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Mechanisms and manifestations in musculoskeletal pain: from experimental to clinical pain settings. Pain 2022; 163:S29-S45. [PMID: 35984370 DOI: 10.1097/j.pain.0000000000002690] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/09/2022] [Indexed: 01/18/2023]
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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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Wiesinger B, Häggman-Henrikson B, Eklund A, Wänman A, Hellström F. Multimodal Sensory Stimulation of the Masseter Muscle Reduced Precision but Not Accuracy of Jaw-Opening Movements. Front Neurosci 2019; 13:1083. [PMID: 31649503 PMCID: PMC6795680 DOI: 10.3389/fnins.2019.01083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 09/25/2019] [Indexed: 11/13/2022] Open
Abstract
A functional integration between the trigeminal and craniocervical sensorimotor systems has been demonstrated, with simultaneous jaw and head–neck movements during jaw opening–closing. We previously showed that pain induction in the masseter muscle increased the relative contribution of the neck component of integrated jaw–neck movements. Induced pain or manipulation of proprioception by vibration did not affect accuracy during a jaw-opening task in men. It is not known how multimodal sensory stimulation, with a combination of pain induction and vibration, affects jaw-opening accuracy and precision. The aim was to investigate how jaw–neck movements, and specifically accuracy and precision of jaw-opening, are affected during concomitant nociceptive and proprioceptive stimulation of the masseter muscle. Twenty-one healthy men performed jaw-opening to a target position, defined as 75% of individual maximum jaw opening, during control (Ctr), vibration of masseter muscles (Vib), pain induction in the masseter (Pain), and concomitant vibration and pain induction in the masseter muscle (VibPain). Simultaneous jaw and head movements were recorded with an optoelectronic system and amplitudes calculated for each jaw opening–closing cycle. Accuracy of jaw movements was defined as the achievement of the target position. Precision of jaw movements was defined as the cycle-to-cycle variability from the mean of cycles 2–10 (coefficient of variation, CV). Differences between the trials were analyzed with Friedman’s test, Dunn’s test, and Benjamini–Hochberg correction. There were no significant differences between the trials for jaw movement amplitudes. For head movements, amplitudes for cycles 2–10 were larger during Pain compared to Ctr and Vib (both p = 0.034), and larger during VibPain compared to Ctr (p = 0.034) and Vib (p = 0.035). There were no differences in accuracy of jaw movements between the trials. For precision of jaw movements, the cycle-to-cycle variability was larger during VibPain compared to Ctr (p = 0.027) and Vib (p = 0.018). For integrated jaw–neck motor strategy, there was a difference between pain and non-pain trials, but no differences between unimodal and multimodal stimulation trials. For achievement of jaw-opening to a target position, the results show no effect on accuracy, but a reduced precision of jaw movements during combined proprioceptive and nociceptive multimodal stimulation.
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Affiliation(s)
- Birgitta Wiesinger
- Department of Odontology, Clinical Oral Physiology, Umeå University, Umeå, Sweden.,Department of Research and Development, Västernorrland County Council, Umeå University, Sundsvall, Sweden
| | - Birgitta Häggman-Henrikson
- Department of Odontology, Clinical Oral Physiology, Umeå University, Umeå, Sweden.,Department of Orofacial Pain and Jaw Function, Malmö University, Malmö, Sweden
| | - Anton Eklund
- Department of Odontology, Clinical Oral Physiology, Umeå University, Umeå, Sweden
| | - Anders Wänman
- Department of Odontology, Clinical Oral Physiology, Umeå University, Umeå, Sweden
| | - Fredrik Hellström
- Centre for Musculoskeletal Research, Gävle University College, Umeå, Sweden
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Pasinato F, Santos-Couto-Paz CC, Zeredo JLL, Macedo SB, Corrêa EC. Experimentally induced masseter-pain changes masseter but not sternocleidomastoid muscle-related activity during mastication. J Electromyogr Kinesiol 2016; 31:88-95. [DOI: 10.1016/j.jelekin.2016.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 07/30/2016] [Accepted: 09/26/2016] [Indexed: 11/24/2022] Open
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Widmer CG, Morris-Wiman J. Mouse preferential incising force orientation changes during jaw closing muscle hyperalgesia and is sex dependent. Physiol Behav 2016; 167:132-144. [PMID: 27619173 DOI: 10.1016/j.physbeh.2016.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/22/2016] [Accepted: 09/08/2016] [Indexed: 10/25/2022]
Abstract
INTRODUCTION Mouse incising is controlled by a central pattern generator and this activity can change in the presence of pain. The incising frequency and maximum force generation decreases with pain. In this study, we used repetitive acidic injections in the left masseter muscle of male and female mice to determine differences between baseline and jaw muscle pain conditions and the effect of sex on preferential incising direction. METHODS A within subject design was used to evaluate data previously acquired using multi-axis force data (X, Y and Z) from the 4th baseline recording day and day 7 post-injection (day of maximal pain response) for each mouse of each sex. A total of 34 female and male (age 3-9months) CD-1 mice were evaluated. After mathematically rotating the X and Y axes to align the Y axis to be parallel to the wire struts of the cage top, data were analyzed to determine incising direction preference during baseline (non-pain) and pain (day 7) conditions and between sex. Radar plots of X-Y, X-Z and Y-Z axes depicted the average direction of incising preference between baseline and pain conditions for each sex. Statistical differences among groups were tested using a mixed model ANOVA. RESULTS Similar to previous findings, female mice had a more robust difference in incising direction preference when comparing male and female pain conditions and this was most evident in the X-Z axes. The incising frequencies most commonly affected were 5.3, 6.2 and 7.6Hz. Male mice varied little in their incising direction preference between the baseline and pain conditions. In addition, statistical comparison of ratios of the percent of time spent incising in the Z versus X axes for each incising frequency found that the incising preference was not different when comparing 5.3 and 7.6Hz frequencies. Finally, female mice used a novel approach to minimize pain while incising by rotating their head and body nearly 180 degrees while males did not use this strategy as frequently. CONCLUSIONS The preferred incising direction changes in a jaw muscle pain condition and this information can be used to further characterize functional pain in the masticatory muscle system. The changes were dependent on the incising frequency generated by the central pattern generator for incising.
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Affiliation(s)
- C G Widmer
- Dept. of Orthodontics, Box 100444, JHMHSC, University of Florida, Gainesville, FL 32610-0444, USA.
| | - J Morris-Wiman
- Biomedical Sciences, West Virginia School of Osteopathic Medicine, 400 North Lee St., Lewisburg, VA 24901, USA.
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Amhamed M, Whittle T, Maulina T, Gal J, Akhter R, Murray GM. Effect of experimental anterior temporalis muscle pain on jaw movements. J Oral Rehabil 2016; 43:889-899. [PMID: 27739087 DOI: 10.1111/joor.12449] [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] [Accepted: 10/08/2016] [Indexed: 11/28/2022]
Abstract
To test the hypotheses that experimental noxious stimulation of the anterior temporalis muscle results in significant decreases in jaw movement amplitude and velocity, and there are significant correlations between scores of mood or pain-related cognitions and amplitude and velocity. The jaw movements of 14 asymptomatic participants were recorded during standardised open/close jaw movements and free and standardised chewing tasks. Tonic infusion of hypertonic saline into the right anterior temporalis muscle maintained pain intensity between 40 and 60 mm on a 100-mm visual analogue scale. Tasks were performed in a single session in the following sequence: baseline condition, test 1 condition (during hypertonic or isotonic saline infusion), test 2 condition (during saline infusion) (10-min rest between conditions). Participants completed the Depression, Anxiety and Stress Scale (DASS-21) and the Pain Catastrophizing Scale (PCS). Amplitude and velocity of opening and closing were compared between conditions with a repeated-measures analysis of variance (anova), and Spearman's rank correlation coefficient explored correlations; statistical significance: P < 0·05. For any of the three tasks, there were no significant differences in kinematic variables between any condition and no significant correlations between DASS-21 or PCS scores and kinematic variables during hypertonic saline infusion. The absence of a significant reduction in velocity or amplitude of open/close or chewing jaw movements during experimental temporalis muscle pain is not consistent with the Pain Adaptation Model proposing decreases in kinematic measures in pain. The lack of significant correlations between psychological variables and measures of jaw movement may reflect the low scores reported by our study sample.
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Affiliation(s)
- M Amhamed
- Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia.,Level 2, Westmead Hospital Centre for Oral Health, Westmead, NSW, Australia
| | - T Whittle
- Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia.,Level 2, Westmead Hospital Centre for Oral Health, Westmead, NSW, Australia
| | - T Maulina
- Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia.,Level 2, Westmead Hospital Centre for Oral Health, Westmead, NSW, Australia
| | - J Gal
- Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia.,Level 2, Westmead Hospital Centre for Oral Health, Westmead, NSW, Australia
| | - R Akhter
- Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia.,Level 2, Westmead Hospital Centre for Oral Health, Westmead, NSW, Australia
| | - G M Murray
- Jaw Function and Orofacial Pain Research Unit, Faculty of Dentistry, University of Sydney, Sydney, NSW, Australia.,Level 2, Westmead Hospital Centre for Oral Health, Westmead, NSW, Australia
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Kirkpatrick DR, McEntire DM, Smith TA, Dueck NP, Kerfeld MJ, Hambsch ZJ, Nelson TJ, Reisbig MD, Agrawal DK. Transmission pathways and mediators as the basis for clinical pharmacology of pain. Expert Rev Clin Pharmacol 2016; 9:1363-1387. [PMID: 27322358 PMCID: PMC5215101 DOI: 10.1080/17512433.2016.1204231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Mediators in pain transmission are the targets of a multitude of different analgesic pharmaceuticals. This review explores the most significant mediators of pain transmission as well as the pharmaceuticals that act on them. Areas covered: The review explores many of the key mediators of pain transmission. In doing so, this review uncovers important areas for further research. It also highlights agents with potential for producing novel analgesics, probes important interactions between pain transmission pathways that could contribute to synergistic analgesia, and emphasizes transmission factors that participate in transforming acute injury into chronic pain. Expert commentary: This review examines current pain research, particularly in the context of identifying novel analgesics, highlighting interactions between analgesic transmission pathways, and discussing factors that may contribute to the development of chronic pain after an acute injury.
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Affiliation(s)
- Daniel R. Kirkpatrick
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Dan M. McEntire
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Tyler A. Smith
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Nicholas P. Dueck
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Mitchell J. Kerfeld
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Zakary J. Hambsch
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Taylor J. Nelson
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Mark D. Reisbig
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
| | - Devendra K. Agrawal
- Departments of Clinical and Translational Science and Anesthesiology, Creighton University School of Medicine, Omaha, NE 68178 USA
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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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9
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Queme F, Taguchi T, Mizumura K, Graven-Nielsen T. Muscular Heat and Mechanical Pain Sensitivity After Lengthening Contractions in Humans and Animals. THE JOURNAL OF PAIN 2013; 14:1425-36. [DOI: 10.1016/j.jpain.2013.07.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 06/25/2013] [Accepted: 07/06/2013] [Indexed: 11/26/2022]
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10
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Shimada A, Hara S, Svensson P. Effect of experimental jaw muscle pain on EMG activity and bite force distribution at different level of clenching. J Oral Rehabil 2013; 40:826-33. [PMID: 23992609 DOI: 10.1111/joor.12096] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/09/2013] [Indexed: 11/30/2022]
Abstract
Bite force at different levels of clenching and the corresponding electromyographic (EMG) activity in jaw-closing muscles were recorded in 16 healthy women before, during and after painful stimulation of the left masseter muscle. Experimental pain was induced by infusion of 5·8% hypertonic saline (HS), and 0·9% isotonic saline (IS) was infused as a control. EMG activity was recorded bilaterally from the masseter and temporalis muscles, and static bite force was assessed by pressure-sensitive films (Dental Pre-scale) at 5, 50 and 100% of maximal voluntary contraction (MVC) during each session. Visual feedback was applied by showing EMG activity to help the subject perform clenching at 5, 50 and 100% MVC, respectively. EMG activity at 100% MVC in left and right masseter decreased significantly during painful HS infusion (1·7-44·6%; P < 0·05). EMG activity at 5% and 50% MVC was decreased during HS infusion in the painful masseter muscle (4·8-18·6%; P < 0·05); however, EMG activity in the other muscles increased significantly (18·5-128·3%; P < 0·05). There was a significant increase in bite force in the molar regions at 50% MVC during HS infusion and in the post-infusion condition (P < 0·05). However, there were no significant differences in the distribution of forces at 100% MVC. In conclusion, experimental pain in the masseter muscle has an inhibitory effect on jaw muscle activity at maximal voluntary contraction, and compensatory mechanisms may influence the recruitment pattern at submaximal efforts.
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Affiliation(s)
- A Shimada
- Section of Clinical Oral Physiology, Department of Dentistry, Aarhus University, Aarhus, Denmark
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11
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O'Neill J, Brock C, Olesen AE, Andresen T, Nilsson M, Dickenson AH. Unravelling the mystery of capsaicin: a tool to understand and treat pain. Pharmacol Rev 2013; 64:939-71. [PMID: 23023032 DOI: 10.1124/pr.112.006163] [Citation(s) in RCA: 220] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A large number of pharmacological studies have used capsaicin as a tool to activate many physiological systems, with an emphasis on pain research but also including functions such as the cardiovascular system, the respiratory system, and the urinary tract. Understanding the actions of capsaicin led to the discovery its receptor, transient receptor potential (TRP) vanilloid subfamily member 1 (TRPV1), part of the superfamily of TRP receptors, sensing external events. This receptor is found on key fine sensory afferents, and so the use of capsaicin to selectively activate pain afferents has been exploited in animal studies, human psychophysics, and imaging studies. Its effects depend on the dose and route of administration and may include sensitization, desensitization, withdrawal of afferent nerve terminals, or even overt death of afferent fibers. The ability of capsaicin to generate central hypersensitivity has been valuable in understanding the consequences and mechanisms behind enhanced central processing of pain. In addition, capsaicin has been used as a therapeutic agent when applied topically, and antagonists of the TRPV1 receptor have been developed. Overall, the numerous uses for capsaicin are clear; hence, the rationale of this review is to bring together and discuss the different types of studies that exploit these actions to shed light upon capsaicin working both as a tool to understand pain but also as a treatment for chronic pain. This review will discuss the various actions of capsaicin and how it lends itself to these different purposes.
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Affiliation(s)
- Jessica O'Neill
- Neuroscience, Physiology and Pharmacology, University College London, London.
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12
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Ortega-Álvaro A, Berrocoso E, Rey-Brea R, Leza JC, Mico JA. Comparison of the antinociceptive effects of ibuprofen arginate and ibuprofen in rat models of inflammatory and neuropathic pain. Life Sci 2012; 90:13-20. [DOI: 10.1016/j.lfs.2011.10.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 08/08/2011] [Accepted: 09/24/2011] [Indexed: 10/16/2022]
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Benoliel R, Svensson P, Heir GM, Sirois D, Zakrzewska J, Oke-Nwosu J, Torres SR, Greenberg MS, Klasser GD, Katz J, Eliav E. Persistent orofacial muscle pain. Oral Dis 2011; 17 Suppl 1:23-41. [PMID: 21382137 DOI: 10.1111/j.1601-0825.2011.01790.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The pathophysiology of persistent orofacial myalgia has been the centre of much controversy. In this article we suggest a novel descriptive term; 'persistent orofacial muscle pain' (POMP) and review current evidence that supports the hypothesis that the induction of POMP involves the interplay between a peripheral nociceptive source in muscle, a faulty central nervous system component and decreased coping ability. In this context it is widely accepted that a complex interaction of variable intrinsic and extrinsic factors act to induce POMP and dysfunction.
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Affiliation(s)
- R Benoliel
- Department of Oral Medicine, The Faculty of Dentistry, Hebrew University-Hadassah, Jerusalem, Israel.
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Guo S, Vecsei L, Ashina M. The L-kynurenine signalling pathway in trigeminal pain processing: A potential therapeutic target in migraine? Cephalalgia 2011; 31:1029-38. [DOI: 10.1177/0333102411404717] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Introduction: In recent years the kynurenine family of compounds, metabolites of tryptophan, has become an area of intensive research because of its neuroactive properties. Two metabolites of this family have become of interest in relation to migraine and pain processing. Discussion: Experimental studies have shown that kynurenic acid (KYNA) plays an important role in the transmission of sensory impulses in the trigeminovascular system and that increased levels of KYNA decrease the sensitivity of the cerebral cortex to cortical spreading depression. Furthermore, another metabolite of the kynurenine family, L-kynurenine, exerts vasodilating effects similar to nitric oxide by increasing cyclic guanosine monophosphate. Conclusion: This review summarizes current knowledge of the role of kynurenine signalling in trigeminal and central pain processing, including its therapeutic prospects in migraine treatment.
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Affiliation(s)
- Song Guo
- University of Copenhagen, Denmark
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15
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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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