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Erdogan O, Michot B, Xia J, Alabdulaaly L, Yesares Rubi P, Ha V, Chiu IM, Gibbs JL. Neuronal-immune axis alters pain and sensory afferent damage during dental pulp injury. Pain 2024; 165:392-403. [PMID: 37903298 DOI: 10.1097/j.pain.0000000000003029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/15/2023] [Indexed: 11/01/2023]
Abstract
ABSTRACT Dental pulp tissue is densely innervated by afferent fibers of the trigeminal ganglion. When bacteria cause dental decay near the pulpal tissue, a strong neuronal and immune response occurs, creating pulpitis, which is associated with severe pain and pulp tissue damage. Neuroimmune interactions have the potential to modulate both the pain and pathological outcome of pulpitis. We first investigated the role of the neuropeptide calcitonin gene-related peptide (CGRP), released from peptidergic sensory afferents, in dental pain and immune responses by using Calca knockout (Calca -/- ) and wild-type (Calca +/+ ) mice, in a model of pulpitis by creating a mechanical exposure of the dental pulp horn. We found that the neuropeptide CGRP, facilitated the recruitment of myeloid cells into the pulp while also increasing spontaneous pain-like behavior 20% to 25% at an early time point. Moreover, when we depleted neutrophils and monocytes, we found that there was 20% to 30% more sensory afferent loss and increased presence of bacteria in deeper parts of the tissue, whereas there was a significant reduction in mechanical pain response scores compared with the control group at a later time point. Overall, we showed that there is a crosstalk between peptidergic neurons and neutrophils in the pulp, modulating the pain and inflammatory outcomes of the disease.
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Affiliation(s)
- Ozge Erdogan
- Department of Restorative Dentistry and Biomaterial Sciences, Harvard School of Dental Medicine, Boston, MA, United States
| | - Benoit Michot
- Department of Restorative Dentistry and Biomaterial Sciences, Harvard School of Dental Medicine, Boston, MA, United States
| | - Jinya Xia
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA, United States
| | - Lama Alabdulaaly
- Department of Oral Medicine, Infection, and Immunity, Harvard School of Dental Medicine, Boston, MA, United States
- Division of Oral Medicine and Dentistry, Brigham and Women's Hospital, Boston, MA, United States
| | - Pilar Yesares Rubi
- Department of Restorative Dentistry and Biomaterial Sciences, Harvard School of Dental Medicine, Boston, MA, United States
| | - Vivian Ha
- Department of Restorative Dentistry and Biomaterial Sciences, Harvard School of Dental Medicine, Boston, MA, United States
| | - Isaac M Chiu
- Department of Immunology, Blavatnik Institute, Harvard Medical School, Boston, MA, United States
| | - Jennifer L Gibbs
- Department of Restorative Dentistry and Biomaterial Sciences, Harvard School of Dental Medicine, Boston, MA, United States
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Chronic Orofacial Pain: Models, Mechanisms, and Genetic and Related Environmental Influences. Int J Mol Sci 2021; 22:ijms22137112. [PMID: 34281164 PMCID: PMC8268972 DOI: 10.3390/ijms22137112] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/23/2021] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
Chronic orofacial pain conditions can be particularly difficult to diagnose and treat because of their complexity and limited understanding of the mechanisms underlying their aetiology and pathogenesis. Furthermore, there is considerable variability between individuals in their susceptibility to risk factors predisposing them to the development and maintenance of chronic pain as well as in their expression of chronic pain features such as allodynia, hyperalgesia and extraterritorial sensory spread. The variability suggests that genetic as well as environmental factors may contribute to the development and maintenance of chronic orofacial pain. This article reviews these features of chronic orofacial pain, and outlines findings from studies in animal models of the behavioural characteristics and underlying mechanisms related to the development and maintenance of chronic orofacial pain and trigeminal neuropathic pain in particular. The review also considers the role of environmental and especially genetic factors in these models, focussing on findings of differences between animal strains in the features and underlying mechanisms of chronic pain. These findings are not only relevant to understanding underlying mechanisms and the variability between patients in the development, expression and maintenance of chronic orofacial pain, but also underscore the importance for considering the strain of the animal to model and explore chronic orofacial pain processes.
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Murano H, Kaneko T, Zaw SYM, Sone PP, Zaw ZCT, Okada Y, Sunakawa M, Katsube KI, Okiji T. Pulp inflammation induces Kv1.1 K + channel down-regulation in rat thalamus. Oral Dis 2021; 28:1674-1681. [PMID: 33811796 DOI: 10.1111/odi.13866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 03/07/2021] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES Signals from inflamed tooth pulp activate thalamic neurons to evoke central sensitization. We aimed to gain insights into the mechanisms mediating the early phase of pulpal inflammation-induced thalamic neural and glial activation. MATERIALS AND METHODS Pulpal inflammation was induced via the application of mustard oil (MO) to the upper first molar of Wistar rats with local anesthesia (LA) or saline injection. After 0.5, 1, 2, and 24 hr, contralateral thalami were subjected to microarrays, a real-time polymerase chain reaction and immunohistochemistry to identify differentially expressed genes and assess potassium voltage-gated channel subfamily A member 1 (Kv1.1)-expressing axons and glial fibrillary acidic protein (GFAP)-expressing astrocytes. RESULTS The Kv1.1 gene (Kcna1) was down-regulated and the density of Kv1.1-expressing axons decreased in non-anesthetized rats, but not in anesthetized rats 1 hr after the MO treatment. The density of GFAP-expressing astrocytes increased in both groups until 24 hr after the MO treatment, with a greater increase being observed in the saline-injection group than in the LA group. CONCLUSIONS MO induced the transient down-regulation of Kcna1, transiently reduced the density of Kv1.1-expressing axons, and increased astrocytes in thalami within 1 hr of pulpal application. These results suggest central sensitization represented by neuronal hyperexcitability and astrocyte activation.
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Affiliation(s)
- Hiroki Murano
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Tomoatsu Kaneko
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Su Yee Myo Zaw
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Phyo Pyai Sone
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Zar Chi Thein Zaw
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Yamato Okada
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Mitsuhiro Sunakawa
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | | | - Takashi Okiji
- Department of Pulp Biology and Endodontics, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
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Increased substance P and synaptic remodeling occur in the trigeminal sensory system with sustained osteoarthritic temporomandibular joint sensitivity. Pain Rep 2021; 6:e911. [PMID: 33977183 PMCID: PMC8104398 DOI: 10.1097/pr9.0000000000000911] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/24/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022] Open
Abstract
Supplemental Digital Content is Available in the Text. Increased substance P and a loss of inhibitory synapses occurs within the brain's trigeminal sensory system with persistent, but not transient, temporomandibular joint sensitivity. Introduction: Temporomandibular joint (TMJ) pain is among the most prevalent musculoskeletal conditions and can result from atypical joint loading. Although TMJ pain is typically self-resolving, 15% of patients develop chronic TMJ pain that is recalcitrant to therapy and may be attributed to changes in pain processing centers. Although TMJ overloading induces pain and osteoarthritis, whether neuronal modifications in the trigeminal sensory system contribute to persistent TMJ pain is unknown. Objective: This study investigates changes in excitatory neuropeptides and synaptic transmission proteins in cases of transient and persistent TMJ sensitivity in a rat model. Methods: Rats underwent repeated jaw loading that produces transient (2N-load) or persistent (3.5N-load) sensitivity. In both groups, immunolabeling was used to assess substance P in the spinal trigeminal nucleus caudalis (Sp5C) and glutamate transporter 1 in the ventroposteriomedial thalamus early after loading. Synaptosomal Western blots were used to measure synaptic proteins in the caudal medulla and thalamus at a later time after loading. Results: Substance P increases transiently in the Sp5C early after loading that induces persistent sensitivity. However, glutamate transporter 1 is unchanged in the ventroposteriomedial thalamus. At a later time, synaptosomal Western blots show loss of the presynaptic tethering protein, synapsin, and the inhibitory scaffolding protein, gephyrin, in the thalamus with persistent, but not transient, sensitivity. No changes are identified in synapsin, phosphorylated synapsin, homer, or gephyrin in the caudal medulla. Conclusions: Substance P in the Sp5C and later loss of inhibitory synapses in the thalamus likely contribute to, or indicate, persistent TMJ pain.
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5
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The Source of Hemisensory Disturbances in Complex Regional Pain Syndrome. Clin J Pain 2020; 37:79-85. [DOI: 10.1097/ajp.0000000000000893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/13/2020] [Indexed: 11/26/2022]
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6
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Allison JR, Stone SJ, Pigg M. The painful tooth: mechanisms, presentation and differential diagnosis of odontogenic pain. ACTA ACUST UNITED AC 2020. [DOI: 10.1111/ors.12481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- J. R. Allison
- School of Dental Sciences Faculty of Medical Sciences Newcastle University Newcastle upon Tyne UK
| | - S. J. Stone
- School of Dental Sciences Faculty of Medical Sciences Newcastle University Newcastle upon Tyne UK
| | - M. Pigg
- Department of Endodontics Faculty of Odontology Scandinavian Centre for Orofacial Neurosciences (SCON) Malmö University Malmö Sweden
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Wang Z, Huang S, Yu X, Li L, Yang M, Liang S, Liu W, Tao J. Altered thalamic neurotransmitters metabolism and functional connectivity during the development of chronic constriction injury induced neuropathic pain. Biol Res 2020; 53:36. [PMID: 32843088 PMCID: PMC7448455 DOI: 10.1186/s40659-020-00303-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/08/2020] [Indexed: 11/17/2022] Open
Abstract
Background To investigate the thalamic neurotransmitters and functional connections in the development of chronic constriction injury (CCI)-induced neuropathic pain. Methods The paw withdrawal threshold was measured by mechanical stimulation the right hind paw with the von frey hair in the rats of CCI-induced neuropathic pain. The N-acetylaspartate (NAA) and Glutamate (Glu) in thalamus were detected by magnetic resonance spectrum (MRS) process. The thalamic functional connectivity with other brain regions was scanned by functional magnetic resonance image (fMRI). Results The paw withdrawal threshold of the ipsilateral side showed a noticeable decline during the pathological process. Increased concentrations of Glu and decreased levels of NAA in the thalamus were significantly correlated with mechanical allodynia in the neuropathic pain states. The thalamic regional homogeneity (ReHo) decreased during the process of neuropathic pain. The functional connectivity among the thalamus with the insula and somatosensory cortex were significantly increased at different time points (7, 14, 21 days) after CCI surgery. Conclusion Our study suggests that dynamic changes in thalamic NAA and Glu levels contribute to the thalamic functional connection hyper-excitation during CCI-induced neuropathic pain. Enhanced thalamus-insula functional connection might have a significant effect on the occurrence of neuropathic pain.
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Affiliation(s)
- Zhifu Wang
- College of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Sheng Huang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Xiangmei Yu
- College of Integrated Traditional Chinese and Western Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Long Li
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Minguang Yang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Shengxiang Liang
- National-Local Joint Engineering Research Center of Rehabilitation Medicine Technology, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, Fujian, China.,Fujian Collaborative Innovation Center for Rehabilitation Technology, Fuzhou, 350122, Fujian, China
| | - Weilin Liu
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China
| | - Jing Tao
- College of Rehabilitation Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou, 350122, China.
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8
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Bista P, Imlach WL. Pathological Mechanisms and Therapeutic Targets for Trigeminal Neuropathic Pain. MEDICINES (BASEL, SWITZERLAND) 2019; 6:E91. [PMID: 31443547 PMCID: PMC6789505 DOI: 10.3390/medicines6030091] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/31/2022]
Abstract
Trigeminal neuropathic pain is a chronic pain condition caused by damage or inflammation of the trigeminal nerve or its branches, with both peripheral and central nervous system dysfunction contributing to the disorder. Trigeminal pain conditions present with diagnostic and therapeutic challenges to healthcare providers and often require multiple therapeutic approaches for pain reduction. This review will provide the overview of pathophysiology in peripheral and central nociceptive circuits that are involved in neuropathic pain conditions involving the trigeminal nerve and the current therapeutics that are used to treat these disorders. Recent advances in treatment of trigeminal pain, including novel therapeutics that target ion channels and receptors, gene therapy and monoclonal antibodies that have shown great promise in preclinical studies and clinical trials will also be described.
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Affiliation(s)
- Pawan Bista
- Department of Physiology & Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Wendy L Imlach
- Department of Physiology & Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia.
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9
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Khan J, Puchimada B, Kadouri D, Zusman T, Javed F, Eliav E. The anti-nociceptive effects of Porphyromonas gingivalis lipopolysaccharide. Arch Oral Biol 2019; 102:193-198. [PMID: 31071639 DOI: 10.1016/j.archoralbio.2019.04.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 04/15/2019] [Accepted: 04/19/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE The objective of this study was to assess the effect of Porphyromonas gingivalis lipopolysaccharide (PG LPS) on acute pain-related behaviour induced in rats and to measure its impact on the levels of pro-inflammatory cytokines (IL-1β, IL-6) and anti-inflammatory (IL-10) cytokines. DESIGN The Brennan model was used to induce acute pain like signs in rats' hind paw. Twenty-four hours following the surgery the rats were divided into 5 groups and the affected paws were injected with 0.2 m l of one of three commercialized forms PG LPS doses (high - 1 mg/ml, medium - 0.6 mg/m l and low - 0.2 mg/m l), diclofenac sodium (1 mg/kg) or saline. Tactile allodynia, mechanical hyperalgesia, body temperature and paw swelling were assessed at baseline, 24 h postoperatively and 2 h after the paw injection. The affected and contra-lateral paw tissue was assessed for the mentioned above cytokines levels employing enzyme-linked immunosorbent assay. RESULTS This study may suggest that PG LPS can reduce pain like behaviour via increased levels of anti-inflammatory cytokine IL-10 (5900 ± 748, p < 0.05). The high PG LPS dose and diclofenac reduced the tactile allodynia and mechanical hyperalgesia significantly (42.2 ± 4 and1.6 ± 0.3, p < 0.05). PG LPS high dose increase IL-10 levels while diclofenac reduces IL-1β levels significantly (5900 ± 748 and 1760 ± 271.2). The LPS administration had no effect on paw swelling and did not increase rat's body temperature. CONCLUSION The results demonstrated that PG LPS local application could possess anti- nociceptive properties, which at least in part is mediated by an increase in IL-10 levels.
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Affiliation(s)
- Junad Khan
- Orofacial Pain and Temporomandibular Joint Disorders, Eastman Institute for Oral Health, University of Rochester, 625 Elmwood Avenue, Rochester, NY, 14620, USA.
| | - Bollama Puchimada
- Department of Diagnostic Sciences, Rutgers School of Dental Medicine, NJ, USA
| | - Daniel Kadouri
- Oral Biology, Rutgers School of Dental Medicine, NJ, USA
| | - Tali Zusman
- Department of Diagnostic Sciences, Rutgers School of Dental Medicine, NJ, USA
| | - Fawad Javed
- Department of Periodontology, Stony Brook University, Stony Brook, NY, USA; Laboratory for Periodontal-, Implant-, Phototherapy (LA-PIP), School of Dental Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Eli Eliav
- Eastman Institute for Oral Health, University of Rochester, NY, USA
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10
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Strand J, Stinson C, Bellinger LL, Peng Y, Kramer PR. G i protein functions in thalamic neurons to decrease orofacial nociceptive response. Brain Res 2018; 1694:63-72. [PMID: 29763576 PMCID: PMC6026072 DOI: 10.1016/j.brainres.2018.05.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 02/27/2018] [Accepted: 05/12/2018] [Indexed: 01/01/2023]
Abstract
Orofacial pain includes neuronal pathways that project from the trigeminal nucleus to and through the thalamus. What role the ventroposterior thalamic complex (VP) has on orofacial pain transmission is not understood. To begin to address this question an inhibitory G protein (Gi) designer receptor exclusively activated by a designer drug (DREADD) was transfected in cells of the VP using adeno-associated virus isotype 8. Virus infected cells were identified by a fluorescent tag and immunostaining. Cells were silenced after injecting the designer drug clozapine-n-oxide, which binds the designer receptor activating Gi. Facial rubbing and local field potentials (LFP) in the VP were then recorded in awake, free moving Sprague Dawley rats after formalin injection of the masseter muscle to induce nociception. Formalin injection significantly increased LFP and the nociceptive behavioral response. Activation of DREADD Gi with clozapine-n-oxide significantly reduced LFP in the VP and reduced the orofacial nociceptive response. Because DREADD silencing can result from Gi-coupled inwardly-rectifying potassium channels (GIRK), the GIRK channel blocker tertiapin-Q was injected. Injection of GIRK blocker resulted in an increase in the nociceptive response and increased LFP activity. Immunostaining of the VP for glutamate vesicular transporter (VGLUT2) and gamma-aminobutyric acid vesicular transporter (VGAT) indicated a majority of the virally transfected cells were excitatory (VGLUT2 positive) and a minority were inhibitory (VGAT positive). We conclude first, that inhibition of the excitatory neurons within the VP reduced electrical activity and the orofacial nociceptive response and that the effect on excitatory neurons overwhelmed any change resulting from inhibitor neurons. Second, inhibition of LFP and nociception was due, in part, to GIRK activation.
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Affiliation(s)
- Jennifer Strand
- Department of Psychology, University of Texas at Arlington, Arlington, TX 76019, United States
| | - Crystal Stinson
- Texas A&M University College of Dentistry, Dallas, TX 75246, United States
| | - Larry L Bellinger
- Texas A&M University College of Dentistry, Dallas, TX 75246, United States
| | - Yuan Peng
- Department of Psychology, University of Texas at Arlington, Arlington, TX 76019, United States
| | - Phillip R Kramer
- Texas A&M University College of Dentistry, Dallas, TX 75246, United States.
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11
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Xie YF, Wang J, Bonin RP. Optogenetic exploration and modulation of pain processing. Exp Neurol 2018; 306:117-121. [PMID: 29729250 DOI: 10.1016/j.expneurol.2018.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/21/2018] [Accepted: 05/01/2018] [Indexed: 12/26/2022]
Abstract
Intractable pain is the single most common cause of disability, affecting more than 20% of the population world-wide. There is accordingly a global effort to decipher how changes in nociceptive processing in the peripheral and central nervous systems contribute to the onset and maintenance of chronic pain. The past several years have brought rapid progress in the adaptation of optogenetic approaches to study and manipulate the activity of sensory afferents and spinal cord neurons in freely behaving animals, and to investigate cortical processing and modulation of pain responses. This review discusses methodological advances that underlie this recent progress, and discusses practical considerations for the optogenetic modulation of nociceptive sensory processing.
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Affiliation(s)
- Yu-Feng Xie
- Leslie Dan Faculty of Pharmacy, University of Toronto, Canada.
| | - Jing Wang
- The Department of Osteoporosis, the People's Hospital of Baoan District, Shenzhen, Guangdong Province, China
| | - Robert P Bonin
- Leslie Dan Faculty of Pharmacy, University of Toronto, Canada.
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12
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Yao D, Sessle BJ. Face sensorimotor cortex undergoes neuroplastic changes in a rat model of trigeminal neuropathic pain. Exp Brain Res 2018. [PMID: 29520443 DOI: 10.1007/s00221-018-5226-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Trigeminal nerve injury can result in neuropathic pain behavior and alterations in motor function, but it is unclear if such injury produces neuroplastic alterations in face sensorimotor cortex that could contribute to the alterations in motor function. Therefore, this study aimed to determine if trigeminal nerve injury in a rat neuropathic pain model induces neuroplastic changes in jaw and tongue motor representations in face sensorimotor cortex in association with facial nociceptive behavior. Right infraorbital nerve transection was performed in adult male Sprague-Dawley rats; sham-operated rats served as controls. Nociceptive behavior was assessed by testing facial mechanical sensitivity pre-operatively and post-operatively (1-28 days). Intracortical microstimulation was also applied post-operatively in a series of microelectrode penetrations to map jaw and tongue motor representations in the face sensorimotor cortex by analyzing anterior digastric and genioglossus electromyographic activities evoked by microstimulation at histologically verified sites in face primary somatosensory cortex (face-SI) as well as face primary motor cortex (face-MI). Compared to sham, infraorbital nerve injury induced a significant (2-way repeated-measures analysis of variance, P < 0.001) bilateral decrease in facial mechanical threshold that lasted up to 28 days post-operatively. Nerve injury also induced a significant bilateral decrease compared to sham (P < 0.05) in the number of anterior digastric and/or genioglossus sites in face-MI and in face-SI. These findings indicate that trigeminal nerve injury induces neuroplastic alterations in jaw and tongue motor representations in face sensorimotor cortex that are associated with facial nociceptive behavior and that may contribute to sensorimotor changes following trigeminal nerve injury.
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Affiliation(s)
- Dongyuan Yao
- School of Pharmaceutical Science and Jiangxi Mental Hospital, Nanchang University, 461 Bayi Road, Nanchang, 330006, Jiangxi, China. .,Department of Physiology, Faculty of Dentistry, and Faculty of Medicine, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada.
| | - Barry J Sessle
- Department of Physiology, Faculty of Dentistry, and Faculty of Medicine, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada
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13
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Avivi-Arber L, Seltzer Z, Friedel M, Lerch JP, Moayedi M, Davis KD, Sessle BJ. Widespread Volumetric Brain Changes following Tooth Loss in Female Mice. Front Neuroanat 2017; 10:121. [PMID: 28119577 PMCID: PMC5220047 DOI: 10.3389/fnana.2016.00121] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/01/2016] [Indexed: 12/19/2022] Open
Abstract
Tooth loss is associated with altered sensory, motor, cognitive and emotional functions. These changes vary highly in the population and are accompanied by structural and functional changes in brain regions mediating these functions. It is unclear to what extent this variability in behavior and function is caused by genetic and/or environmental determinants and which brain regions undergo structural plasticity that mediates these changes. Thus, the overall goal of our research program is to identify genetic variants that control structural and functional plasticity following tooth loss. As a step toward this goal, here our aim was to determine whether structural magnetic resonance imaging (sMRI) is sensitive to detect quantifiable volumetric differences in the brains of mice of different genetic background receiving tooth extraction or sham operation. We used 67 adult female mice of 7 strains, comprising the A/J (A) and C57BL/6J (B) strains and a randomly selected sample of 5 of the 23 AXB-BXA strains (AXB1, AXB4, AXB24, BXA14, BXA24) that were produced from the A and B parental mice by recombinations and inbreeding. This panel of 25 inbred strains of genetically diverse inbred strains of mice is used for mapping chromosomal intervals throughout the genome that harbor candidate genes controlling the phenotypic variance of any trait under study. Under general anesthesia, 39 mice received extraction of 3 right maxillary molar teeth and 28 mice received sham operation. On post-extraction day 21, post-mortem whole-brain high-resolution sMRI was used to quantify the volume of 160 brain regions. Compared to sham operation, tooth extraction was associated with a significantly reduced regional and voxel-wise volumes of cortical brain regions involved in processing somatosensory, motor, cognitive and emotional functions, and increased volumes in subcortical sensorimotor and temporal limbic forebrain regions including the amygdala. Additionally, comparison of the 10 BXA14 and 21 BXA24 mice revealed significant volumetric differences between the two strains in several brain regions. These findings highlight the utility of high-resolution sMRI for studying tooth loss-induced structural brain plasticity in mice, and provide a foundation for further phenotyping structural brain changes following tooth loss in the full AXB-BXA panel to facilitate mapping genes that control brain plasticity following orofacial injury.
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Affiliation(s)
- Limor Avivi-Arber
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
| | - Ze'ev Seltzer
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
- Department of Anesthesiology, University Health NetworkToronto, ON, Canada
- Central Institute of Mental Health, University of HeidelbergMannheim, Germany
| | - Miriam Friedel
- Mouse Imaging Centre, Hospital for Sick ChildrenToronto, ON, Canada
| | - Jason P. Lerch
- Mouse Imaging Centre, Hospital for Sick ChildrenToronto, ON, Canada
- Medical Biophysics, Faculty of Medicine, University of TorontoToronto, ON, Canada
| | - Massieh Moayedi
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
| | - Karen D. Davis
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Department of Surgery, University of TorontoToronto, ON, Canada
- Institute of Medical Science, University of TorontoToronto, ON, Canada
- Division of Brain, Imaging and Behaviour - Systems Neuroscience, Krembil Research Institute, Toronto Western Hospital, University Health NetworkToronto, ON, Canada
| | - Barry J. Sessle
- University of Toronto Centre for the Study of Pain, University of TorontoToronto, ON, Canada
- Faculty of Dentistry, University of TorontoToronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of TorontoToronto, ON, Canada
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The role of histamine H1, H2 and H3 receptors of ventral posteromedial nucleus of thalamus in modulation of trigeminal pain. Eur J Pharmacol 2016; 791:696-702. [DOI: 10.1016/j.ejphar.2016.09.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/02/2016] [Accepted: 09/28/2016] [Indexed: 11/19/2022]
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15
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Pun H, Awamleh L, Lee JC, Avivi-Arber L. Decreased face primary motor cortex (face-M1) excitability induced by noxious stimulation of the rat molar tooth pulp is dependent on the functional integrity of medullary astrocytes. Exp Brain Res 2015; 234:645-57. [DOI: 10.1007/s00221-015-4448-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 09/18/2015] [Indexed: 02/03/2023]
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16
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Awamleh L, Pun H, Lee JC, Avivi-Arber L. Decreased face primary motor cortex (face-M1) excitability induced by noxious stimulation of the rat molar tooth pulp is dependent on the functional integrity of face-M1 astrocytes. Exp Brain Res 2015; 233:1261-72. [DOI: 10.1007/s00221-015-4198-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 01/05/2015] [Indexed: 02/04/2023]
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Hansson P. Translational aspects of central sensitization induced by primary afferent activity: what it is and what it is not. Pain 2014; 155:1932-1934. [PMID: 25067835 DOI: 10.1016/j.pain.2014.07.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Per Hansson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden Department of Pain Management and Research, Oslo University Hospital, Oslo, Norway
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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: 31] [Impact Index Per Article: 2.8] [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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Kumar V, Thakur AK, Barothia ND, Chatterjee SS. Therapeutic potentials of Brassica juncea: an overview. ACTA ACUST UNITED AC 2011. [DOI: 10.5667/tang.2011.0005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Chang Z, Okamoto K, Bereiter DA. Differential ascending projections of temporomandibular joint-responsive brainstem neurons to periaqueductal gray and posterior thalamus of male and female rats. Neuroscience 2011; 203:230-43. [PMID: 22155654 DOI: 10.1016/j.neuroscience.2011.11.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 11/13/2011] [Accepted: 11/18/2011] [Indexed: 01/03/2023]
Abstract
Several craniofacial pain conditions, including temporomandibular joint disorders (TMJDs), are more prevalent in women than men. The basis for sex differences in deep craniofacial pain is not known. The present study compared the magnitude of ascending projections from temporomandibular joint (TMJ)-responsive neurons in trigeminal brainstem with the ventrolateral periaqueductal gray (vlPAG) or posterior nucleus of the thalamus (Po) in males and female rats. Fluorogold (FG) was injected into vlPAG or Po, and TMJ-responsive neurons were identified by Fos-like immunoreactivity (Fos-LI) after mustard oil injection. TMJ-evoked Fos-LI was similar in males and females; however, significant differences in cell counts were seen for FG single-labeled and Fos/FG double-labeled neurons in trigeminal brainstem. After vlPAG injections, the number of FG-labeled neurons in trigeminal subnucleus interpolaris (Vi), ventral interpolaris/caudalis transition (vl-Vi/Vc), and dorsal paratrigeminal region (dPa5) was greater in females than males. The percentage of Fos/FG double-labeled neurons in vl-Vi/Vc and dPa5 after vlPAG injection also was greater in females than males. In contrast, after Po injections, males displayed a greater number of FG-labeled neurons in superficial laminae (Lam I/II) of trigeminal subnucleus caudalis (Vc) and upper cervical spinal cord (C(1-2)) and deeper laminae (Lam III/V) at C(1-2) than females. The percentage of Fos/FG double-labeled neurons in Lam I/II of Vc after Po injection also was greater in males than females. These data revealed significant sex differences in ascending projections from TMJ-responsive neurons in trigeminal brainstem. Such differences may influence the ability of males and females to recruit autonomic reflexes and endogenous pain control circuits relevant for TMJ nociception.
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Affiliation(s)
- Z Chang
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, 18-214 Moos Tower, 515 Delaware Street Southeast, Minneapolis, MN 55455, USA
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Itoh K, Chiang CY, Li Z, Lee JC, Dostrovsky JO, Sessle BJ. Central sensitization of nociceptive neurons in rat medullary dorsal horn involves purinergic P2X7 receptors. Neuroscience 2011; 192:721-31. [PMID: 21763757 PMCID: PMC3172718 DOI: 10.1016/j.neuroscience.2011.06.083] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/13/2011] [Accepted: 06/28/2011] [Indexed: 12/22/2022]
Abstract
Central sensitization is a crucial process underlying the increased neuronal excitability of nociceptive pathways following peripheral tissue injury and inflammation. Our previous findings have suggested that extracellular adenosine 5'-triphosphate (ATP) molecules acting at purinergic receptors located on presynaptic terminals (e.g., P2X2/3, P2X3 subunits) and glial cells are involved in the glutamatergic-dependent central sensitization induced in medullary dorsal horn (MDH) nociceptive neurons by application to the tooth pulp of the inflammatory irritant mustard oil (MO). Since growing evidence indicates that activation of P2X7 receptors located on glia is involved in chronic inflammatory and neuropathic pain, the aim of the present study was to test in vivo for P2X7 receptor involvement in this acute inflammatory pain model. Experiments were carried out in anesthetized Sprague-Dawley male rats. Single unit recordings were made in MDH functionally identified nociceptive neurons for which mechanoreceptive field, mechanical activation threshold and responses to noxious stimuli were tested. We found that continuous intrathecal (i.t.) superfusion over MDH of the potent P2X7 receptor antagonists brilliant blue G and periodated oxidized ATP could each significantly attenuate the MO-induced MDH central sensitization. MDH central sensitization could also be produced by i.t. superfusion of ATP and even more effectively by the P2X7 receptor agonist benzoylbenzoyl ATP. Superfusion of the microglial blocker minocycline abolished the MO-induced MDH central sensitization, consistent with reports that dorsal horn P2X7 receptors are mostly expressed on microglia. In control experiments, superfusion over MDH of vehicle did not produce any significant changes. These novel findings suggest that activation of P2X7 receptors in vivo may be involved in the development of central sensitization in an acute inflammatory pain model.
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Affiliation(s)
- Kazunori Itoh
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6
| | - Chen-Yu Chiang
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6
| | - Zhaohui Li
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6
| | - Jye-Chang Lee
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6
| | - Jonathan O. Dostrovsky
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6
- Department of Physiology, Faculty of Medicine, University of Toronto, Ontario, Canada M5S 1A8
| | - Barry J. Sessle
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada M5G 1G6
- Department of Physiology, Faculty of Medicine, University of Toronto, Ontario, Canada M5S 1A8
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Kobayashi A, Shinoda M, Sessle BJ, Honda K, Imamura Y, Hitomi S, Tsuboi Y, Okada-Ogawa A, Iwata K. Mechanisms involved in extraterritorial facial pain following cervical spinal nerve injury in rats. Mol Pain 2011; 7:12. [PMID: 21310020 PMCID: PMC3048571 DOI: 10.1186/1744-8069-7-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 02/10/2011] [Indexed: 11/21/2022] Open
Abstract
Background The aim of this study is to clarify the neural mechanisms underlying orofacial pain abnormalities after cervical spinal nerve injury. Nocifensive behavior, phosphorylated extracellular signal-regulated kinase (pERK) expression and astroglial cell activation in the trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal dorsal horn (C1-C2) neurons were analyzed in rats with upper cervical spinal nerve transection (CNX). Results The head withdrawal threshold to mechanical stimulation of the lateral facial skin and head withdrawal latency to heating of the lateral facial skin were significantly lower and shorter respectively in CNX rats compared to Sham rats. These nocifensive effects were apparent within 1 day after CNX and lasted for more than 21 days. The numbers of pERK-like immunoreactive (LI) cells in superficial laminae of Vc and C1-C2 were significantly larger in CNX rats compared to Sham rats following noxious and non-noxious mechanical or thermal stimulation of the lateral facial skin at day 7 after CNX. Two peaks of pERK-LI cells were observed in Vc and C1-C2 following mechanical and heat stimulation of the lateral face. The number of pERK-LI cells in C1-C2 was intensity-dependent and increased when the mechanical and heat stimulations of the face were increased. The decrements of head withdrawal latency to heat and head withdrawal threshold to mechanical stimulation were reversed during intrathecal (i.t.) administration of MAPK/ERK kinase 1/2 inhibitor PD98059. The area of activated astroglial cells was significantly higher in CNX rats (at day 7 after CNX). The heat and mechanical nocifensive behaviors were significantly depressed and the number of pERK-LI cells in Vc and C1-C2 following noxious and non-noxious mechanical stimulation of the face was also significantly decreased following i.t. administration of the astroglial inhibitor fluoroacetate. Conclusions The present findings have demonstrated that mechanical allodynia and thermal hyperalgesia occur in the lateral facial skin after CNX and also suggest that ERK phosphorylation of Vc and C1-C2 neurons and astroglial cell activation are involved in orofacial extraterritorial pain following cervical nerve injury.
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Affiliation(s)
- Azusa Kobayashi
- Department of Oral Diagnosis, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo, 101-8310, Japan
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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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Park J, Clark G, Kim Y, Chung J. Analysis of thermal pain sensitivity and psychological profiles in different subgroups of TMD patients. Int J Oral Maxillofac Surg 2010; 39:968-74. [DOI: 10.1016/j.ijom.2010.06.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Revised: 04/23/2010] [Accepted: 06/02/2010] [Indexed: 10/19/2022]
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Abstract
Pain is one of the most common reasons for which patients seek dental and medical care. Orofacial pain conditions consist of a wide range of disorders including odontalgia (toothache), temporomandibular disorders, trigeminal neuralgia and others. Most of these conditions are either inflammatory or neuropathic in nature. This chapter provides an overview of the commonly used models to study inflammatory and neuropathic orofacial pain.
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Affiliation(s)
- Asma Khan
- Department of Endodontics, University of North Carolina, Chapel Hill, NC, USA
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Jeong Y, Holden JE. Lateral Hypothalamic-Induced Alpha-Adrenoceptor Modulation Occurs in a Model of Inflammatory Pain in Rats. Biol Res Nurs 2009; 10:331-9. [DOI: 10.1177/1099800408325053] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Previous work from our lab showed that stimulation of the lateral hypothalamus (LH) produces analgesia (antinociception) in a model of thermal nociceptive pain. This antinociceptive effect is mediated by α2-adrenoceptors in the spinal cord dorsal horn. However, a concomitant, opposing hyperalgesic (pro-nociceptive) response also occurs, which is mediated by α1-adrenoceptors in the dorsal horn. Antinociception predominates but is attenuated by the pronociceptive response. To determine whether such an effect occurs in a model of inflammatory pain, we applied mustard oil (allyl isothiocyanate; 20 μl) to the left ankle of female Sprague-Dawley rats. We then stimulated the LH using carbamylcholine chloride (carbachol; 125 nmol). The foot withdrawal latencies were measured. Some rats received intrathecal α-adrenoceptor antagonists to determine whether the opposing α-adrenoceptor response was present. Mustard oil application produced hyperalgesia in the affected paw, while the LH stimulation increased the foot withdrawal latencies for the mustard oil paw as compared to the control group. Following carbachol microinjection in the LH, WB4101, an α1-adrenoceptor antagonist, produced significantly longer foot withdrawal latencies compared to saline controls, while yohimbine, an α2-antagonist, decreased the foot withdrawal latencies from 10 min postinjection ( p < .05). These findings support the hypothesis that the LH-induced nociceptive modulation is mediated through an α-adrenoceptor opposing response in a model of inflammatory pain.
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Affiliation(s)
- Younhee Jeong
- College of Nursing Science, Kyunghee University, Seoul,
Korea
| | - Janean E. Holden
- University of Illinois at Chicago, and Department of
Medical-Surgical Nursing, College of Nursing, Chicago, Illinois,
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Haidarliu S, Yu C, Rubin N, Ahissar E. Lemniscal and Extralemniscal Compartments in the VPM of the Rat. Front Neuroanat 2008; 2:4. [PMID: 18958201 PMCID: PMC2567104 DOI: 10.3389/neuro.05.004.2008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 09/02/2008] [Indexed: 11/18/2022] Open
Abstract
The ventral posteromedial thalamic nucleus (VPM) of the rat contains at least two major vibrissa-representing compartments: the dorsomedial (VPMdm), which belongs to the lemniscal afferent pathway, and the ventrolateral (VPMvl), which belongs to the extralemniscal afferent pathway. Although input–output projections and functional characteristics that distinguish these two compartments were recently clarified, a comprehensive structural analysis of these compartments and the border between them was lacking. This paper addresses structural and functional relationships between the VPMdm and VPMvl. We found that the size of the VPM is almost constant across individual rats. Next, we computed a canonical map of the VPM in the oblique plane, where structural borders are best visualized. Using the canonical map, and sequential slices cut in oblique and coronal planes, we determined the border between the VPMdm and VPMvl in the standard coronal plane, and verified it with in vivo extracellular recordings. The position of the border between these two vibrissal sub-nuclei changes along the rostrocaudal extent within the VPM due to the relative sizes of these sub-nuclei at any point. The border between the VPMdm and VPMvl, which was revealed by this technique, can now be included in atlases of the rat brain and should facilitate experimental correlation of tactile functions with thalamic regions.
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Affiliation(s)
- Sebastian Haidarliu
- Department of Neurobiology, The Weizmann Institute of Science Rehovot, Israel
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MARKOWITZ K, PASHLEY DH. Discovering new treatments for sensitive teeth: the long path from biology to therapy. J Oral Rehabil 2008; 35:300-15. [DOI: 10.1111/j.1365-2842.2007.01798.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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31
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Bermejo Velasco PE, Velasco Calvo R. Nuevos fármacos antiepilépticos y dolor neuropático. De la medicina molecular a la clínica. Med Clin (Barc) 2007; 129:542-50. [DOI: 10.1157/13111432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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32
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FRISTAD INGE, BLETSA ATHANASIA, BYERS MARGARET. Inflammatory nerve responses in the dental pulp. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1601-1546.2010.00247.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Park SJ, Zhang S, Chiang CY, Hu JW, Dostrovsky JO, Sessle BJ. Central sensitization induced in thalamic nociceptive neurons by tooth pulp stimulation is dependent on the functional integrity of trigeminal brainstem subnucleus caudalis but not subnucleus oralis. Brain Res 2006; 1112:134-45. [PMID: 16930568 DOI: 10.1016/j.brainres.2006.06.115] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 06/23/2006] [Accepted: 06/25/2006] [Indexed: 11/21/2022]
Abstract
We have previously demonstrated that application of the inflammatory irritant mustard oil (MO) to the rat molar tooth pulp induces central sensitization in nociceptive neurons within the contralateral ventroposterior medial (VPM) nucleus and posterior nuclear group (PO) of the thalamus as well as brainstem subnucleus caudalis (Vc) and subnucleus oralis (Vo). Since Vc and Vo are important relays of pulp afferent input to thalamus, the aim of this study was to test if local application of the synaptic blocker CoCl2 to Vc or Vo influences the pulp-induced thalamic central sensitization. The activity of 32 nociceptive-specific (NS) neurons within the rat VPM and immediately adjacent PO was recorded. Spontaneous activity, mechanoreceptive field (RF), mechanical activation threshold and evoked responses to graded mechanical stimuli were assessed before and after MO application to the pulp. MO application evoked immediate but short-lasting neuronal discharges in 21 of the 32 NS neurons tested, as well as central sensitization reflected in significant and long-lasting (> 60 min) RF expansion, decrease in activation threshold, and increase in graded pinch-evoked responses in all 32 NS neurons. CoCl2 applied to the ipsilateral Vc significantly attenuated these pulp-induced changes for 20 min or more. In contrast, CoCl2 applied to the ipsilateral Vo did not reverse this MO-induced central sensitization. Isotonic saline applied to Vc or Vo was also ineffective. These findings indicate that central sensitization induced in nociceptive neurons within VPM and PO by noxious stimulation of the tooth pulp is dependent upon the functional integrity of Vc but not Vo.
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Affiliation(s)
- Soo Joung Park
- Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, ON, Canada M5G 1G6
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