1
|
Sadighparvar S, Al-Hamed FS, Sharif-Naeini R, Meloto CB. Preclinical orofacial pain assays and measures and chronic primary orofacial pain research: where we are and where we need to go. FRONTIERS IN PAIN RESEARCH 2023; 4:1150749. [PMID: 37293433 PMCID: PMC10244561 DOI: 10.3389/fpain.2023.1150749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/11/2023] [Indexed: 06/10/2023] Open
Abstract
Chronic primary orofacial pain (OFP) conditions such as painful temporomandibular disorders (pTMDs; i.e., myofascial pain and arthralgia), idiopathic trigeminal neuralgia (TN), and burning mouth syndrome (BMS) are seemingly idiopathic, but evidence support complex and multifactorial etiology and pathophysiology. Important fragments of this complex array of factors have been identified over the years largely with the help of preclinical studies. However, findings have yet to translate into better pain care for chronic OFP patients. The need to develop preclinical assays that better simulate the etiology, pathophysiology, and clinical symptoms of OFP patients and to assess OFP measures consistent with their clinical symptoms is a challenge that needs to be overcome to support this translation process. In this review, we describe rodent assays and OFP pain measures that can be used in support of chronic primary OFP research, in specific pTMDs, TN, and BMS. We discuss their suitability and limitations considering the current knowledge of the etiology and pathophysiology of these conditions and suggest possible future directions. Our goal is to foster the development of innovative animal models with greater translatability and potential to lead to better care for patients living with chronic primary OFP.
Collapse
Affiliation(s)
- Shirin Sadighparvar
- Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
| | | | - Reza Sharif-Naeini
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Department of Physiology and Cell Information Systems, McGill University, Montreal, QC, Canada
| | - Carolina Beraldo Meloto
- The Alan Edwards Centre for Research on Pain, McGill University, Montreal, QC, Canada
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC, Canada
| |
Collapse
|
2
|
Liu J, Jia S, Huang F, He H, Fan W. Peripheral role of glutamate in orofacial pain. Front Neurosci 2022; 16:929136. [PMID: 36440288 PMCID: PMC9682037 DOI: 10.3389/fnins.2022.929136] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 10/10/2022] [Indexed: 09/10/2023] Open
Abstract
Glutamate is the principal excitatory neurotransmitter in the central nervous system. In the periphery, glutamate acts as a transmitter and involves in the signaling and processing of sensory input. Glutamate acts at several types of receptors and also interacts with other transmitters/mediators under various physiological and pathophysiological conditions including chronic pain. The increasing amount of evidence suggests that glutamate may play a role through multiple mechanisms in orofacial pain processing. In this study, we reviewed the current understanding of how peripheral glutamate mediates orofacial pain, how glutamate is regulated in the periphery, and how these findings are translated into therapies for pain conditions.
Collapse
Affiliation(s)
- Jinyue Liu
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Shilin Jia
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Fang Huang
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Hongwen He
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Wenguo Fan
- Hospital of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, China
| |
Collapse
|
3
|
Yao D, Li J, Yoshida M, Sessle BJ. NMDA and purinergic processes modulate neck muscle activity evoked by noxious stimulation of dura. J Oral Pathol Med 2020; 49:547-554. [PMID: 32531859 DOI: 10.1111/jop.13072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/04/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Adenosine triphosphate (ATP) and glutamate are associated with some headache conditions, and purinergic (P2X) and glutamatergic N-methyl-D-aspartate (NMDA) receptor-related processes in the medulla can modulate the effects of trigeminal nociceptive afferent inputs into the brainstem on craniofacial sensorimotor circuits. This study aimed to test whether neck muscle activity can be induced in rats by noxious stimulation of the frontal dura or superior sagittal sinus that involves P2X or NMDA receptor-dependent mechanisms. METHODS While electromyographic activities of neck and craniofacial muscles were being recorded in anesthetized rats (n = 46), the inflammatory irritant mustard oil (0.2 µL, 20% MO) or vehicle (mineral oil) was topically applied to the dura or sinus, preceded by 10 µL of the ATP antagonist 2',3'-O-(2,4,6- trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP, 0.1 mmol/L; n = 8) or 2-amino-5-phosphonopentanoic acid (APV, 0.05 mmol/L; n = 7) or phosphate-buffered saline (PBS as vehicle control; n = 10). RESULTS Application of MO but not vehicle to the frontal dura significantly increased (P < .05) neck electromyographic activity whereas MO application to the superior sagittal sinus did not significantly increase neck electromyographic activity unless MO had previously been applied to the dura. Pre-treatment (i.t.) with TNP-ATP or APV but not vehicle control significantly reduced neck electromyographic activity evoked by MO application to the dura. CONCLUSIONS These data suggest that noxious stimulation of the frontal dura (but not superior sagittal sinus) may enhance neck muscle activity that is P2X and NMDA receptor-dependent. These effects may contribute to neck muscle stiffness that occurs in some headache conditions.
Collapse
Affiliation(s)
- Dongyuan Yao
- Neurological Institute of Jiangxi Province and Department of Neurology, Jiangxi Provincial People's Hospital and School of Pharmaceutical Science, Nanchang University, Nanchang, China.,Faculty of Dentistry and Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Jian Li
- Department of Prosthodontics, School and Hospital of Stomatology and National Clinical Research Center for Oral Diseases, Peking University, Beijing, China
| | - Mitsuhiro Yoshida
- Section of Dental Anesthesiology, Department of Oral and Maxillofacial Surgery and Oral Medicine, Hiroshima University Hospital, Hiroshima, Japan
| | - Barry J Sessle
- Faculty of Dentistry and Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
4
|
Filippini HF, Molska GR, Zanjir M, Arudchelvan Y, Gong SG, Campos MM, Avivi-Arber L, Sessle BJ. Toll-Like Receptor 4 in the Rat Caudal Medulla Mediates Tooth Pulp Inflammatory Pain. Front Neurosci 2020; 14:643. [PMID: 32655361 PMCID: PMC7324534 DOI: 10.3389/fnins.2020.00643] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 05/25/2020] [Indexed: 12/20/2022] Open
Abstract
The aims of this study were to investigate if Toll-like receptor 4 (TLR4) is expressed in the medullary dorsal horn (MDH) and if medullary application of a TLR4 antagonist (lipopolysaccharides from Rhodobacter sphaeroides, LPS-RS) can attenuate changes in nociceptive sensorimotor responses or TLR4 expression that might be evoked by mustard oil (MO) application to the right maxillary first molar tooth pulp. Of 41 adult male Sprague-Dawley rats used in the study, 23 received intrathecal application of the TLR4 antagonist LPS-RS (25 μg/10 μl; LPS-RS group) or isotonic saline (10 μl; vehicle control group) 10 min before pulpal application of MO (95%; 0.2 μl). Bilateral electromyographic (EMG) activities of the anterior digastric and masseter muscles were recorded continuously before and until 15 min after the MO application to the pulp. In 6 of these 23 rats and an additional 18 rats, the caudal medulla containing the ipsilateral and contralateral MDH was removed after euthanasia for subsequent Western Blot analysis of TLR4 expression in LPS-RS (n = 8) and vehicle (n = 8) groups and a naïve group (n = 8). The % change from baseline in the MO-evoked EMG activities within the anterior digastric muscles were significantly smaller in the LPS-RS group than the control group (two-way ANOVA, post hoc Bonferroni, P < 0.0001). Western Blot analysis revealed similar levels of TLR4 expression in the caudal medulla of the naïve, vehicle and LPS-RS groups. These novel findings suggest that TLR4 signaling in the caudal medulla may mediate MO-induced acute dental inflammatory pain in rats.
Collapse
Affiliation(s)
- Helena F Filippini
- Programa de Pós-graduação em Odontologia, Escola de Ciência da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.,Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | | | - Maryam Zanjir
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | | | - Siew-Ging Gong
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Maria M Campos
- Programa de Pós-graduação em Odontologia, Escola de Ciência da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.,Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Limor Avivi-Arber
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.,Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada
| | - Barry J Sessle
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.,Centre for the Study of Pain, University of Toronto, Toronto, ON, Canada.,Departament of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
5
|
Sulfated polysaccharide from the green marine algae Caulerpa racemosa reduces experimental pain in the rat temporomandibular joint. Int J Biol Macromol 2020; 150:253-260. [DOI: 10.1016/j.ijbiomac.2020.01.272] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/20/2020] [Accepted: 01/27/2020] [Indexed: 01/13/2023]
|
6
|
Early Phase of Type 1 Diabetes Decreases the Responsiveness of C-Fiber Nociceptors in the Temporomandibular Joint of Rats. Neuroscience 2019; 416:229-238. [DOI: 10.1016/j.neuroscience.2019.08.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 01/19/2023]
|
7
|
Lamana SMS, Napimoga MH, Nascimento APC, Freitas FF, de Araujo DR, Quinteiro MS, Macedo CG, Fogaça CL, Clemente-Napimoga JT. The anti-inflammatory effect of tramadol in the temporomandibular joint of rats. Eur J Pharmacol 2017; 807:82-90. [PMID: 28412371 DOI: 10.1016/j.ejphar.2017.04.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/05/2017] [Accepted: 04/11/2017] [Indexed: 12/27/2022]
Abstract
Tramadol is a centrally acting analgesic drug able to prevent nociceptor sensitization when administered into the temporomandibular joint (TMJ) of rats. The mechanism underlying the peripheral anti-inflammatory effect of tramadol remains unknown. This study demonstrated that intra-TMJ injection of tramadol (500µg/TMJ) was able to inhibit the nociceptive response induced by 1.5% formalin or 1.5% capsaicin, suggesting that tramadol has an antinociceptive effect, acting directly on the primary nociceptive neurons activating the nitric oxide/cyclic guanosine monophosphate signaling pathway. Tramadol also inhibited the nociceptive response induced by carrageenan (100µg/TMJ) or 5-hydroxytryptamine (225µg/TMJ) along with inhibition of inflammatory cytokines levels, leukocytes migration and plasma extravasation. In conclusion, the results demonstrate that peripheral administration of tramadol has a potential antinociceptive and anti-inflammatory effect. The antinociceptive effect is mediated by activation of the intracellular nitric oxide/cyclic guanosine monophosphate pathway, at least in part, independently from the opioid system.
Collapse
Affiliation(s)
- Simone Monaliza S Lamana
- Department of Physiological Sciences, Laboratory of Orofacial Pain, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
| | - Marcelo H Napimoga
- Laboratory of Immunology and Molecular Biology, São Leopoldo Mandic Institute and Research Center, Campinas, SP, Brazil
| | - Ana Paula Camatta Nascimento
- Laboratory of Immunology and Molecular Biology, São Leopoldo Mandic Institute and Research Center, Campinas, SP, Brazil
| | - Fabiana F Freitas
- Department of Physiological Sciences, Laboratory of Orofacial Pain, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
| | - Daniele R de Araujo
- Center of Human and Natural Sciences, Federal University of ABC, Santo André, SP, Brazil
| | - Mariana S Quinteiro
- Department of Physiological Sciences, Laboratory of Orofacial Pain, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
| | - Cristina G Macedo
- Department of Physiological Sciences, Laboratory of Orofacial Pain, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil; Laboratory of Immunology and Molecular Biology, São Leopoldo Mandic Institute and Research Center, Campinas, SP, Brazil
| | - Carlos L Fogaça
- Department of Physiological Sciences, Laboratory of Orofacial Pain, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil
| | - Juliana T Clemente-Napimoga
- Department of Physiological Sciences, Laboratory of Orofacial Pain, Piracicaba Dental School, University of Campinas - UNICAMP, Piracicaba, SP, Brazil; Laboratory of Immunology and Molecular Biology, São Leopoldo Mandic Institute and Research Center, Campinas, SP, Brazil.
| |
Collapse
|
8
|
Ke T, Li R, Chen W. Inhibition of the NMDA receptor protects the rat sciatic nerve against ischemia/reperfusion injury. Exp Ther Med 2016; 11:1563-1572. [PMID: 27168774 PMCID: PMC4840580 DOI: 10.3892/etm.2016.3148] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 11/25/2015] [Indexed: 12/23/2022] Open
Abstract
Inhibition of the N-methyl-D-aspartate (NMDA) receptor by MK-801 reduces ischemia/reperfusion (I/R) injury in the central nervous system. However, few previous studies have evaluated the neuroprotective effects of MK-801 against peripheral I/R injury. The present study aimed to investigate the protective effects of MK-801 pretreatment against I/R injury in the rat sciatic nerve (SN). Sprague-Dawley rats were subjected to a sham surgery (n=8) or to a 5-h ischemic insult by femoral artery clamping (I/R and I/R+MK-801 groups; n=48 per group). I/R+MK-801 rats were intraperitoneally injected with MK-801 (0.5 ml or 1 mg/kg) at 15 min prior to reperfusion. The rats were sacrificed at 0, 6, 12, 24, 72 h, or 7 days following reperfusion. Plasma malondialdehyde (MDA) and nitric oxide (NO) concentrations, and SN inducible NO synthase (iNOS) protein expression levels, were measured using colorimetry. In addition, the protein expression levels of tumor necrosis factor-α (TNF-α) were measured using immunohistochemistry, and histological analyses of the rat SN were conducted using light and electron microscopy. Alterations in the mRNA expression levels of TNF-α and TNF-α converting enzyme (TACE) in the rat SN were detected using reverse transcription-quantitative polymerase chain reaction. In the I/R group, plasma concentrations of NO (175.3±4.2 µmol/l) and MDA (16.2±1.9 mmol/l), and the levels of iNOS (2.5±0.3) in the SN, peaked at 24 h post-reperfusion. At 24 h, pretreatment with MK-801 significantly reduced plasma NO (107.3±3.6 µmol/l) and MDA (11.8±1.6 mmol/l), and SN iNOS (1.65±0.2) levels (all P<0.01). The mRNA expression levels of TNF-α and TACE in the SN were significantly reduced in the I/R+MK-801 group, as compared with the I/R group (P<0.05). Furthermore, MK-801 pretreatment was shown to have alleviated histological signs of I/R injury, including immune cell infiltration and axon demyelination. The results of the present study suggested that pretreatment with MK-801 may alleviate I/R injury of the SN by inhibiting the activation of TNF-α and reducing the levels of iNOS in the SN.
Collapse
Affiliation(s)
- Tie Ke
- Department of Emergency Surgery, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, Fujian 350001, P.R. China; Emergency Center of Fujian Province, Fujian Medical University, Fuzhou, Fujian 350001, P.R. China; Provincial Clinical Medical College, Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| | - Renbin Li
- Department of Orthopedics, The Affiliated Fuzhou Second Hospital, Xiamen University, Fuzhou, Fujian 350007, P.R. China
| | - Wenchang Chen
- Department of Emergency Surgery, Fujian Provincial Hospital, Fujian Medical University, Fuzhou, Fujian 350001, P.R. China
| |
Collapse
|
9
|
Hawkins JL, Durham PL. Prolonged Jaw Opening Promotes Nociception and Enhanced Cytokine Expression. J Oral Facial Pain Headache 2016; 30:34-41. [PMID: 26817031 PMCID: PMC5894825 DOI: 10.11607/ofph.1557] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
AIMS To test the hypothesis that prolonged jaw opening, as can occur during routine dental procedures, increases nociceptive sensitivity of the masseter muscle and increases cytokine expression. METHODS Sprague-Dawley rats were used to investigate behavioral and cellular changes in response to prolonged jaw opening. A surgical retractor was placed around the maxillary and mandibular incisors, and the jaw was held at near maximal opening for 20 minutes. Head-withdrawal responses to mechanical stimuli applied to the facial skin overlying the left and right masseter muscles were determined following jaw opening. Cytokine levels in the upper cervical spinal cord containing the caudal part of the spinal trigeminal nucleus were evaluated using protein antibody microarrays (n = 3). Statistical analysis was performed using a nonparametric Mann-Whitney U test. RESULTS Prolonged jaw opening significantly increased nocifensive head withdrawal to mechanical stimuli at 2 hours, and days 3 and 7 postinduction (P < .05). The increase in nociceptive response resolved after 14 days. Sustained jaw opening also stimulated differential cytokine expression in the trigeminal ganglion and upper cervical spinal cord that persisted 14 days postprocedure (P < .05). CONCLUSION These findings provide evidence that near maximal jaw opening can lead to activation and prolonged sensitization of trigeminal neurons that results in nociceptive behavior evoked by stimulation of the masseter muscle, a physiologic event often associated with temporomandibular disorders (TMD). Results from this study may provide a plausible explanation for why some patients develop TMD after routine dental procedures that involve prolonged jaw opening.
Collapse
|
10
|
Narita N, Kumar N, Cherkas PS, Chiang CY, Dostrovsky JO, Coderre TJ, Sessle BJ. Systemic pregabalin attenuates sensorimotor responses and medullary glutamate release in inflammatory tooth pain model. Neuroscience 2012; 218:359-66. [PMID: 22609939 DOI: 10.1016/j.neuroscience.2012.05.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2012] [Revised: 04/18/2012] [Accepted: 05/04/2012] [Indexed: 11/16/2022]
Abstract
Our previous studies have demonstrated that application of inflammatory irritant mustard oil (MO) to the tooth pulp induces medullary glutamate release and central sensitization in the rat medullary dorsal horn (MDH), as well as nociceptive sensorimotor responses in craniofacial muscles in rats. There is recent evidence that anticonvulsant drugs such as pregabalin that influence glutamatergic neurotransmission are effective in several pain states. The aim of this study was to examine whether systemic administration of pregabalin attenuated glutamate release in the medulla as well as these nociceptive effects reflected in increased electromyographic (EMG) activity induced by MO application to the tooth pulp. Male adult rats were anesthetized with isofluorane (1.0-1.2%), and jaw and tongue muscle EMG activities were recorded by needle electrodes inserted bilaterally into masseter and anterior digastric muscles and into the genioglossus muscle, and also the medullary release of glutamate was assessed by in vivo microdialysis. Pregabalin or vehicle control (isotonic saline) was administered 30 min before the pulpal application of MO or vehicle control (mineral oil). Application of mineral oil to the maxillary first molar tooth pulp produced no change in baseline EMG activity and glutamate release. However, application of MO to the pulp significantly increased both the medullary release of glutamate and EMG activity in the jaw and tongue muscles for several minutes. In contrast, pre-medication with pregabalin, but not vehicle control, significantly and dose-dependently attenuated the medullary glutamate release and EMG activity in these muscles after MO application to the tooth pulp (analysis of variance (ANOVA), p<0.05). These results suggest that pregabalin may attenuate the medullary release of glutamate and associated nociceptive sensorimotor responses in this acute inflammatory pulpal pain model, and that it may prove useful for the treatment of orofacial inflammatory pain states.
Collapse
Affiliation(s)
- N Narita
- Nihon University School of Dentistry at Matsudo, Department of Removable Prosthodontics, 2-870-1, Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan.
| | | | | | | | | | | | | |
Collapse
|
11
|
Jennings EA, Williams MC, Staikopoulos V, Ivanusic JJ. Neurobiology of Temporomandibular Joint Pain: Therapeutic Implications. Semin Orthod 2012. [DOI: 10.1053/j.sodo.2011.10.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
12
|
Peripheral glutamate receptors are required for hyperalgesia induced by capsaicin. PAIN RESEARCH AND TREATMENT 2011; 2012:915706. [PMID: 22110945 PMCID: PMC3199092 DOI: 10.1155/2012/915706] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Accepted: 08/06/2011] [Indexed: 12/25/2022]
Abstract
Transient receptor potential vanilloid1 (TRPV1) and glutamate receptors (GluRs) are located in small diameter primary afferent neurons (nociceptors), and it was speculated that glutamate released in the peripheral tissue in response to activation of TRPV1 might activate nociceptors retrogradely. But, it was not clear which types of GluRs are functioning in the nociceptive sensory transmission. In the present study, we examined the c-Fos expression in spinal cord dorsal horn following injection of drugs associated with glutamate receptors with/without capsaicin into the hindpaw. The subcutaneous injection of capsaicin or glutamate remarkably evoked c-Fos expression in ipsilateral sides of spinal cord dorsal horn. This capsaicin evoked increase of c-Fos expression was significantly prevented by concomitant administration of MK801, CNQX, and CPCCOEt. On the other hand, there were not any significant changes in coinjection of capsaicin and MCCG or MSOP. These results reveal that the activation of iGluRs and group I mGluR in peripheral afferent nerves play an important role in mechanisms whereby capsaicin evokes/maintains nociceptive responses.
Collapse
|
13
|
Honda K, Noma N, Shinoda M, Miyamoto M, Katagiri A, Kita D, Liu MG, Sessle BJ, Yasuda M, Iwata K. Involvement of peripheral ionotropic glutamate receptors in orofacial thermal hyperalgesia in rats. Mol Pain 2011; 7:75. [PMID: 21952000 PMCID: PMC3216263 DOI: 10.1186/1744-8069-7-75] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 09/28/2011] [Indexed: 11/10/2022] Open
Abstract
Background The purpose of the present study was to elucidate the mechanisms that may underlie the sensitization of trigeminal spinal subnucleus caudalis (Vc) and upper cervical spinal cord (C1-C2) neurons to heat or cold stimulation of the orofacial region following glutamate (Glu) injection. Results Glu application to the tongue or whisker pad skin caused an enhancement of head-withdrawal reflex and extracellular signal-regulated kinase (ERK) phosphorylation in Vc-C2 neurons. Head-withdrawal reflex and ERK phosphorylation were also enhanced following cold stimulation of the tongue but not whisker pad skin in Glu-injected rats, and the head-withdrawal reflex and ERK phosphorylation were enhanced following heat stimulation of the tongue or whisker pad skin. The enhanced head-withdrawal reflex and ERK phosphorylation after heat stimulation of the tongue or whisker pad skin, and those following cold stimulation of the tongue but not whisker pad skin were suppressed following ionotropic glutamate receptor antagonists administration into the tongue or whisker pad skin. Furthermore, intrathecal administration of MEK1/2 inhibitor PD98059 caused significant suppression of enhanced head-withdrawal reflex in Glu-injected rats, heat head-withdrawal reflex in the rats with Glu injection into the tongue or whisker pad skin and cold head-withdrawal reflex in the rats with Glu injection into the tongue. Conclusions The present findings suggest that peripheral Glu receptor mechanisms may contribute to cold hyperalgesia in the tongue but not in the facial skin, and also contribute to heat hyperalgesia in the tongue and facial skin, and that the mitogen-activated protein kinase cascade in Vc-C2 neurons may be involved in these Glu-evoked hyperalgesic effects.
Collapse
Affiliation(s)
- Kuniya Honda
- Department of Physiology, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
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.
Collapse
Affiliation(s)
- Kenneth E Miller
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK 74107, United States.
| | | | | | | |
Collapse
|
15
|
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]
|
16
|
Ivanusic JJ, Beaini D, Hatch RJ, Staikopoulos V, Sessle BJ, Jennings EA. Peripheral N-methyl-d-aspartate receptors contribute to mechanical hypersensitivity in a rat model of inflammatory temporomandibular joint pain. Eur J Pain 2010; 15:179-85. [PMID: 20675160 DOI: 10.1016/j.ejpain.2010.07.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 07/07/2010] [Accepted: 07/07/2010] [Indexed: 11/29/2022]
Abstract
The aim of this study was to determine whether peripheral N-methyl-d-aspartate (NMDA) receptors are involved in inflammation-induced mechanical hypersensitivity of the temporomandibular joint (TMJ) region. We developed a rat model of mechanical sensitivity to Complete Freund's Adjuvant (CFA; 2μl containing 1μg Mycobacterium tuberculosis)-induced inflammation of the TMJ and examined changes in sensitivity following injection of NMDA receptor antagonists (dl-2-amino-5-phosphonovaleric acid (AP5) or Ifenprodil) with CFA. CFA injected into the TMJ resulted in an increase in mechanical sensitivity relative to pre-injection that peaked at day 1 and lasted for up to 3days (n=8, P<0.05). There was no change in mechanical sensitivity in vehicle-injected rats at any time-point (n=9). At day 1, there was a significant increase in mechanical sensitivity in animals injected with CFA+vehicle (n=7) relative to those injected with vehicle alone (n=7, P<0.05), and co-injection of AP5 (n=6) or Ifenprodil (n=7) with CFA blocked this hypersensitivity. Subcutaneous injection of AP5 (n=7) and Ifenprodil (n=5) instead of into the TMJ had no significant effect on CFA-induced hypersensitivity of the TMJ region. Western blot analysis revealed constitutive expression of the NR1 and NR2B subunits in trigeminal ganglion lysates. Immunohistochemical studies showed that 99% and 28% of trigeminal ganglion neurons that innervated the TMJ contained the NR1 and NR2B subunits respectively. Our findings suggest a role for peripheral NMDA receptors in inflammation-induced pain of the TMJ region. Targeting peripheral NMDA receptors with peripheral application of NMDA receptor antagonists could provide therapeutic benefit and avoid side effects associated with blockade of NMDA receptors in the central nervous system.
Collapse
Affiliation(s)
- J J Ivanusic
- Department of Anatomy and Cell Biology, University of Melbourne, Melbourne 3010, Australia
| | | | | | | | | | | |
Collapse
|
17
|
Interactions of glutamate and capsaicin-evoked muscle pain on jaw motor functions of men. Clin Neurophysiol 2010; 121:950-6. [DOI: 10.1016/j.clinph.2010.01.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2009] [Revised: 01/08/2010] [Accepted: 01/15/2010] [Indexed: 11/21/2022]
|
18
|
Watanabe T, Tsuboi Y, Sessle BJ, Iwata K, Hu JW. P2X and NMDA receptor involvement in temporomandibular joint-evoked reflex activity in rat jaw muscles. Brain Res 2010; 1346:83-91. [PMID: 20501327 DOI: 10.1016/j.brainres.2010.05.055] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2010] [Revised: 05/18/2010] [Accepted: 05/18/2010] [Indexed: 11/28/2022]
Abstract
We have previously shown that injection of the excitatory amino glutamate into the rat temporomandibular joint (TMJ) evokes reflex activity in both anterior digastric (DIG) and masseter (MASS) muscles that can be attenuated by prior TMJ injection of an N-methyl-d-aspartate (NMDA) receptor antagonist. The aim of the present study was to test if jaw muscle activity could also be evoked by P2X receptor agonist injection into the rat TMJ region and if the reflex activity could be modulated by TMJ injection of P2X receptor antagonist or NMDA receptor antagonist. The selective P2X subtype agonist alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-me ATP) and vehicle (phosphate-buffered saline) or the selective P2X antagonist, 2'-(or-3')-O-(2,4,6-trinitrophenyl) adenosine 5'-triphosphate (TNP-ATP) or the selective NMDA antagonist (+/-)-d-2-amino-5-phosphonovalerate(APV) were injected into the rat TMJ region. Electromyographic (EMG) reflex activity was recorded in both DIG and MASS muscles. Compared with the baseline EMG activity, alpha,beta-me-ATP injection into the TMJ (but not its systemic administration) following pre-injection of the vehicle significantly increased the magnitude and the duration of ipsilateral DIG and MASS EMG activity in a dose-dependent manner. The alpha,beta-me-ATP-evoked responses could be antagonized by pre-injection of TNP-ATP into the same TMJ site but contralateral TMJ injection of TNP-ATP proved ineffective. Furthermore, the alpha,beta-me-ATP-evoked responses could also be antagonized by APV injected into the same TMJ site but not by its systemic injection. These results indicate the interaction of peripheral purinergic as well as glutamatergic receptor mechanisms in the processing of TMJ nociceptive afferent inputs that evoke reflex activity in jaw muscles.
Collapse
Affiliation(s)
- T Watanabe
- Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | | | | | | | | |
Collapse
|
19
|
Jin YH, Yamaki F, Takemura M, Koike Y, Furuyama A, Yonehara N. Capsaicin-induced glutamate release is implicated in nociceptive processing through activation of ionotropic glutamate receptors and group I metabotropic glutamate receptor in primary afferent fibers. J Pharmacol Sci 2009; 109:233-41. [PMID: 19202316 DOI: 10.1254/jphs.08262fp] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Glutamate (Glu) is the major excitatory neurotransmitter in the central nervous system. The role of peripheral Glu and Glu receptors (GluRs) in nociceptive transmission is, however, still unclear. In the present study, we examined Glu levels released in the subcutaneous perfusate of the rat hind instep using a microdialysis catheter and the thermal withdrawal latency using the Plantar Test following injection of drugs associated with GluRs with/without capsaicin into the hindpaw. The injection of capsaicin into the rat hind instep caused an increase of Glu level in the s.c. perfusate. Capsaicin also significantly decreased withdrawal latency to irradiation. These effects of capsaicin were inhibited by pretreatment with capsazepine, a transient receptor potential vanilloid receptor 1 (TRPV1) competitive antagonist. Capsaicin-induced Glu release was also suppressed by combination with each antagonist of ionotropic GluRs (iGluRs: NMDA/AMPA receptors) and group I metabotropic GluR (mGluR), but not group II and group III mGluRs. Furthermore, these GluRs antagonists showed remarkable inhibition against capsaicin-induced thermal hyperalgesia. These results suggest that Glu is released from the peripheral endings of small-diameter afferent fibers by noxious stimulation and then activates peripheral iGluRs and group I mGluR in development and/or maintenance of nociception. Furthermore, the activation of peripheral NMDA/AMPA receptors and group I mGluR may be important in mechanisms whereby capsaicin evokes nociceptive responses.
Collapse
Affiliation(s)
- You-Hong Jin
- Department of Pharmacology, Osaka University Graduate School of Dentistry, Suita, Japan
| | | | | | | | | | | |
Collapse
|
20
|
Lam DK, Sessle BJ, Hu JW. Glutamate and capsaicin effects on trigeminal nociception II: Activation and central sensitization in brainstem neurons with deep craniofacial afferent input. Brain Res 2009; 1253:48-59. [DOI: 10.1016/j.brainres.2008.11.056] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 11/17/2008] [Accepted: 11/17/2008] [Indexed: 10/21/2022]
|
21
|
Gibson W, Arendt-Nielsen L, Sessle BJ, Graven-Nielsen T. Glutamate and capsaicin-induced pain, hyperalgesia and modulatory interactions in human tendon tissue. Exp Brain Res 2009; 194:173-82. [PMID: 19139865 DOI: 10.1007/s00221-008-1683-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Accepted: 12/05/2008] [Indexed: 10/21/2022]
Abstract
Experimental glutamate and capsaicin-induced pain has not been described in tendon tissue despite the implications of addressing these receptors in pain management strategies. This study investigated pain induction and modulatory interactions by injecting glutamate (0.5 ml, 1 M) and capsaicin (0.5 ml, 5 microg, 33 microM) to human tendon tissue. Following the initial glutamate or capsaicin injection, a second injection of either glutamate (following capsaicin), capsaicin (following glutamate) or hypertonic saline (after both glutamate and capsaicin) was given. Twelve male volunteers participated. Subjects had four sequences of injections to tibialis anterior tendon over two sessions 1 week apart. Pain intensity responses were scored on a visual analogue scale (VAS). Pressure pain thresholds (PPTs) were assessed before, during and after pain induction. Capsaicin caused significantly higher peak pain scores compared to glutamate (P < 0.003) whilst glutamate pain was of significantly longer duration (P < 0.0003). Capsaicin following glutamate resulted in significantly higher average VAS scores 180-450 s after injection compared to capsaicin as primary injection (P < 0.05). PPTs were significantly reduced during capsaicin pain (72 +/- 5 and 80 +/- 6% of pre-pain values at the injection site and 2 cm proximal, P < 0.002). Following capsaicin, hypertonic saline and glutamate showed significant reductions in PPT at the same sites and to a similar degree compared to baseline (P < 0.002). The results indicate in tendon tissue a facilitation of response to capsaicin injection following glutamate injection. PPTs were only reliably reduced by capsaicin injection. These results emphasize the possible importance of peripheral glutamate receptor antagonists in pain management in musculoskeletal conditions.
Collapse
Affiliation(s)
- William Gibson
- Laboratory for Experimental Pain Research, Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Fredrik Bajers Vej 7D-3, 9220, Aalborg, Denmark.
| | | | | | | |
Collapse
|
22
|
Tsujimura T, Kondo M, Kitagawa J, Tsuboi Y, Saito K, Tohara H, Ueda K, Sessle BJ, Iwata K. Involvement of ERK phosphorylation in brainstem neurons in modulation of swallowing reflex in rats. J Physiol 2009; 587:805-17. [PMID: 19124539 DOI: 10.1113/jphysiol.2008.165324] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In order to evaluate the neuronal mechanisms underlying functional abnormalities of swallowing in orofacial pain patients, this study investigated the effects of noxious orofacial stimulation on the swallowing reflex, phosphorylated extracellular signal-regulated kinase (pERK) and gamma-aminobutyric acid (GABA) immunohistochemical features in brainstem neurons, and also analysed the effects of brainstem lesioning and of microinjection of GABA receptor agonist or antagonist into the nucleus tractus solitarii (NTS) on the swallowing reflex in anaesthetized rats. The swallowing reflex elicited by topical administration of distilled water to the pharyngolaryngeal region was inhibited after capsaicin injection into the facial (whisker pad) skin or lingual muscle. The capsaicin-induced inhibitory effect on the swallowing reflex was itself depressed after the intrathecal administration of MAPK kinase (MEK) inhibitor. No change in the capsaicin-induced inhibitory effect was observed after trigeminal spinal subnucleus caudalis lesioning, but the inhibitory effect was diminished by paratrigeminal nucleus (Pa5) lesioning. Many pERK-like immunoreactive neurons in the NTS showed GABA immunoreactivity. The local microinjection of the GABA(A) receptor agonist muscimol into the NTS produced a significant reduction in swallowing reflex, and the capsaicin-induced depression of the swallowing reflex was abolished by microinjection of the GABA(A) receptor antagonist bicuculline into the NTS. The present findings suggest that facial skin-NTS, lingual muscle-NTS and lingual muscle-Pa5-NTS pathways are involved in the modulation of swallowing reflex by facial and lingual pain, respectively, and that the activation of GABAergic NTS neurons is involved in the inhibition of the swallowing reflex following noxious stimulation of facial and intraoral structures.
Collapse
Affiliation(s)
- Takanori Tsujimura
- Department of Dysphagia Rehabilitation, Nihon University School of Dentistry, Tokyo, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
23
|
Lam DK, Sessle BJ, Hu JW. Glutamate and capsaicin effects on trigeminal nociception I: Activation and peripheral sensitization of deep craniofacial nociceptive afferents. Brain Res 2008; 1251:130-9. [PMID: 19056361 DOI: 10.1016/j.brainres.2008.11.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 10/08/2008] [Accepted: 11/10/2008] [Indexed: 12/24/2022]
Abstract
We have examined the effect of the peripheral application of glutamate and capsaicin to deep craniofacial tissues in influencing the activation and peripheral sensitization of deep craniofacial nociceptive afferents. The activity of single trigeminal nociceptive afferents with receptive fields in deep craniofacial tissues were recorded extracellularly in 55 halothane-anesthetized rats. The mechanical activation threshold (MAT) of each afferent was assessed before and after injection of 0.5 M glutamate (or vehicle) and 1% capsaicin (or vehicle) into the receptive field. A total of 68 afferents that could be activated by blunt noxious mechanical stimulation of the deep craniofacial tissues (23 masseter, 5 temporalis, 40 temporomandibular joint) were studied. When injected alone, glutamate and capsaicin activated and induced peripheral sensitization reflected as MAT reduction in many afferents. Following glutamate injection, capsaicin-evoked activity was greater than that evoked by capsaicin alone, whereas following capsaicin injection, glutamate-evoked responses were similar to glutamate alone. These findings indicate that peripheral application of glutamate or capsaicin may activate or induce peripheral sensitization in a subpopulation of trigeminal nociceptive afferents innervating deep craniofacial tissues, as reflected in changes in MAT and other afferent response properties. The data further suggest that peripheral glutamate and capsaicin receptor mechanisms may interact to modulate the activation and peripheral sensitization in some deep craniofacial nociceptive afferents.
Collapse
Affiliation(s)
- David K Lam
- Faculty of Dentistry, University of Toronto 124 Edward Street, Toronto, Ontario, Canada M5G 1G6
| | | | | |
Collapse
|
24
|
Lam D, Sessle B, Hu J. Surgical incision can alter capsaicin-induced central sensitization in rat brainstem nociceptive neurons. Neuroscience 2008; 156:737-47. [DOI: 10.1016/j.neuroscience.2008.07.058] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 07/15/2008] [Accepted: 07/30/2008] [Indexed: 11/30/2022]
|
25
|
Adachi K, Murray GM, Lee JC, Sessle BJ. Noxious Lingual Stimulation Influences the Excitability of the Face Primary Motor Cerebral Cortex (Face MI) in the Rat. J Neurophysiol 2008; 100:1234-44. [DOI: 10.1152/jn.90609.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanisms whereby orofacial pain affects motor function are poorly understood. The aims were to determine whether 1) lingual algesic chemical stimulation affected face primary motor cerebral cortex (face MI) excitability defined by intracortical microstimulation (ICMS); and 2) any such effects were limited to the motor efferent MI zones driving muscles in the vicinity of the noxious stimulus. Ketamine-anesthetized Sprague–Dawley male rats were implanted with electromyographic (EMG) electrodes into anterior digastric, masseter, and genioglossus muscles. In 38 rats, three microelectrodes were located in left face MI at ICMS-defined sites for evoking digastric and/or genioglossus responses. ICMS thresholds for evoking EMG activity from each site were determined every 15 min for 1 h, then the right anterior tongue was infused (20 μl, 120 μl/h) with glutamate (1.0 M, n = 18) or isotonic saline ( n = 7). Subsequently, ICMS thresholds were determined every 15 min for 4 h. In intact control rats ( n = 13), ICMS thresholds were recorded over 5 h. Only left and right genioglossus ICMS thresholds were significantly increased (≤350%) in the glutamate infusion group compared with intact and isotonic saline groups ( P < 0.05). These dramatic effects of glutamate on ICMS-evoked genioglossus activity contrast with its weak effects only on right genioglossus activity evoked from the internal capsule or hypoglossal nucleus. This is the first documentation that intraoral noxious stimulation results in prolonged neuroplastic changes manifested as a decrease in face MI excitability. These changes appear to occur predominantly in those parts of face MI that provide motor output to the orofacial region receiving the noxious stimulation.
Collapse
|
26
|
Ayesh EE, Jensen TS, Svensson P. Effects of intra-articular ketamine on pain and somatosensory function in temporomandibular joint arthralgia patients. Pain 2008; 137:286-294. [DOI: 10.1016/j.pain.2007.09.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 08/23/2007] [Accepted: 09/05/2007] [Indexed: 12/29/2022]
|
27
|
Arendt-Nielsen L, Svensson P, Sessle BJ, Cairns BE, Wang K. Interactions between glutamate and capsaicin in inducing muscle pain and sensitization in humans. Eur J Pain 2007; 12:661-70. [PMID: 18162423 DOI: 10.1016/j.ejpain.2007.10.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 10/12/2007] [Accepted: 10/24/2007] [Indexed: 11/18/2022]
Abstract
The aim of the study was to investigate the interaction between glutamate and capsaicin in inducing muscle pain and sensitization in humans. Fifteen male volunteers participated. Glutamate or capsaicin or isotonic saline, in a paired-sequence order, was injected randomly into the right or left masseter muscle. Two injections were given in a double-blinded design 25 min apart in 1 session/week over 4 weeks: saline (A1) followed by glutamate (A2), capsaicin (B1) followed by glutamate (B2), saline (C1) followed by capsaicin (C2), and glutamate (D1) followed by capsaicin (D2). The subjects drew the area of perceived pain and scored pain intensity on a 0-10 visual analogue scale (VAS). Pressure pain threshold (PPT) at the injection site, at a site 2-cm away, and on the contralateral side, as well as pressure pain tolerance (PPTol) at the injection site and contralateral site, were also measured before and after injection and subsequently at 5-min intervals. Paired t-test analyses showed that the pain drawing area was significantly smaller in the B2 compared to the A2 condition (P=0.028), and significantly larger in the D2 compared to the C2 condition (P=0.027). It also revealed significantly lower VAS peak pain intensity (P=0.008) and smaller VAS area under the curve (P=0.003) for the B2 compared to the A2 condition, and significantly higher VAS peak pain (P=0.015) and larger VAS area under the curve (P=0.037) for the D2 compared to the C2 condition. There was a significant PPT and PPTol decrease at the injection site after glutamate or capsaicin injection (ANOVA: P<0.028). The percentage decrease in PPT or PPTol (at the injection site) was not significantly different for the B2 compared to the A2 condition (Paired t-test: P>0.682) or for the D2 compared to the C2 condition (P>0.133). Significant PPT changes were also observed at the site 2 cm away, but not on the contralateral side. In conclusion, these findings indicate that intramuscular administrations of glutamate and capsaicin interact and influence pain and sensitization of muscle nociceptors: glutamate causes a sensitization to subsequent administration of capsaicin, whereas capsaicin is associated with a desensitization to subsequent injection of glutamate. These findings support previous animal data.
Collapse
Affiliation(s)
- L Arendt-Nielsen
- Center for Sensory-Motor Interaction, Orofacial Pain Laboratory, Aalborg University, DK-9220 Aalborg, Denmark
| | | | | | | | | |
Collapse
|
28
|
Gazerani P, Wang K, Cairns BE, Svensson P, Arendt-Nielsen L. Effects of subcutaneous administration of glutamate on pain, sensitization and vasomotor responses in healthy men and women. Pain 2006; 124:338-348. [PMID: 16919390 DOI: 10.1016/j.pain.2006.06.015] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Revised: 06/06/2006] [Accepted: 06/09/2006] [Indexed: 10/24/2022]
Abstract
The present study aimed to investigate if (1) subcutaneous injection of glutamate induces pain, sensitization and vasomotor responses in humans and (2) if sex differences exist in these responses. Thirty healthy volunteers (men-15 and women-15) were included. Each subject received four subcutaneous injections (0.1ml; glutamate 100, 10, 1mM and isotonic saline 0.9%) into the forehead skin in two sessions separated by one week. Assessments of pain intensity (VAS), quality, distribution; area of pinprick hyperalgesia; pressure pain threshold (PPT) at the injection site; surface skin temperature and local blood flow were performed at predetermined time points. The highest concentration of glutamate evoked the highest pain intensity, the longest duration of pain and the largest pain area under the VAS-time curve (P<0.001) in both men and women, although responses in women were larger than in men (P<0.05). The face-chart pain area was the largest for the highest concentration of glutamate (P<0.001) and women drew a larger pain area than men (P=0.024). The area of pinprick hyperalgesia was the largest for glutamate 100mM (P<0.001) and women indicated a larger area than men (P<0.001). Concentration-dependent local vasomotor responses were found following the subcutaneous injection of glutamate but there was no sex difference in this effect. Glutamate 100mM significantly reduced the PPT values (P<0.001) without sex-related differences. The present study demonstrates for the first time that subcutaneous injection of glutamate evokes pain, vasomotor responses and pinprick hyperalgesia in human volunteers and that there are sex-related differences in some of these responses.
Collapse
Affiliation(s)
- Parisa Gazerani
- Center for Sensory - Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, 9220 Aalborg, Denmark Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, V6T 1Z3 Vancouver, Canada Department of Clinical Oral Physiology, School of Dentistry, Aarhus University, 8000 Aarhus C, Denmark
| | | | | | | | | |
Collapse
|