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Katagiri A, Kishimoto S, Okamoto Y, Yamada M, Niwa H, Bereiter DA, Kato T. Effect of chronic intermittent hypoxia on ocular and intraoral mechanical allodynia mediated via the calcitonin gene-related peptide in a rat. Sleep 2024; 47:zsad332. [PMID: 38166171 PMCID: PMC10925949 DOI: 10.1093/sleep/zsad332] [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: 08/09/2023] [Revised: 12/15/2023] [Indexed: 01/04/2024] Open
Abstract
STUDY OBJECTIVES Obstructive sleep apnea, a significant hypoxic condition, may exacerbate several orofacial pain conditions. The study aims to define the involvement of calcitonin gene-related peptide (CGRP) in peripheral and central sensitization and in evoking orofacial mechanical allodynia under chronic intermittent hypoxia (CIH). METHODS Male rats were exposed to CIH. Orofacial mechanical allodynia was assessed using the eyeblink test and the two-bottle preference drinking test. The CGRP-immunoreactive neurons in the trigeminal ganglion (TG), CGRP-positive primary afferents projecting to laminae I-II of the trigeminal spinal subnucleus caudalis (Vc), and neural responses in the second-order neurons of the Vc were determined by immunohistochemistry. CGRP receptor antagonist was administrated in the TG. RESULTS CIH-induced ocular and intraoral mechanical allodynia. CGRP-immunoreactive neurons and activated satellite glial cells (SGCs) were significantly increased in the TG and the number of cFos-immunoreactive cells in laminae I-II of the Vc were significantly higher in CIH rats compared to normoxic rats. Local administration of the CGRP receptor antagonist in the TG of CIH rats attenuated orofacial mechanical allodynia; the number of CGRP-immunoreactive neurons and activated SGCs in the TG, and the density of CGRP-positive primary afferent terminals and the number of cFos-immunoreactive cells in laminae I-II of the Vc were significantly lower compared to vehicle-administrated CIH rats. CONCLUSIONS An increase in CGRP in the TG induced by CIH, as well as orofacial mechanical allodynia and central sensitization of second-order neurons in the Vc, supported the notion that CGRP plays a critical role in CIH-induced orofacial mechanical allodynia.
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Affiliation(s)
- Ayano Katagiri
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Saki Kishimoto
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
- Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Yoshie Okamoto
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Masaharu Yamada
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
- Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - Hitoshi Niwa
- Department of Dental Anesthesiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - David A Bereiter
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, MN, USA
| | - Takafumi Kato
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
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2
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Sangalli L, Prakapenka AV, Chaurasia A, Miller CS. A review of animal models for burning mouth syndrome: Mechanistic insights and knowledge gaps. Oral Dis 2024. [PMID: 38438317 DOI: 10.1111/odi.14914] [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: 10/20/2023] [Revised: 01/24/2024] [Accepted: 02/16/2024] [Indexed: 03/06/2024]
Abstract
OBJECTIVES The underlying mechanisms of burning mouth syndrome (BMS) remain unclear leading to challenges and unsatisfactory management. Current treatments focus primarily on symptom relief, with few consistently achieving a 50% reduction in pain. This review aims to explore animal models of BMS to gain a better understanding of the underlying mechanisms and to discuss potential and existing knowledge gaps. METHODS A comprehensive review of PubMed® , Google Scholar, and Scopus was performed to assess advances and significant gaps of existing rodent models that mimic BMS-related symptoms. RESULTS Rodent models of BMS involve reproduction of dry-tongue, chorda tympani transection, or overexpression of artemin protein. Existing preclinical models tend to highlight one specific etiopathogenesis and often overlook sex- and hormone-specific factors. CONCLUSION Combining aspects from various BMS models could prove beneficial in developing comprehensive experimental designs and outcomes encompassing the multifaceted nature of BMS.
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Affiliation(s)
- Linda Sangalli
- College of Dental Medicine-Illinois, Midwestern University, Downers Grove, Illinois, USA
| | | | - Akhilanand Chaurasia
- Department of Oral Medicine and Radiology, King George's Medical University, Lucknow, India
| | - Craig S Miller
- Division of Oral Diagnosis, Oral Medicine, and Oral Radiology, College of Dentistry, University of Kentucky, Lexington, Kentucky, USA
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3
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Puja G, Sonkodi B, Bardoni R. Mechanisms of Peripheral and Central Pain Sensitization: Focus on Ocular Pain. Front Pharmacol 2021; 12:764396. [PMID: 34916942 PMCID: PMC8669969 DOI: 10.3389/fphar.2021.764396] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/09/2021] [Indexed: 12/14/2022] Open
Abstract
Persistent ocular pain caused by corneal inflammation and/or nerve injury is accompanied by significant alterations along the pain axis. Both primary sensory neurons in the trigeminal nerves and secondary neurons in the spinal trigeminal nucleus are subjected to profound morphological and functional changes, leading to peripheral and central pain sensitization. Several studies using animal models of inflammatory and neuropathic ocular pain have provided insight about the mechanisms involved in these maladaptive changes. Recently, the advent of new techniques such as optogenetics or genetic neuronal labelling has allowed the investigation of identified circuits involved in nociception, both at the spinal and trigeminal level. In this review, we will describe some of the mechanisms that contribute to the perception of ocular pain at the periphery and at the spinal trigeminal nucleus. Recent advances in the discovery of molecular and cellular mechanisms contributing to peripheral and central pain sensitization of the trigeminal pathways will be also presented.
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Affiliation(s)
- Giulia Puja
- Department of Life Sciences, University of Modena and Reggio Emilia, Emilia-Romagna, Italy
| | - Balazs Sonkodi
- Department of Health Sciences and Sport Medicine, University of Physical Education, Budapest, Hungary
| | - Rita Bardoni
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Emilia-Romagna, Italy
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4
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Koyama R, Iwata K, Hayashi Y, Hitomi S, Shibuta I, Furukawa A, Asano S, Kaneko T, Yonehara Y, Shinoda M. Pannexin 1-Mediated ATP Signaling in the Trigeminal Spinal Subnucleus Caudalis Is Involved in Tongue Cancer Pain. Int J Mol Sci 2021; 22:ijms222111404. [PMID: 34768835 PMCID: PMC8584113 DOI: 10.3390/ijms222111404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/19/2022] Open
Abstract
Pain is one of the most severe concerns in tongue cancer patients. However, the underlying mechanisms of tongue cancer pain are not fully understood. We investigated the molecular mechanisms of tongue cancer-induced mechanical allodynia in the tongue by squamous cell carcinoma (SCC) inoculation in rats. The head-withdrawal threshold of mechanical stimulation (MHWT) to the tongue was reduced following SCC inoculation, which was inhibited by intracisternal administration of 10Panx, an inhibitory peptide for pannexin 1 (PANX1) channels. Immunohistochemical analyses revealed that the expression of PANX1 was upregulated in the trigeminal spinal subnucleus caudalis (Vc) following SCC inoculation. The majority of PANX1 immunofluorescence was merged with ionized calcium-binding adapter molecule 1 (Iba1) fluorescence and a part of it was merged with glial fibrillary acidic protein (GFAP) fluorescence. Spike frequencies of Vc nociceptive neurons to noxious mechanical stimulation were significantly enhanced in SCC-inoculated rats, which was suppressed by intracisternal 10Panx administration. Phosphorylated extracellular signal-regulated kinase (pERK)-immunoreactive (IR) neurons increased significantly in the Vc after SCC inoculation, which was inhibited by intracisternal 10Panx administration. SCC inoculation-induced MHWT reduction and increased pERK-IR Vc neuron numbers were inhibited by P2X7 purinoceptor (P2X7R) antagonism. Conversely, these effects were observed in the presence of P2X7R agonist in SCC-inoculated rats with PANX1 inhibition. SCC inoculation-induced MHWT reduction was significantly recovered by intracisternal interleukin-1 receptor antagonist administration. These observations suggest that SCC inoculation causes PANX1 upregulation in Vc microglia and adenosine triphosphate released through PANX1 sensitizes nociceptive neurons in the Vc, resulting in tongue cancer pain.
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Affiliation(s)
- Ryo Koyama
- Department of Oral and Maxillofacial Surgery II, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (R.K.); (A.F.); (T.K.); (Y.Y.)
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (K.I.); (S.H.); (I.S.); (S.A.); (M.S.)
| | - Yoshinori Hayashi
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (K.I.); (S.H.); (I.S.); (S.A.); (M.S.)
- Correspondence: ; Tel.: +81-3-3219-8122
| | - Suzuro Hitomi
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (K.I.); (S.H.); (I.S.); (S.A.); (M.S.)
| | - Ikuko Shibuta
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (K.I.); (S.H.); (I.S.); (S.A.); (M.S.)
| | - Akihiko Furukawa
- Department of Oral and Maxillofacial Surgery II, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (R.K.); (A.F.); (T.K.); (Y.Y.)
| | - Sayaka Asano
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (K.I.); (S.H.); (I.S.); (S.A.); (M.S.)
| | - Tadayoshi Kaneko
- Department of Oral and Maxillofacial Surgery II, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (R.K.); (A.F.); (T.K.); (Y.Y.)
| | - Yoshiyuki Yonehara
- Department of Oral and Maxillofacial Surgery II, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (R.K.); (A.F.); (T.K.); (Y.Y.)
| | - Masamichi Shinoda
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan; (K.I.); (S.H.); (I.S.); (S.A.); (M.S.)
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5
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Is a neuropathic mechanism involved in the perception of oral dryness? Arch Oral Biol 2021; 130:105213. [PMID: 34339966 DOI: 10.1016/j.archoralbio.2021.105213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 11/20/2022]
Abstract
OBJECTIVES The aim of the present study was to review the existing phenomena which could affect subjective oral dryness and to consider the possibility that neural processing is involved in the perception of oral dryness. DESIGN A comprehensive review of scientific literatures relevant to contributing factors of dry mouth symptoms including salivary parameters related with oral dryness and role of neural mechanisms in perception of dry mouth symptoms was conducted. RESULTS Several previous reports suggested the possibility of neural processing mechanisms in perception of oral dryness. The decreased pain threshold in the oral cavity of rats with dry tongue and complaints of subjective oral dryness in patients with burning mouth syndrome, of which lacked an actual decrease in salivary output and mucosal wetness, could support this idea. Sensory changes in the oral mucosa and oral dryness may have a bi-directional influence that patients with oral dryness would be more subject to neuropathic pain in the oral mucosa, and those with neuropathic pain in the oral cavity could have complaints associated with higher levels of dry mouth symptoms. CONCLUSION A bi-directional influence between sensory change in the oral mucosa and subjective oral dryness could be assumed. We suggest the administration of neuropathic pain medications for controlling subjective oral dryness in patients without objective sign of hyposalivation.
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Liu L, Xu XB, Qu ZY, Zhao LP, Zhang CS, Li ZJ, Lyu TL, Wang XF, Jing XH, Li B. Determining 5HT 7R's Involvement in Modifying the Antihyperalgesic Effects of Electroacupuncture on Rats With Recurrent Migraine. Front Neurosci 2021; 15:668616. [PMID: 34163324 PMCID: PMC8215279 DOI: 10.3389/fnins.2021.668616] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/20/2021] [Indexed: 01/14/2023] Open
Abstract
Electroacupuncture (EA) is widely used in clinical practice to relieve migraine pain. 5-HT7 receptor (5-HT7R) has been reported to play an excitatory role in neuronal systems and regulate hyperalgesic pain and neurogenic inflammation. 5-HT7R could influence phosphorylation of protein kinase A (PKA)- or extracellular signal-regulated kinase1 / 2 (ERK1 / 2)-mediated signaling pathways, which mediate sensitization of nociceptive neurons via interacting with cyclic adenosine monophosphate (cAMP). In this study, we evaluated the role of 5-HT7R in the antihyperalgesic effects of EA and the underlying mechanism through regulation of PKA and ERK1 / 2 in trigeminal ganglion (TG) and trigeminal nucleus caudalis (TNC). Hyperalgesia was induced in rats with dural injection of inflammatory soup (IS) to cause meningeal neurogenic inflammatory pain. Electroacupuncture was applied for 15 min every other day before IS injection. Von Frey filaments, tail-flick, hot-plate, and cold-plated tests were used to evaluate the mechanical and thermal hyperalgesia. Neuronal hyperexcitability in TNC was studied by an electrophysiological technique. The 5-HT7R antagonist (SB269970) or 5-HT7R agonist (AS19) was administered intrathecally before each IS application at 2-day intervals during the 7-day injection protocol. The changes in 5-HT7R and 5-HT7R-associated signaling pathway were examined by real-time polymerase chain reaction (RT-PCR), Western blot, immunofluorescence, and enzyme-linked immunosorbent assay (ELISA) analyses. When compared with IS group, mechanical and thermal pain thresholds of the IS + EA group were significantly increased. Furthermore, EA prevented the enhancement of both spontaneous activity and evoked responses of second-order trigeminovascular neurons in TNC. Remarkable decreases in 5-HT7R mRNA expression and protein levels were detected in the IS + EA group. More importantly, 5-HT7R agonist AS19 impaired the antihyperalgesic effects of EA on p-PKA and p-ERK1 / 2. Injecting 5-HT7R antagonist SB-269970 into the intrathecal space of IS rats mimicked the effects of EA antihyperalgesia and inhibited p-PKA and p-ERK1 / 2. Our findings indicate that 5-HT7R mediates the antihyperalgesic effects of EA on IS-induced migraine pain by regulating PKA and ERK1 / 2 in TG and TNC.
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Affiliation(s)
- Lu Liu
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Xiao-Bai Xu
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Zheng-Yang Qu
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Luo-Peng Zhao
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China.,Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Institute of Traditional Chinese Medicine, Beijing, China
| | - Claire-Shuiqing Zhang
- School of Health and Biomedical Sciences, RMIT University, Melbourne, VIC, Australia
| | - Zhi-Juan Li
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Tian-Li Lyu
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Xue-Fei Wang
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
| | - Xiang-Hong Jing
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Bin Li
- Department of Acupuncture and Moxibustion, Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Key Laboratory of Acupuncture Neuromodulation, Beijing, China
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7
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Tang JS, Chiang CY, Dostrovsky JO, Yao D, Sessle BJ. Responses of neurons in rostral ventromedial medulla to nociceptive stimulation of craniofacial region and tail in rats. Brain Res 2021; 1767:147539. [PMID: 34052258 DOI: 10.1016/j.brainres.2021.147539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/24/2021] [Accepted: 05/24/2021] [Indexed: 02/06/2023]
Abstract
The rostral ventromedial medulla (RVM) plays a key role in the endogenous modulation of nociceptive transmission in the central nervous system (CNS). The primary aim of this study was to examine whether the activities of RVM neurons were related to craniofacial nociceptive behaviour (jaw-motor response, JMR) as well as the tail-flick response (TF). The activities of RVM neurons and TF and JMR evoked by noxious heating of the tail or perioral skin were recorded simultaneously in lightly anaesthetized rats. Tail or perioral heating evoked the TF and JMR, and the latency of the JMR was significantly shorter (P < 0.001) than that of the TF. Of 89 neurons recorded in RVM, 40 were classified as ON-cells, 27 as OFF-cells, and 22 as NEUTRAL-cells based on their responsiveness to heating of the tail. Heating at either site caused an increase in ON-cell and decrease in OFF-cell activity before the occurrence of the TF and JMR, but did not alter the activity of NEUTRAL cells. Likewise, noxious stimulation of the temporomandibular joint had similar effects on RVM neurons. These findings reveal that the JMR is a measure of the excitability of trigeminal and spinal nociceptive circuits in the CNS, and that the JMR as well as TF can be used for studying processes related to descending modulation of pain. The findings also support the view that RVM ON- and OFF-cells play an important role in the elaboration of diverse nociceptive behaviours evoked by noxious stimulation of widely separated regions of the body.
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Affiliation(s)
- Jing-Shi Tang
- Department of Physiology and Pathophysiology, Xi'an Jiaotong University, Medical School, Xi'an, Shaanxi 710061, PR China
| | - Chen Yu Chiang
- Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G 1G6, Canada
| | | | - Dongyuan Yao
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital, and Queen Mary College, Nanchang University, Jiangxi, PR China
| | - Barry J Sessle
- Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G 1G6, Canada.
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8
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Iwata K, Sessle BJ. The Evolution of Neuroscience as a Research Field Relevant to Dentistry. J Dent Res 2020; 98:1407-1417. [PMID: 31746682 DOI: 10.1177/0022034519875724] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The field of neuroscience did not exist as such when the Journal of Dental Research was founded 100 y ago. It has emerged as an important scientific field relevant to dentistry in view of the many neurally based functions manifested in the orofacial area (e.g., pain, taste, chewing, swallowing, salivation). This article reviews many of the novel insights that have been gained through neuroscience research into the neural basis of these functions and their clinical relevance to the diagnosis and management of pain and sensorimotor disorders. These include the neural pathways and brain circuitry underlying each of these functions and the role of nonneural as well as neural processes and their "plasticity" in modulating these functions and allowing for adaptation to tissue injury and pain and for learning or rehabilitation of orofacial functions.
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Affiliation(s)
- K Iwata
- Department of Physiology, Nihon University, School of Dentistry, Tokyo, Japan
| | - B J Sessle
- Faculty of Dentistry and Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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9
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Imamura Y, Okada-Ogawa A, Noma N, Shinozaki T, Watanabe K, Kohashi R, Shinoda M, Wada A, Abe O, Iwata K. A perspective from experimental studies of burning mouth syndrome. J Oral Sci 2020; 62:165-169. [PMID: 32161235 DOI: 10.2334/josnusd.19-0459] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Burning mouth syndrome (BMS) is one of the most frequently seen idiopathic pain conditions in a dental setting. Peri- and postmenopausal women are most frequently affected, and patients who experience BMS complain of persistent burning pain mainly at the tip and the bilateral border of the tongue. Recent studies have assessed whether BMS is a neuropathic pain condition, based on morphologic changes in biopsied tongue specimens, and whether there are abnormal pain responses in patients with this disease. Somatosensory studies have reported some abnormal findings in sensory and pain detection thresholds with inconsistency; however, the most distinct finding was exaggerated responses to painful stimuli. Imaging and electrophysiologic studies have suggested the possibility of dysregulation of the pain-modulating system in the central nervous system, which may explain the enhanced pain responses despite the lack of typical responses toward quantitative sensory tests. Basic studies have suggested the possible involvement of neuroprotective steroids, although the underlying mechanisms of this condition have not been elucidated. Experimental studies are looking for preferable supportive therapies for BMS patients despite the obscure pathogenesis.
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Affiliation(s)
- Yoshiki Imamura
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry.,Division of Clinical Research, Dental Research Institute, Nihon University School of Dentistry
| | - Akiko Okada-Ogawa
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry.,Division of Clinical Research, Dental Research Institute, Nihon University School of Dentistry
| | - Noboru Noma
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry.,Division of Clinical Research, Dental Research Institute, Nihon University School of Dentistry
| | - Takahiro Shinozaki
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry.,Division of Clinical Research, Dental Research Institute, Nihon University School of Dentistry
| | - Kosuke Watanabe
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry
| | - Ryutaro Kohashi
- Department of Dental Radiology, Nihon University School of Dentistry
| | - Masamichi Shinoda
- Department of Physiology, Nihon University School of Dentistry.,Division of Functional Morphology, Dental Research Institute, Nihon University School of Dentistry
| | - Akihiko Wada
- Department of Radiology, Juntendo University Faculty of Medicine
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry.,Division of Functional Morphology, Dental Research Institute, Nihon University School of Dentistry
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Long T, He W, Pan Q, Zhang S, Zhang D, Qin G, Chen L, Zhou J. Microglia P2X4R-BDNF signalling contributes to central sensitization in a recurrent nitroglycerin-induced chronic migraine model. J Headache Pain 2020; 21:4. [PMID: 31937253 PMCID: PMC6961410 DOI: 10.1186/s10194-019-1070-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 12/23/2019] [Indexed: 12/11/2022] Open
Abstract
Background According to our previous study, microglia P2X4 receptors (P2X4Rs) play a pivotal role in the central sensitization of chronic migraine (CM). However, the molecular mechanism that underlies the crosstalk between microglia P2X4Rs and neurons of the trigeminal nucleus caudalis (TNC) is not fully understood. Therefore, the aim of this study is to examine the exact P2X4Rs signalling pathway in the development of central sensitization in a CM animal model. Methods We used an animal model with recurrent intermittent administration of nitroglycerin (NTG), which closely mimics CM. NTG-induced basal mechanical and thermal hypersensitivity were evaluated using a von Frey filament test and an increasing-temperature hot plate apparatus (IITC). We detected P2X4Rs, brain-derived neurotrophic factor (BDNF) and phosphorylated p38 mitogen-activated protein kinase (p-p38-MAPK) expression profiles in the TNC. We investigated the effects of a P2X4R inhibitor (5-BDBD) and an agonist (IVM) on NTG-induced hyperalgesia and neurochemical changes as well as on the expression of p-p38-MAPK and BDNF. We also detected the effects of a tropomyosin-related kinase B (TrkB) inhibitor (ANA-12) on the CM animal model in vivo. Then, we evaluated the effect of 5-BDBD and SB203580 (a p38-MAPK inhibitors) on the release and synthesis of BDNF in BV2 microglia cells treated with 50 μM adenosine triphosphate (ATP). Results Chronic intermittent administration of NTG resulted in chronic mechanical and thermal hyperalgesia, accompanied by the upregulation of P2X4Rs and BDNF expression. 5-BDBD or ANA-12 prevented hyperalgesia induced by NTG, which was associated with a significant inhibition of the NTG-induced increase in phosphorylated extracellular regulated protein kinases (p-ERK) and calcitonin gene related peptide (CGRP) release in the TNC. Repeated administration of IVM produced sustained hyperalgesia and significantly increased the levels of p-ERK and CGRP release in the TNC. Activating P2X4Rs with ATP triggered BDNF release and increased BDNF synthesis in BV2 microglia, and these results were then reduced by 5-BDBD or SB203580. Conclusions Our results indicated that the P2X4R contributes to the central sensitization of CM by releasing BDNF and promoting TNC neuronal hyper-excitability. Blocking microglia P2X4R-BDNF signalling may have an effect on the prevention of migraine chronification.
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Affiliation(s)
- Ting Long
- Department of Neurology, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Wei He
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1st Youyi Road, Yuzhong District, Chongqing, 400016, China
| | - Qi Pan
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1st Youyi Road, Yuzhong District, Chongqing, 400016, China
| | - Shanshan Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1st Youyi Road, Yuzhong District, Chongqing, 400016, China
| | - Dunke Zhang
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Guangcheng Qin
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lixue Chen
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jiying Zhou
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, 1st Youyi Road, Yuzhong District, Chongqing, 400016, China.
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Chen JY, Kubo A, Shinoda M, Okada-Ogawa A, Imamura Y, Iwata K. Involvement of TRPV4 ionotropic channel in tongue mechanical hypersensitivity in dry-tongue rats. J Oral Sci 2020; 62:13-17. [DOI: 10.2334/josnusd.18-0468] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Affiliation(s)
- Jui Yen Chen
- Department of Physiology, Nihon University School of Dentistry
| | - Asako Kubo
- Department of Physiology, Nihon University School of Dentistry
| | | | - Akiko Okada-Ogawa
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry
| | - Yoshiki Imamura
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry
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Imamura Y, Shinozaki T, Okada-Ogawa A, Noma N, Shinoda M, Iwata K, Wada A, Abe O, Wang K, Svensson P. An updated review on pathophysiology and management of burning mouth syndrome with endocrinological, psychological and neuropathic perspectives. J Oral Rehabil 2019; 46:574-587. [PMID: 30892737 DOI: 10.1111/joor.12795] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/19/2019] [Accepted: 03/12/2019] [Indexed: 12/17/2022]
Abstract
Burning mouth syndrome (BMS) is a chronic oro-facial pain disorder of unknown cause. It is more common in peri- and post-menopausal women, and sex hormone dysregulation is believed to be an important causative factor. Psychosocial events often trigger or exacerbate symptoms, and persons with BMS appear to be predisposed towards anxiety and depression. Atrophy of small nerve fibres in the tongue epithelium has been reported, and potential neuropathic mechanisms for BMS are now widely investigated. Historically, BMS was thought to comprise endocrinological, psychosocial and neuropathic components. Neuroprotective steroids and glial cell line-derived neurotrophic factor family ligands may have pivotal roles in the peripheral mechanisms associated with atrophy of small nerve fibres. Denervation of chorda tympani nerve fibres that innervate fungiform buds leads to alternative trigeminal innervation, which results in dysgeusia and burning pain when eating hot foods. With regard to the central mechanism of BMS, depletion of neuroprotective steroids alters the brain network-related mood and pain modulation. Peripheral mechanistic studies support the use of topical clonazepam and capsaicin for the management of BMS, and some evidence supports the use of cognitive behavioural therapy. Hormone replacement therapy may address the causes of BMS, although adverse effects prevent its use as a first-line treatment. Selective serotonin reuptake inhibitors (SSRIs) and serotonin and noradrenaline reuptake inhibitors (SNRIs) may have important benefits, and well-designed controlled studies are expected. Other treatment options to be investigated include brain stimulation and TSPO (translocator protein 18 kDa) ligands.
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Affiliation(s)
- Yoshiki Imamura
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Takahiro Shinozaki
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Akiko Okada-Ogawa
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Noboru Noma
- Department of Oral Diagnostic Sciences, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.,Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan
| | - Masahiro Shinoda
- Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan.,Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Koichi Iwata
- Nihon University School of Dentistry Dental Research Center, Chiyoda-ku, Tokyo, Japan.,Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | - Akihiko Wada
- Department of Radiology, Faculty of Medicine, Juntendo University, Bunkyo-ku, Tokyo, Japan
| | - Osamu Abe
- Department of Radiology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Kelun Wang
- Department of Health Science and Technology, Center for Sensory-Motor Interaction, Aalborg University, Aalborg, Denmark
| | - Peter Svensson
- Department of Dentistry and Oral Health, Section for Orofacial Pain and Jaw Function, Aarhus University, Aarhus, Denmark
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Nav1.7 via Promotion of ERK in the Trigeminal Ganglion Plays an Important Role in the Induction of Pulpitis Inflammatory Pain. BIOMED RESEARCH INTERNATIONAL 2019; 2019:6973932. [PMID: 31032358 PMCID: PMC6458889 DOI: 10.1155/2019/6973932] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 02/17/2019] [Indexed: 12/19/2022]
Abstract
The trigeminal ganglion (TG) refers to sensory neurons bodies that innervate the spinal cord and peripheral axons that innervate teeth. The tetrodotoxin-sensitive sodium (NA) channels (Nav1.7) play important roles in the pathophysiology of pain. In this study, we investigated the TG expression of Nav1.7 and extracellular signal-regulated kinase (ERK) in a rat model of pulpitis to explore the correlation between these channels and inflammatory pain. Pulpitis was confirmed by hematoxylin-eosin staining. In this study, we demonstrated that the reflex of rats to mechanical stimulation increases after pulp exposure and that the exposed rat molar pulp can upregulate the expression of Nav1.7 and ERK in the rat TG. Three days after rat pulp exposure, the expression levels of the two ion channels in the TG increased. TG target injection of PF04856264, a Nav1.7 inhibitor, dose-dependently increased the mechanical pain threshold and was able to inhibit ERK expression. TG target injection of PD98059, an ERK inhibitor, dose-dependently increased the mechanical pain threshold. These factors simultaneously resulted in the highest production. In this study, with the established link to inflammatory pain, we found that Nav1.7 and ERK both play important roles in the induction of inflammatory pain caused by pulpitis. We also found a correlation between the expression levels of Nav1.7 and ERK and the degree of inflammatory pain. Furthermore, ERK signaling pathways were promoted by the Nav1.7 in TG after pulpitis.
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