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Pergolizzi JV, LeQuang JA, El-Tallawy SN, Wagner M, Ahmed RS, Varrassi G. An update on pharmacotherapy for trigeminal neuralgia. Expert Rev Neurother 2024:1-14. [PMID: 38870050 DOI: 10.1080/14737175.2024.2365946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/05/2024] [Indexed: 06/15/2024]
Abstract
INTRODUCTION Trigeminal neuralgia is a rare condition that can be effectively treated by carbamazepine or oxcarbazepine but these older drugs are associated with dose-dependent and potentially treatment-limiting adverse effects. Third-generation anticonvulsants, new calcitonin gene-related peptide blockers for migraine, and older drugs such as ketamine and cannabinoids may be promising adjuvants or monotherapeutic options. AREAS COVERED The new drugs, their presumed mechanisms of action, safety and efficacy are discussed herein. There is a paucity of robust clinical evidence in support of these drugs for trigeminal neuralgia. New migraine agents are considered as well although migraines and trigeminal neuralgia are distinct, albeit similar, conditions. No new drugs have been released to market in recent years with the specific indication of trigeminal neuralgia. EXPERT OPINION In real-world clinical practice, about half of trigeminal neuralgia patients take more than one agent for prevention and combination therapy may be the optimal approach. Combination therapy might allow for lower doses of carbamazepine or oxcarbazepine, thus reducing the number and severity of potential adverse events but the potential for pharmacokinetic drug-drug interactions must be considered. Drug therapy for trigeminal neuralgia involves acute or abortive treatments, often administered in hospital versus long-term preventive therapy, usually involving oral agents.
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Affiliation(s)
| | | | - Salah N El-Tallawy
- Anesthesia and Pain Department, King Khalid University Hospital, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Anesthesia Department, Medicine, Minia University & NCI, Minia, Egypt
| | | | - Rania S Ahmed
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
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Wei HR, Tang L, Yang XL, Chen CM, Li LX, Mao Y, Wang D, Kang F, Qun S, Zhang Z, Cao P, Jin Y. A microglial activation cascade across cortical regions underlies secondary mechanical hypersensitivity to amputation. Cell Rep 2024; 43:113804. [PMID: 38368612 DOI: 10.1016/j.celrep.2024.113804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 08/03/2023] [Accepted: 01/31/2024] [Indexed: 02/20/2024] Open
Abstract
Neural mechanisms underlying amputation-related secondary pain are unclear. Using in vivo two-photon imaging, three-dimensional reconstruction, and fiber photometry recording, we show that a microglial activation cascade from the primary somatosensory cortex of forelimb (S1FL) to the primary somatosensory cortex of hindlimb (S1HL) mediates the disinhibition and subsequent hyperexcitation of glutamatergic neurons in the S1HL (S1HLGlu), which then drives secondary mechanical hypersensitivity development in ipsilateral hindpaws of mice with forepaw amputation. Forepaw amputation induces rapid S1FL microglial activation that further activates S1HL microglia via the CCL2-CCR2 signaling pathway. Increased engulfment of GABAergic presynapses by activated microglia stimulates S1HLGlu neuronal activity, ultimately leading to secondary mechanical hypersensitivity of hindpaws. It is widely believed direct neuronal projection drives interactions between distinct brain regions to prime specific behaviors. Our study reveals microglial interactions spanning different subregions of the somatosensory cortex to drive a maladaptive neuronal response underlying secondary mechanical hypersensitivity at non-injured sites.
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Affiliation(s)
- Hong-Rui Wei
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Lan Tang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Xin-Lu Yang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Department of Anesthesiology, The First Affiliated Hospital of Wannan Medical College, Wuhu, Anhui 241000, China
| | - Chang-Mao Chen
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Le-Xian Li
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Yu Mao
- Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China
| | - Di Wang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Fang Kang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Sen Qun
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | - Zhi Zhang
- Department of Anesthesiology, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China; Center for Advanced Interdisciplinary Science and Biomedicine, Institute of Health and Medicine, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
| | - Peng Cao
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
| | - Yan Jin
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China.
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Lisboa MRP, Pereira AF, Alves BWDF, Dias DBS, Alves LCV, da Silva CMP, Lima-Júnior RCP, Gondim DV, Vale ML. Blockage of the fractalkine pathway reduces hyperalgesia and prevents morphological glial alterations-Comparison between inflammatory and neuropathic orofacial pain in male rats. J Neurosci Res 2024; 102:e25269. [PMID: 38284851 DOI: 10.1002/jnr.25269] [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: 04/14/2023] [Revised: 10/09/2023] [Accepted: 10/22/2023] [Indexed: 01/30/2024]
Abstract
This study aimed to evaluate the effects of inhibitors of the fractalkine pathway in hyperalgesia in inflammatory and neuropathic orofacial pain in male rats and the morphological changes in microglia and satellite glial cells (SGCs). Rats were submitted to zymosan-induced arthritis of the temporomandibular joint or infraorbital nerve constriction, and treated intrathecally with a P2 X7 antagonist, a cathepsin S inhibitor or a p-38 mitogen-activated protein kinase (MAPK) inhibitor. Mechanical hyperalgesia was evaluated 4 and 6 h following arthritis induction or 7 and 14 days following nerve ligation. The expression of the receptor CX3 CR1 , phospho-p-38 MAPK, ionized calcium-binding adapter molecule-1 (Iba-1), and glutamine synthetase and the morphological changes in microglia and SGCs were evaluated by confocal microscopy. In both inflammatory and neuropathic models, untreated animals presented a higher expression of CX3 CR1 and developed hyperalgesia and up-regulation of phospho-p-38 MAPK, which was prevented by all drugs (p < .05). The number of microglial processes endpoints and the total branch length were lower in the untreated animals, but the overall immunolabeling of Iba-1 was altered only in neuropathic rats (p < .05). The mean area of SGCs per neuron was significantly altered only in the inflammatory model (p < .05). All morphological alterations were reverted by modulating the fractalkine pathway (p < .05). In conclusion, the blockage of the fractalkine pathway seemed to be a possible therapeutic strategy for inflammatory and neuropathic orofacial pain, reducing mechanical hyperalgesia by impairing the phosphorylation of p-38 MAPK and reverting morphological alterations in microglia and SGCs.
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Affiliation(s)
- Mario Roberto Pontes Lisboa
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Graduation in Dentistry, Christus University Center, Fortaleza, Brazil
| | - Anamaria Falcão Pereira
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | | | - Diego Bernarde Souza Dias
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | | | | | - Roberto César Pereira Lima-Júnior
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Drug Research and Development Center, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Delane Viana Gondim
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Drug Research and Development Center, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
| | - Mariana Lima Vale
- Department of Morphology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
- Drug Research and Development Center, Faculty of Medicine, Federal University of Ceará, Fortaleza, Brazil
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Long DD, Zhang YZ, Liu A, Shen L, Wei HR, Lou QQ, Hu SS, Chen DY, Chai XQ, Wang D. Microglia sustain anterior cingulate cortex neuronal hyperactivity in nicotine-induced pain. J Neuroinflammation 2023; 20:81. [PMID: 36944965 PMCID: PMC10031886 DOI: 10.1186/s12974-023-02767-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/17/2023] [Indexed: 03/23/2023] Open
Abstract
BACKGROUND Long-term smoking is a risk factor for chronic pain, and chronic nicotine exposure induces pain-like effects in rodents. The anterior cingulate cortex (ACC) has been demonstrated to be associated with pain and substance abuse. This study aims to investigate whether ACC microglia are altered in response to chronic nicotine exposure and their interaction with ACC neurons and subsequent nicotine-induced allodynia in mice. METHODS We utilized a mouse model that was fed nicotine water for 28 days. Brain slices of the ACC were collected for morphological analysis to evaluate the impacts of chronic nicotine on microglia. In vivo calcium imaging and whole-cell patch clamp were used to record the excitability of ACC glutamatergic neurons. RESULTS Compared to the vehicle control, the branch endpoints and the length of ACC microglial processes decreased in nicotine-treated mice, coinciding with the hyperactivity of glutamatergic neurons in the ACC. Inhibition of ACC glutamatergic neurons alleviated nicotine-induced allodynia and reduced microglial activation. On the other hand, reactive microglia sustain ACC neuronal excitability in response to chronic nicotine, and pharmacological inhibition of microglia by minocycline or liposome-clodronate reduces nicotine-induced allodynia. The neuron-microglia interaction in chronic nicotine-induced allodynia is mediated by increased expression of neuronal CX3CL1, which activates microglia by acting on CX3CR1 receptors on microglial cells. CONCLUSION Together, these findings underlie a critical role of ACC microglia in the maintenance of ACC neuronal hyperactivity and resulting nociceptive hypersensitivity in chronic nicotine-treated mice.
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Affiliation(s)
- Dan-Dan Long
- Pain Clinic, Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China (USTC), Hefei, 230001, China
| | - Yu-Zhuo Zhang
- Institute of Clinical Pharmacology, Anhui Medical University, Hefei, 230032, China
| | - An Liu
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, 230032, China
| | - Liang Shen
- Pain Clinic, Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China (USTC), Hefei, 230001, China
| | - Hong-Rui Wei
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Qian-Qian Lou
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Shan-Shan Hu
- Department of Clinical Laboratory, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China (USTC), Hefei, 230001, China
| | - Dan-Yang Chen
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Xiao-Qing Chai
- Pain Clinic, Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China (USTC), Hefei, 230001, China
| | - Di Wang
- Pain Clinic, Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China (USTC), Hefei, 230001, China.
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Farzinpour Z, Liu A, Cao P, Mao Y, Zhang Z, Jin Y. Microglial Engulfment of Spines in the Ventral Zona Incerta Regulates Anxiety-Like Behaviors in a Mouse Model of Acute Pain. Front Cell Neurosci 2022; 16:898346. [PMID: 35910255 PMCID: PMC9337222 DOI: 10.3389/fncel.2022.898346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/17/2022] [Indexed: 12/20/2022] Open
Abstract
Although activation of microglial cells is critical in developing brain disorders, their role in anxiety-like behaviors in pain is still vague. This study indicates that alteration of microglia’s neuronal spine engulfment capacity in ventral zona incerta (ZIV) leads to significant pain and anxiety-like behaviors in mice 1-day post-injection of Complete Freud’s Adjuvant (CFA1D). Performing whole-cell patch-clamp recordings in GABAergic neurons in the ZIV (ZIVGABA) in brain slices, we observed decreased activity in ZIvGABA and reduced frequency of the miniature excitatory postsynaptic currents (mEPSCs) in ZIVGABA of CFA1D mice compared with the saline1D mice. Besides, chemogenetic activation of ZIVGABA significantly relieved pain and anxiety-like behaviors in CFA1D mice. Conversely, in naïve mice, chemogenetic inhibition of ZIVGABA induced pain and anxiety-like behaviors. Interestingly, we found changes in the density and morphology of ZIVMicroglia and increased microglial engulfment of spines in ZIV of CFA1D mice. Furthermore, pain sensitization and anxiety-like behaviors were reversed when the ZIVMicroglia of CFA1D-treated mice were chemically inhibited by intra-ZIV minocycline injection, accompanied by the recovery of decreased ZIVGABA excitability. Conclusively, our results provide novel insights that dysregulation of microglial engulfment capacity encodes maladaptation of ZIVGABA, thus promoting the development of anxiety-like behaviors in acute pain.
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Affiliation(s)
- Zahra Farzinpour
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - An Liu
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Peng Cao
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yu Mao
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Zhi Zhang
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- *Correspondence: Zhi Zhang,
| | - Yan Jin
- Stroke Center and Department of Neurology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Yan Jin,
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Gao W, Shen L, Long DD, Pan TT, Wang D, Chai XQ, Hu SS. Angiotensin II type 2 receptor pharmacological agonist, C21, reduces the inflammation and pain hypersensitivity in mice with joint inflammatory pain. Int Immunopharmacol 2022; 110:108921. [PMID: 35724606 DOI: 10.1016/j.intimp.2022.108921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Revised: 05/19/2022] [Accepted: 06/01/2022] [Indexed: 11/15/2022]
Abstract
Primary and secondary hyperalgesia develop in response to chronic joint inflammation due to peripheral and central mechanisms. Synovial macrophage and spinal microglia are involved in pain sensitization in arthritis. The level of angiotensin II type 2 receptor (AT2R) is related to the severity of arthritis. This study aimed to determine the role of AT2R in primary and secondary hyperalgesia in joint inflammatory pain in mice. After intra-articular CFA injection, primary hyperalgesia in the ipsilateral knee joint was measured by pressure application meter and gait analysis, secondary hypersensitivity in ipsilateral hind-paw was measured by von-Frey and Hargreaves tests following a combination of global AT2R-deficient (Agtr2-/-) mice and AT2R pharmacological agonist C21. Synovial macrophage and spinal microglia were collected for flow cytometry. Morphological reconstruction of microglia was detected by immunostaining. AT2R expression was investigated by quantitative polymerase chain reaction and western blot. Neuronal hyperactivity was evaluated by c-Fos and CGRP immunostaining. We found that pain hypersensitivity and synovial inflammation in Agtr2-/- mice were significantly exacerbated compared with wild-type mice; conversely, systemically administrated C21 attenuated both of the symptoms. Additionally, spinal microglia were activated, and an abundant increase of spinal AT2R was expressed on activated microglia in response to peripheral joint inflammation. Intrathecally-administrated C21 reversed the secondary hypersensitivity, accompanied by alleviation of spinal microglial activation, spinal neuronal hyperactivity, and calcitonin gene-related peptide content. These findings revealed a beneficial role of AT2R activating stimulation against pain hypersensitivity in joint inflammatory pain via direct modulation of synovial macrophage and spinal microglial activity.
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Affiliation(s)
- Wei Gao
- Anhui Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Liang Shen
- Department of Anesthesiology, Anhui Provincial Hospital Affiliated to Medical University, Hefei 230036, China
| | - Dan-Dan Long
- Department of Anesthesiology, Anhui Provincial Hospital Affiliated to Medical University, Hefei 230036, China
| | - Ting-Ting Pan
- Department of Anesthesiology, Anhui Provincial Hospital Affiliated to Medical University, Hefei 230036, China
| | - Di Wang
- Department of Anesthesiology, Anhui Provincial Hospital Affiliated to Medical University, Hefei 230036, China
| | - Xiao-Qing Chai
- Anhui Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, China.
| | - Shan-Shan Hu
- Department of Clinical Laboratory, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
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Pan TT, Gao W, Song ZH, Long DD, Cao P, Hu R, Chen DY, Zhou WJ, Jin Y, Hu SS, Wei W, Chai XQ, Zhang Z, Wang D. Glutamatergic neurons and myeloid cells in the anterior cingulate cortex mediate secondary hyperalgesia in chronic joint inflammatory pain. Brain Behav Immun 2022; 101:62-77. [PMID: 34973395 DOI: 10.1016/j.bbi.2021.12.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 12/20/2021] [Accepted: 12/24/2021] [Indexed: 02/06/2023] Open
Affiliation(s)
- Ting-Ting Pan
- Pain Clinic, Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China
| | - Wei Gao
- Pain Clinic, Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China
| | - Zi-Hua Song
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China; Innovation Laboratory of Terahertz Biophysics, National Innovation Institute of Defense Technology, Beijing 100071, China
| | - Dan-Dan Long
- Pain Clinic, Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China
| | - Peng Cao
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Rui Hu
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Dan-Yang Chen
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Wen-Jie Zhou
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Yan Jin
- Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Shan-Shan Hu
- Institute of Clinical Pharmacology, Anhui Medical University, Hefei 230032, China
| | - Wei Wei
- Institute of Clinical Pharmacology, Anhui Medical University, Hefei 230032, China
| | - Xiao-Qing Chai
- Pain Clinic, Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China
| | - Zhi Zhang
- Pain Clinic, Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China; Department of Neurobiology, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Di Wang
- Pain Clinic, Department of Anesthesiology, First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230001, China.
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Chronic Orofacial Pain: Models, Mechanisms, and Genetic and Related Environmental Influences. Int J Mol Sci 2021; 22:ijms22137112. [PMID: 34281164 PMCID: PMC8268972 DOI: 10.3390/ijms22137112] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic orofacial pain conditions can be particularly difficult to diagnose and treat because of their complexity and limited understanding of the mechanisms underlying their aetiology and pathogenesis. Furthermore, there is considerable variability between individuals in their susceptibility to risk factors predisposing them to the development and maintenance of chronic pain as well as in their expression of chronic pain features such as allodynia, hyperalgesia and extraterritorial sensory spread. The variability suggests that genetic as well as environmental factors may contribute to the development and maintenance of chronic orofacial pain. This article reviews these features of chronic orofacial pain, and outlines findings from studies in animal models of the behavioural characteristics and underlying mechanisms related to the development and maintenance of chronic orofacial pain and trigeminal neuropathic pain in particular. The review also considers the role of environmental and especially genetic factors in these models, focussing on findings of differences between animal strains in the features and underlying mechanisms of chronic pain. These findings are not only relevant to understanding underlying mechanisms and the variability between patients in the development, expression and maintenance of chronic orofacial pain, but also underscore the importance for considering the strain of the animal to model and explore chronic orofacial pain processes.
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Nagakura Y, Nagaoka S, Kurose T. Potential Molecular Targets for Treating Neuropathic Orofacial Pain Based on Current Findings in Animal Models. Int J Mol Sci 2021; 22:ijms22126406. [PMID: 34203854 PMCID: PMC8232571 DOI: 10.3390/ijms22126406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/11/2021] [Accepted: 06/13/2021] [Indexed: 01/25/2023] Open
Abstract
This review highlights potential molecular targets for treating neuropathic orofacial pain based on current findings in animal models. Preclinical research is currently elucidating the pathophysiology of the disease and identifying the molecular targets for better therapies using animal models that mimic this category of orofacial pain, especially post-traumatic trigeminal neuropathic pain (PTNP) and primary trigeminal neuralgia (PTN). Animal models of PTNP and PTN simulate their etiologies, that is, trauma to the trigeminal nerve branch and compression of the trigeminal root entry zone, respectively. Investigations in these animal models have suggested that biological processes, including inflammation, enhanced neuropeptide-mediated pain signal transmission, axonal ectopic discharges, and enhancement of interactions between neurons and glial cells in the trigeminal pathway, are underlying orofacial pain phenotypes. The molecules associated with biological processes, whose expressions are substantially altered following trigeminal nerve damage or compression of the trigeminal nerve root, are potentially involved in the generation and/or exacerbation of neuropathic orofacial pain and can be potential molecular targets for the discovery of better therapies. Application of therapeutic candidates, which act on the molecular targets and modulate biological processes, attenuates pain-associated behaviors in animal models. Such therapeutic candidates including calcitonin gene-related peptide receptor antagonists that have a reasonable mechanism for ameliorating neuropathic orofacial pain and meet the requirements for safe administration to humans seem worth to be evaluated in clinical trials. Such prospective translation of the efficacy of therapeutic candidates from animal models to human patients would help develop better therapies for neuropathic orofacial pain.
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Affiliation(s)
- Yukinori Nagakura
- School of Pharmacy at Fukuoka, International University of Health and Welfare, 137-1 Enokizu, Okawa-city, Fukuoka 831-8501, Japan
- Correspondence:
| | - Shogo Nagaoka
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan; (S.N.); (T.K.)
| | - Takahiro Kurose
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan; (S.N.); (T.K.)
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10
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Han YY, Jin K, Pan QS, Li B, Wu ZQ, Gan L, Yang L, Long C. Microglial activation in the dorsal striatum participates in anxiety-like behavior in Cyld knockout mice. Brain Behav Immun 2020; 89:326-338. [PMID: 32688031 DOI: 10.1016/j.bbi.2020.07.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/06/2020] [Accepted: 07/10/2020] [Indexed: 12/26/2022] Open
Abstract
CYLD lysine 63 deubiquitinase (CYLD), that is mainly involved in immune responses and inflammation, is expressed at high levels in the brain, especially in the dorsal striatum, but its physiological function of CYLD in the brain remains unexplored. The present study investigated the effect of Cyld gene knockout on behavior relevant to the dorsal striatum, such as motor activity and depression-like and anxiety-like behavior. Microglia and the pro-inflammatory cytokines including interleukin (IL)-1 β and tumor necrosis factor (TNF)- α were evaluated in the dorsal striatum to elucidate the underlying mechanism. Cyld knockout (Cyld-/-) mice exhibited anxiety-like behavior, but not motor deficits or depression-like behavior. Microglia were activated and the mRNA levels of IL-1 β and TNF- α were increased in the dorsal striatum of Cyld-/- mice compared to Cyld+/+ mice. The microglial modulator minocycline partially reversed the anxiety-like behavior, microglial activation and increase in IL-1 β and TNF- α mRNA and protein levels in the dorsal striatum of Cyld-/- mice. Collectively, these results suggest that Cyld knockout leading to microglial activation promotes IL-1 β and TNF- α expression and acts as a critical pathway in the pathophysiology of anxiety.
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Affiliation(s)
- Yuan-Yuan Han
- School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
| | - Kai Jin
- School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
| | - Qi-Sheng Pan
- School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
| | - Bo Li
- School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
| | - Zhuo-Qing Wu
- School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
| | - Lin Gan
- School of Life Sciences, South China Normal University, Guangzhou 510631, PR China
| | - Li Yang
- School of Life Sciences, Guangzhou University, Guangzhou 510006, PR China.
| | - Cheng Long
- School of Life Sciences, South China Normal University, Guangzhou 510631, PR China; South China Normal University-Panyu Central Hospital Joint Laboratory of Translational Medical Research, Panyu Central Hospital, Guangzhou 511400, PR China.
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Are glia targets for neuropathic orofacial pain therapy? J Am Dent Assoc 2020; 152:774-779. [PMID: 32921390 DOI: 10.1016/j.adaj.2020.05.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 05/14/2020] [Indexed: 01/06/2023]
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12
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On the Role of Microglia in Trigeminal Neuropathic Pain. Neuroscience 2019; 414:297-298. [PMID: 31199893 DOI: 10.1016/j.neuroscience.2019.05.056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Accepted: 05/27/2019] [Indexed: 11/22/2022]
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