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Zou Z, Fan W, Liu H, Liu Q, He H, Huang F. The roles of 5-HT in orofacial pain. Oral Dis 2024. [PMID: 38622872 DOI: 10.1111/odi.14960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 03/10/2024] [Accepted: 04/02/2024] [Indexed: 04/17/2024]
Abstract
OBJECTIVES Acute and chronic orofacial pain are very common and remain a vexing health problem that has a negative effect on the quality of life. Serotonin (5-HydroxyTryptamine, 5-HT) is a kind of monoamine neurotransmitter that is involved in many physiological and pathological processes. However, its role in orofacial pain remains inconclusive. Therefore, this review aims to summarize the recent advances in understanding the effect exerted by 5-HT on the modulation of orofacial pain. SUBJECTS AND METHODS An extensive search was conducted on PubMed and Web of Science for pertinent studies focusing on the effects of 5-HT on the modulation of orofacial pain. RESULTS In this review, we concisely review how 5-HT mediates orofacial pain, how 5-HT is regulated and how we can translate these findings into clinical applications for the prevention and/or treatment of orofacial pain. CONCLUSIONS 5-HT plays a key role in the modulation of orofacial pain, implying that 5-HT modulators may serve as effective treatment for orofacial pain. However, further research on the precise mechanisms underlying the modulation of orofacial pain is still warranted.
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Affiliation(s)
- Zhishan Zou
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
- Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Wenguo Fan
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
- Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Haotian Liu
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Qing Liu
- Paediatric Dentistry and Orthodontics, Faculty of Dentistry, The University of Hong Kong, Hong Kong, SAR, China
| | - Hongwen He
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
- Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Fang Huang
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
- Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, China
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Sas D, Gaudel F, Verdier D, Kolta A. Hyperexcitability of muscle spindle afferents in jaw-closing muscles in experimental myalgia: Evidence for large primary afferents involvement in chronic pain. Exp Physiol 2024; 109:100-111. [PMID: 38103003 PMCID: PMC10988680 DOI: 10.1113/ep090769] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
The goals of this review are to improve understanding of the aetiology of chronic muscle pain and identify new targets for treatments. Muscle pain is usually associated with trigger points in syndromes such as fibromyalgia and myofascial syndrome, and with small spots associated with spontaneous electrical activity that seems to emanate from fibers inside muscle spindles in EMG studies. These observations, added to the reports that large-diameter primary afferents, such as those innervating muscle spindles, become hyperexcitable and develop spontaneous ectopic firing in conditions leading to neuropathic pain, suggest that changes in excitability of these afferents might make an important contribution to the development of pathological pain. Here, we review evidence that the muscle spindle afferents (MSAs) of the jaw-closing muscles become hyperexcitable in a model of chronic orofacial myalgia. In these afferents, as in other large-diameter primary afferents in dorsal root ganglia, firing emerges from fast membrane potential oscillations that are supported by a persistent sodium current (INaP ) mediated by Na+ channels containing the α-subunit NaV 1.6. The current flowing through NaV 1.6 channels increases when the extracellular Ca2+ concentration decreases, and studies have shown that INaP -driven firing is increased by S100β, an astrocytic protein that chelates Ca2+ when released in the extracellular space. We review evidence of how astrocytes, which are known to be activated in pain conditions, might, through their regulation of extracellular Ca2+ , contribute to the generation of ectopic firing in MSAs. To explain how ectopic firing in MSAs might cause pain, we review evidence supporting the hypothesis that cross-talk between proprioceptive and nociceptive pathways might occur in the periphery, within the spindle capsule.
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Affiliation(s)
- Dar'ya Sas
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Fanny Gaudel
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Dorly Verdier
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
| | - Arlette Kolta
- Département de NeurosciencesUniversité de MontréalMontréalQuébecCanada
- Centre Interdisciplinaire de Recherche sur le Cerveau et l'Apprentissage (CIRCA)MontréalQuébecCanada
- Faculté de Médecine DentaireUniversité de MontréalMontréalQuébecCanada
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Hajati A, Brondani M, Angerstig L, Klein V, Liljeblad L, Al-Moraissi EA, Louca Jounger S, Brondani B, Christidis N. Chocolate intake and muscle pain sensation: A randomized experimental study. PLoS One 2023; 18:e0284769. [PMID: 37224109 DOI: 10.1371/journal.pone.0284769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 03/31/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Chocolate, as a cocoa-derived product rich in flavanols, has been used for medical and anti-inflammatory purposes. Therefore, the aim of this study was to investigate if the ingestion of different percentages of cocoa products affects the experimentally induced pain caused by intramuscular hypertonic saline injections in the masseter muscle of healthy men and women. METHODS This experimental randomized, double-blind, and controlled study included 15 young, healthy, and pain-free men and 15 age-matched women and involved three visits with at least a 1-week washout. Pain was induced twice at each visit with intramuscular injections of 0.2 mL hypertonic saline (5%), before and after intake of one of the different chocolate types: white (30% cocoa content), milk (34% cocoa content), and dark (70% cocoa content). Pain duration, pain area, peak pain, and pressure pain threshold (PPT) were assessed every fifth minute after each injection, up until 30 min after the initial injection. Descriptive and inferential statistics were performed using IBM® SPSS (Version 27); significance level was set to p<0.05. RESULTS This study showed that intake of chocolate, no matter the type, reduced the induced pain intensity significantly more than no intake of chocolate (p<0.05, Tukey test). There were no differences between the chocolate types. Further, men showed a significantly greater pain reduction than women after intake of white chocolate (p<0.05, Tukey test). No other differences between pain characteristics or sexes were revealed. CONCLUSION Intake of chocolate before a painful stimulus had a pain-reducing effect no matter the cocoa concentration. The results indicate that perhaps it is not the cocoa concentration (e.g., flavanols) alone that explains the positive effect on pain, but likely a combination of preference and taste-experience. Another possible explanation could be the composition of the chocolate, i.e. the concentration of the other ingredients such as sugar, soy, and vanilla. ClinicalTrials.gov Identifier: NCT05378984.
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Affiliation(s)
- Alexandra Hajati
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
| | - Mario Brondani
- Division of Dental Public Health, Department of Oral Health Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Lina Angerstig
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
| | - Victoria Klein
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
| | - Linda Liljeblad
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
| | - Essam Ahmed Al-Moraissi
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Thamar University, Thamar, Yemen
| | - Sofia Louca Jounger
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
| | - Bruna Brondani
- Division of Dental Public Health, Department of Oral Health Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Nikolaos Christidis
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences, Huddinge, Sweden
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Alhilou AM, Shimada A, Svensson CI, Svensson P, Ernberg M, Cairns BE, Christidis N. Nerve growth factor and glutamate increase the density and expression of substance P-containing nerve fibers in healthy human masseter muscles. Sci Rep 2021; 11:15673. [PMID: 34341446 PMCID: PMC8328992 DOI: 10.1038/s41598-021-95229-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/16/2021] [Indexed: 11/21/2022] Open
Abstract
Nocifensive behavior induced by injection of glutamate or nerve growth factor (NGF) into rats masseter muscle is mediated, in part, through the activation of peripheral NMDA receptors. However, information is lacking about the mechanism that contributes to pain and sensitization induced by these substances in humans. Immunohistochemical analysis of microbiopsies obtained from human masseter muscle was used to investigate if injection of glutamate into the NGF-sensitized masseter muscle alters the density or expression of the NMDA receptor subtype 2B (NR2B) or NGF by putative sensory afferent (that express SP) fibers. The relationship between expression and pain characteristics was also examined. NGF and glutamate administration increased the density and expression of NR2B and NGF by muscle putative sensory afferent fibers (P < 0.050). This increase in expression was greater in women than in men (P < 0.050). Expression of NR2B receptors by putative sensory afferent fibers was positively correlated with pain characteristics. Results suggest that increased expression of peripheral NMDA receptors partly contributes to the increased pain and sensitivity induced by intramuscular injection of NGF and glutamate in healthy humans; a model of myofascial temporomandibular disorder (TMD) pain. Whether a similar increase in peripheral NMDA expression occurs in patients with painful TMDs warrants further investigation.
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Affiliation(s)
- Abdelrahman M Alhilou
- Department of Restorative Dentistry, College of Dentistry, Umm Al-Qura University, Makkah al Mukarramah, Saudi Arabia.
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences (SCON), Box 4064, 141 04, Huddinge, Sweden.
| | - Akiko Shimada
- Department of Geriatric Dentistry, Osaka Dental University, Osaka, Japan
| | - Camilla I Svensson
- Department of Physiology and Pharmacology, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Peter Svensson
- Department of Dentistry and Oral Health, Aarhus University, and Center for Orofacial Neurosciences (SCON), Aarhus, Denmark
| | - Malin Ernberg
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences (SCON), Box 4064, 141 04, Huddinge, Sweden
| | - Brian E Cairns
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Nikolaos Christidis
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, and Scandinavian Center for Orofacial Neurosciences (SCON), Box 4064, 141 04, Huddinge, Sweden
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Louca Jounger S, Svedenlöf J, Elenius R, Källkrans C, Scheid E, Ernberg M, Christidis N. Sterile water; a novel and promising human experimental craniofacial muscle pain model. J Oral Rehabil 2021; 48:654-665. [PMID: 33449396 DOI: 10.1111/joor.13148] [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: 11/12/2020] [Accepted: 12/21/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND The aim of this study was to investigate if intramuscular injection of sterile water can be used as a human experimental pain model that resembles clinical craniofacial muscle pain and to analyse if the effects differ between sexes. METHODS This randomised, double-blind, placebo-controlled cross-over study included 30 healthy age-matched women and men (23.6 ± 2.4 years). At three sessions, with at least one week of washout in between, 0.2 mL of either sterile water (test-substance), hypertonic saline (58.5 mg/mL; active control) or isotonic saline (0.9 mg/mL; passive control) was randomly injected into the right masseter muscle. Pain intensity (VAS) was continuously assessed during 5 min whereafter pain duration (s) and pain area (au) were calculated; pressure pain thresholds (PPT;kPa) were recorded every 5 minutes during 30 minutes. RESULTS Sterile water evoked pain of similar intensity (74.5 ± 49.9) as hypertonic saline (74.0 ± 50.5); whereas, isotonic saline evoked low-intensity pain (11.4 ± 23.4). The pain induced by sterile water and hypertonic saline had higher intensity (P < 0.001), longer duration (P < 0.001) and larger pain area (P < 0.001) than isotonic saline. There were no significant differences in any pain variable between sterile water and hypertonic saline. The PPT did not change significantly after any substance, except for in women 5 minutes after sterile water injection (P < 0.002). Pain duration was longer in the men for all substances (P < 0.006), while the pain area was larger in women after injection of hypertonic saline (P < 0.003). CONCLUSION These results indicate that pain evoked by sterile water resembles clinical muscle pain and may offer a novel and simpler alternative to hypertonic saline injections.
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Affiliation(s)
- Sofia Louca Jounger
- Division of Oral Diagnostics and Rehabilitatiowen, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neuroscience (SCON), Huddinge, Sweden
| | - Johanna Svedenlöf
- Division of Oral Diagnostics and Rehabilitatiowen, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Reija Elenius
- Division of Oral Diagnostics and Rehabilitatiowen, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Christoffer Källkrans
- Division of Oral Diagnostics and Rehabilitatiowen, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Emil Scheid
- Division of Oral Diagnostics and Rehabilitatiowen, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Malin Ernberg
- Division of Oral Diagnostics and Rehabilitatiowen, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neuroscience (SCON), Huddinge, Sweden
| | - Nikolaos Christidis
- Division of Oral Diagnostics and Rehabilitatiowen, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neuroscience (SCON), Huddinge, Sweden
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Louca Jounger S, Eriksson N, Lindskog H, Oscarsson A, Simonsson V, Ernberg M, Christidis N. Repeated buffered acidic saline infusion in the human masseter muscle as a putative experimental pain model. Sci Rep 2019; 9:15474. [PMID: 31664156 PMCID: PMC6820748 DOI: 10.1038/s41598-019-51670-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 10/04/2019] [Indexed: 12/20/2022] Open
Abstract
This study investigated if repeated buffered acidic saline infusions into the masseter muscles induced muscle pain and mechanical sensitization. Fourteen healthy men participated in this double-blind, randomized, and placebo-controlled study. Two repeated infusions (day 1 and 3) were given in the masseter muscles with either a buffered acidic saline solution (pH 5.2) or an isotonic saline solution (pH 6) as control. After 10 days of wash-out, the experiment was repeated with the other substance. Pressure pain thresholds (PPT), pain intensity, maximum unassisted mouth opening (MUO), and pain drawings were assessed before, directly following, and after each infusion at 5, 15, and 30 min and on day 4 and 7. Fatigue and pain intensity were assessed after a one-minute chewing test 30 min after infusions and day 4 and 7. Acidic saline induced higher pain intensity than control day 3 up to 5 min after infusions, but did not affect PPT. The chewing test did not evoke higher fatigue during chewing or MUO or after acidic saline infusion compared to control. Repeated acidic saline infusions in the masseter muscles induced a short-lasting muscle pain without mechanical hyperalgesia or functional pain. Hence, this model might not be superior to already existing experimental muscle pain models.
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Affiliation(s)
- Sofia Louca Jounger
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden. .,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden.
| | - Niklas Eriksson
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Helena Lindskog
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Anna Oscarsson
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Vivian Simonsson
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden
| | - Malin Ernberg
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
| | - Nikolaos Christidis
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, SE-141 04, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
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Influence of Polymorphisms in the HTR3A and HTR3B Genes on Experimental Pain and the Effect of the 5-HT3 Antagonist Granisetron. PLoS One 2016; 11:e0168703. [PMID: 28002447 PMCID: PMC5176308 DOI: 10.1371/journal.pone.0168703] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 12/04/2016] [Indexed: 02/08/2023] Open
Abstract
The aim of this study was to investigate experimentally if 5-HT3 single nucleotide polymorphisms (SNP) contribute to pain perception and efficacy of the 5-HT3-antagonist granisetron and sex differences. Sixty healthy participants were genotyped regarding HTR3A (rs1062613) and HTR3B (rs1176744). First, pain was induced by bilateral hypertonic saline injections (HS, 5.5%, 0.2 mL) into the masseter muscles. Thirty min later the masseter muscle on one side was pretreated with 0.5 mL granisetron (1 mg/mL) and on the other side with 0.5 mL placebo (isotonic saline) followed by another HS injection (0.2 mL). Pain intensity, pain duration, pain area and pressure pain thresholds (PPTs) were assessed after each injection. HS evoked moderate pain, with higher intensity in the women (P = 0.023), but had no effect on PPTs. None of the SNPs influenced any pain variable in general, but compared to men, the pain area was larger in women carrying the C/C (HTR3A) (P = 0.015) and pain intensity higher in women with the A/C alleles (HTR3B) (P = 0.019). Pre-treatment with granisetron reduced pain intensity, duration and area to a lesser degree in women (P < 0.05), but the SNPs did not in general influence the efficacy of granisetron. Women carrying the C/T & T/T (HTR3A) genotype had less reduction of pain intensity (P = 0.041) and area (P = 0.005), and women with the C/C genotype (HTR3B) had less reduction of pain intensity (P = 0.030), duration (P = 0.030) and area compared to men (P = 0.017). In conclusion, SNPs did not influence experimental muscle pain or the effect of granisetron on pain variables in general, but there were some sex differences in pain variables that seem to be influenced by genotypes. However, due to the small sample size further research is needed before any firm conclusions can be drawn.
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Munkholm TK, Arendt-Nielsen L. The interaction between NGF-induced hyperalgesia and acid-provoked pain in the infrapatellar fat pad and tibialis anterior muscle of healthy volunteers. Eur J Pain 2016; 21:474-485. [PMID: 27634419 DOI: 10.1002/ejp.941] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 11/08/2022]
Abstract
BACKGROUND Tissue pH is lowered in inflamed tissues, and the increased proton concentration activates acid-sensing ion channels (ASICs), contributing to pain and hyperalgesia. ASICs can be upregulated by nerve growth factor (NGF). The aim of this study was to investigate two new human experimental pain models combining NGF- and acid-induced pain in a randomized, controlled, double-blind study. METHODS In experiment 1, volunteers (N = 16) received an injection of either NGF or isotonic saline in each infrapatellar fat pad (IFP). One day after 5 mL of phosphate-buffered acidic saline was infused into each IFP at a rate of 20 mL/h. In experiment 2, the tibialis anterior (TA) muscle of additional volunteers (N = 16) was examined, following the same procedure except that the volume and infusion rate of acid were different (10 mL, 30 mL/h). Continuous pain ratings were recorded during and after acid infusions. In addition, soreness scores on a Likert scale and pressure pain thresholds (PPTs) were assessed. RESULTS The PPT of the IFP was significantly decreased at the NGF injection site on day 1, but acid-provoked pain ratings and the change in PPT from pre- to postinfusion between the knees were similar. In the muscle pain model, local mechanical hyperalgesia developed 3 h after the NGF injection and a significant additional decrease in PPT was found after acid infusion compared to preinfusion. CONCLUSIONS NGF sensitization in the IFP was not facilitated by acid, whereas an acid-provoked enhancement of muscle hyperalgesia was found. NGF sensitization of adipose tissue responds differently to acid provocation compared to muscle tissue. SIGNIFICANCE Quantification of two novel pain models combining NGF and acid. Hyperalgesia developed after NGF injection in the infrapatellar fat pad, but it was not facilitated by acid provocation. Contrary, NGF-induced hyperalgesia in muscle tissue was enhanced by acid.
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Affiliation(s)
- T K Munkholm
- Center for Sensory-Motor Interaction (SMI), Aalborg University, Denmark
| | - L Arendt-Nielsen
- Center for Sensory-Motor Interaction (SMI), Aalborg University, Denmark
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Christidis N, Omrani S, Fredriksson L, Gjelset M, Louca S, Hedenberg-Magnusson B, Ernberg M. Repeated tender point injections of granisetron alleviate chronic myofascial pain--a randomized, controlled, double-blinded trial. J Headache Pain 2015; 16:104. [PMID: 26634569 PMCID: PMC4669334 DOI: 10.1186/s10194-015-0588-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/30/2015] [Indexed: 12/29/2022] Open
Abstract
Background Serotonin (5-HT) mediates pain by peripheral 5-HT3-receptors. Results from a few studies indicate that intramuscular injections of 5-HT3-antagonists may reduce musculoskeletal pain. The aim of this study was to investigate if repeated intramuscular tender-point injections of the 5-HT3-antagonist granisetron alleviate pain in patients with myofascial temporomandibular disorders (M-TMD). Methods This prospective, randomized, controlled, double blind, parallel-arm trial (RCT) was carried out during at two centers in Stockholm, Sweden. The randomization was performed by a researcher who did not participate in data collection with an internet-based application (www.randomization.com). 40 patients with a diagnose of M-TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were randomized to receive repeated injections, one week apart, with either granisetron (GRA; 3 mg) or isotonic saline as control (CTR). Results The median weekly pain intensities decreased significantly at all follow-ups (1-, 2-, 6-months) in the GRA-group (Friedman test; P < 0.05), but not in the CTR-group (Friedman-test; P > 0.075). The numbers needed to treat (NNT) were 4 at the 1- and 6-month follow-ups, and 3.3 at the 2-month follow-up in favor of granisetron. Conclusions Repeated intramuscular tender-point injections with granisetron provide a new pharmacological treatment possibility for myofascial pain patients with repeated intramuscular tender-point injections with the serotonin type 3 antagonist granisetron. It showed a clinically relevant pain reducing effect in the temporomandibular region, both in a short- and long-term aspect. Trial registration European Clinical Trials Database 2005-006042-41 as well as at Clinical Trials NCT02230371.
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Affiliation(s)
- Nikolaos Christidis
- Department of Dental Medicine, Section for Orofacial Pain and Jaw Function, Karolinska Institutet, and the Scandinavian Center for Orofacial Neurosciences (SCON), Box 4064, Huddinge, SE-141 04, Sweden. .,Department of Clinical Oral Physiology at the Eastman Institute, Stockholm Public Dental Health, Dalagatan 11, Stockholm, SE-113 24, Sweden.
| | - Shahin Omrani
- Department of Clinical Oral Physiology at the Eastman Institute, Stockholm Public Dental Health, Dalagatan 11, Stockholm, SE-113 24, Sweden.
| | - Lars Fredriksson
- Department of Clinical Oral Physiology at the Eastman Institute, Stockholm Public Dental Health, Dalagatan 11, Stockholm, SE-113 24, Sweden.
| | - Mattias Gjelset
- Department of Dental Medicine, Section for Orofacial Pain and Jaw Function, Karolinska Institutet, and the Scandinavian Center for Orofacial Neurosciences (SCON), Box 4064, Huddinge, SE-141 04, Sweden.
| | - Sofia Louca
- Department of Dental Medicine, Section for Orofacial Pain and Jaw Function, Karolinska Institutet, and the Scandinavian Center for Orofacial Neurosciences (SCON), Box 4064, Huddinge, SE-141 04, Sweden.
| | - Britt Hedenberg-Magnusson
- Department of Clinical Oral Physiology at the Eastman Institute, Stockholm Public Dental Health, Dalagatan 11, Stockholm, SE-113 24, Sweden.
| | - Malin Ernberg
- Department of Dental Medicine, Section for Orofacial Pain and Jaw Function, Karolinska Institutet, and the Scandinavian Center for Orofacial Neurosciences (SCON), Box 4064, Huddinge, SE-141 04, Sweden.
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