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Sessle BJ. Modulatory Processes in Craniofacial Pain States. ADVANCES IN NEUROBIOLOGY 2024; 35:107-124. [PMID: 38874720 DOI: 10.1007/978-3-031-45493-6_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
Pain is a common symptom associated with many disorders affecting the craniofacial tissues that include the teeth and their supporting structures, the jaw, face and tongue muscles, and the temporomandibular joint. Most acute craniofacial pain states are easily recognized and readily treated, but chronic craniofacial pain states (e.g., temporomandibular disorders [TMD], trigeminal neuropathies, and some headaches) may be especially challenging to manage successfully. This chapter provides an overview of the processes that underlie craniofacial pain, with a focus on the pain-modulatory mechanisms operating in craniofacial tissues and in the central nervous system (CNS), including the role of endogenous chemical processes such as those involving opioids. The chapter outlines in particular findings from preclinical studies that have provided substantial information about the neural as well as nonneural (e.g., glial) processes involved in the initiation, transmission, and modulation of nociceptive signals in the trigeminal system, and also draws attention to their clinical correlates. The increased understanding gained from these preclinical studies of how nociceptive signals can be modulated will contribute to improvements in presently available therapeutic approaches to manage craniofacial pain as well as to the development of novel analgesic approaches.
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Affiliation(s)
- Barry J Sessle
- Department of Oral Physiology Faculty of Dentistry, Department of Physiology Faculty of Medicine, Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada.
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Sadighparvar S, Al-Hamed FS, Sharif-Naeini R, Meloto CB. Preclinical orofacial pain assays and measures and chronic primary orofacial pain research: where we are and where we need to go. FRONTIERS IN PAIN RESEARCH 2023; 4:1150749. [PMID: 37293433 PMCID: PMC10244561 DOI: 10.3389/fpain.2023.1150749] [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: 01/24/2023] [Accepted: 04/11/2023] [Indexed: 06/10/2023] Open
Abstract
Chronic primary orofacial pain (OFP) conditions such as painful temporomandibular disorders (pTMDs; i.e., myofascial pain and arthralgia), idiopathic trigeminal neuralgia (TN), and burning mouth syndrome (BMS) are seemingly idiopathic, but evidence support complex and multifactorial etiology and pathophysiology. Important fragments of this complex array of factors have been identified over the years largely with the help of preclinical studies. However, findings have yet to translate into better pain care for chronic OFP patients. The need to develop preclinical assays that better simulate the etiology, pathophysiology, and clinical symptoms of OFP patients and to assess OFP measures consistent with their clinical symptoms is a challenge that needs to be overcome to support this translation process. In this review, we describe rodent assays and OFP pain measures that can be used in support of chronic primary OFP research, in specific pTMDs, TN, and BMS. We discuss their suitability and limitations considering the current knowledge of the etiology and pathophysiology of these conditions and suggest possible future directions. Our goal is to foster the development of innovative animal models with greater translatability and potential to lead to better care for patients living with chronic primary OFP.
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Affiliation(s)
- Shirin Sadighparvar
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | | | - Reza Sharif-Naeini
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Department of Physiology and Cell Information Systems, McGill University, Montreal, QC, Canada
| | - Carolina Beraldo Meloto
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
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Chung MK, Wang S, Alshanqiti I, Hu J, Ro JY. The degeneration-pain relationship in the temporomandibular joint: Current understandings and rodent models. FRONTIERS IN PAIN RESEARCH 2023; 4:1038808. [PMID: 36846071 PMCID: PMC9947567 DOI: 10.3389/fpain.2023.1038808] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 01/18/2023] [Indexed: 02/11/2023] Open
Abstract
Temporomandibular disorders (TMD) represent a group of musculoskeletal conditions involving the temporomandibular joints (TMJ), the masticatory muscles and associated structures. Painful TMD are highly prevalent and conditions afflict 4% of US adults annually. TMD include heterogenous musculoskeletal pain conditions, such as myalgia, arthralgia, and myofascial pain. A subpopulations of TMD patients show structural changes in TMJ, including disc displacement or degenerative joint diseases (DJD). DJD is a slowly progressing, degenerative disease of the TMJ characterized by cartilage degradation and subchondral bone remodeling. Patients with DJD often develop pain (TMJ osteoarthritis; TMJ OA), but do not always have pain (TMJ osteoarthrosis). Therefore, pain symptoms are not always associated with altered TMJ structures, which suggests that a causal relationship between TMJ degeneration and pain is unclear. Multiple animal models have been developed for determining altered joint structure and pain phenotypes in response to various TMJ injuries. Rodent models of TMJOA and pain include injections to induce inflammation or cartilage destruction, sustained opening of the oral cavity, surgical resection of the articular disc, transgenic approaches to knockout or overexpress key genes, and an integrative approach with superimposed emotional stress or comorbidities. In rodents, TMJ pain and degeneration occur during partially overlapping time periods in these models, which suggests that common biological factors may mediate TMJ pain and degeneration over different time courses. While substances such as intra-articular pro-inflammatory cytokines commonly cause pain and joint degeneration, it remains unclear whether pain or nociceptive activities are causally associated with structural degeneration of TMJ and whether structural degeneration of TMJ is necessary for producing persistent pain. A thorough understanding of the determining factors of pain-structure relationships of TMJ during the onset, progression, and chronification by adopting novel approaches and models should improve the ability to simultaneously treat TMJ pain and TMJ degeneration.
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Affiliation(s)
- Man-Kyo Chung
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, University of Maryland Baltimore, Baltimore, MD, United States
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Liu J, Jia S, Huang F, He H, Fan W. Peripheral role of glutamate in orofacial pain. Front Neurosci 2022; 16:929136. [PMID: 36440288 PMCID: PMC9682037 DOI: 10.3389/fnins.2022.929136] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 10/10/2022] [Indexed: 09/10/2023] Open
Abstract
Glutamate is the principal excitatory neurotransmitter in the central nervous system. In the periphery, glutamate acts as a transmitter and involves in the signaling and processing of sensory input. Glutamate acts at several types of receptors and also interacts with other transmitters/mediators under various physiological and pathophysiological conditions including chronic pain. The increasing amount of evidence suggests that glutamate may play a role through multiple mechanisms in orofacial pain processing. In this study, we reviewed the current understanding of how peripheral glutamate mediates orofacial pain, how glutamate is regulated in the periphery, and how these findings are translated into therapies for pain conditions.
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Affiliation(s)
- Jinyue Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Shilin Jia
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Fang Huang
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Hongwen He
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Wenguo Fan
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
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Lei F, Yan Z. Antinociceptive and Anti-inflammatory Effect of Corynoline in Different Nociceptive and Inflammatory Experimental Models. Appl Biochem Biotechnol 2022; 194:4783-4799. [PMID: 35247154 DOI: 10.1007/s12010-022-03843-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/28/2022] [Indexed: 11/30/2022]
Abstract
Pain is growing to be a massive health issue across the globe. It is reported that one in every five adults tends to suffer from pain worldwide each year, regardless of age and gender. Inflammation caused by tissue damage, chemical stimulus, and foreign substances is commonly associated with pain. Inflammatory pain is mainly caused by the direct effect of inflammatory mediators on particular classes of nociceptive neurons. In the current investigation, the antinociceptive and anti-inflammatory effect of corynoline, a phytochemical compound isolated from Corydalis bungeana Turcz., has been evaluated in experimental mice. The experimental mice were divided into 5 groups of 6 animals each. The first control group was fed with water. The second, third, and fourth groups received different doses of corynoline and the fifth group of mice received positive controls. Nociception was induced with the help of acetic acid, formalin, glutamate, capsaicin, hot plate, and tail immersion in mice whereas carrageenan was used to induce inflammation. The peritoneal cavity leukocyte infiltration and pro-inflammatory mediator generation were also analyzed to confirm the anti-inflammatory effect and the natural locomotor activity was determined using an open field test. Corynoline treatment significantly suppressed the paw licking, writhing in the abdominal region, and displayed high nociceptive inhibitory reaction in a dose-related manner. Additionally, corynoline significantly reduced the carrageenan-triggered paw edema and also reduced the levels of pro-inflammatory cytokines. Thus, the antinociceptive and anti-inflammatory activity of corynoline has been successfully established.
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Affiliation(s)
- Feng Lei
- Department of Anesthesiology, Beijing Jishuitan Hospital, Beijing, 100035, China
| | - Zhou Yan
- Department of Anesthesiology, Beijing Jishuitan Hospital, Beijing, 100035, China.
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Guerrero-Toro C, Koroleva K, Ermakova E, Gafurov O, Abushik P, Tavi P, Sitdikova G, Giniatullin R. Testing the Role of Glutamate NMDA Receptors in Peripheral Trigeminal Nociception Implicated in Migraine Pain. Int J Mol Sci 2022; 23:ijms23031529. [PMID: 35163452 PMCID: PMC8835926 DOI: 10.3390/ijms23031529] [Citation(s) in RCA: 2] [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: 12/21/2021] [Revised: 01/20/2022] [Accepted: 01/26/2022] [Indexed: 01/18/2023] Open
Abstract
The pro-nociceptive role of glutamate in the CNS in migraine pathophysiology is well established. Glutamate, released from trigeminal afferents, activates second order nociceptive neurons in the brainstem. However, the function of peripheral glutamate receptors in the trigeminovascular system suggested as the origin site for migraine pain, is less known. In the current project, we used calcium imaging and patch clamp recordings from trigeminal ganglion (TG) neurons, immunolabelling, CGRP assay and direct electrophysiological recordings from rat meningeal afferents to investigate the role of glutamate in trigeminal nociception. Glutamate, aspartate, and, to a lesser extent, NMDA under free-magnesium conditions, evoked calcium transients in a fraction of isolated TG neurons, indicating functional expression of NMDA receptors. The fraction of NMDA sensitive neurons was increased by the migraine mediator CGRP. NMDA also activated slowly desensitizing currents in 37% of TG neurons. However, neither glutamate nor NMDA changed the level of extracellular CGRP. TG neurons expressed both GluN2A and GluN2B subunits of NMDA receptors. In addition, after removal of magnesium, NMDA activated persistent spiking activity in a fraction of trigeminal nerve fibers in meninges. Thus, glutamate activates NMDA receptors in somas of TG neurons and their meningeal nerve terminals in magnesium-dependent manner. These findings suggest that peripherally released glutamate can promote excitation of meningeal afferents implicated in generation of migraine pain in conditions of inherited or acquired reduced magnesium blockage of NMDA channels and support the usage of magnesium supplements in migraine.
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Affiliation(s)
- Cindy Guerrero-Toro
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
| | - Kseniia Koroleva
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
| | - Elizaveta Ermakova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
| | - Oleg Gafurov
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
| | - Polina Abushik
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
- Laboratory of Comparative Neurophysiology, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223 Saint Petersburg, Russia
| | - Pasi Tavi
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
| | - Guzel Sitdikova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
- Correspondence: (G.S.); (R.G.); Tel.: +7-9033061092 (G.S.); +358-403553665 (R.G.)
| | - Rashid Giniatullin
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
- Correspondence: (G.S.); (R.G.); Tel.: +7-9033061092 (G.S.); +358-403553665 (R.G.)
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Xing B, Feng N, Zhang J, Li Y, Hou X, Wu H, Liu W, Han G. Pinocembrin relieves hip fracture-induced pain by repressing spinal substance P signaling in aged rats. J Neurophysiol 2022; 127:397-404. [PMID: 34986062 DOI: 10.1152/jn.00517.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Whether pinocembrin (PCN) could be utilized to alleviate hip fracture-induced pain is investigated in this research. Aged rats with hip fractures were treated with vehicle or 80 mg/kg/day PCN from week 3 to week 4. Then hind paw mechanical allodynia, unweighting, warmth, and thickness were measured. The microglia and astrocytes activation and proliferation markers in the spinal dorsal horn were detected with real-time PCR and immunofluorescence staining. The relative expression of substance P and its receptor, tachykinin receptor 1 (Tacr1), were detected with enzyme-linked immunosorbent assay (ELISA) and Western blots. The antinociceptive effect of Tacr1 inhibitor LY303870 was also testified. PCN alleviated hip fracture-induced hind paw nociceptive (allodynia and unweighting) and vascular changes (warmth and thickness) in aged rats with diminished microglia and astrocytes activation and proliferation in the spinal dorsal horn. Up-regulated substance P and Tacr1 were induced after hip fracture, which could be reversed by PCN treatment. Furthermore, LY303870 treatment partially reversed both spinal nociceptive sensitization and vascular changes after hip fracture. Substance P signaling contributes to the nociceptive and vascular changes observed in the hip fracture, which could be alleviated by PCN.
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Affiliation(s)
- Baorui Xing
- Department of Traumatology and Orthopedics, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
| | - Nana Feng
- Science and Education Department, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
| | - Juan Zhang
- Department of Western Pharmaceutical Sciences, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
| | - Yunmei Li
- Department of Traumatology and Orthopedics, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
| | - Xiuxiu Hou
- Department of Traumatology and Orthopedics, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
| | - Hao Wu
- Department of Traumatology and Orthopedics, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
| | - Wendong Liu
- Department of Traumatology and Orthopedics, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
| | - Guangpu Han
- Department of Traumatology and Orthopedics, Cangzhou Hospital of integrated traditional Chinese medicine and Western medicine, Cangzhou, China
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Chung MK, Ro JY. Peripheral glutamate receptor and transient receptor potential channel mechanisms of craniofacial muscle pain. Mol Pain 2021; 16:1744806920914204. [PMID: 32189565 PMCID: PMC7153498 DOI: 10.1177/1744806920914204] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Temporomandibular joint disorder is a common chronic craniofacial pain condition,
often involving persistent, widespread craniofacial muscle pain. Although the
etiology of chronic muscle pain is not well known, sufficient clinical and
preclinical information supports a contribution of trigeminal nociceptors to
craniofacial muscle pain processing under various experimental and pathological
conditions. Here, we review cellular and molecular mechanisms underlying
sensitization of muscle nociceptive afferents. In particular, we summarize
findings on pronociceptive roles of peripheral glutamate in humans, and we
discuss mechanistic contributions of glutamate receptors, including
N-methyl-D-aspartate receptors and metabotropic glutamate receptors, which have
considerably increased our understanding of peripheral mechanisms of
craniofacial muscle pain. Several members of the transient receptor potential
(TRP) family, such as transient receptor potential vanilloid 1 (TRPV1) and
transient receptor potential ankyrin 1, also play essential roles in the
development of spontaneous pain and mechanical hypersensitivity in craniofacial
muscles. Furthermore, glutamate receptors and TRP channels functionally and
bi-directionally interact to modulate trigeminal nociceptors. Activation of
glutamate receptors invokes protein kinase C, which leads to the phosphorylation
of TRPV1. Sensitization of TRPV1 by inflammatory mediators and glutamate
receptors in combination with endogenous ligands contributes to masseter
hyperalgesia. The distinct intracellular signaling pathways through which both
receptor systems engage and specific molecular regions of TRPV1 are offered as
novel targets for the development of mechanism-based treatment strategies for
myogenous craniofacial pain conditions.
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Affiliation(s)
- Man-Kyo Chung
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, The University of Maryland, Baltimore, MD, USA
| | - Jin Y Ro
- Department of Neural and Pain Sciences, School of Dentistry, Program in Neuroscience, Center to Advance Chronic Pain Research, The University of Maryland, Baltimore, MD, USA
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Parvalbumin-, substance P- and calcitonin gene-related peptide-immunopositive axons in the human dental pulp differ in their distribution of varicosities. Sci Rep 2020; 10:10672. [PMID: 32606338 PMCID: PMC7327034 DOI: 10.1038/s41598-020-67804-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022] Open
Abstract
Information on the frequency and spatial distribution of axonal varicosities associated with release of neurotransmitters in the dental pulp is important to help elucidate the peripheral mechanisms of dental pain, mediated by myelinated versus unmyelinated fibers. For this, we investigated the distribution of axonal varicosities in the human dental pulp using light- and electron-microscopic immunohistochemistry for the vesicular glutamate transporter 2 (VGLUT2), which is involved in the glutamatergic transmission, and syntaxin-1 and synaptosomal nerve-associated protein 25 (SNAP-25), combined with parvalbumin (PV), which is expressed mostly in myelinated axons, and substance P (SP) and calcitonin gene-related peptide (CGRP), which are expressed mostly in unmyelinated axons. We found that the varicosities of the SP- and CGRP-immunopositive (+) axons were uniformly distributed throughout the dental pulp, whereas those of PV+ axons were only dense in the peripheral pulp, and that the expression of PV, VGLUT2, syntaxin-1, SNAP-25, SP and CGRP was significantly higher in the varicosities than in the axonal segments between them. These findings are consistent with the release of glutamate and neuropeptides by axonal varicosities of SP+ and CGRP+ unmyelinated fibers, involved in pulpal pain throughout the human dental pulp, and by varicosities of PV+ fibers, arising from parent myelinated fibers, and involved in dentin sensitivity primarily in the peripheral pulp.
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Gazerani P, Cairns BE. Activation of rat masticatory muscle afferent fibres by acidic pH. Somatosens Mot Res 2018; 35:86-94. [PMID: 29848210 DOI: 10.1080/08990220.2018.1473246] [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: 10/14/2022]
Abstract
Previous research findings have suggested an important role for acid sensing ion channels (ASICs) in muscle pain mechanisms. This study was conducted to determine if masticatory muscle afferent fibres express ASICs, if there are sex differences in this expression, and to compare the effects of low pH and hypertonic saline on afferent fibres that innervate the masticatory muscle in vivo. Immunohistochemistry methods were applied to examine the expression of ASICs in trigeminal ganglion neurons, while in vivo electrophysiology techniques were employed to examine changes in masticatory muscle afferent fibre excitability. Both ASIC1 and ASIC3 were expressed by predominantly larger masticatory muscle ganglion neurons, but the frequency of ASIC3 expression (56%) was significantly greater than ASIC1 (35%). No sex-related differences in expression were identified. Injection of pH 5.8, but not pH 6.8, phosphate buffered saline evoked afferent discharges that were significantly greater than those evoked by pH 7.4 buffer (control). Since ASIC3 channels are not activated until the pH is around 6, these results indicate that activation of both channels contributes to excitation of masticatory muscle afferent fibres. The results further show that many masticatory muscle afferent fibres, which respond to low pH, are low threshold mechanoreceptors. These findings may explain why injection of low pH solutions into the masticatory muscles of healthy humans is not associated with significant muscle pain.
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Affiliation(s)
- Parisa Gazerani
- a Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg East , Denmark
| | - Brian Edwin Cairns
- a Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg East , Denmark.,b Faculty of Pharmaceutical Sciences , The University of British Columbia , Vancouver , Canada
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Araya EI, Nones CFM, Ferreira LEN, Kopruszinski CM, Cunha JMD, Chichorro JG. Role of peripheral and central TRPV1 receptors in facial heat hyperalgesia in streptozotocin-induced diabetic rats. Brain Res 2017; 1670:146-155. [PMID: 28606782 DOI: 10.1016/j.brainres.2017.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/10/2017] [Accepted: 06/03/2017] [Indexed: 01/08/2023]
Abstract
There is increasing evidence that diabetes may be related to sensory changes in the trigeminal system. Long lasting facial heat hyperalgesia has been described in diabetic rats, but the mechanisms remain to be elucidated. Herein, the contribution of peripheral and central TRPV1 receptors to facial heat hyperalgesia in diabeticrats was investigated. Diabetes was induced in male Wistar rats by streptozotocin (60mg/kg, i.p) and facial heat hyperalgesia was assessed once a week up to four weeks. The role of TRPV1 receptors in the heat hyperalgesia in diabetic rats was evaluated through: 1) the ablation of TRPV1 receptors by resiniferatoxin (RTX) treatment and 2) injection of the TRPV1 antagonist, capsazepine, into the upper lip, trigeminal ganglion or medullary subarachnoid space, at doses that completed prevented the heat hyperalgesia induced by capsaicin in naïve rats. Western blot was used to estimate the changes in TRPV1 expression in diabetic rats. Diabetic rats exhibited facial heat hyperalgesia from the first up to the fourth week after streptozotocin injection, which was prevented by insulin treatment. Ablation of TRPV1-expressing fibers prevented facial hyperalgesia in diabetic rats. Capsazepine injection in all sites resulted in significant reduction of facial heat hyperalgesia in diabetic rats. Diabetic rats exhibited a significant decrease in TRPV1 expression in the trigeminal nerve, increased expression in the trigeminal ganglion and no changes in subnucleus caudalis when compared to normoglycemic ones. In conclusion, our results suggest that facial heat hyperalgesia in diabetic rats is maintained by peripheral and central TRPV1 receptors activation.
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Affiliation(s)
- Erika Ivanna Araya
- Department of Pharmacology, Federal University of Parana, Curitiba, Parana, Brazil
| | | | - Luiz Eduardo Nunes Ferreira
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP - Piracicaba, São Paulo, Brazil
| | | | - Joice Maria da Cunha
- Department of Pharmacology, Federal University of Parana, Curitiba, Parana, Brazil
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Grondin F, Hall T, von Piekartz H. Does altered mandibular position and dental occlusion influence upper cervical movement: A cross-sectional study in asymptomatic people. Musculoskelet Sci Pract 2017; 27:85-90. [PMID: 27847242 DOI: 10.1016/j.math.2016.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 05/25/2016] [Accepted: 06/07/2016] [Indexed: 12/23/2022]
Abstract
OBJECTIVE Gross mandibular position and masticatory muscle activity have been shown to influence cervical muscles electromyographic activity. The purpose of this study was to investigate the influence of three different mandible positions including conscious occlusion, tongue tip against the anterior hard palate (Palate tongue position) and natural resting position (Rest), on sagittal plane cervical spine range of motion (ROM) as well as the flexion-rotation test (FRT) in asymptomatic subjects. MATERIALS AND METHODS An experienced single blinded examiner evaluated ROM using an Iphone in 22 subjects (7 females; mean age of 29.91years, SD 5.44). RESULTS Intra-rater reliability for range recorded was good for the FRT with ICC (intraclass correlation) 0.95 (95% CI: 0.88-0.98) and good for sagittal plane cervical ROM with ICC 0.90 (95% CI: 0.77-0.96). A repeated measures ANOVA determined that mean ROM recorded during the FRT differed significantly between assessment points (F(1.99, 41.83) = 19.88, P < 0.001). Bonferroni Post hoc tests revealed that both conscious Occlusion and Palate tongue position elicited a significant large reduction in ROM recorded during the FRT from baseline (p < 0.01). Despite this, one activation strategy did not influence ROM more than the other. An additional repeated measures ANOVA determined that mean sagittal cervical ROM did not significantly vary between assessment points (F(2, 42) = 8.18, P = 0.08). CONCLUSION This current study provided further evidence for the influence of the temporomandibular region on upper cervical ROM. Results suggest that clinicians should focus on the natural mandible rest position when evaluating upper cervical mobility.
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Affiliation(s)
- Francis Grondin
- Laboratory of Anatomy, Bordeaux University Hospital, Hôpital Pellegrin, Place Amélie-Raba-Léon, 33076, Bordeaux, France.
| | - Toby Hall
- School of Physiotherapy and Exercise Science, Curtin University, P.O. Box U1987, Perth, WA, 6845, Australia.
| | - Harry von Piekartz
- University of Applied Science, Department of Rehabilitation, Osnabrück, Germany.
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Grondin F, Hall T. Changes in cervical movement impairment and pain following orofacial treatment in patients with chronic arthralgic temporomandibular disorder with pain: A prospective case series. Physiother Theory Pract 2016; 33:52-61. [PMID: 27911133 DOI: 10.1080/09593985.2016.1247934] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The purpose of this study was to investigate the influence of isolated temporomandibular joint (TMJ) manual therapy on pain and range of motion (ROM) of the TMJ and cervical spine including flexion-rotation test (FRT) in people suffering chronic pain arising from chronic arthralgic temporomandibular disorder (TMD). An experienced clinician managed a case series of 12 patients with TMD (mean duration 28.6 months +/- 26.9). The intervention comprised four-weekly sessions of transverse medial accessory TMJ mobilization and advice. Patients were examined prior to and one-week following the intervention period. Outcome measures included jaw disability (JFLS-20), jaw pain measured by Visual Analogue Scale (VAS), maximal mouth opening ROM, cervical ROM including FRT, and pain during cervical movement. A paired t-test revealed significant improvement following the intervention in disability (p < 0.001), VAS pain score at rest (p < 0.001) and at maximum mouth opening (p < 0.001), jaw opening ROM (p < 0.001), FRT ROM to the left (p = 0.024) and right (p = 0.001). In contrast, no significant change was identified for total cervical ROM (p = 0.905). After the intervention, five patients (41.66%) had no pain at rest or at maximal mouth opening, and all had a negative FRT. The effect sizes indicate a moderate to strong, clinically significant effect for all variables apart from total cervical ROM. While a case series cannot identify a cause and effect relationship, these results provide preliminary evidence for the influence of TMJ manual therapy on measures of TMD including pain, as well as upper but not whole cervical movement and associated pain in patients with a diagnosis of TMJ arthralgia.
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Affiliation(s)
- Francis Grondin
- a Laboratory of Anatomy , Bordeaux University , Bordeaux Cedex, France
| | - Toby Hall
- b School of Physiotherapy and Exercise Science , Curtin University of Technology , Perth , WA , Australia
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14
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Veres G, Fejes-Szabó A, Zádori D, Nagy-Grócz G, László AM, Bajtai A, Mándity I, Szentirmai M, Bohár Z, Laborc K, Szatmári I, Fülöp F, Vécsei L, Párdutz Á. A comparative assessment of two kynurenic acid analogs in the formalin model of trigeminal activation: a behavioral, immunohistochemical and pharmacokinetic study. J Neural Transm (Vienna) 2016; 124:99-112. [PMID: 27629500 DOI: 10.1007/s00702-016-1615-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 08/31/2016] [Indexed: 12/20/2022]
Abstract
Kynurenic acid (KYNA) has well-established protective properties against glutamatergic neurotransmission, which plays an essential role in the activation and sensitization process during some primary headache disorders. The goal of this study was to compare the effects of two KYNA analogs, N-(2-N,N-dimethylaminoethyl)-4-oxo-1H-quinoline-2-carboxamide hydrochloride (KA-1) and N-(2-N-pyrrolidinylethyl)-4-oxo-1H-quinoline-2-carboxamide hydrochloride (KA-2), in the orofacial formalin test of trigeminal pain. Following pretreatment with KA-1 or KA-2, rats were injected with subcutaneous formalin solution in the right whisker pad. Thereafter, the rubbing activity and c-Fos immunoreactivity changes in the spinal trigeminal nucleus pars caudalis (TNC) were investigated. To obtain pharmacokinetic data, KA-1, KA-2 and KYNA concentrations were measured following KA-1 or KA-2 injection. Behavioral tests demonstrated that KA-2 induced larger amelioration of formalin-evoked alterations as compared with KA-1 and the assessment of c-Fos immunoreactivity in the TNC yielded similar results. Although KA-1 treatment resulted in approximately four times larger area under the curve values in the serum relative to KA-2, the latter resulted in a higher KYNA elevation than in the case of KA-1. With regard to TNC, the concentration of KA-1 was under the limit of detection, while that of KA-2 was quite small and there was no major difference in the approximately tenfold KYNA elevations. These findings indicate that the differences between the beneficial effects of KA-1 and KA-2 may be explained by the markedly higher peripheral KYNA levels following KA-2 pretreatment. Targeting the peripheral component of trigeminal pain processing would provide an option for drug design which might prove beneficial in headache conditions.
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Affiliation(s)
- Gábor Veres
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary.,MTA-SZTE Neuroscience Research Group, Szeged, Hungary
| | - Annamária Fejes-Szabó
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
| | - Dénes Zádori
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
| | - Gábor Nagy-Grócz
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary.,Faculty of Health Sciences and Social Studies, University of Szeged, Szeged, Hungary
| | - Anna M László
- Department of Biometrics and Agricultural Informatics, Faculty of Horticultural Science, Szent Istvan University, Budapest, Hungary
| | - Attila Bajtai
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
| | - István Mándity
- Institute of Pharmaceutical Chemistry, University of Szeged, Szeged, Hungary
| | - Márton Szentirmai
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
| | - Zsuzsanna Bohár
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary.,MTA-SZTE Neuroscience Research Group, Szeged, Hungary
| | - Klaudia Laborc
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
| | - István Szatmári
- Institute of Pharmaceutical Chemistry, University of Szeged, Szeged, Hungary
| | - Ferenc Fülöp
- Institute of Pharmaceutical Chemistry, University of Szeged, Szeged, Hungary
| | - László Vécsei
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary. .,MTA-SZTE Neuroscience Research Group, Szeged, Hungary.
| | - Árpád Párdutz
- Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Clinical Center, University of Szeged, Semmelweis u. 6, 6725, Szeged, Hungary
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15
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Kim YS, Kim TH, McKemy DD, Bae YC. Expression of vesicular glutamate transporters in transient receptor potential melastatin 8 (TRPM8)-positive dental afferents in the mouse. Neuroscience 2015; 303:378-88. [PMID: 26166724 DOI: 10.1016/j.neuroscience.2015.07.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/01/2015] [Accepted: 07/02/2015] [Indexed: 01/31/2023]
Abstract
Transient receptor potential melastatin 8 (TRPM8) is activated by innocuous cool and noxious cold and plays a crucial role in cold-induced acute pain and pain hypersensitivity. To help understand the mechanism of TRPM8-mediated cold perception under normal and pathologic conditions, we used light microscopic immunohistochemistry and Western blot analysis in mice expressing a genetically encoded axonal tracer in TRPM8-positive (+) neurons. We investigated the coexpression of TRPM8 and vesicular glutamate transporter 1 (VGLUT1) and VGLUT2 in the trigeminal ganglion (TG) and the dental pulp before and after inducing pulpal inflammation. Many TRPM8+ neurons in the TG and axons in the dental pulp expressed VGLUT2, while none expressed VGLUT1. TRPM8+ axons were dense in the pulp horn and peripheral pulp and also frequently observed in the dentinal tubules. Following pulpal inflammation, the proportion of VGLUT2+ and of VGLUT2+/TRPM8+ neurons increased significantly, whereas that of TRPM8+ neurons remained unchanged. Our findings suggest the existence of VGLUT2 (but not VGLUT1)-mediated glutamate signaling in TRPM8+ neurons possibly underlying the cold-induced acute pain and hypersensitivity to cold following pulpal inflammation.
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Affiliation(s)
- Y S Kim
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, South Korea
| | - T H Kim
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, South Korea
| | - D D McKemy
- Neurobiology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Y C Bae
- Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu 700-412, South Korea.
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16
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Hulse RP, Beazley-Long N, Hua J, Kennedy H, Prager J, Bevan H, Qiu Y, Fernandes ES, Gammons MV, Ballmer-Hofer K, Gittenberger de Groot AC, Churchill AJ, Harper SJ, Brain SD, Bates DO, Donaldson LF. Regulation of alternative VEGF-A mRNA splicing is a therapeutic target for analgesia. Neurobiol Dis 2014; 71:245-59. [PMID: 25151644 PMCID: PMC4194316 DOI: 10.1016/j.nbd.2014.08.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 07/29/2014] [Accepted: 08/06/2014] [Indexed: 12/02/2022] Open
Abstract
Vascular endothelial growth factor-A (VEGF-A) is best known as a key regulator of the formation of new blood vessels. Neutralization of VEGF-A with anti-VEGF therapy e.g. bevacizumab, can be painful, and this is hypothesized to result from a loss of VEGF-A-mediated neuroprotection. The multiple vegf-a gene products consist of two alternatively spliced families, typified by VEGF-A165a and VEGF-A165b (both contain 165 amino acids), both of which are neuroprotective. Under pathological conditions, such as in inflammation and cancer, the pro-angiogenic VEGF-A165a is upregulated and predominates over the VEGF-A165b isoform. We show here that in rats and mice VEGF-A165a and VEGF-A165b have opposing effects on pain, and that blocking the proximal splicing event – leading to the preferential expression of VEGF-A165b over VEGF165a – prevents pain in vivo. VEGF-A165a sensitizes peripheral nociceptive neurons through actions on VEGFR2 and a TRPV1-dependent mechanism, thus enhancing nociceptive signaling. VEGF-A165b blocks the effect of VEGF-A165a. After nerve injury, the endogenous balance of VEGF-A isoforms switches to greater expression of VEGF-Axxxa compared to VEGF-Axxxb, through an SRPK1-dependent pre-mRNA splicing mechanism. Pharmacological inhibition of SRPK1 after traumatic nerve injury selectively reduced VEGF-Axxxa expression and reversed associated neuropathic pain. Exogenous VEGF-A165b also ameliorated neuropathic pain. We conclude that the relative levels of alternatively spliced VEGF-A isoforms are critical for pain modulation under both normal conditions and in sensory neuropathy. Altering VEGF-Axxxa/VEGF-Axxxb balance by targeting alternative RNA splicing may be a new analgesic strategy. The different vegf-a splice variants, VEGF-A165a and VEGF-A165b have pro- and anti-nociceptive actions respectively. Pro-nociceptive actions of VEGF-A165a are dependent on TRPV1. Alternative pre-mRNA splicing underpins peripheral sensitization by VEGF-A isoforms in normal and neuropathic animals.
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Affiliation(s)
- R P Hulse
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK; Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham NG2 7UH, UK
| | - N Beazley-Long
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK; School of Life Sciences, The Medical School, University of Nottingham, Queen's Medical Centre, Nottingham NG2 7UH, UK
| | - J Hua
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | - H Kennedy
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | - J Prager
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | - H Bevan
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | - Y Qiu
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | | | - M V Gammons
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | | | | | - A J Churchill
- Clinical Sciences, University of Bristol, Bristol BS1 2LX, UK
| | - S J Harper
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK
| | - S D Brain
- King's College London, London SE1 9NH, UK
| | - D O Bates
- Cancer Biology, Division of Cancer and Stem Cells, School of Medicine, University of Nottingham, Queen's Medical Centre, Nottingham NG2 7UH, UK.
| | - L F Donaldson
- Physiology and Pharmacology, University of Bristol, Bristol BS8 1TD, UK; School of Life Sciences, The Medical School, University of Nottingham, Queen's Medical Centre, Nottingham NG2 7UH, UK.
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17
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Simonic-Kocijan S, Zhao X, Liu W, Wu Y, Uhac I, Wang K. TRPV1 channel-mediated bilateral allodynia induced by unilateral masseter muscle inflammation in rats. Mol Pain 2013; 9:68. [PMID: 24377488 PMCID: PMC3880456 DOI: 10.1186/1744-8069-9-68] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 12/17/2013] [Indexed: 11/12/2022] Open
Abstract
Pain in masticatory muscles is among the most prominent symptoms of temperomandibular disorders (TMDs) that have diverse and complex etiology. A common complaint of TMD is that unilateral pain of craniofacial muscle can cause a widespread of bilateral pain sensation, although the underlying mechanism remains unknown. To investigate whether unilateral inflammation of masseter muscle can cause a bilateral allodynia, we generated masseter muscle inflammation induced by unilateral injection of complete Freund’s adjuvant (CFA) in rats, and measured the bilateral head withdrawal threshold at different time points using a von Frey anesthesiometer. After behavioral assessment, both right and left trigeminal ganglia (TRG) were dissected and examined for histopathology and transient receptor potential vanilloid 1 (TRPV1) mRNA expression using quantitative real-time PCR analysis. A significant increase in TRPV1 mRNA expression occurred in TRG ipsilateral to CFA injected masseter muscle, whereas no significant alteration in TRPV1 occurred in the contralateral TRG. Interestingly, central injection of TRPV1 antagonist 5-iodoresiniferatoxin into the hippocampus significantly attenuated the head withdrawal response of both CFA injected and non-CFA injected contralateral masseter muscle. Our findings show that unilateral inflammation of masseter muscle is capable of inducing bilateral allodynia in rats. Upregulation of TRPV1 at the TRG level is due to nociception caused by inflammation, whereas contralateral nocifensive behavior in masticatory muscle nociception is likely mediated by central TRPV1, pointing to the involvement of altered information processing in higher centers.
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Affiliation(s)
| | | | | | | | | | - KeWei Wang
- Department of Neurobiology, Neuroscience Research Institute, Peking University Health Science Center, Beijing, China.
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18
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Ruparel S, Hargreaves KM, Eskander M, Rowan S, de Almeida JFA, Roman L, Henry MA. Oxidized linoleic acid metabolite-cytochrome P450 system (OLAM-CYP) is active in biopsy samples from patients with inflammatory dental pain. Pain 2013; 154:2363-2371. [PMID: 23867730 DOI: 10.1016/j.pain.2013.07.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 06/26/2013] [Accepted: 07/10/2013] [Indexed: 11/26/2022]
Abstract
Endogenous TRPV1 agonists such as oxidized linoleic acid metabolites (OLAMs) and the enzymes releasing them [eg, cytochrome P450 (CYP)] are up-regulated after inflammation in the rat. However, it is not known whether such agonists are elevated in human inflammatory pain conditions. Because TRPV1 is expressed in human dental pulp nociceptors, we hypothesized that OLAM-CYP machinery is active in this tissue type and is increased under painful inflammatory conditions such as irreversible pulpitis (IP). The aim of this study was to compare CYP expression and linoleic acid (LA) metabolism in normal vs inflamed human dental pulp. Our data showed that exogenous LA metabolism was significantly increased in IP tissues compared to normal tissues and that pretreatment with a CYP inhibitor, ketoconazole, significantly inhibited LA metabolism. Additionally, extracts obtained from LA-treated inflamed tissues evoked significant inward currents in trigeminal ganglia neurons and were blocked by pretreatment with the TRPV1 antagonist IRTX. Moreover, extracts obtained from ketoconazole-pretreated inflamed tissues significantly reduced inward currents in trigeminal ganglia neurons. These data suggest that LA metabolites produced in human inflamed tissues act as TRPV1 agonists and that the metabolite production can be targeted by CYP inhibition. In addition, immunohistochemical analysis of 2 CYP isoforms, CYP2J and CYP3A1, were shown to be predominately expressed in immune cells infiltrating the inflamed dental pulp, emphasizing the paracrine role of CYP enzymes in OLAM regulation. Collectively, our data indicate that the machinery responsible for OLAM production is up-regulated during inflammation and can be targeted to develop potential analgesics for inflammatory-induced dental pain.
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Affiliation(s)
- Shivani Ruparel
- Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA Department of Pharmacology, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
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19
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Matsuura S, Shimizu K, Shinoda M, Ohara K, Ogiso B, Honda K, Katagiri A, Sessle BJ, Urata K, Iwata K. Mechanisms underlying ectopic persistent tooth-pulp pain following pulpal inflammation. PLoS One 2013; 8:e52840. [PMID: 23341909 PMCID: PMC3547043 DOI: 10.1371/journal.pone.0052840] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 11/21/2012] [Indexed: 01/03/2023] Open
Abstract
In order to clarify the peripheral mechanisms of ectopic persistent pain in a tooth pulp following pulpal inflammation of an adjacent tooth, masseter muscle activity, phosphorylated extracellular signal-regulated protein kinase (pERK) and TRPV1 immunohistochemistries and satellite cell activation using glial fibrillary acidic protein (GFAP) immunohistochemistry in the trigeminal ganglion (TG) were studied in the rats with molar tooth-pulp inflammation. And, Fluorogold (FG) and DiI were also used in a neuronal tracing study to analyze if some TG neurons innervate more than one tooth pulp. Complete Freund's adjuvant (CFA) or saline was applied into the upper first molar tooth pulp (M1) in pentobarbital-anesthetized rats, and capsaicin was applied into the upper second molar tooth pulp (M2) on day 3 after the CFA or saline application. Mean EMG activity elicited in the masseter muscle by capsaicin application to M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. The mean number of pERK-immunoreactive (IR) TG cells was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats. Application of the satellite cell inhibitor fluorocitrate (FC) into TG caused a significant depression of capsaicin-induced masseter muscle activity and a significant reduction of satellite cell activation. The number of TRPV1-IR TG cells innervating M2 was significantly larger in M1 CFA-applied rats compared with M1 vehicle-applied rats, and that was decreased following FC injection into TG. Furthermore, 6% of TG neurons innervating M1 and/or M2 innervated both M1 and M2. These findings suggest that satellite cell activation following tooth pulp inflammation and innervation of multiple tooth pulps by single TG neurons may be involved in the enhancement of the activity of TG neurons innervating adjacent non-inflamed teeth that also show enhancement of TRPV1 expression in TG neurons, resulting in the ectopic persistent tooth-pulp pain following pulpal inflammation of adjacent teeth.
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Affiliation(s)
- Shingo Matsuura
- Department of Endodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Kohei Shimizu
- Department of Endodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Masamichi Shinoda
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Kinuyo Ohara
- Department of Endodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Bunnai Ogiso
- Department of Endodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Kuniya Honda
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Ayano Katagiri
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
| | - Barry J. Sessle
- Department of Oral Physiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Kentaro Urata
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, Tokyo, Japan
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry, Tokyo, Japan
- Division of Applied System Neuroscience Advanced Medical Research Center, Nihon University Graduate School of Medical Science, Tokyo, Japan
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Takeda M, Takahashi M, Matsumoto S. Suppression of neurokinin-1 receptor in trigeminal ganglia attenuates central sensitization following inflammation. J Peripher Nerv Syst 2012; 17:169-81. [PMID: 22734902 DOI: 10.1111/j.1529-8027.2012.00404.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This study examined whether local application of a neurokinin-1 (NK1) receptor antagonist into the trigeminal ganglia (TRGs) modulates hyperexcitability of trigeminal spinal nucleus caudalis (SpVc) wide-dynamic range (WDR) neuron activity innervating both the temporomandibular joint (TMJ) region and facial skin following TMJ inflammation. Extracellular single unit recording combined with multibarrel electrodes was used. TMJ inflammation was induced by the injection of complete Freund's adjuvant (CFA). WDR neurons responding to electrical stimuli of the TMJ region and facial skin were recorded from the SpVc in anesthetized rats. The spontaneous and mechanical stimulation-induced discharge frequencies of WDR neurons were significantly larger in inflamed rats than in control rats. The spontaneous WDR activities were current-dependently decreased by local iontophoretic application of an NK1 receptor antagonist into the TRGs after 1 and 2 days of inflammation. The firing frequency of WDR neurons and threshold evoked by mechanical stimulation of facial skin returned to control levels by application of the NK1 receptor antagonist into TRGs after 1 day, but not 2 days, of inflammation. These results suggest that in the early stages of inflammation suppression of the NK1 receptor mechanism in TRGs may prevent central sensitization of SpVc nociceptive neurons.
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Affiliation(s)
- Mamoru Takeda
- Department of Physiology, School of Life Dentistry at Tokyo, Nippon Dental University, Tokyo, Japan.
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21
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Lee J, Saloman JL, Weiland G, Auh QS, Chung MK, Ro JY. Functional interactions between NMDA receptors and TRPV1 in trigeminal sensory neurons mediate mechanical hyperalgesia in the rat masseter muscle. Pain 2012; 153:1514-1524. [PMID: 22609428 DOI: 10.1016/j.pain.2012.04.015] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 03/07/2012] [Accepted: 04/12/2012] [Indexed: 12/18/2022]
Abstract
The NMDA and TRPV1 receptors that are expressed in sensory neurons have been independently demonstrated to play important roles in peripheral pain mechanisms. In the present study, we investigated whether the 2 receptor-channel systems form a functional complex that provides the basis for the development of mechanical hyperalgesia. In the masseter muscle, direct application of NMDA induced a time-dependent increase in mechanical sensitivity, which was significantly blocked when the muscle was pretreated with a specific TRPV1 antagonist, AMG9810. The NR1 subunit of the NMDA receptor and TRPV1 were coexpressed in 32% of masseter afferents in trigeminal ganglia (TG). Furthermore, NR1 and NR2B formed protein-protein complexes with TRPV1 in TG as demonstrated by coimmunoprecipitation experiments. Calcium imaging analyses further corroborated that NMDA and TRPV1 receptors functionally interact. In TG culture, application of NMDA resulted in phosphorylation of serine, but not threonine or tyrosine, residues of TRPV1 in a time course similar to that of the development of NMDA-induced mechanical hyperalgesia. The NMDA-induced phosphorylation was significantly attenuated by CaMKII and PKC inhibitors, but not by a PKA inhibitor. Consistent with the biochemical data, the NMDA-induced mechanical hyperalgesia was also effectively blocked when the muscle was pretreated with a CaMKII or PKC inhibitor. Thus, NMDA receptors and TRPV1 functionally interact via CaMKII and PKC signaling cascades and contribute to mechanical hyperalgesia. These data offer novel mechanisms by which 2 ligand-gated channels in sensory neurons interact and reinforce the notion that TRPV1 functions as a signal integrator under pathological conditions.
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Affiliation(s)
- Jongseok Lee
- University of Maryland School of Dentistry, Department of Neural and Pain Sciences, Program in Neuroscience, Baltimore, MA, USA Kyung Hee University, School of Dentistry, Department of Oral Medicine, Seoul, Republic of Korea
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22
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Honda K, Noma N, Shinoda M, Miyamoto M, Katagiri A, Kita D, Liu MG, Sessle BJ, Yasuda M, Iwata K. Involvement of peripheral ionotropic glutamate receptors in orofacial thermal hyperalgesia in rats. Mol Pain 2011; 7:75. [PMID: 21952000 PMCID: PMC3216263 DOI: 10.1186/1744-8069-7-75] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/28/2011] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of the present study was to elucidate the mechanisms that may underlie the sensitization of trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal cord (C1-C2) neurons to heat or cold stimulation of the orofacial region following glutamate (Glu) injection. Results Glu application to the tongue or whisker pad skin caused an enhancement of head-withdrawal reflex and extracellular signal-regulated kinase (ERK) phosphorylation in Vc-C2 neurons. Head-withdrawal reflex and ERK phosphorylation were also enhanced following cold stimulation of the tongue but not whisker pad skin in Glu-injected rats, and the head-withdrawal reflex and ERK phosphorylation were enhanced following heat stimulation of the tongue or whisker pad skin. The enhanced head-withdrawal reflex and ERK phosphorylation after heat stimulation of the tongue or whisker pad skin, and those following cold stimulation of the tongue but not whisker pad skin were suppressed following ionotropic glutamate receptor antagonists administration into the tongue or whisker pad skin. Furthermore, intrathecal administration of MEK1/2 inhibitor PD98059 caused significant suppression of enhanced head-withdrawal reflex in Glu-injected rats, heat head-withdrawal reflex in the rats with Glu injection into the tongue or whisker pad skin and cold head-withdrawal reflex in the rats with Glu injection into the tongue. Conclusions The present findings suggest that peripheral Glu receptor mechanisms may contribute to cold hyperalgesia in the tongue but not in the facial skin, and also contribute to heat hyperalgesia in the tongue and facial skin, and that the mitogen-activated protein kinase cascade in Vc-C2 neurons may be involved in these Glu-evoked hyperalgesic effects.
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Affiliation(s)
- Kuniya Honda
- Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
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23
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Miller KE, Hoffman EM, Sutharshan M, Schechter R. Glutamate pharmacology and metabolism in peripheral primary afferents: physiological and pathophysiological mechanisms. Pharmacol Ther 2011; 130:283-309. [PMID: 21276816 DOI: 10.1016/j.pharmthera.2011.01.005] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Accepted: 01/05/2011] [Indexed: 11/25/2022]
Abstract
In addition to using glutamate as a neurotransmitter at central synapses, many primary sensory neurons release glutamate from peripheral terminals. Primary sensory neurons with cell bodies in dorsal root or trigeminal ganglia produce glutaminase, the synthetic enzyme for glutamate, and transport the enzyme in mitochondria to peripheral terminals. Vesicular glutamate transporters fill neurotransmitter vesicles with glutamate and they are shipped to peripheral terminals. Intense noxious stimuli or tissue damage causes glutamate to be released from peripheral afferent nerve terminals and augmented release occurs during acute and chronic inflammation. The site of action for glutamate can be at the autologous or nearby nerve terminals. Peripheral nerve terminals contain both ionotropic and metabotropic excitatory amino acid receptors (EAARs) and activation of these receptors can lower the activation threshold and increase the excitability of primary afferents. Antagonism of EAARs can reduce excitability of activated afferents and produce antinociception in many animal models of acute and chronic pain. Glutamate injected into human skin and muscle causes acute pain. Trauma in humans, such as arthritis, myalgia, and tendonitis, elevates glutamate levels in affected tissues. There is evidence that EAAR antagonism at peripheral sites can provide relief in some chronic pain sufferers.
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Affiliation(s)
- Kenneth E Miller
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, United States.
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Sessle BJ. Peripheral and central mechanisms of orofacial inflammatory pain. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 97:179-206. [DOI: 10.1016/b978-0-12-385198-7.00007-2] [Citation(s) in RCA: 147] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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25
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Physiological mechanisms of neuropathic pain: the orofacial region. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 97:227-50. [PMID: 21708313 DOI: 10.1016/b978-0-12-385198-7.00009-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neuropathic pain in the orofacial region is the clinical manifestation of trigeminal nerve injury following oral surgeries such as tooth extraction, dental implantation or tooth pulp treatment. Normally non-noxious touching of the facial skin or oral mucosa elicits strong pain named allodynia, and normally noxious stimulation causes intolerable pain named hyperalgesia in the trigeminal neuropathic pain patients. Although the mechanisms underlying trigeminal neuropathic pain have been studied by many researchers, the detailed mechanisms are still unknown. In this chapter, we are focusing on trigeminal neuropathic pain, and describe our recent studies using animal models of trigeminal neuropathic pain. We also present the clinical assessment of trigeminal neuropathic pain patients to develop the appropriate treatment of trigeminal neuropathic pain.
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Hwang SM, Koo NY, Jin M, Davies AJ, Chun GS, Choi SY, Kim JS, Park K. Intracellular acidification is associated with changes in free cytosolic calcium and inhibition of action potentials in rat trigeminal ganglion. J Biol Chem 2010; 286:1719-29. [PMID: 21068392 DOI: 10.1074/jbc.m109.090951] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The effect of intracellular acidification and subsequent pH recovery in sensory neurons has not been well characterized. We have studied the mechanisms underlying Ca(2+)-induced acidification and subsequent recovery of intracellular pH (pH(i)) in rat trigeminal ganglion neurons and report their effects on neuronal excitability. Glutamate (500 μM) and capsaicin (1 μM) increased intracellular Ca(2+) concentration ([Ca(2+)](i)) with a following decrease in pH(i). The recovery of [Ca(2+)](i) to the prestimulus level was inhibited by LaCl(3) (1 mM) and o-vanadate (10 mM), a plasma membrane Ca(2+)/ATPase (PMCA) inhibitor. Removal of extracellular Ca(2+) also completely inhibited the acidification induced by capsaicin. TRPV1 was expressed only in small and medium sized trigeminal ganglion neurons. mRNAs for Na(+)/H(+) exchanger type 1 (NHE1), pancreatic Na(+)-HCO(3)(-) cotransporter type 1 (pNBC1), NBC3, NBC4, and PMCA types 1-3 were detected by RT-PCR. pH(i) recovery was significantly inhibited by pretreatment with NHE1 or pNBC1 siRNA. We found that the frequency of action potentials (APs) was dependent on pH(i). Application of the NHE1 inhibitor 5'-(N-ethyl-N-isopropyl) amiloride (5 μM) or the pNBC1 inhibitor 4',4'-di-isothiocyanostilbene-2',2'-sulfonic acid (500 μM) delayed pH(i) recovery and decreased AP frequency. Simultaneous application of 5'-(N-ethyl-N-isopropyl) amiloride and 4',4'-di-isothiocyanostilbene-2',2'-sulfonic acid almost completely inhibited APs. In summary, our results demonstrate that the rise in [Ca(2+)](i) in sensory neurons by glutamate and capsaicin causes intracellular acidification by activation of PMCA type 3, that the pH(i) recovery from acidification is mediated by membrane transporters NHE1 and pNBC1 specifically, and that the activity of these transporters has direct consequences for neuronal excitability.
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Affiliation(s)
- Sung-Min Hwang
- Department of Physiology, School of Dentistry, Seoul National University and Dental Research Institute, Yeongeondong 28, Chongnoku, Seoul 110-749, Korea
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Guo W, Wang H, Zou S, Wei F, Dubner R, Ren K. Long lasting pain hypersensitivity following ligation of the tendon of the masseter muscle in rats: a model of myogenic orofacial pain. Mol Pain 2010; 6:40. [PMID: 20633279 PMCID: PMC2914030 DOI: 10.1186/1744-8069-6-40] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Accepted: 07/15/2010] [Indexed: 02/28/2023] Open
Abstract
Background A major subgroup of patients with temporomandibular joint (TMJ) disorders have masticatory muscle hypersensitivity. To study myofacial temporomandibular pain, a number of preclinical models have been developed to induce myogenic pain of the masseter muscle, one of the four muscles involved in mastication. The currently used models, however, generate pain that decreases over time and only lasts from hours to weeks and hence are not suitable for studying chronicity of the myogenic pain in TMJ disorders. Here we report a model of constant myogenic orofacial pain that lasts for months. Results The model involves unilateral ligation of the tendon of the anterior superficial part of the rat masseter muscle (TASM). The ligation of the TASM was achieved with two chromic gut (4.0) ligatures via an intraoral approach. Nocifensive behavior of the rat was assessed by probing the skin site above the TASM with a series of von Frey filaments. The response frequencies were determined and an EF50 value, defined as the von Frey filament force that produces a 50% response frequency, was derived and used as a measure of mechanical sensitivity. Following TASM ligation, the EF50 of the injured side was significantly reduced and maintained throughout the 8-week observation period, suggesting the presence of mechanical hyperalgesia/allodynia. In sham-operated rats, the EF50 of the injured side was transiently reduced for about a week, likely due to injury produced by the surgery. Somatotopically relevant Fos protein expression was indentified in the subnucleus caudalis of the spinal trigeminal sensory complex. In the same region, persistent upregulation of NMDA receptor NR1 phosphorylation and protein expression and increased expression of glial markers glial fibrillary acidic protein (astroglia) and CD11b (microglia) were found. Morphine (0.4-8 mg/kg, s.c.) and duloxetine (0.4-20 mg/kg, i.p.), a selective serotonin-norepinephrine reuptake inhibitor, produced dose-dependent attenuation of hyperalgesia. Conclusions Ligation injury of the TASM in rats led to long-lasting and constant mechanical hypersensitivity of myogenic origin. The model will be particularly useful in studying the chronicity of myogenic pain TMJ disorders. The model can also be adapted to other regions of the body for studying pathology of painful tendinopathy seen in sports injury, muscle overuse, and rheumatoid arthritis.
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Affiliation(s)
- Wei Guo
- Department of Neural and Pain Sciences, Dental School & Program in Neuroscience, University of Maryland, Baltimore, MD 21201, USA
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Interactions of glutamate and capsaicin-evoked muscle pain on jaw motor functions of men. Clin Neurophysiol 2010; 121:950-6. [DOI: 10.1016/j.clinph.2010.01.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 01/08/2010] [Accepted: 01/15/2010] [Indexed: 11/21/2022]
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Watanabe T, Tsuboi Y, Sessle BJ, Iwata K, Hu JW. P2X and NMDA receptor involvement in temporomandibular joint-evoked reflex activity in rat jaw muscles. Brain Res 2010; 1346:83-91. [PMID: 20501327 DOI: 10.1016/j.brainres.2010.05.055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Revised: 05/18/2010] [Accepted: 05/18/2010] [Indexed: 11/28/2022]
Abstract
We have previously shown that injection of the excitatory amino glutamate into the rat temporomandibular joint (TMJ) evokes reflex activity in both anterior digastric (DIG) and masseter (MASS) muscles that can be attenuated by prior TMJ injection of an N-methyl-d-aspartate (NMDA) receptor antagonist. The aim of the present study was to test if jaw muscle activity could also be evoked by P2X receptor agonist injection into the rat TMJ region and if the reflex activity could be modulated by TMJ injection of P2X receptor antagonist or NMDA receptor antagonist. The selective P2X subtype agonist alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-me ATP) and vehicle (phosphate-buffered saline) or the selective P2X antagonist, 2'-(or-3')-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP) or the selective NMDA antagonist (+/-)-d-2-amino-5-phosphonovalerate(APV) were injected into the rat TMJ region. Electromyographic (EMG) reflex activity was recorded in both DIG and MASS muscles. Compared with the baseline EMG activity, alpha,beta-me-ATP injection into the TMJ (but not its systemic administration) following pre-injection of the vehicle significantly increased the magnitude and the duration of ipsilateral DIG and MASS EMG activity in a dose-dependent manner. The alpha,beta-me-ATP-evoked responses could be antagonized by pre-injection of TNP-ATP into the same TMJ site but contralateral TMJ injection of TNP-ATP proved ineffective. Furthermore, the alpha,beta-me-ATP-evoked responses could also be antagonized by APV injected into the same TMJ site but not by its systemic injection. These results indicate the interaction of peripheral purinergic as well as glutamatergic receptor mechanisms in the processing of TMJ nociceptive afferent inputs that evoke reflex activity in jaw muscles.
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Affiliation(s)
- T Watanabe
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
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Cairns BE. Pathophysiology of TMD pain--basic mechanisms and their implications for pharmacotherapy. J Oral Rehabil 2010; 37:391-410. [PMID: 20337865 DOI: 10.1111/j.1365-2842.2010.02074.x] [Citation(s) in RCA: 186] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This article discusses the pathophysiology of temporomandibular disorders (TMD)-related pain and its treatment with analgesic drugs. Temporomandibular disorders are comprised of a group of conditions that result in temporomandibular joint pain (arthralgia, arthritis) and/or masticatory muscle pain (myofascial TMD). In at least some patients with TMD, a peripheral mechanism contributes to this pain. However, there is often a poor correlation between the severity of TMD-related pain complaints and evidence of definitive tissue pathology. This has led to the concept that pain in some patients with TMD may result from altered central nervous system pain processing and further that this altered pain processing may be attributable to specific genes that are heritable. Psychosocial stressors are also thought to contribute to the development of TMD-related pain, particularly masticatory muscle pain. Finally, substantially more women suffer from TMD than men. Although there are arguably multiple reasons for sex-related differences in the prevalence of TMD, one candidate for the increased occurrence of this disorder in women has been suggested to be the female sex hormone oestrogen. Analgesic drugs are an integral part of the primary treatment for TMD-related pain and dysfunction with more that 90% of treatment recommendations involving use of medications. The most commonly used agents include non-steroidal anti-inflammatory drugs, corticosteroids, muscle relaxants, anxiolytics, opiates and tricyclic antidepressants, however, evidence in support of the effectiveness of these drugs is lacking. Continued research into the pathophysiology of TMD-related pain and the effectiveness of analgesic treatments for this pain is required.
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Affiliation(s)
- B E Cairns
- Canada Research Chair in Neuropharmacology, Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver, Canada.
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Tesser-Viscaíno SA, Denadai-Souza A, Teixeira SA, Ervolino E, Cruz-Rizzolo RJ, Costa SK, Muscará MN, Casatti CA. Putative antinociceptive action of nitric oxide in the caudal part of the spinal trigeminal nucleus during chronic carrageenan-induced arthritis in the rat temporomandibular joint. Brain Res 2009; 1302:85-96. [DOI: 10.1016/j.brainres.2009.09.056] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 09/14/2009] [Accepted: 09/14/2009] [Indexed: 12/31/2022]
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Sharma HS. 5th World Congress: Official Congress of the World Institute of Pain. FUTURE NEUROLOGY 2009. [DOI: 10.2217/fnl.09.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 5th World Institute of Pain congress highlighted new developments in pain therapy related to various aspects of chronic pain syndrome, such as, neuropathic pain, and also provided new insights into processing of pain information and pain pathways in the CNS. In addition, a new strategy for combination therapy and drug delivery to the spinal cord including nanodrug delivery for better therapeutic efficacy was discussed in detail.
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Affiliation(s)
- Hari Shanker Sharma
- Docent in Neuroanatomy (UU), Professor of Neurobiology (MRC) Laboratory of Cerebrovascular Research & Pain Research Laboratory, Department of Surgical Sciences, Anaesthesiology & Intensive Care Medicine, University Hospital, SE-75185 Uppsala, Sweden
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Ro JY, Lee JS, Zhang Y. Activation of TRPV1 and TRPA1 leads to muscle nociception and mechanical hyperalgesia. Pain 2009; 144:270-277. [PMID: 19464796 DOI: 10.1016/j.pain.2009.04.021] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Revised: 03/26/2009] [Accepted: 04/20/2009] [Indexed: 10/20/2022]
Abstract
The involvement of TRPV1 and TRPA1 in mediating craniofacial muscle nociception and mechanical hyperalgesia was investigated in male Sprague-Dawley rats. First, we confirmed the expression of TRPV1 in masseter afferents in rat trigeminal ganglia (TG), and provided new data that TRPA1 is also expressed in primary afferents innervating masticatory muscles in double-labeling immunohistochemistry experiments. We then examined whether the activation of each TRP channel in the masseter muscle evokes acute nocifensive responses and leads to the development of masseter hypersensitivity to mechanical stimulation using the behavioral models that have been specifically designed and validated for the craniofacial system. Intramuscular injections with specific agonists for TRPV1 and TRPA1, capsaicin and mustard oil (MO), respectively, produced immediate nocifensive hindpaw responses followed by prolonged mechanical hyperalgesia in a concentration-dependent manner. Pretreatment of the muscle with a TRPV1 antagonist, capsazepine, effectively attenuated the capsaicin-induced muscle nociception and mechanical hyperalgesia. Similarly, pretreatment of the muscle with a selective TRPA1 antagonist, AP18, significantly blocked the MO-induced muscle nociception and mechanical hyperalgesia. We confirmed these data with another set of selective antagonist for TRPV1 and TRPA1, AMG9810 and HC030031, respectively. Collectively, these results provide compelling evidence that TRPV1 and TRPA1 can functionally contribute to muscle nociception and hyperalgesia, and suggest that TRP channels expressed in muscle afferents can engage in the development of pathologic muscle pain conditions.
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Affiliation(s)
- Jin Y Ro
- University of Maryland Baltimore School of Dentistry, Program in Neuroscience, Department of Neural and Pain Sciences, 650 W. Baltimore Street, Baltimore, MD 21201, USA
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Lam DK, Sessle BJ, Hu JW. Glutamate and capsaicin effects on trigeminal nociception II: Activation and central sensitization in brainstem neurons with deep craniofacial afferent input. Brain Res 2009; 1253:48-59. [DOI: 10.1016/j.brainres.2008.11.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 11/17/2008] [Accepted: 11/17/2008] [Indexed: 10/21/2022]
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