and hyper-responsiveness of the WDR neurons in CCI rats. Conclusion The modulation of the spinal GABAA receptors after nerve injury can offer further insights to design new therapeutic agents to reduce neuropathic pain symptoms.
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Affiliation(s)
- Mehdi Sadeghi
- Department of Physiology, Faculty of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Homa Manaheji
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Jalal Zaringhalam
- Neurophysiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.,Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Abbas Haghparast
- Neuroscience Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Samad Nazemi
- Department of Physiology, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Zahra Bahari
- Department of Physiology and Medical Physics, Faculty of Medicine, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Seyed Mohammad Noorbakhsh
- Department of Physiology, Faculty of Medicine, Sabzevar University of Medical Sciences, Sabzevar, Iran
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Gazzo G, Melchior M, Caussaint A, Gieré C, Lelièvre V, Poisbeau P. Overexpression of chloride importer NKCC1 contributes to the sensory-affective and sociability phenotype of rats following neonatal maternal separation. Brain Behav Immun 2021; 92:193-202. [PMID: 33316378 DOI: 10.1016/j.bbi.2020.12.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/04/2020] [Accepted: 12/08/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Early life stress is known to affect the development of the nervous system and its function at a later age. It increases the risk to develop psychiatric disorders as well as chronic pain and its associated affective comorbidities across the lifespan. GABAergic inhibition is important for the regulation of central function and related behaviors, including nociception, anxiety or social interactions, and requires low intracellular chloride levels. Of particular interest, the oxytocinergic (OTergic) system exerts potent anxiolytic, analgesic and pro-social properties and is known to be involved in the regulation of chloride homeostasis and to be impaired following early life stress. METHODS We used behavioral measures to evaluate anxiety, social interactions and pain responses in a rat model of neonatal maternal separation (NMS). Using quantitative PCR, we investigated whether NMS was associated with alterations in the expression of chloride transporters in the cerebrum and spinal cord. Finally, we evaluated the contribution of OTergic signaling and neuro-inflammatory processes in the observed phenotype. RESULTS NMS animals displayed a long-lasting upregulation of chloride importer Na-K-Cl cotransporter type 1 (NKCC1) expression in the cerebrum and spinal cord. Neonatal administration of the NKCC1 inhibitor bumetanide or oxytocin successfully normalized the anxiety-like symptoms and the lack of social preference observed in NMS animals. Phenotypic alterations were associated with a pro-inflammatory state which could contribute to NKCC1 upregulation. CONCLUSIONS This work suggests that an impaired chloride homeostasis, linked to oxytocin signaling dysfunction and to neuro-inflammatory processes, could contribute to the sensori-affective phenotype following NMS.
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Affiliation(s)
- Géraldine Gazzo
- Centre National de la Recherche Scientifique and University of Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, 67000 Strasbourg, France
| | - Meggane Melchior
- Centre National de la Recherche Scientifique and University of Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, 67000 Strasbourg, France
| | - Andréa Caussaint
- Centre National de la Recherche Scientifique and University of Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, 67000 Strasbourg, France
| | - Clémence Gieré
- Centre National de la Recherche Scientifique and University of Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, 67000 Strasbourg, France
| | - Vincent Lelièvre
- Centre National de la Recherche Scientifique and University of Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, 67000 Strasbourg, France
| | - Pierrick Poisbeau
- Centre National de la Recherche Scientifique and University of Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, 67000 Strasbourg, France.
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Abstract
Brain-derived neurotrophic factor (BDNF) and the high-affinity receptor tropomyosin receptor kinase B (TrkB) have important roles in neuronal survival and in spinal sensitization mechanisms associated with chronic pain. Recent clinical evidence also supports a peripheral role of BDNF in osteoarthritis (OA), with synovial expression of TrkB associated with higher OA pain. The aim of this study was to use clinical samples and animal models to explore the potential contribution of knee joint BDNF/TrkB signalling to chronic OA pain. Brain-derived neurotrophic factor and TrkB mRNA and protein were present in knee synovia from OA patients (16 women, 14 men, median age 67 years [interquartile range: 61-73]). There was a significant positive correlation between mRNA expression of NTRK2 (TrkB) and the proinflammatory chemokine fractalkine in the OA synovia. Using the surgical medial meniscal transection (MNX) model and the chemical monosodium iodoacetate (MIA) model of OA pain in male rats, the effects of peripheral BDNF injection, vs sequestering endogenous BDNF with TrkB-Fc chimera, on established pain behaviour were determined. Intra-articular injection of BDNF augmented established OA pain behaviour in MIA rats, but had no effect in controls. Intra-articular injection of the TrkB-Fc chimera acutely reversed pain behaviour to a similar extent in both models of OA pain (weight-bearing asymmetry MIA: -11 ± 4%, MNX: -12 ± 4%), compared to vehicle treatment. Our data suggesting a contribution of peripheral knee joint BDNF/TrkB signalling in the maintenance of chronic OA joint pain support further investigation of the therapeutic potential of this target.
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Ferrini F, Salio C, Boggio EM, Merighi A. Interplay of BDNF and GDNF in the Mature Spinal Somatosensory System and Its Potential Therapeutic Relevance. Curr Neuropharmacol 2021; 19:1225-1245. [PMID: 33200712 PMCID: PMC8719296 DOI: 10.2174/1570159x18666201116143422] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2020] [Revised: 09/17/2020] [Accepted: 10/05/2020] [Indexed: 11/22/2022] Open
Abstract
The growth factors BDNF and GDNF are gaining more and more attention as modulators of synaptic transmission in the mature central nervous system (CNS). The two molecules undergo a regulated secretion in neurons and may be anterogradely transported to terminals where they can positively or negatively modulate fast synaptic transmission. There is today a wide consensus on the role of BDNF as a pro-nociceptive modulator, as the neurotrophin has an important part in the initiation and maintenance of inflammatory, chronic, and/or neuropathic pain at the peripheral and central level. At the spinal level, BDNF intervenes in the regulation of chloride equilibrium potential, decreases the excitatory synaptic drive to inhibitory neurons, with complex changes in GABAergic/glycinergic synaptic transmission, and increases excitatory transmission in the superficial dorsal horn. Differently from BDNF, the role of GDNF still remains to be unraveled in full. This review resumes the current literature on the interplay between BDNF and GDNF in the regulation of nociceptive neurotransmission in the superficial dorsal horn of the spinal cord. We will first discuss the circuitries involved in such a regulation, as well as the reciprocal interactions between the two factors in nociceptive pathways. The development of small molecules specifically targeting BDNF, GDNF and/or downstream effectors is opening new perspectives for investigating these neurotrophic factors as modulators of nociceptive transmission and chronic pain. Therefore, we will finally consider the molecules of (potential) pharmacological relevance for tackling normal and pathological pain.
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Affiliation(s)
- Francesco Ferrini
- Department of Veterinary Sciences, University of Turin, Grugliasco, Italy
- Department of Psychiatry & Neuroscience, Université Laval, Québec, Canada
| | - Chiara Salio
- Department of Veterinary Sciences, University of Turin, Grugliasco, Italy
| | - Elena M. Boggio
- Department of Veterinary Sciences, University of Turin, Grugliasco, Italy
| | - Adalberto Merighi
- Department of Veterinary Sciences, University of Turin, Grugliasco, Italy
- National Institute of Neuroscience, Grugliasco, Italy
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Andrews K, Josiah SS, Zhang J. The Therapeutic Potential of Neuronal K-Cl Co-Transporter KCC2 in Huntington's Disease and Its Comorbidities. Int J Mol Sci 2020; 21:E9142. [PMID: 33266310 PMCID: PMC7730145 DOI: 10.3390/ijms21239142] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/16/2020] [Accepted: 11/28/2020] [Indexed: 02/05/2023] Open
Abstract
Intracellular chloride levels in the brain are regulated primarily through the opposing effects of two cation-chloride co-transporters (CCCs), namely K+-Cl- co-transporter-2 (KCC2) and Na+-K+-Cl- co-transporter-1 (NKCC1). These CCCs are differentially expressed throughout the course of development, thereby determining the excitatory-to-inhibitory γ-aminobutyric acid (GABA) switch. GABAergic excitation (depolarisation) is important in controlling the healthy development of the nervous system; as the brain matures, GABAergic inhibition (hyperpolarisation) prevails. This developmental switch in excitability is important, as uncontrolled regulation of neuronal excitability can have implications for health. Huntington's disease (HD) is an example of a genetic disorder whereby the expression levels of KCC2 are abnormal due to mutant protein interactions. Although HD is primarily considered a motor disease, many other clinical manifestations exist; these often present in advance of any movement abnormalities. Cognitive change, in addition to sleep disorders, is prevalent in the HD population; the effect of uncontrolled KCC2 function on cognition and sleep has also been explored. Several mechanisms by which KCC2 expression is reduced have been proposed recently, thereby suggesting extensive investigation of KCC2 as a possible therapeutic target for the development of pharmacological compounds that can effectively treat HD co-morbidities. Hence, this review summarizes the role of KCC2 in the healthy and HD brain, and highlights recent advances that attest to KCC2 as a strong research and therapeutic target candidate.
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Affiliation(s)
| | | | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, College of Medicine and Health, University of Exeter, Hatherly Laboratories, Exeter EX4 4PS, UK; (K.A.); (S.S.J.)
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Zarei M, Sabetkasaei M, Moini-Zanjani T. Effect of Paroxetine on the Neuropathic Pain: A Molecular Study. IRANIAN BIOMEDICAL JOURNAL 2020; 24:306-13. [PMID: 32429644 PMCID: PMC7392138 DOI: 10.29252/ibj.24.5.301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 10/28/2019] [Indexed: 12/30/2022]
Abstract
Background Neuropathic pain, due to peripheral nerve damage, has influenced millions of people living all over the world. It has been shown that paroxetine can relieve neuropathic pain. Recently, the role of certain proteins like brain-derived neurotrophic factor (BDNF), GABAA receptor, and K+-Cl- cotransporter 2 (KCC2) transporter in the occurrence of neuropathic pain has been documented. In the current study, the expression of these proteins affected by paroxetine was evaluated. Methods Male Wistar rats were allocated into two main groups of pre- and post-injury. Rats in each main group received paroxetine before nerve injury and at day seven after nerve damage till day 14, respectively. The lumbar spinal cord of animals was extracted to assess the expression of target genes and proteins. Results In the preventive study, paroxetine decreased BDNF and increased KCC2 and GABAA gene and protein expression, while in the post-injury paradigm, it decreased BDNF and increased KCC2 genes and protein expression. In this regard, an increase in the protein expression of GABAA was observed. Conclusion It seems that paroxetine with a change in the expression of three significant proteins involved in neuropathic pain could attenuate this type of chronic pain.
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Affiliation(s)
| | - Masoumeh Sabetkasaei
- Department of Pharmacology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Wan L, Li Z, Liu T, Chen X, Xu Q, Yao W, Zhang C, Zhang Y. Epoxyeicosatrienoic acids: Emerging therapeutic agents for central post-stroke pain. Pharmacol Res 2020; 159:104923. [PMID: 32461186 DOI: 10.1016/j.phrs.2020.104923] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 05/05/2020] [Accepted: 05/08/2020] [Indexed: 01/23/2023]
Abstract
Central post-stroke pain (CPSP) is chronic neuropathic pain due to a lesion or dysfunction of the central nervous system following cerebrovascular insult. This syndrome is characterized by chronic somatosensory abnormalities including spontaneous pain, hyperalgesia and allodynia, which localize to body areas corresponding to the injured brain region. However, despite its potential to impair activities of daily life and cause mood disorders after stroke, it is probably the least recognized complication of stroke. All currently approved treatments for CPSP have limited efficacy but troublesome side effects. The detailed mechanism underlying CPSP is still under investigation; however, its diverse clinical features indicate excessive central neuronal excitability, which is attributed to loss of inhibition and excessive neuroinflammation. Recently, exogenous epoxyeicosatrienoic acids (EETs) have been used to attenuate the mechanical allodynia in CPSP rats and proven to provide a quicker onset and superior pain relief compared to the current first line drug gabapentin. This anti-nociceptive effect is mediated by reserving the normal thalamic inhibition state through neurosteroid-GABA signaling. Moreover, mounting evidence has revealed that EETs exert anti-inflammatory effects by inhibiting the expression of vascular adhesion molecules, activating NFκB, inflammatory cytokines secretion and COX-2 gene induction. The present review focuses on the extensive evidence supporting the potential of EETs to be a multi-functional therapeutic approach for CPSP. Additionally, the role of EETs in the crosstalk between anti-CPSP and the comorbid mood disorder is reviewed herein.
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Affiliation(s)
- Li Wan
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Zuofan Li
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Tongtong Liu
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xuhui Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qiaoqiao Xu
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wenlong Yao
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chuanhan Zhang
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yue Zhang
- Department of Anaesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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15
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Beverungen H, Klaszky SC, Klaszky M, Côté MP. Rehabilitation Decreases Spasticity by Restoring Chloride Homeostasis through the Brain-Derived Neurotrophic Factor-KCC2 Pathway after Spinal Cord Injury. J Neurotrauma 2020; 37:846-859. [PMID: 31578924 PMCID: PMC7071070 DOI: 10.1089/neu.2019.6526] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Activity-based therapy is routinely integrated in rehabilitation programs to facilitate functional recovery after spinal cord injury (SCI). Among its beneficial effects is a reduction of hyperreflexia and spasticity, which affects ∼75% of the SCI population. Unlike current anti-spastic pharmacological treatments, rehabilitation attenuates spastic symptoms without causing an active depression in spinal excitability, thus avoiding further interference with motor recovery. Understanding how activity-based therapies contribute to decrease spasticity is critical to identifying new pharmacological targets and to optimize rehabilitation programs. It was recently demonstrated that a decrease in the expression of KCC2, a neuronal Cl- extruder, contributes to the development spasticity in SCI rats. Although exercise can decrease spinal hyperexcitability and increase KCC2 expression on lumbar motoneurons after SCI, a causal effect remains to be established. Activity-dependent processes include an increase in brain-derived neurotrophic factor (BDNF) expression. Interestingly, BDNF is a regulator of KCC2 but also a potent modulator of spinal excitability. Therefore, we hypothesized that after SCI, the activity-dependent increase in KCC2 expression: 1) functionally contributes to reduce hyperreflexia, and 2) is regulated by BDNF. SCI rats chronically received VU0240551 (KCC2 blocker) or TrkB-IgG (BDNF scavenger) during the daily rehabilitation sessions and the frequency-dependent depression of the H-reflex, a monitor of hyperreflexia, was recorded 4 weeks post-injury. Our results suggest that the activity-dependent increase in KCC2 functionally contributes to H-reflex recovery and critically depends on BDNF activity. This study provides a new perspective in understanding how exercise impacts hyperreflexia by identifying the biological basis of the recovery of function.
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Affiliation(s)
- Henrike Beverungen
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Samantha Choyke Klaszky
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Michael Klaszky
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Marie-Pascale Côté
- Department of Neurobiology and Anatomy, Marion Murray Spinal Cord Research Center, Drexel University College of Medicine, Philadelphia, Pennsylvania
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Lorenzo LE, Godin AG, Ferrini F, Bachand K, Plasencia-Fernandez I, Labrecque S, Girard AA, Boudreau D, Kianicka I, Gagnon M, Doyon N, Ribeiro-da-Silva A, De Koninck Y. Enhancing neuronal chloride extrusion rescues α2/α3 GABA A-mediated analgesia in neuropathic pain. Nat Commun 2020; 11:869. [PMID: 32054836 PMCID: PMC7018745 DOI: 10.1038/s41467-019-14154-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 12/16/2019] [Indexed: 02/06/2023] Open
Abstract
Spinal disinhibition has been hypothesized to underlie pain hypersensitivity in neuropathic pain. Apparently contradictory mechanisms have been reported, raising questions on the best target to produce analgesia. Here, we show that nerve injury is associated with a reduction in the number of inhibitory synapses in the spinal dorsal horn. Paradoxically, this is accompanied by a BDNF-TrkB-mediated upregulation of synaptic GABAARs and by an α1-to-α2GABAAR subunit switch, providing a mechanistic rationale for the analgesic action of the α2,3GABAAR benzodiazepine-site ligand L838,417 after nerve injury. Yet, we demonstrate that impaired Cl- extrusion underlies the failure of L838,417 to induce analgesia at high doses due to a resulting collapse in Cl- gradient, dramatically limiting the benzodiazepine therapeutic window. In turn, enhancing KCC2 activity not only potentiated L838,417-induced analgesia, it rescued its analgesic potential at high doses, revealing a novel strategy for analgesia in pathological pain, by combined targeting of the appropriate GABAAR-subtypes and restoring Cl- homeostasis.
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Affiliation(s)
- Louis-Etienne Lorenzo
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
| | - Antoine G Godin
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Department of Psychiatry & Neuroscience, Université Laval, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Francesco Ferrini
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Department of Psychiatry & Neuroscience, Université Laval, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
- Department of Veterinary Sciences, University of Turin, Turin, Italy
| | - Karine Bachand
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
| | - Isabel Plasencia-Fernandez
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Simon Labrecque
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
| | - Alexandre A Girard
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Ecole Polytechnique, IP Paris, Palaiseau, France
| | - Dominic Boudreau
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Irenej Kianicka
- Chlorion Pharma, Laval, Québec, QC, Canada
- Laurent Pharmaceuticals Inc., Montreal, QC, Canada
| | - Martin Gagnon
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Centre for Innovation, University of Otago, Dunedin, New Zealand
| | - Nicolas Doyon
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada
- Finite Element Interdisciplinary Research Group (GIREF), Université Laval, Québec, QC, Canada
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada
- Department of Anatomy & Cell Biology, McGill University, Montreal, QC, Canada
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | - Yves De Koninck
- CERVO Brain Research Centre, Quebec Mental Health Institute, Québec, QC, Canada.
- Department of Pharmacology & Therapeutics, McGill University, Montreal, QC, Canada.
- Department of Psychiatry & Neuroscience, Université Laval, Québec, QC, Canada.
- Graduate program in Neuroscience, Université Laval, Québec, QC, Canada.
- Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada.
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Ding H, Chen J, Su M, Lin Z, Zhan H, Yang F, Li W, Xie J, Huang Y, Liu X, Liu B, Zhou X. BDNF promotes activation of astrocytes and microglia contributing to neuroinflammation and mechanical allodynia in cyclophosphamide-induced cystitis. J Neuroinflammation 2020; 17:19. [PMID: 31931832 PMCID: PMC6958761 DOI: 10.1186/s12974-020-1704-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 01/07/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Patients with interstitial cystitis/bladder pain syndrome (IC/BPS) often grieve over a low quality of life brought about by chronic pain. In our previous studies, we determined that neuroinflammation of the spinal dorsal horn (SDH) was associated with mechanisms of interstitial cystitis. Moreover, it has been shown that brain-derived neurotrophic factor (BDNF) participates in the regulation of neuroinflammation and pathological pain through BDNF-TrkB signaling; however, whether it plays a role in cyclophosphamide (CYP)-induced cystitis remains unclear. This study aimed to confirm whether BDNF-TrkB signaling modulates neuroinflammation and mechanical allodynia in CYP-induced cystitis and determine how it occurs. METHODS Systemic intraperitoneal injection of CYP was performed to establish a rat cystitis model. BDNF-TrkB signaling was modulated by intraperitoneal injection of the TrkB receptor antagonist, ANA-12, or intrathecal injection of exogenous BDNF. Mechanical allodynia in the suprapubic region was assessed using the von Frey filaments test. The expression of BDNF, TrkB, p-TrkB, Iba1, GFAP, p-p38, p-JNK, IL-1β, and TNF-α in the L6-S1 SDH was measured by Western blotting and immunofluorescence analysis. RESULTS BDNF-TrkB signaling was upregulated significantly in the SDH after CYP was injected. Similarly, the expressions of Iba1, GFAP, p-p38, p-JNK, IL-1β, and TNF-α in the SDH were all upregulated. Treatment with ANA-12 could attenuate mechanical allodynia, restrain activation of astrocytes and microglia and alleviate neuroinflammation. Besides, the intrathecal injection of exogenous BDNF further decreased the mechanical withdrawal threshold, promoted activation of astrocytes and microglia, and increased the release of TNF-α and IL-1β in the SDH of our CYP-induced cystitis model. CONCLUSIONS In our CYP-induced cystitis model, BDNF promoted the activation of astrocytes and microglia to release TNF-α and IL-1β, aggravating neuroinflammation and leading to mechanical allodynia through BDNF-TrkB-p38/JNK signaling.
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Affiliation(s)
- Honglu Ding
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Jialiang Chen
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Minzhi Su
- Department of Rehabilitation, The Third Affiliated Hospital and Lingnan Hospital of the Sun Yat-Sen University, 2693 Kaichuang Rd, Guangzhou, 510700, China
| | - Zhijun Lin
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Hailun Zhan
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Fei Yang
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Wenbiao Li
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Juncong Xie
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Yong Huang
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China
| | - Xianguo Liu
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine of Sun Yat-sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.,Guangdong Provincial Key Laboratory of Brain Function and Disease, 74 Zhongshan Rd. 2, Guangzhou, 510080, China
| | - Bolong Liu
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China.
| | - Xiangfu Zhou
- Department of Urology, the Third Affiliated hospital of Sun Yat-Sen University, 600 Tianhe Rd, Guangzhou, 510630, China.
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18
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Tan CY, Wang YP, Han YY, Lu BH, Ji W, Zhu LC, Wang Y, Shi WY, Shan LY, Zhang L, Ma KT, Li L, Si JQ. Expression and effect of sodium-potassium-chloride cotransporter on dorsal root ganglion neurons in a rat model of chronic constriction injury. Neural Regen Res 2020; 15:912-921. [PMID: 31719257 PMCID: PMC6990784 DOI: 10.4103/1673-5374.268904] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Sodium-potassium-chloride cotransporter 1 (NKCC1) and potassium-chloride cotransporter 2 (KCC2) are associated with the transmission of peripheral pain. We investigated whether the increase of NKCC1 and KCC2 is associated with peripheral pain transmission in dorsal root ganglion neurons. To this aim, rats with persistent hyperalgesia were randomly divided into four groups. Rats in the control group received no treatment, and the rat sciatic nerve was only exposed in the sham group. Rats in the chronic constriction injury group were established into chronic constriction injury models by ligating sciatic nerve and rats were given bumetanide, an inhibitor of NKCC1, based on chronic constriction injury modeling in the chronic constriction injury + bumetanide group. In the experiment measuring thermal withdrawal latency, bumetanide (15 mg/kg) was intravenously administered. In the patch clamp experiment, bumetanide (10 µg/µL) and acutely isolated dorsal root ganglion neurons (on day 14) were incubated for 1 hour, or bumetanide (5 µg/µL) was intrathecally injected. The Hargreaves test was conducted to detect changes in thermal hyperalgesia in rats. We found that the thermal withdrawal latency of rats was significantly decreased on days 7, 14, and 21 after model establishment. After intravenous injection of bumetanide, the reduction in thermal retraction latency caused by model establishment was significantly inhibited. Immunohistochemistry and western blot assay results revealed that the immune response and protein expression of NKCC1 in dorsal root ganglion neurons of the chronic constriction injury group increased significantly on days 7, 14, and 21 after model establishment. No immune response or protein expression of KCC2 was observed in dorsal root ganglion neurons before and after model establishment. The Cl– (chloride ion) fluorescent probe technique was used to evaluate the change of Cl– concentration in dorsal root ganglion neurons of chronic constriction injury model rats. We found that the relative optical density of N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide (a Cl– fluorescent probe whose fluorescence intensity decreases as Cl– concentration increases) in the dorsal root ganglion neurons of the chronic constriction injury group was significantly decreased on days 7 and 14 after model establishment. The whole-cell patch clamp technique revealed that the resting potential and action potential frequency of dorsal root ganglion neurons increased, and the threshold and rheobase of action potentials decreased in the chronic constriction injury group on day 14 after model establishment. After bumetanide administration, the above indicators were significantly suppressed. These results confirm that CCI can induce abnormal overexpression of NKCC1, thereby increasing the Cl– concentration in dorsal root ganglion neurons; this then enhances the excitability of dorsal root ganglion neurons and ultimately promotes hyperalgesia and allodynia. In addition, bumetanide can achieve analgesic effects. All experiments were approved by the Institutional Ethics Review Board at the First Affiliated Hospital, College of Medicine, Shihezi University, China on February 22, 2017 (approval No. A2017-169-01).
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Affiliation(s)
- Chao-Yang Tan
- Department of Physiology, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region; Department of Physiology, Medical College of Jiaxing University, Jiaxing, Zhejiang Province; Department of Health, Karamay Army Division, Chinese People's Liberation Army, Karamay, Xinjiang Uygur Autonomous Region, China
| | - Yan-Ping Wang
- Department of Physiology; Department of Nursing, Medical College of Jiaxing University, Jiaxing, Zhejiang Province, China
| | - Yuan-Yuan Han
- Department of Physiology, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region; Department of Clinical Medicine, Karamay College of Xinjiang Medical University, Karamay, Xinjiang Uygur Autonomous Region, China
| | - Bi-Han Lu
- Department of Physiology, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Wei Ji
- Department of Physiology, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Li-Cang Zhu
- Department of Neurosurgery, First Affiliated Hospital, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Yang Wang
- Department of Physiology, College of Medicine; The key Laboratory of Xinjiang Endemic and Ethnic Diseases, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Wen-Yan Shi
- Department of Physiology, College of Medicine; The key Laboratory of Xinjiang Endemic and Ethnic Diseases, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Li-Ya Shan
- Department of Physiology, College of Medicine; The key Laboratory of Xinjiang Endemic and Ethnic Diseases, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Liang Zhang
- Department of Physiology, College of Medicine; The key Laboratory of Xinjiang Endemic and Ethnic Diseases, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Ke-Tao Ma
- Department of Physiology, College of Medicine; The key Laboratory of Xinjiang Endemic and Ethnic Diseases, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Li Li
- Department of Physiology, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region; Department of Physiology, Medical College of Jiaxing University, Jiaxing, Zhejiang Province; The key Laboratory of Xinjiang Endemic and Ethnic Diseases, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region, China
| | - Jun-Qiang Si
- Department of Physiology; The key Laboratory of Xinjiang Endemic and Ethnic Diseases, College of Medicine, Shihezi University, Shihezi, Xinjiang Uygur Autonomous Region; Department of Physiology, School of Basic Medical Sciences, Wuhan University; Department of Physiology, School of Basic Medical Sciences, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
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Impaired Autophagy of GABAergic Interneurons in Neuropathic Pain. Pain Res Manag 2018; 2018:9185368. [PMID: 30356379 PMCID: PMC6176324 DOI: 10.1155/2018/9185368] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/12/2018] [Indexed: 12/30/2022]
Abstract
Neuropathic pain (NP) is caused by lesions of the peripheral fibers and central neurons in the somatosensory nervous system and affects 7-10% of the general population. Although the distinct cause of neuropathic pain has been investigated in primary afferent neurons over the years, pain modulation by central sensitization remains controversial. NP is believed to be driven by cell type-specific spinal synaptic plasticity in the dorsal horn. Upon intense afferent stimulation, spinothalamic tract neurons are potentiated, whereas GABAergic interneurons are inhibited leading to long-term depression. Growing evidences suggest that the inhibition of GABAergic neurons plays pivotal roles in the manifestation of neuropathic and inflammatory pain states. Downregulation of GABA transmission and impairment of GABAergic interneurons in the dorsal horn are critical consequences after spinal cord and peripheral nerve injuries. These impairments in GABAergic interneurons may be associated with dysfunctional autophagy, resulting in neuropathic pain. Here, we review an emerging number of investigations that suggest a pivotal role of impaired autophagy of GABAergic interneurons in NP. We discuss relevant research spurring the development of new targets and therapeutic agents of NP and emphasize the need for a multidisciplinary approach to manage NP in the future.
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Sánchez-Brualla I, Boulenguez P, Brocard C, Liabeuf S, Viallat-Lieutaud A, Navarro X, Udina E, Brocard F. Activation of 5-HT 2A Receptors Restores KCC2 Function and Reduces Neuropathic Pain after Spinal Cord Injury. Neuroscience 2018; 387:48-57. [PMID: 28844001 DOI: 10.1016/j.neuroscience.2017.08.033] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 07/26/2017] [Accepted: 08/14/2017] [Indexed: 11/30/2022]
Abstract
Downregulation of the potassium chloride cotransporter type 2 (KCC2) after a spinal cord injury (SCI) disinhibits motoneurons and dorsal horn interneurons causing spasticity and neuropathic pain, respectively. We showed recently (Bos et al., 2013) that specific activation of 5-HT2A receptors by TCB-2 [(4-bromo-3,6-dimethoxybenzocyclobuten-1-yl)methylamine hydrobromide] upregulates KCC2 function, restores motoneuronal inhibition and reduces SCI-induced spasticity. Here, we tested the potential analgesic effect of TCB-2 on central (thoracic hemisection) and peripheral [spared nerve injury (SNI)] neuropathic pain. We found mechanical and thermal hyperalgesia reduced by an acute administration of TCB-2 in rats with SCI. This analgesic effect was associated with an increase in dorsal horn membrane KCC2 expression and was prevented by pharmacological blockade of KCC2 with an intrathecal injection of DIOA [(dihydroindenyl)oxy]alkanoic acid]. In contrast, the SNI-induced neuropathic pain was not attenuated by TCB-2 although there was a slight increase of membrane KCC2 expression in the dorsal horn ipsilateral to the lesion. Up-regulation of KCC2 function by targeting 5-HT2A receptors, therefore, has therapeutic potential in the treatment of neuropathic pain induced by SCI but not by SNI.
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Affiliation(s)
- Irene Sánchez-Brualla
- Team P3M, Institut de Neurosciences de la Timone, UMR7289, Aix Marseille Université and Centre National de la Recherche Scientifique (CNRS), Marseille, France; Department of Cell Biology, Physiology, and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Pascale Boulenguez
- Team P3M, Institut de Neurosciences de la Timone, UMR7289, Aix Marseille Université and Centre National de la Recherche Scientifique (CNRS), Marseille, France
| | - Cécile Brocard
- Team P3M, Institut de Neurosciences de la Timone, UMR7289, Aix Marseille Université and Centre National de la Recherche Scientifique (CNRS), Marseille, France
| | - Sylvie Liabeuf
- Team P3M, Institut de Neurosciences de la Timone, UMR7289, Aix Marseille Université and Centre National de la Recherche Scientifique (CNRS), Marseille, France
| | - Annelise Viallat-Lieutaud
- Team P3M, Institut de Neurosciences de la Timone, UMR7289, Aix Marseille Université and Centre National de la Recherche Scientifique (CNRS), Marseille, France
| | - Xavier Navarro
- Department of Cell Biology, Physiology, and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Esther Udina
- Department of Cell Biology, Physiology, and Immunology, Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Institute of Neurosciences, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Frédéric Brocard
- Team P3M, Institut de Neurosciences de la Timone, UMR7289, Aix Marseille Université and Centre National de la Recherche Scientifique (CNRS), Marseille, France.
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21
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Dai S, Qi Y, Fu J, Li N, Zhang X, Zhang J, Zhang W, Xu H, Zhou H, Ma Z. Dexmedetomidine attenuates persistent postsurgical pain by upregulating K +-Cl - cotransporter-2 in the spinal dorsal horn in rats. J Pain Res 2018; 11:993-1004. [PMID: 29872336 PMCID: PMC5973459 DOI: 10.2147/jpr.s158737] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Dexmedetomidine (DEX) could have an analgesic effect on pain transmission through the modulation of brain-derived neurotrophic factor (BDNF). In addition, KCC2-induced shift in neuronal Cl− homeostasis is crucial for postsynaptic inhibition mediated by GABAA receptors. Accumulating evidence shows that nerve injury, peripheral inflammation and stress activate the spinal BDNF/TrkB signal, which results in the downregulation of KCC2 transport and expression, eventually leads to GAGAergic disinhibition and hyperalgesia. The aim of this experiment was to explore the interaction between DEX and KCC2 at a molecular level in rats in the persistent postsurgical pain (PPSP). Methods PPSP in rats was evoked by the skin/muscle incision and retraction (SMIR). Mechanical hypersensitivity was assessed with the Dynamic Plantar Aesthesiometer. Western blot and immunofluorescence assay were used to assess the expressions of related proteins. Results In the first part of our experiment, the results revealed that the BDNF/TrkB-KCC2 signal plays a critical role in the development of SMIR-evoked PPSP; the second part showed that intraperitoneal administrations of 40 µg/kg DEX at 15 min presurgery and 1 to 3 days post-surgery significantly attenuated SMIR-evoked PPSP. Simultaneously, SMIR-induced KCC2 downregulation was partly reversed, which coincided with the inhibition of the BDNF/TrkB signal in the spinal dorsal horn. Moreover, intrathecal administrations of KCC2 inhibitor VU0240551 significantly reduced the analgesic effect of DEX on SMIR-evoked PPSP. Conclusion The results of our study indicated that DEX attenuated PPSP by restoring KCC2 function through reducing BDNF/TrkB signal in the spinal dorsal horn in rats, which provides a new insight into the treatment of chronic pain in clinical postsurgical pain management.
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Affiliation(s)
- Shuhong Dai
- Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China
| | - Yu Qi
- Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China
| | - Jie Fu
- Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China
| | - Na Li
- Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China
| | - Xu Zhang
- Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China
| | - Juan Zhang
- The Affiliated Nanjing Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
| | - Wei Zhang
- The Affiliated Nanjing Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
| | - Haijun Xu
- Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China
| | - Hai Zhou
- Department of Anesthesiology, XuZhou Central Hospital, Xuzhou, China
| | - Zhengliang Ma
- The Affiliated Nanjing Drum Tower Hospital, Medical School, Nanjing University, Nanjing, China
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22
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Li SS, Tu WZ, Jia CQ, Jiang X, Qian XR, Yang GH, Hu QM, Chen WC, Lu B, Jiang SH. KCC2-GABAA pathway correlates with the analgesic effect of electro-acupuncture in CCI rats. Mol Med Rep 2018; 17:6961-6968. [PMID: 29568893 PMCID: PMC5928653 DOI: 10.3892/mmr.2018.8766] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 05/08/2017] [Indexed: 01/08/2023] Open
Abstract
Potassium-chloride cotransporter 2 (KCC2) has been indicated to serve a crucial role during chronic neuropathic pain (NP). Following the emergence of NP, γ‑aminobutyric acid (GABA) A receptor‑mediated signaling may be further impaired by the changes of KCC2 chloride anion gradient. In the present study, the authors investigate the effect of electro-acupuncture (EA) on the behavior and the expression of KCC2 and GABAA receptor γ2 subunit in the spinal cord of chronic constriction injury (CCI) model rats. A total of 60 adult male Sprague‑Dawley rats were divided into four groups: Normal group, sham‑CCI group, CCI group and CCI+EA group. The effect of EA was assessed via the values of mechanical withdrawal threshold and thermal withdrawal latency, which were significantly improved upon stimulation of the ST‑36 and GB‑34 acupoints. In addition, a marked reduction in both the mRNA and protein levels of KCC2 and GABAA receptor γ2 subunit was observed in the spinal cord following loose ligation of the sciatic nerve. The reductions in KCC2 and GABAA receptor γ2 subunit expression were reversed by EA treatment. These results support the notion that KCC2 and GABAA receptor γ2 subunit contribute to NP following peripheral nerve injury and extend the understanding of the analgesic effects of EA on NP.
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Affiliation(s)
- Si-Si Li
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
| | - Wen-Zhan Tu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
- Integrative and Optimized Medicine Research Center, China-US Institute for Acupuncture and Rehabilitation of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
| | - Cheng-Qian Jia
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
| | - Xia Jiang
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
| | - Xin-Ru Qian
- Integrative and Optimized Medicine Research Center, China-US Institute for Acupuncture and Rehabilitation of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
- Department of Rehabilitation, NYU Langone Medical Center, New York, NY 10016, USA
| | - Guan-Hu Yang
- Integrative and Optimized Medicine Research Center, China-US Institute for Acupuncture and Rehabilitation of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
- Department of Specialty Medicine, Ohio University, Athens, OH 45701, USA
| | - Qi-Miao Hu
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
| | - Wen-Ci Chen
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
| | - Bin Lu
- Protein Quality Control and Diseases Laboratory, Attardi Institute of Mitochondrial Biomedicine, School of Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, P.R. China
| | - Song-He Jiang
- Department of Physical Medicine and Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
- Integrative and Optimized Medicine Research Center, China-US Institute for Acupuncture and Rehabilitation of Wenzhou Medical University, Wenzhou, Zhejiang 325027, P.R. China
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23
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Abstract
K+-Cl- co-transporter 2 (KCC2/SLC12A5) is a neuronal specific cation chloride co-transporter which is active under isotonic conditions, and thus a key regulator of intracellular Cl- levels. It also has an ion transporter-independent structural role in modulating the maturation and regulation of excitatory glutamatergic synapses. KCC2 levels are developmentally regulated, and a postnatal upregulation of KCC2 generates a low intracellular chloride concentration that allows the neurotransmitters γ-aminobutyric acid (GABA) and glycine to exert inhibitory neurotransmission through its Cl- permeating channel. Functional expression of KCC2 at the neuronal cell surface is necessary for its activity, and impairment in KCC2 cell surface transport and/or internalization may underlie a range of neuropathological conditions. Although recent advances have shed light on a range of cellular mechanisms regulating KCC2 activity, little is known about its membrane trafficking itinerary and regulatory proteins. In this review, known membrane trafficking signals, pathways and mechanisms pertaining to KCC2's functional surface expression are discussed.
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Affiliation(s)
- Bor Luen Tang
- a Department of Biochemistry, Yong Loo Lin School of Medicine , National University Health System , Singapore.,b NUS Graduate School for Integrative Sciences and Engineering , National University of Singapore , Singapore
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24
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Marcos J, Galleguillos D, Pelissier T, Hernández A, Velásquez L, Villanueva L, Constandil L. Role of the spinal TrkB-NMDA receptor link in the BDNF-induced long-lasting mechanical hyperalgesia in the rat: A behavioural study. Eur J Pain 2017; 21:1688-1696. [DOI: 10.1002/ejp.1075] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2017] [Indexed: 11/05/2022]
Affiliation(s)
- J.L. Marcos
- Laboratory of Neurobiology; Department of Biology; Faculty of Chemistry and Biology; University of Santiago of Chile; Chile
- Laboratory of Veterinary Pharmacology and Therapeutics; School of Veterinary Science; Viña del Mar University; Chile
| | - D. Galleguillos
- Laboratory of Neurobiology; Department of Biology; Faculty of Chemistry and Biology; University of Santiago of Chile; Chile
| | - T. Pelissier
- Program of Molecular and Clinical Pharmacology; Institute of Biomedical Sciences (ICBM); Faculty of Medicine; University of Chile; Santiago Chile
| | - A. Hernández
- Laboratory of Neurobiology; Department of Biology; Faculty of Chemistry and Biology; University of Santiago of Chile; Chile
| | - L. Velásquez
- Center for Integrative Medicine and Innovative Science (CIMIS); Faculty of Medicine; Andres Bello University; Santiago Chile
| | - L. Villanueva
- Centre de Psychiatrie et Neurosciences; INSERM UMR 894; Paris France
| | - L. Constandil
- Laboratory of Neurobiology; Department of Biology; Faculty of Chemistry and Biology; University of Santiago of Chile; Chile
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA); University of Santiago of Chile; Chile
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25
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Castro A, Li Y, Raver C, Chandra R, Masri R, Lobo MK, Keller A. Neuropathic pain after chronic nerve constriction may not correlate with chloride dysregulation in mouse trigeminal nucleus caudalis neurons. Pain 2017; 158:1366-1372. [PMID: 28426550 PMCID: PMC5482239 DOI: 10.1097/j.pain.0000000000000926] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Changes in chloride reversal potential in rat spinal cord neurons have previously been associated with persistent pain in nerve injury and inflammation models. These changes correlate with a decrease in the expression of the potassium chloride transporter, KCC2, and with increases in neuronal excitability. Here, we test the hypothesis that similar changes occur in mice with neuropathic pain induced by chronic constriction injury of the trigeminal infraorbital nerve (CCI-ION). This model allows us to distinguish an acute pain phase (3-5 days after injury) from a persistent pain phase (12-14 days after CCI-ION). Chronic constriction injury of the trigeminal infraorbital nerve induced significant decreases in mechanical pain thresholds in both the acute and persistent phases. To estimate GABAA reversal potentials in neurons from trigeminal nucleus caudalis, we obtained perforated patch recordings in vitro. GABAA reversal potential decreased by 8% during the acute phase in unidentified neurons, but not in GABAergic interneurons. However, at 12 to 14 days after CCI-ION, GABAA reversal potential recovered to normal values. Quantitative real-time polymerase chain reaction analysis revealed no significant changes, at either 3 to 5 days or 12 to 14 days after CCI-ION, in either KCC2 or NKCC1. These findings suggest that CCI-ION in mice results in transient and modest changes in chloride reversal potentials, and that these changes may not persist during the late phase. This suggests that, in the mouse model of CCI-ION, chloride dysregulation may not have a prominent role in the central mechanisms leading to the maintenance of chronic pain.
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Affiliation(s)
- Alberto Castro
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine
- Program in Neuroscience, University of Maryland
| | - Ying Li
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine
- Program in Neuroscience, University of Maryland
| | - Charles Raver
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine
- Program in Neuroscience, University of Maryland
| | - Ramesh Chandra
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine
- Program in Neuroscience, University of Maryland
| | - Radi Masri
- Program in Neuroscience, University of Maryland
- Department of Endodontics, Prosthodontics and Operative Surgery, Baltimore College of Dentistry. Baltimore, MD 21201
| | - Mary Kay Lobo
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine
- Program in Neuroscience, University of Maryland
| | - Asaf Keller
- Department of Anatomy & Neurobiology, University of Maryland School of Medicine
- Program in Neuroscience, University of Maryland
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26
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Yousuf MS, Zubkow K, Tenorio G, Kerr B. The chloride co-transporters, NKCC1 and KCC2, in experimental autoimmune encephalomyelitis (EAE). Neuroscience 2017; 344:178-186. [PMID: 28057537 DOI: 10.1016/j.neuroscience.2016.12.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 12/23/2016] [Accepted: 12/26/2016] [Indexed: 12/16/2022]
Abstract
Patients with multiple sclerosis (MS) often complain of neuropathic pain. According to the Gate Control Theory of Pain, spinal networks of GABAergic inhibitory interneurons are important in modulating nociceptive inputs from the periphery. Na+-K+-2Cl- co-transporter 1 (NKCC1) and K+-Cl- co-transporter 2 (KCC2) generally dictate the tone of GABA/glycine inhibition by regulating intracellular chloride concentrations. In this study, we investigated the role of NKCC1 and KCC2 in neuropathic pain observed in the animal model, experimental autoimmune encephalomyelitis (EAE), a commonly used model to study the pathophysiology of MS. Quantitative real-time polymerase chain reactions (qRT-PCR) analysis revealed no change in NKCC1 mRNA transcripts in dorsal root ganglia throughout EAE disease course. However, NKCC1 and KCC2 mRNA levels in the dorsal spinal cord were significantly reduced at disease onset and peak only to recover by the chronic time point. Similarly, Western blot data revealed a significant downregulation of NKCC1 and KCC2 in the dorsal spinal cord at disease onset but an upregulation of NKCC1 protein in the dorsal root ganglia at this time point. Treatment with bumetanide, an NKCC inhibitor, had no effect on mechanical hypersensitivity seen in mice with EAE even though it reversed the changes in the levels of NKCC1 and KCC2. We noted that bumetanide treatment, while effective at reversing the changes in monomeric KCC2 levels was ineffective at reversing the changes in oligomeric KCC2 which remained repressed. These results indicate that mechanical hypersensitivity in EAE is not mediated by altered levels of NKCC1.
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MESH Headings
- Animals
- Bumetanide/pharmacology
- Disease Progression
- Encephalomyelitis, Autoimmune, Experimental/drug therapy
- Encephalomyelitis, Autoimmune, Experimental/metabolism
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Female
- Ganglia, Spinal/drug effects
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/pathology
- Gene Expression/drug effects
- Hyperalgesia/drug therapy
- Hyperalgesia/metabolism
- Hyperalgesia/pathology
- Mice, Inbred C57BL
- Myelin-Oligodendrocyte Glycoprotein
- Neuralgia/drug therapy
- Neuralgia/metabolism
- Neuralgia/pathology
- Peptide Fragments
- RNA, Messenger/metabolism
- Sodium Potassium Chloride Symporter Inhibitors/pharmacology
- Solute Carrier Family 12, Member 2/metabolism
- Spinal Cord/drug effects
- Spinal Cord/metabolism
- Spinal Cord/pathology
- Symporters/metabolism
- K Cl- Cotransporters
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Affiliation(s)
- Muhammad Saad Yousuf
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Kasia Zubkow
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Gustavo Tenorio
- Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB T6G 2G3, Canada
| | - Bradley Kerr
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada; Department of Pharmacology, University of Alberta, Edmonton, AB T6E 2H7, Canada; Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, AB T6G 2G3, Canada.
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27
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Lin CR, Cheng JK, Wu CH, Chen KH, Liu CK. Epigenetic suppression of potassium-chloride co-transporter 2 expression in inflammatory pain induced by complete Freund's adjuvant (CFA). Eur J Pain 2017; 21:309-321. [PMID: 27506893 DOI: 10.1002/ejp.925] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2016] [Indexed: 12/14/2022]
Abstract
BACKGROUND Multiple mechanisms contribute to the stimulus-evoked pain hypersensitivity that may be experienced after peripheral inflammation. Persistent pathological stimuli in many pain conditions affect the expression of certain genes through epigenetic alternations. The main purpose of our study was to investigate the role of epigenetic modification on potassium-chloride co-transporter 2 (KCC2) gene expression in the persistence of inflammatory pain. METHODS Persistent inflammatory pain was induced through the injection of complete Freund's adjuvant (CFA) in the left hind paw of rats. Acetyl-histone H3 and H4 level was determined by chromatin immunoprecipitation in the spinal dorsal horn. Pain behaviour and inhibitory synaptic function of spinal cord were determined before and after CFA injection. KCC2 expression was determined by real time RT-PCR and Western blot. Intrathecal KCC2 siRNA (2 μg per 10 μL per rat) or HDAC inhibitor (10 μg per 10 μL per rat) was injected once daily for 3 days before CFA injection. RESULTS Persistent inflammatory pain epigenetically suppressed KCC2 expression through histone deacetylase (HDAC)-mediated histone hypoacetylation, resulting in decreased inhibitory signalling efficacy. KCC2 knock-down caused by intrathecal administration of KCC2 siRNA in naïve rats reduced KCC2 expression in the spinal cord, leading to sensitized pain behaviours and impaired inhibitory synaptic transmission in their spinal cords. Moreover, intrathecal HDAC inhibitor injection in CFA rats increased KCC2 expression, partially restoring the spinal inhibitory synaptic transmission and relieving the sensitized pain behaviour. CONCLUSION These findings suggest that the transcription of spinal KCC2 is regulated by histone acetylation epigenetically following CFA. SIGNIFICANCE Persistent pain suppresses KCC2 expression through HDAC-mediated histone hypoacetylation and consequently impairs the inhibitory function of inhibitory interneurons. Drugs such as HDAC inhibitors that suppress the influences of persistent pain on the expression of KCC2 may serve as a novel analgesic.
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Affiliation(s)
- C-R Lin
- Department of Anesthesiology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - J-K Cheng
- Department of Anesthesiology, MacKay Memorial Hospital, Taipei, Taiwan
| | - C-H Wu
- Department of Anesthesiology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - K-H Chen
- Department of Anesthesiology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
| | - C-K Liu
- Department of Anesthesiology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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28
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Huang YJ, Lee KH, Grau JW. Complete spinal cord injury (SCI) transforms how brain derived neurotrophic factor (BDNF) affects nociceptive sensitization. Exp Neurol 2017; 288:38-50. [PMID: 27818188 DOI: 10.1016/j.expneurol.2016.11.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/25/2016] [Accepted: 11/01/2016] [Indexed: 11/17/2022]
Abstract
Noxious stimulation can induce a lasting increase in neural excitability within the spinal cord (central sensitization) that can promote pain and disrupt adaptive function (maladaptive plasticity). Brain-derived neurotrophic factor (BDNF) is known to regulate the development of plasticity and has been shown to impact the development of spinally-mediated central sensitization. The latter effect has been linked to an alteration in GABA-dependent inhibition. Prior studies have shown that, in spinally transected rats, exposure to regular (fixed spaced) stimulation can counter the development of maladaptive plasticity and have linked this effect to an up-regulation of BDNF. Here it is shown that application of the irritant capsaicin to one hind paw induces enhanced mechanical reactivity (EMR) after spinal cord injury (SCI) and that the induction of this effect is blocked by pretreatment with fixed spaced shock. This protective effect was eliminated if rats were pretreated with the BDNF sequestering antibody TrkB-IgG. Intrathecal (i.t.) application of BDNF prevented, but did not reverse, capsaicin-induced EMR. BDNF also attenuated cellular indices (ERK and pERK expression) of central sensitization after SCI. In uninjured rats, i.t. BDNF enhanced, rather than attenuated, capsaicin-induced EMR and ERK/pERK expression. These opposing effects were related to a transformation in GABA function. In uninjured rats, BDNF reduced membrane-bound KCC2 and the inhibitory effect of the GABAA agonist muscimol. After SCI, BDNF increased KCC2 expression, which would help restore GABAergic inhibition. The results suggest that SCI transforms how BDNF affects GABA function and imply that the clinical usefulness of BDNF will depend upon the extent of fiber sparing.
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Affiliation(s)
- Yung-Jen Huang
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA.
| | - Kuan H Lee
- Center for Pain Research, Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - James W Grau
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA
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29
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Gu W, Zhang W, Lei Y, Cui Y, Chu S, Gu X, Ma Z. Activation of spinal alpha-7 nicotinic acetylcholine receptor shortens the duration of remifentanil-induced postoperative hyperalgesia by upregulating KCC2 in the spinal dorsal horn in rats. Mol Pain 2017; 13:1744806917704769. [PMID: 28425312 PMCID: PMC6997724 DOI: 10.1177/1744806917704769] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 02/28/2017] [Accepted: 03/15/2017] [Indexed: 12/15/2022] Open
Abstract
Background Accumulating evidence has shown that the signal from spinal brain-derived neurotrophic factor/tyrosine receptor kinase B-K+-Cl- cotransporter-2 plays a critical role in the process of pain hypersensitivity. The activation of alpha-7 nicotinic acetylcholine receptors could have an analgesic effect on remifentanil-induced postoperative hyperalgesia. Nevertheless, whether intrathecal administration of PNU-120596, an alpha-7 nicotinic acetylcholine receptors selective type II positive allosteric modulator, before surgery could affect the duration of remifentanil-induced postoperative hyperalgesia remains unknown, and the effects of alpha-7 nicotinic acetylcholine receptors activation on the brain-derived neurotrophic factor/tyrosine receptor kinase B-K+-Cl- cotransporter-2 signal in the spinal dorsal horn of rats with remifentanil-induced postoperative hyperalgesia is still enigmatic. Results We demonstrated that the brain-derived neurotrophic factor/tyrosine receptor kinase B-K+-Cl- cotransporter-2 signal played a critical role in the development of remifentanil-induced postoperative hyperalgesia. Intrathecal administration of PNU-120596 (8 µg/kg, 15 min before surgery) was associated with earlier signs of recovery from remifentanil-induced postoperative hyperalgesia. Simultaneously, remifentanil-induced postoperative hyperalgesia-induced K+-Cl- cotransporter-2 downregulation was partly reversed and coincided with a decreased expression of brain-derived neurotrophic factor/tyrosine receptor kinase B in the spinal dorsal horn, approximately correlating with the time course of the nociceptive behavior. Moreover, intrathecal administration of the K+-Cl- cotransporter-2 inhibitor VU0240551 significantly reduced the analgesic effect of PNU-120596 on remifentanil-induced postoperative hyperalgesia. Conclusions The activation of alpha-7 nicotinic acetylcholine receptors induced a shorter duration of remifentanil-induced postoperative hyperalgesia by restoring the brain-derived neurotrophic factor/tyrosine receptor kinase B-K+-Cl- cotransporter-2 signal in the spinal dorsal horn of rats, which provides new insight into treatment in clinical postoperative pain management.
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Affiliation(s)
- Wei Gu
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China
| | - Wei Zhang
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China
| | - Yishan Lei
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, China
| | - Yin Cui
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, China
| | - Shuaishuai Chu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, China
| | - Xiaoping Gu
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, China
| | - Zhengliang Ma
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Clinical College of Nanjing Medical University, Nanjing, China
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30
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Kim MJ, Park YH, Yang KY, Ju JS, Bae YC, Han SK, Ahn DK. Participation of central GABA A receptors in the trigeminal processing of mechanical allodynia in rats. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2016; 21:65-74. [PMID: 28066142 PMCID: PMC5214912 DOI: 10.4196/kjpp.2017.21.1.65] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 10/12/2016] [Accepted: 10/13/2016] [Indexed: 01/28/2023]
Abstract
Here we investigated the central processing mechanisms of mechanical allodynia and found a direct excitatory link with low-threshold input to nociceptive neurons. Experiments were performed on male Sprague-Dawley rats weighing 230-280 g. Subcutaneous injection of interleukin 1 beta (IL-1β) (1 ng/10 µL) was used to produce mechanical allodynia and thermal hyperalgesia. Intracisternal administration of bicuculline, a gamma aminobutyric acid A (GABAA) receptor antagonist, produced mechanical allodynia in the orofacial area under normal conditions. However, intracisternal administration of bicuculline (50 ng) produced a paradoxical anti-allodynic effect under inflammatory pain conditions. Pretreatment with resiniferatoxin (RTX), which depletes capsaicin receptor protein in primary afferent fibers, did not alter the paradoxical anti-allodynic effects produced by the intracisternal injection of bicuculline. Intracisternal injection of bumetanide, an Na-K-Cl cotransporter (NKCC 1) inhibitor, reversed the IL-1β-induced mechanical allodynia. In the control group, application of GABA (100 µM) or muscimol (3 µM) led to membrane hyperpolarization in gramicidin perforated current clamp mode. However, in some neurons, application of GABA or muscimol led to membrane depolarization in the IL-1β-treated rats. These results suggest that some large myelinated Aβ fibers gain access to the nociceptive system and elicit pain sensation via GABAA receptors under inflammatory pain conditions.
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Affiliation(s)
- Min Ji Kim
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Young Hong Park
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Kui Ye Yang
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Jin Sook Ju
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Yong Chul Bae
- Department of Oral Anatomy, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Seong Kyu Han
- Department of Oral Physiology, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju 54896, Korea
| | - Dong Kuk Ahn
- Department of Oral Physiology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
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Huang YJ, Lee KH, Murphy L, Garraway SM, Grau JW. Acute spinal cord injury (SCI) transforms how GABA affects nociceptive sensitization. Exp Neurol 2016; 285:82-95. [PMID: 27639636 PMCID: PMC5926208 DOI: 10.1016/j.expneurol.2016.09.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 09/09/2016] [Accepted: 09/12/2016] [Indexed: 10/21/2022]
Abstract
Noxious input can sensitize pain (nociceptive) circuits within the spinal cord, inducing a lasting increase in spinal cord neural excitability (central sensitization) that is thought to contribute to chronic pain. The development of spinally-mediated central sensitization is regulated by descending fibers and GABAergic interneurons. The current study provides evidence that spinal cord injury (SCI) transforms how GABA affects nociceptive transmission within the spinal cord, recapitulating an earlier developmental state wherein GABA has an excitatory effect. In spinally transected rats, noxious electrical stimulation and inflammation induce enhanced mechanical reactivity (EMR), a behavioral index of nociceptive sensitization. Pretreatment with the GABAA receptor antagonist bicuculline blocked these effects. Peripheral application of an irritant (capsaicin) also induced EMR. Both the induction and maintenance of this effect were blocked by bicuculline. Cellular indices of central sensitization [c-fos expression and ERK phosphorylation (pERK)] were also attenuated. In intact (sham operated) rats, bicuculline had the opposite effect. Pretreatment with a GABA agonist (muscimol) attenuated nociceptive sensitization in intact, but not spinally injured, rats. The effect of SCI on GABA function was linked to a reduction in the Cl- transporter, KCC2, leading to a reduction in intracellular Cl- that would attenuate GABA-mediated inhibition. Pharmacologically blocking the KCC2 channel (with i.t. DIOA) in intact rats mimicked the effect of SCI. Conversely, a pharmacological treatment (bumetanide) that should increase intracellular Cl- levels blocked the effect of SCI. The results suggest that GABAergic neurons drive, rather than inhibit, the development of nociceptive sensitization after spinal injury.
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Affiliation(s)
- Yung-Jen Huang
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA.
| | - Kuan H Lee
- Center for Pain Research, Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Lauren Murphy
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA
| | - Sandra M Garraway
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30307, USA
| | - James W Grau
- Behavioral and Cellular Neuroscience, Department of Psychology, Texas A&M University, College Station, TX 77843, USA
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Hu XM, Cao SB, Zhang HL, Lyu DM, Chen LP, Xu H, Pan ZQ, Shen W. Downregulation of miR-219 enhances brain-derived neurotrophic factor production in mouse dorsal root ganglia to mediate morphine analgesic tolerance by upregulating CaMKIIγ. Mol Pain 2016; 12:12/0/1744806916666283. [PMID: 27599867 PMCID: PMC5014090 DOI: 10.1177/1744806916666283] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 07/26/2016] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Increasing evidence suggests that microRNAs are functionally involved in the initiation and maintenance of pain hypersensitivity, including chronic morphine analgesic tolerance, through the posttranscriptional regulation of pain-related genes. We have previously demonstrated that miR-219 regulates inflammatory pain in the spinal cord by targeting calcium/calmodulin-dependent protein kinase II gamma (CaMKIIγ). However, whether miR-219 regulates CaMKIIγ expression in the dorsal root ganglia to mediate morphine tolerance remains unclear. RESULTS MiR-219 expression was downregulated and CaMKIIγ expression was upregulated in mouse dorsal root ganglia following chronic morphine treatment. The changes in miR-219 and CaMKIIγ expression closely correlated with the development of morphine tolerance, which was measured using the reduction of percentage of maximum potential efficiency to thermal stimuli. Morphine tolerance was markedly delayed by upregulating miR-219 expression using miR-219 mimics or downregulating CaMKIIγ expression using CaMKIIγ small interfering RNA. The protein and mRNA expression of brain-derived neurotrophic factor were also induced in dorsal root ganglia by prolonged morphine exposure in a time-dependent manner, which were transcriptionally regulated by miR-219 and CaMKIIγ. Scavenging brain-derived neurotrophic factor via tyrosine receptor kinase B-Fc partially attenuated morphine tolerance. Moreover, functional inhibition of miR-219 via miR-219-sponge in naive mice elicited thermal hyperalgesia and spinal neuronal sensitization, which were both suppressed by CaMKIIγ small interfering RNA or tyrosine receptor kinase B-Fc. CONCLUSIONS These results demonstrate that miR-219 contributes to the development of chronic tolerance to morphine analgesia in mouse dorsal root ganglia by targeting CaMKIIγ and enhancing CaMKIIγ-dependent brain-derived neurotrophic factor expression.
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Affiliation(s)
- Xue-Ming Hu
- Department of Pain Medicine, the Affiliated Hospital of Xuzhou Medical University, Xuzhou, China Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China Department of Integrative Medicine and Neurobiology, School of Basic Medical Sciences, Shanghai Medical College, Shanghai, China Institutes of Brain Science, Brain Science Collaborative Innovation Center, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Shou-Bin Cao
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China Department of Anesthesiology, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Hai-Long Zhang
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Dong-Mei Lyu
- Department of Pharmacology, the Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Li-Ping Chen
- Department of Pain Medicine, the Affiliated Hospital of Xuzhou Medical University, Xuzhou, China Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Heng Xu
- Department of Pain Medicine, the Affiliated Hospital of Xuzhou Medical University, Xuzhou, China Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Zhi-Qiang Pan
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
| | - Wen Shen
- Department of Pain Medicine, the Affiliated Hospital of Xuzhou Medical University, Xuzhou, China Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou Medical University, Xuzhou, China
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Jaggi AS, Kaur A, Bali A, Singh N. Expanding Spectrum of Sodium Potassium Chloride Co-transporters in the Pathophysiology of Diseases. Curr Neuropharmacol 2016; 13:369-88. [PMID: 26411965 PMCID: PMC4812803 DOI: 10.2174/1570159x13666150205130359] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Sodium potassium chloride co-transporter (NKCC) belongs to cation-dependent chloride co-transporter family, whose activation allows the entry of Na(+), K(+) and 2Cl(-) inside the cell. It acts in concert with K(+) Cl(-) co-transporter (KCC), which extrudes K(+) and Cl(-) ions from cell. NKCC1 is widely distributed throughout the body, while NKCC2 is exclusively present in kidney. Protein kinase A, protein kinase C, Ste20-related proline-alanine-rich kinase, oxidative stress responsive kinases, With No K=lysine kinase and protein phosphatase type 1 control the phosphorylation/dephosphorylation of key threonine residues of in regulatory domain of NKCC1. The selective inhibitors of NKCC1 including bumetanide and furosemide are conventionally employed as diuretics. However, recent studies have indicated that NKCC1 may be involved in the pathophysiology of anxiety, cerebral ischemia, epilepsy, neuropathic pain, fragile X syndrome, autism and schizophrenia. The inhibitors of NKCC1 are shown to produce anxiolytic effects; attenuate cerebral ischemia-induced neuronal injury; produce antiepileptic effects and attenuate neuropathic pain. In the early developing brain, GABAA activation primarily produces excitatory actions due to high NKCC1/KCC2 ratio. However, as the development progresses, the ratio of NKCC1/KCC2 ratio reverses and there is switch in the polarity of GABAA actions and latter acquires the inhibitory actions. The recapitulation of developmental-like state during pathological state may be associated with increase in the expression and functioning of NKCC1, which decreases the strength of inhibitory GABAergic neurotransmission. The present review describes the expanding role and mechanism of NKCC1 in the pathophysiology of different diseases.
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Affiliation(s)
- Amteshwar Singh Jaggi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University Patiala, Patiala- 147002.
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Abstract
Painful neuropathy, like the other complications of diabetes, is a growing healthcare concern. Unfortunately, current treatments are of variable efficacy and do not target underlying pathogenic mechanisms, in part because these mechanisms are not well defined. Rat and mouse models of type 1 diabetes are frequently used to study diabetic neuropathy, with rats in particular being consistently reported to show allodynia and hyperalgesia. Models of type 2 diabetes are being used with increasing frequency, but the current literature on the progression of indices of neuropathic pain is variable and relatively few therapeutics have yet been developed in these models. While evidence for spontaneous pain in rodent models is sparse, measures of evoked mechanical, thermal and chemical pain can provide insight into the pathogenesis of the condition. The stocking and glove distribution of pain tantalizingly suggests that the generator site of neuropathic pain is found within the peripheral nervous system. However, emerging evidence demonstrates that amplification in the spinal cord, via spinal disinhibition and neuroinflammation, and also in the brain, via enhanced thalamic activity or decreased cortical inhibition, likely contribute to the pathogenesis of painful diabetic neuropathy. Several potential therapeutic strategies have emerged from preclinical studies, including prophylactic treatments that intervene against underlying mechanisms of disease, treatments that prevent gains of nociceptive function, treatments that suppress enhancements of nociceptive function, and treatments that impede normal nociceptive mechanisms. Ongoing challenges include unraveling the complexity of underlying pathogenic mechanisms, addressing the potential disconnect between the perceived location of pain and the actual pain generator and amplifier sites, and finding ways to identify which mechanisms operate in specific patients to allow rational and individualized choice of targeted therapies.
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Affiliation(s)
- Corinne A Lee-Kubli
- Graduate School of Biomedical Sciences, Sanford-Burnham Institute for Molecular Medicine, La Jolla, CA, USA; Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Nigel A Calcutt
- Department of Pathology, University of California San Diego, La Jolla, CA, USA.
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Yousuf MS, Kerr BJ. The Role of Regulatory Transporters in Neuropathic Pain. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 75:245-71. [PMID: 26920015 DOI: 10.1016/bs.apha.2015.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Neuropathic pain arises from an injury or disease of the somatosensory nervous system rather than stimulation of pain receptors. As a result, the fine balance between excitation and inhibition is perturbed leading to hyperalgesia and allodynia. Various neuropathic pain models provide considerable evidence that changes in the glutamatergic, GABAergic, and monoaminergic systems. Neurotransmitter reuptake transporter proteins have the potential to change the temporal and spatial profile of various neurotransmitters throughout the nervous system. This, in turn, can affect the downstream effects of these neurotransmitters and hence modulate pain. This chapter explores various reuptake transporter systems and implicates their role in pain processing. Understanding the transporter systems will enhance drug discovery targeting different facets of neuropathic pain.
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Affiliation(s)
- Muhammad Saad Yousuf
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Bradley J Kerr
- Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada; Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada; Department of Anesthesiology and Pain Medicine, University of Alberta, Edmonton, Alberta, Canada.
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Tsuruga K, Hashimoto T, Kato R, Kato R, Uchida Y, Hase T, Morimoto Y. Plantar injection of formalin in rats reduces the expression of a potassium chroride cotransporter KCC2 in the spinal cord and a kinase inhibitor suppresses this reduction. Biomed Res 2016; 37:243-9. [PMID: 27545000 DOI: 10.2220/biomedres.37.243] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is released from activated microglia during neuropathic pain and is hypothesized to downregulate the expression of the potassium chloride cotransporter 2 (KCC2) via the TrkB receptor. Previous studies reported that KCC2 is downregulated 5 min after the plantar injection of formalin in rats; however, the mechanism behind this decrease in KCC2 expression during acute inflammatory pain remains unknown. In this study, we determined whether the TrkB receptor contributes to the expression of KCC2 during the acute pain. Five minutes after the plantar injection of formalin in rats, the ratio of KCC2-immunoreactive area in layer II of the spinal cord significantly decreased on the stimulated side compared to the unaffected side. On the other hand, this response was inhibited by the injection of a kinase inhibitor, K252a, in the subarachnoid space 15 min before the formalin injection. These findings suggest that in acute pain, the TrkB receptor may contribute to the decrease in the expression of KCC2.
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Shi W, Ding Y, Yu A, Wang Q, Zhang Z, Zhang LC. BDNF/TRK/KCC2 pathway in nicotine withdrawal-induced hyperalgesia. Transl Neurosci 2015; 6:208-213. [PMID: 28123805 PMCID: PMC4936630 DOI: 10.1515/tnsci-2015-0022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/09/2015] [Indexed: 01/19/2023] Open
Abstract
Purpose To investigate the effect of brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase (Trk) on potassium chloride cotransporter 2 (KCC2) in rats following nicotine withdrawal and the roles played by BDNF/Trk/KCC2 pathway in nicotine withdrawal-induced hyperalgesia. Methods Seventy-eight rats were randomly assigned to five groups: control group (n = 12) without any treatment, normal saline group (NS group, n = 12) and nicotine withdrawal group (NW group, n = 30) receiving a subcutaneous injection of saline or nicotine for 7 days, respectively. The NW + dimethyl sulfoxide (DMSO) (n = 12) and NW+ Trk antagonist K252a groups (n = 12) received an intrathecal injection of DMSO (10 μl) and K252a (10 μg/10 μl) for 3 days after nicotine withdrawal, respectively. Nicotine withdrawal was precipitated by subcutaneous injection of nonselective and noncompetitive antagonist of nicotinic acetylcholine receptors mecamylamine. Pain was tested using thermal withdrawal latency (TWL). A Western blot was used to examine the expression of BDNF and KCC2. Results The TWL was significantly decreased in NW group relative to control and NS groups (P < 0.01). Compared with the NW group, the NW+K252a group manifested a significantly higher latency (P < 0.01). The BDNF expression was increased and KCC2 was decreased in NW group compared with the control group (P < 0.01). K252a reduced KCC2 downregulation. Conclusion BDNF/Trk signaling may contribute to nicotine withdrawal-induced hyperalgesia via downregulation of KCC2.
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Affiliation(s)
- Wenhui Shi
- Jiangsu Province Key Laboratory of Anesthesiology & Jiangsu Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou, Jiangsu 221000, P. R. China
| | - Yonghong Ding
- Jiangsu Province Key Laboratory of Anesthesiology & Jiangsu Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou, Jiangsu 221000, P. R. China
| | - Ailan Yu
- Department of Anesthesiology, Laocheng People’s Hospital, Liaocheng, Shandong 252000, P. R. China
| | - Qinghe Wang
- Jiangsu Province Key Laboratory of Anesthesiology & Jiangsu Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou, Jiangsu 221000, P. R. China
| | - Zongwang Zhang
- Jiangsu Province Key Laboratory of Anesthesiology & Jiangsu Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou, Jiangsu 221000, P. R. China
- Department of Anesthesiology, Laocheng People’s Hospital, Liaocheng, Shandong 252000, P. R. China
- E-mail:
| | - Li-Cai Zhang
- Jiangsu Province Key Laboratory of Anesthesiology & Jiangsu Key Laboratory of Anesthesia and Analgesia Application Technology, Xuzhou, Jiangsu 221000, P. R. China
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Involvement of medullary GABAergic system in extraterritorial neuropathic pain mechanisms associated with inferior alveolar nerve transection. Exp Neurol 2015; 267:42-52. [DOI: 10.1016/j.expneurol.2015.02.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 12/03/2014] [Accepted: 02/22/2015] [Indexed: 01/15/2023]
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Ford A, Castonguay A, Cottet M, Little JW, Chen Z, Symons-Liguori AM, Doyle T, Egan TM, Vanderah TW, De Koninck Y, Tosh DK, Jacobson KA, Salvemini D. Engagement of the GABA to KCC2 signaling pathway contributes to the analgesic effects of A3AR agonists in neuropathic pain. J Neurosci 2015; 35:6057-67. [PMID: 25878279 PMCID: PMC4397603 DOI: 10.1523/jneurosci.4495-14.2015] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 02/27/2015] [Accepted: 03/05/2015] [Indexed: 01/18/2023] Open
Abstract
More than 1.5 billion people worldwide suffer from chronic pain, yet current treatment strategies often lack efficacy or have deleterious side effects in patients. Adenosine is an inhibitory neuromodulator that was previously thought to mediate antinociception through the A1 and A2A receptor subtypes. We have since demonstrated that A3AR agonists have potent analgesic actions in preclinical rodent models of neuropathic pain and that A3AR analgesia is independent of adenosine A1 or A2A unwanted effects. Herein, we explored the contribution of the GABA inhibitory system to A3AR-mediated analgesia using well-characterized mouse and rat models of chronic constriction injury (CCI)-induced neuropathic pain. The deregulation of GABA signaling in pathophysiological pain states is well established: GABA signaling can be hampered by a reduction in extracellular GABA synthesis by GAD65 and enhanced extracellular GABA reuptake via the GABA transporter, GAT-1. In neuropathic pain, GABAAR-mediated signaling can be further disrupted by the loss of the KCC2 chloride anion gradient. Here, we demonstrate that A3AR agonists (IB-MECA and MRS5698) reverse neuropathic pain via a spinal mechanism of action that modulates GABA activity. Spinal administration of the GABAA antagonist, bicuculline, disrupted A3AR-mediated analgesia. Furthermore, A3AR-mediated analgesia was associated with reductions in CCI-related GAD65 and GAT-1 serine dephosphorylation as well as an enhancement of KCC2 serine phosphorylation and activity. Our results suggest that A3AR-mediated reversal of neuropathic pain increases modulation of GABA inhibitory neurotransmission both directly and indirectly through protection of KCC2 function, underscoring the unique utility of A3AR agonists in chronic pain.
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Affiliation(s)
- Amanda Ford
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri 63104
| | - Annie Castonguay
- Institut Universitaire en Santé Mentale de Québec, Québec City, Quebec G1J 2G3, Canada, Department of Psychiatry & Neuroscience, Université Laval, Québec City, Quebec G1K 7P4, Canada
| | - Martin Cottet
- Institut Universitaire en Santé Mentale de Québec, Québec City, Quebec G1J 2G3, Canada, Department of Psychiatry & Neuroscience, Université Laval, Québec City, Quebec G1K 7P4, Canada
| | - Joshua W Little
- Department of Surgery, Center for Anatomical Science and Education, St. Louis University School of Medicine, St. Louis, Missouri 63104
| | - Zhoumou Chen
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri 63104
| | - Ashley M Symons-Liguori
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724-5050, and
| | - Timothy Doyle
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri 63104
| | - Terrance M Egan
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri 63104
| | - Todd W Vanderah
- Department of Pharmacology, College of Medicine, University of Arizona, Tucson, Arizona 85724-5050, and
| | - Yves De Koninck
- Institut Universitaire en Santé Mentale de Québec, Québec City, Quebec G1J 2G3, Canada, Department of Psychiatry & Neuroscience, Université Laval, Québec City, Quebec G1K 7P4, Canada
| | - Dilip K Tosh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0810
| | - Daniela Salvemini
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri 63104,
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Dai S, Ma Z. BDNF-trkB-KCC2-GABA pathway may be related to chronic stress-induced hyperalgesia at both the spinal and supraspinal level. Med Hypotheses 2014; 83:772-4. [PMID: 25454160 DOI: 10.1016/j.mehy.2014.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 09/01/2014] [Accepted: 10/10/2014] [Indexed: 01/15/2023]
Abstract
Chronic stresses can induce physiological and psychological changes and result in stress-related neuropsychiatry, sometimes they may also contribute to hypersensitivity to pain known as stress-induced hyperalgesia (SIH). Recently it was found that GABAergic disinhibition is closely related to morphine and chronic inflammation pain induced hyperalgesia in the PAG (periaqueductal gray)-RVM (rostral ventromedial medulla) -spinal descending facilitatory system, the changes of potassium-chloride co-transporter 2 (KCC2) function or expression modulated by brain-derived neurotrophic factor (BDNF) are involved in it. Similarly, chronic stress could induce changes of BDNF, KCC2 and a depolarizing shift in the GABA reversal potential (EGABA). Moreover, the descending facilitatory system has been suggested to be related with SIH, but whether it modulates SIH through disinhibition by the downregulation of KCC2 expression and/or transport function remains unknown. We therefore hypothesized that SIH may be owned to disinhibition caused by the activation of BDNF-trkB-KCC2-GABA pathway, which would provide a new understanding for SIH.
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Affiliation(s)
- Shuhong Dai
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, Jiangsu 210008, China
| | - Zhengliang Ma
- Department of Anesthesiology, Affiliated Drum Tower Hospital of Medical School of Nanjing University, Nanjing, Jiangsu 210008, China.
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Smith PA. BDNF: No gain without pain? Neuroscience 2014; 283:107-23. [DOI: 10.1016/j.neuroscience.2014.05.044] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/16/2014] [Accepted: 05/21/2014] [Indexed: 12/22/2022]
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In Vivo application of RNAi to study pain. Ann Neurosci 2014; 17:142-5. [PMID: 25205892 PMCID: PMC4116988 DOI: 10.5214/ans.0972-7531.1017310] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 08/10/2010] [Accepted: 08/22/2010] [Indexed: 11/25/2022] Open
Abstract
Chronic pain is associated with several disease conditions. The inadequacy of current analgesics to treat chronic pain is the result of a lack of understanding of the mechanisms that mediate pain. RNA interference has emerged in recent years as a new way to evaluate the roles of molecules involved in the pain response. Selective knockout of proteins has proven to be a powerful technique for target validation, but has been limited as a potential therapeutic due to short-lived responses induced by RNAi. The short responses of RNAi illustrate the need for better delivery techniques, which is being addressed by current work to induce RNAi through the cell’s natural mechanisms. In order to gain a better understanding of chronic pain, it will be necessary to evaluate the pain molecules that are expressed as part of an injury induced pain response, which can be modeled by contusion spinal cord injury. RNAi will prove to be an important technique in this work. The present minireview will summarize the work that has been done using RNAi in vivo to study pain and discuss future directions for the use of RNAi to study chronic pain.
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Shen W, Shen L, Chen G, Wang F, Li C, Lin F, Yang X, Fu S. Ovariectomy modulation of morphine analgesia of neuropathic pain is associated with the change of K(+)-Cl(-) cotransporter 2 protein level in spinal dorsal horn. Int J Clin Exp Med 2014; 7:3467-3472. [PMID: 25419384 PMCID: PMC4238531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 09/20/2014] [Indexed: 06/04/2023]
Abstract
Sex differences in opioid analgesia have been confirmed both in clinical and experimental studies. Gonadal hormones (estrogens in particular) have a great role in this process. However, the mechanisms that underlie these sex differences are not very clear. In this study, we used K(+)-Cl(-) cotransporter 2 (KCC2) as a molecule target to investigate the mechanism underlying the phenomenon. Sprague-Dawley rats were randomly assigned to ovariectomy (OVX)+morphine group, OVX+Saline group, sham surgery (OVX-sham)+morphine group and OVX-sham+saline group. All the rats received SNI surgery three weeks after ovariectomy. We used von Frey values as a sign of neuropathic pain. On PO day 14, 1 μg morphine or the vehicle saline was administered intrathecally via a PE-10 catheter formerly implanted. Hindpaw withdrawal threshold was determined before and 30, 60, 90, 120, 150, 180 min after drugs injection. The L4-L5 segments of the spinal cord were removed and immunoblotted for KCC2 protein at the time of 2 and 3 h after drugs administration. We find that ovariectomy can regulate the sensitivity to morphine analgesia of neuropathic pain and KCC2 protein level will change in the spinal dorsal horn.
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Affiliation(s)
- Weijun Shen
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, School of Medicine, Tongji UniversityShanghai 200072, China
| | - Liang Shen
- Department of Anesthesiology, Ruijin Hospital Luwan Branch, School of Medicine, Shanghai Jiaotong UniversityShanghai 200020, China
| | - Guoqiang Chen
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, School of Medicine, Tongji UniversityShanghai 200072, China
| | - Fen Wang
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, School of Medicine, Tongji UniversityShanghai 200072, China
| | - Cheng Li
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, School of Medicine, Tongji UniversityShanghai 200072, China
| | - Fuqing Lin
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, School of Medicine, Tongji UniversityShanghai 200072, China
| | - Xiaohu Yang
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, School of Medicine, Tongji UniversityShanghai 200072, China
| | - Shukun Fu
- Department of Anesthesiology, Shanghai Tenth People’s Hospital, School of Medicine, Tongji UniversityShanghai 200072, China
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Mòdol L, Cobianchi S, Navarro X. Prevention of NKCC1 phosphorylation avoids downregulation of KCC2 in central sensory pathways and reduces neuropathic pain after peripheral nerve injury. Pain 2014; 155:1577-1590. [PMID: 24813295 DOI: 10.1016/j.pain.2014.05.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 04/24/2014] [Accepted: 05/02/2014] [Indexed: 12/24/2022]
Abstract
Neuropathic pain after peripheral nerve injury is characterized by loss of inhibition in both peripheral and central pain pathways. In the adult nervous system, the Na(+)-K(+)-2Cl(-) (NKCC1) and neuron-specific K(+)-Cl(-) (KCC2) cotransporters are involved in setting the strength and polarity of GABAergic/glycinergic transmission. After nerve injury, the balance between these cotransporters changes, leading to a decrease in the inhibitory tone. However, the role that NKCC1 and KCC2 play in pain-processing brain areas is unknown. Our goal was to study the effects of peripheral nerve injury on NKCC1 and KCC2 expression in dorsal root ganglia (DRG), spinal cord, ventral posterolateral (VPL) nucleus of the thalamus, and primary somatosensory (S1) cortex. After sciatic nerve section and suture in adult rats, assessment of mechanical and thermal pain thresholds showed evidence of hyperalgesia during the following 2 months. We also found an increase in NKCC1 expression in the DRG and a downregulation of KCC2 in spinal cord after injury, accompanied by later decrease of KCC2 levels in higher projection areas (VPL and S1) from 2 weeks postinjury, correlating with neuropathic pain signs. Administration of bumetanide (30 mg/kg) during 2 weeks following sciatic nerve lesion prevented the previously observed changes in the spinothalamic tract projecting areas and the appearance of hyperalgesia. In conclusion, the present results indicate that changes in NKCC1 and KCC2 in DRG, spinal cord, and central pain areas may contribute to development of neuropathic pain.
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Affiliation(s)
- Laura Mòdol
- Institute of Neurosciences and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Bellaterra, Spain
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Côté MP, Gandhi S, Zambrotta M, Houlé JD. Exercise modulates chloride homeostasis after spinal cord injury. J Neurosci 2014; 34:8976-87. [PMID: 24990918 PMCID: PMC6608257 DOI: 10.1523/jneurosci.0678-14.2014] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/20/2014] [Accepted: 05/24/2014] [Indexed: 01/09/2023] Open
Abstract
Activity-based therapies are routinely integrated in spinal cord injury (SCI) rehabilitation programs because they result in a reduction of hyperreflexia and spasticity. However, the mechanisms by which exercise regulates activity in spinal pathways to reduce spasticity and improve functional recovery are poorly understood. Persisting alterations in the action of GABA on postsynaptic targets is a signature of CNS injuries, including SCI. The action of GABA depends on the intracellular chloride concentration, which is determined largely by the expression of two cation-chloride cotransporters (CCCs), KCC2 and NKCC1, which serve as chloride exporters and importers, respectively. We hypothesized that the reduction in hyperreflexia with exercise after SCI relies on a return to chloride homeostasis. Sprague Dawley rats received a spinal cord transection at T12 and were assigned to SCI-7d, SCI-14d, SCI-14d+exercise, SCI-28d, SCI-28d+exercise, or SCI-56d groups. During a terminal experiment, H-reflexes were recorded from interosseus muscles after stimulation of the tibial nerve and the low-frequency-dependent depression (FDD) was assessed. We provide evidence that exercise returns spinal excitability and levels of KCC2 and NKCC1 toward normal levels in the lumbar spinal cord. Acutely altering chloride extrusion using the KCC2 blocker DIOA masked the effect of exercise on FDD, whereas blocking NKCC1 with bumetanide returned FDD toward intact levels after SCI. Our results indicate that exercise contributes to reflex recovery and restoration of endogenous inhibition through a return to chloride homeostasis after SCI. This lends support for CCCs as part of a pathway that could be manipulated to improve functional recovery when combined with rehabilitation programs.
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Affiliation(s)
- Marie-Pascale Côté
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Sapan Gandhi
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Marina Zambrotta
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - John D Houlé
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
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Wang D, Couture R, Hong Y. Activated microglia in the spinal cord underlies diabetic neuropathic pain. Eur J Pharmacol 2014; 728:59-66. [PMID: 24508519 DOI: 10.1016/j.ejphar.2014.01.057] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 01/23/2014] [Accepted: 01/29/2014] [Indexed: 12/22/2022]
Abstract
Diabetes mellitus is an increasingly common chronic medical condition. Approximately 30% of diabetic patients develop neuropathic pain, manifested as spontaneous pain, hyperalgesia and allodynia. Hyperglycemia induces metabolic changes in peripheral tissues and enhances oxidative stress in nerve fibers. The damages and subsequent reactive inflammation affect structural properties of Schwann cells and axons leading to the release of neuropoietic mediators, such as pro-inflammatory cytokines and pro-nociceptive mediators. Therefore, diabetic neuropathic pain (DNP) shares some histological features and underlying mechanisms with traumatic neuropathy. DNP displays, however, other distinct features; for instance, sensory input to the spinal cord decreases rather than increasing in diabetic patients. Consequently, development of central sensitization in DNP involves mechanisms that are distinct from traumatic neuropathic pain. In DNP, the contribution of spinal cord microglia activation to central sensitization and pain processes is emerging as a new concept. Besides inflammation in the periphery, hyperglycemia and the resulting production of reactive oxygen species affect the local microenvironment in the spinal cord. All these alterations could trigger resting and sessile microglia to the activated phenotype. In turn, microglia synthesize and release pro-inflammatory cytokines and neuroactive molecules capable of inducing hyperactivity of spinal nociceptive neurons. Hence, it is imperative to elucidate glial mechanisms underlying DNP for the development of effective therapeutic agents. The present review highlights the recent developments regarding the contribution of spinal microglia as compelling target for the treatment of DNP.
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Affiliation(s)
- Dongmei Wang
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, New campus, Fuzhou, Fujian 350108, People׳s Republic of China
| | - Réjean Couture
- Department of Physiology, Faculty of Medicine, Université de Montréal, C.P. 6128, Succursale Downtown, Montréal, Québec, Canada H3C 3J7
| | - Yanguo Hong
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, New campus, Fuzhou, Fujian 350108, People׳s Republic of China.
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Inhibition of carbonic anhydrase augments GABAA receptor-mediated analgesia via a spinal mechanism of action. THE JOURNAL OF PAIN 2014; 15:395-406. [PMID: 24412803 DOI: 10.1016/j.jpain.2014.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 10/22/2013] [Accepted: 01/04/2014] [Indexed: 12/21/2022]
Abstract
UNLABELLED Peripheral nerve injury (PNI) negatively influences spinal gamma-aminobutyric acid (GABA)ergic networks via a reduction in the neuron-specific potassium-chloride (K(+)-Cl(-)) cotransporter (KCC2). This process has been linked to the emergence of neuropathic allodynia. In vivo pharmacologic and modeling studies show that a loss of KCC2 function results in a decrease in the efficacy of GABAA-mediated spinal inhibition. One potential strategy to mitigate this effect entails inhibition of carbonic anhydrase activity to reduce HCO3(-)-dependent depolarization via GABAA receptors when KCC2 function is compromised. We have tested this hypothesis here. Our results show that, similarly to when KCC2 is pharmacologically blocked, PNI causes a loss of analgesic effect for neurosteroid GABAA allosteric modulators at maximally effective doses in naïve mice in the tail-flick test. Remarkably, inhibition of carbonic anhydrase activity with intrathecal acetazolamide rapidly restores an analgesic effect for these compounds, suggesting an important role of carbonic anhydrase activity in regulating GABAA-mediated analgesia after PNI. Moreover, spinal acetazolamide administration leads to a profound reduction in the mouse formalin pain test, indicating that spinal carbonic anhydrase inhibition produces analgesia when primary afferent activity is driven by chemical mediators. Finally, we demonstrate that systemic administration of acetazolamide to rats with PNI produces an antiallodynic effect by itself and an enhancement of the peak analgesic effect with a change in the shape of the dose-response curve of the α1-sparing benzodiazepine L-838,417. Thus, carbonic anhydrase inhibition mitigates the negative effects of loss of KCC2 function after nerve injury in multiple species and through multiple administration routes resulting in an enhancement of analgesic effects for several GABAA allosteric modulators. We suggest that carbonic anhydrase inhibitors, many of which are clinically available, might be advantageously employed for the treatment of pathologic pain states. PERSPECTIVE Using behavioral pharmacology techniques, we show that spinal GABAA-mediated analgesia can be augmented, especially following nerve injury, via inhibition of carbonic anhydrases. Carbonic anhydrase inhibition alone also produces analgesia, suggesting these enzymes might be targeted for the treatment of pain.
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Lee-Kubli CAG, Calcutt NA. Altered rate-dependent depression of the spinal H-reflex as an indicator of spinal disinhibition in models of neuropathic pain. Pain 2013; 155:250-260. [PMID: 24103402 DOI: 10.1016/j.pain.2013.10.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 10/01/2013] [Accepted: 10/01/2013] [Indexed: 12/17/2022]
Abstract
The unpredictable efficacy of current therapies for neuropathic pain may reflect diverse etiological mechanisms operating between, and within, diseases. As descriptions of pain rarely establish specific mechanisms, a tool that can identify underlying causes of neuropathic pain would be useful in developing patient-specific treatments. Rate-dependent depression (RDD), a measure of the change in amplitude of the Hoffman reflex over consecutive stimulations, is attenuated in diabetic rats that also exhibit impaired spinal γ-aminobutyric acid (GABA)A receptor function, reduced spinal potassium chloride co-transporter (KCC2) expression, and indices of painful neuropathy. To investigate whether loss of RDD is a reliable indicator of the contribution of spinal GABAergic dysfunction to neuropathic pain, we assessed RDD, tactile allodynia, and formalin-evoked hyperalgesia in 3 models: rats treated acutely with brain-derived neurotrophic factor (BDNF), diabetic rats treated with the BDNF-sequestering molecule tyrosine receptor kinase B/Fc (TrkB/Fc), and rats with paclitaxel-induced neuropathy. Delivery of BDNF to the spinal cord of normal rats produced RDD deficits and features of painful neuropathy associated with disrupted GABAA receptor-mediated inhibitory function and reduced dorsal spinal KCC2 expression. Treating diabetic rats with TrkB/Fc restored RDD and alleviated indices of painful neuropathy. In paclitaxel-treated rats, RDD was not impaired and behavioral indices of neuropathic pain were not associated with spinal GABAergic dysfunction or reduced dorsal spinal KCC2 expression. Our data reveal BDNF as part of the mechanism underlying spinal cord disinhibition caused by altered GABAA receptor function in diabetic rats and suggest that RDD deficits may be a useful indicator of neuropathic pain states associated with spinal disinhibition, thereby revealing specific therapeutic targets.
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Affiliation(s)
- Corinne A G Lee-Kubli
- Department of Pathology, University of California San Diego, La Jolla, CA 92093, USA Graduate School of Biomedical Sciences, Sanford-Burnham Institute for Medical Research, La Jolla, CA 92037, USA
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Zhang Z, Wang X, Wang W, Lu YG, Pan ZZ. Brain-derived neurotrophic factor-mediated downregulation of brainstem K+-Cl- cotransporter and cell-type-specific GABA impairment for activation of descending pain facilitation. Mol Pharmacol 2013; 84:511-20. [PMID: 23847084 PMCID: PMC3781381 DOI: 10.1124/mol.113.086496] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/11/2013] [Indexed: 11/22/2022] Open
Abstract
Chronic pain is thought to be partly caused by a loss of GABAergic inhibition and resultant neuronal hyperactivation in the central pain-modulating system, but the underlying mechanisms for pain-modulating neurons in the brain are unclear. In this study, we investigated the cellular mechanisms for activation of brainstem descending pain facilitation in rats under persistent pain conditions. In the nucleus raphe magnus (NRM), a critical relay in the brain's descending pain-modulating system, persistent inflammatory pain induced by complete Freund's adjuvant decreased the protein level of K(+)-Cl(-) cotransporter (KCC2) in both total and synaptosomal preparations. Persistent pain also shifted the equilibrium potential of GABAergic inhibitory postsynaptic current (EIPSC) to a more positive level and increased the firing of evoked action potentials selectively in μ-opioid receptor (MOR)-expressing NRM neurons, but not in MOR-lacking NRM neurons. Microinjection of brain-derived neurotrophic factor (BDNF) into the NRM inhibited the KCC2 protein level in the NRM, and both BDNF administration and KCC2 inhibition by furosemide mimicked the pain-induced effects on EIPSC and excitability in MOR-expressing neurons. Furthermore, inhibiting BDNF signaling by NRM infusion of tyrosine receptor kinase B-IgG or blocking KCC2 with furosemide prevented these pain effects in MOR-expressing neurons. These findings demonstrate a cellular mechanism by which the hyperactivity of NRM MOR-expressing neurons, presumably responsible for descending pain facilitation, contributes to pain sensitization through the signaling cascade of BDNF-KCC2-GABA impairment in the development of chronic pain.
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Affiliation(s)
- Zhi Zhang
- Department of Anesthesiology and Pain Medicine, University of Texas, MD Anderson Cancer Center, Houston, Texas (Z.Z., W.W., Z.Z.P.); Department of Neurobiology, University of Science and Technology of China, Hefei, People's Republic of China (Z.Z., X.W.); and Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas (Y.-G.L.)
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50
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Abstract
Inflammation is the process by which an organism responds to tissue injury involving both immune cell recruitment and mediator release. Diverse causes of neuropathic pain are associated with excessive inflammation in both the peripheral and central nervous system which may contribute to the initiation and maintenance of persistent pain. Chemical mediators, such as cytokines, chemokines, and lipid mediators, released during an inflammatory response have the undesired effect of sensitizing and stimulating nociceptors, their central synaptic targets or both. These changes can promote long-term maladaptive plasticity resulting in persistent neuropathic pain. This review aims to provide an overview of inflammatory mechanisms at differing levels of the sensory neuroaxis with a focus on neuropathic pain. We will compare and contrast neuropathic pain states such as traumatic nerve injury which is associated with a vigorous inflammatory response and chemotherapy induced pain in which the inflammatory response is much more modest. Targeting excessive inflammation in neuropathic pain provides potential therapeutic opportunities and we will discuss some of the opportunities but also the clinical challenges in such an approach.
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Affiliation(s)
- A Ellis
- King's College London, Wolfson Wing, Hodgkin Building, Guy's Campus, London SE1 1UL, UK.
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