1
|
Ermakova E, Shaidullova K, Gafurov O, Kabirova A, Nurmieva D, Sitdikova G. Implications of high homocysteine levels in migraine pain: An experimental study of the excitability of peripheral meningeal afferents in rats with hyperhomocysteinemia. Headache 2024; 64:533-546. [PMID: 38650105 DOI: 10.1111/head.14710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 01/23/2024] [Accepted: 02/28/2024] [Indexed: 04/25/2024]
Abstract
OBJECTIVES Investigation of chronic homocysteine action on the excitability and N-methyl-D-aspartate (NMDA) sensitivity of the peripheral trigeminovascular system of rats. BACKGROUND Migraine is a neurological disease that affects 15%-20% of the general population. Epidemiological observations show that an increase of the sulfur-containing amino acid homocysteine in plasma-called hyperhomocysteinemia-is associated with a high risk of migraine, especially migraine with aura. In animal studies, rats with hyperhomocysteinemia demonstrated mechanical allodynia, photophobia, and anxiety, and higher sensitivity to cortical spreading depression. In addition, rats with hyperhomocysteinemia were more sensitive in a model of chronic migraine induced by nitroglycerin which indicated the involvement of peripheral nociceptive mechanisms. The present work aimed to analyze the excitability of meningeal afferents and neurons isolated from the trigeminal ganglion of rats with prenatal hyperhomocysteinemia. METHODS Experiments were performed on male rats born from females fed with a methionine-rich diet before and during pregnancy. The activity of meningeal afferents was recorded extracellularly in hemiskull preparations ex vivo and action potentials were characterized using cluster analysis. The excitability of trigeminal ganglion neurons was assessed using whole-cell patch clamp recording techniques and calcium imaging studies. Meningeal mast cells were stained using toluidine blue. RESULTS The baseline extracellular recorded electrical activity of the trigeminal nerve was higher in the hyperhomocysteinemia group with larger amplitude action potentials. Lower concentrations of KCl caused an increase in the frequency of action potentials of trigeminal afferents recorded in rat hemiskull ex vivo preparations. In trigeminal ganglion neurons of rats with hyperhomocysteinemia, the current required to elicit at least one action potential (rheobase) was lower, and more action potentials were induced in response to stimulus of 2 × rheobase. In controls, short-term application of homocysteine and its derivatives increased the frequency of action potentials of the trigeminal nerve and induced Ca2+ transients in neurons, which are associated with the activation of NMDA receptors. At the same time, in rats with hyperhomocysteinemia, we did not observe an increased response of the trigeminal nerve to NMDA. Similarly, the parameters of Ca2+ transients induced by NMDA, homocysteine, and its derivatives were not changed in rats with hyperhomocysteinemia. Acute incubation of the meninges in homocysteine and homocysteinic acid did not change the state of the mast cells, whereas in the model of hyperhomocysteinemia, an increased degranulation of mast cells in the meninges was observed. CONCLUSIONS Our results demonstrated higher excitability of the trigeminal system of rats with hyperhomocysteinemia. Together with our previous finding about the lower threshold of generation of cortical spreading depression in rats with hyperhomocysteinemia, the present data provide evidence of homocysteine as a factor that increases the sensitivity of the peripheral migraine mechanisms, and the control of homocysteine level may be an important strategy for reducing the risk and/or severity of migraine headache attacks.
Collapse
Affiliation(s)
- Elizaveta Ermakova
- Institute of Fundamental Medicine and Biology, Department of Human and Animal Physiology, Kazan Federal University, Kazan, Russia
| | - Kseniia Shaidullova
- Institute of Fundamental Medicine and Biology, Department of Human and Animal Physiology, Kazan Federal University, Kazan, Russia
| | - Oleg Gafurov
- Institute of Fundamental Medicine and Biology, Department of Human and Animal Physiology, Kazan Federal University, Kazan, Russia
| | - Alsu Kabirova
- Institute of Fundamental Medicine and Biology, Department of Human and Animal Physiology, Kazan Federal University, Kazan, Russia
| | - Dinara Nurmieva
- Institute of Fundamental Medicine and Biology, Department of Human and Animal Physiology, Kazan Federal University, Kazan, Russia
| | - Guzel Sitdikova
- Institute of Fundamental Medicine and Biology, Department of Human and Animal Physiology, Kazan Federal University, Kazan, Russia
| |
Collapse
|
2
|
Ahdoot E, Cohen F. Unraveling the MSG-Headache Controversy: an Updated Literature Review. Curr Pain Headache Rep 2024; 28:119-124. [PMID: 38079074 DOI: 10.1007/s11916-023-01198-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/30/2023] [Indexed: 03/10/2024]
Abstract
PURPOSE OF REVIEW To review the evidence and role of monosodium glutamate (MSG) as a headache and migraine trigger. RECENT FINDINGS MSG is a common food additive, has widely been linked as a trigger of headache, as well as other symptoms. However, the evidence for MSG as a causative agent for headache is debated. Various clinical trials over the past several decades have reported conflicting results, with studies suggesting that MSG does and does not increase the incidence of headache. However, the dosages of MSG exposure are often inconsistent across studies, with many studies administering a dose significantly higher than the average consumption.. Additionally, there are misconceptions about which foods and cuisines have MSG in them. MSG could be a potential trigger for migraine and headaches. It is unclear exactly how MSG plays into the migraine pathophysiology. It's crucial to accurately determine if MSG is present in one's diet to evaluate its potential impact on headaches.
Collapse
Affiliation(s)
- Edmond Ahdoot
- Department of Neurology, Icahn School of Medicine at Mount Sinai, Mount Sinai Hospital, New York, NY, USA
| | - Fred Cohen
- Department of Neurology, Icahn School of Medicine at Mount Sinai, Mount Sinai Hospital, New York, NY, USA.
- Department of Medicine, Icahn School of Medicine at Mount Sinai, Mount Sinai Hospital, New York, NY, USA.
| |
Collapse
|
3
|
Abstract
Targeting CGRP-pathways has substantially expanded our options for treating individuals with migraine. Although the efficacy of these drugs on migraine aura is yet to be fully revealed, it seems from existing studies that CGRP antagonism reduces the number of migraine auras. The present perspective summarizes the evidence linking CGRP to the migraine aura and proposes a model by which targeting the CGRP-pathways and, thus, inhibition the interaction between C- and Aδ-trigeminal fibers might reverse a possible high cortical glutamate level leading to a reduced number of migraine auras.
Collapse
Affiliation(s)
- Mohammad Al-Mahdi Al-Karagholi
- Danish Headache Center, Department of Neurology, Rigshospitalet- Glostrup, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| |
Collapse
|
4
|
Spekker E, Nagy-Grócz G. All Roads Lead to the Gut: The Importance of the Microbiota and Diet in Migraine. Neurol Int 2023; 15:1174-1190. [PMID: 37755364 PMCID: PMC10536453 DOI: 10.3390/neurolint15030073] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/28/2023] Open
Abstract
Migraine, a prevalent neurological condition and the third most common disease globally, places a significant economic burden on society. Despite extensive research efforts, the precise underlying mechanism of the disease remains incompletely comprehended. Nevertheless, it is established that the activation and sensitization of the trigeminal system are crucial during migraine attacks, and specific substances have been recognized for their distinct involvement in the pathomechanism of migraine. Recently, an expanding body of data indicates that migraine attacks can be prevented and treated through dietary means. It is important to highlight that the various diets available pose risks for patients without professional guidance. This comprehensive overview explores the connection between migraine, the gut microbiome, and gastrointestinal disorders. It provides insight into migraine-triggering foods, and discusses potential diets to help reduce the frequency and severity of migraine attacks. Additionally, it delves into the benefits of using pre- and probiotics as adjunctive therapy in migraine treatment.
Collapse
Affiliation(s)
| | - Gábor Nagy-Grócz
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, H-6725 Szeged, Hungary;
- Faculty of Health Sciences and Social Studies, University of Szeged, H-6726 Szeged, Hungary
- Preventive Health Sciences Research Group, Incubation Competence Centre of the Centre of Excellence for Interdisciplinary Research, Development and Innovation of the University of Szeged, H-6720 Szeged, Hungary
| |
Collapse
|
5
|
Royo F, Tames H, Bordanaba-Florit G, Cabrera D, Azparren-Angulo M, Garcia-Vallicrosa C, Margolles A, Ruiz L, Ruas-Madiedo P, Falcon-Perez JM. Orally Administered Bifidobacterium adolescentis Diminishes Serum Glutamate Concentration in Mice. Microbiol Spectr 2023; 11:e0506322. [PMID: 37347184 PMCID: PMC10433951 DOI: 10.1128/spectrum.05063-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 06/04/2023] [Indexed: 06/23/2023] Open
Abstract
Several studies have described the contribution of glutamate-transforming microbiota to the development of chronic ailments. For instance, the blood concentration of glutamate is higher in some patients with fibromyalgia, chronic fatigue, and pain. Taking advantage of a naturally occurring strain of Bifidobacterium that is able to transform glutamate in γ-aminobutyric caid (GABA), B. adolescentis IPLA60004, we designed a placebo-controlled intervention to test if the presence of this GABA-producing bifidobacteria in mice was able to impact the concentration of glutamate in the blood in comparison with the administration of other strain of the same species lacking the genes of the glutamate decarboxylase (gad) cluster. Animals were fed every day with 8 log CFU of bacteria in a sterilized milk vehicle for 14 days. Samples from feces and blood were collected during this period, and afterwards animals were sacrificed, tissues were taken from different organs, and the levels of different metabolites were analyzed by ultrahigh-performance liquid chromatography coupled to mass spectrometry. The results showed that both bacterial strains orally administered survived in the fecal content, and animals fed B. adolescentis IPLA60004 showed a significant reduction of their glutamate serum concentration, while a nonsignificant decrease was observed for animals fed a reference strain, B. adolescentis LGM10502. The variations observed in GABA were influenced by the gender of the animals, and no significant changes were observed in different tissues of the brain. These results suggest that orally administered GABA-producing probiotics could reduce the glutamate concentration in blood, opening a case for a clinical trial study in chronic disease patients. IMPORTANCE This work presents the results of a trial using mice as a model that were fed with a bacterial strain of the species B. adolescentis, which possesses different active genes capable of degrading glutamate and converting it into GABA. Indeed, the bacterium is able to survive the passage through the gastric tract and, more importantly, the animals reduce over time the concentration of glutamate in their blood. The importance of this result lies in the fact that several chronic ailments, such as fibromyalgia, are characterized by an increase in glutamate. Our results indicate that an oral diet with this probiotic-type bacteria could reduce the concentration of glutamate and, therefore, reduce the symptoms associated with the excess of this neurotransmitter.
Collapse
Affiliation(s)
- Felix Royo
- Exosomes Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Derio, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas Y Digestivas, Madrid, Spain
| | - Hector Tames
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas, Villaviciosa, Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Asturias, Spain
| | - Guillermo Bordanaba-Florit
- Exosomes Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Derio, Spain
| | - Diana Cabrera
- Metabolomics Platform, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Derio, Spain
| | - Maria Azparren-Angulo
- Exosomes Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Derio, Spain
| | - Clara Garcia-Vallicrosa
- Exosomes Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Derio, Spain
| | - Abelardo Margolles
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas, Villaviciosa, Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Asturias, Spain
| | - Lorena Ruiz
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas, Villaviciosa, Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Asturias, Spain
| | - Patricia Ruas-Madiedo
- Departamento de Microbiología y Bioquímica, Instituto de Productos Lácteos de Asturias, Consejo Superior de Investigaciones Científicas, Villaviciosa, Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias, Oviedo, Asturias, Spain
| | - Juan M. Falcon-Perez
- Exosomes Laboratory, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Derio, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas Y Digestivas, Madrid, Spain
- Metabolomics Platform, Center for Cooperative Research in Biosciences, Basque Research and Technology Alliance, Derio, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| |
Collapse
|
6
|
Kalatharan V, Al-Karagholi MAM. Targeting Peripheral N-Methyl-D-Aspartate Receptor (NMDAR): A Novel Strategy for the Treatment of Migraine. J Clin Med 2023; 12:jcm12062156. [PMID: 36983158 PMCID: PMC10055974 DOI: 10.3390/jcm12062156] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/23/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023] Open
Abstract
Backgrounds: Several acute and preventive medications were developed for the treatment of migraine. Yet, a significant proportion of patients reports an inadequate response and a lack of tolerability, emphasizing the need for new options. Glutamate is the most important excitatory neurotransmitter in the brain, and glutamate receptors including N-Methyl-D-Aspartate Receptor (NMDAR) are expressed at several levels of the trigeminovascular system, which is the anatomical and physiological substrate of migraine pain. Objective: To review preclinical and clinical studies investigating the role of the NMDAR in migraine pathophysiology. Methods: No protocol was registered for this study. References for the present review were identified from a narrative search of the PubMed database. Search terms such as glutamate, migraine, N-Methyl-D-Aspartate Receptor, and NMDAR were used. No restrictions were made in terms of the language and date of publication. Results: In animal models, administration of monosodium glutamate (MSG) activated and sensitized trigeminovascular neurons. In healthy human participants, consumption of MSG caused headaches, craniofacial sensitivity, and nausea. In in vivo models and through immunolabeling, NMDAR subunits NR1, NR2A, and NR2B were expressed in trigeminal ganglion neurons. In humans, NMDAR antagonists such as ketamine and memantine caused a significant reduction in pain intensity and monthly headache frequency. Conclusions: Accumulative evidence indicates that NMDAR is a promising new target for the treatment of migraine. Selective NMDAR antagonists without central effects are needed to investigate their therapeutic benefit in the treatment of migraine.
Collapse
|
7
|
Microbiome-Driven Proline Biogenesis in Plants under Stress: Perspectives for Balanced Diet to Minimize Depression Disorders in Humans. Microorganisms 2022; 10:microorganisms10112264. [DOI: 10.3390/microorganisms10112264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/08/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
According to the World Health Organization (WHO), depression is a leading cause of disability worldwide and a major contributor to the overall global burden of mental disorders. An increasing number of studies have revealed that among 20 different amino acids, high proline consumption is a dietary factor with the strongest impact on depression in humans and animals, including insects. Recent studies acknowledged that gut microbiota play a key role in proline-related pathophysiology of depression. In addition, the multi-omics approach has alleged that a high level of metabolite proline is directly linked to depression severity, while variations in levels of circulating proline are dependent on microbiome composition. The gut–brain axis proline analysis is a gut microbiome model of studying depression, highlighting the critical importance of diet, but nothing is known about the role of the plant microbiome–food axis in determining proline concentration in the diet and thus about preventing excessive proline intake through food consumption. In this paper, we discuss the protocooperative potential of a holistic study approach combining the microbiota–gut–brain axis with the microbiota–plant–food–diet axis, as both are involved in proline biogenesis and metabolism and thus on in its effect on mood and cognitive function. In preharvest agriculture, the main scientific focus must be directed towards plant symbiotic endophytes, as scavengers of abiotic stresses in plants and modulators of high proline concentration in crops/legumes/vegetables under climate change. It is also implied that postharvest agriculture—including industrial food processing—may be critical in designing a proline-balanced diet, especially if corroborated with microbiome-based preharvest agriculture, within a circular agrifood system. The microbiome is suggested as a target for selecting beneficial plant endophytes in aiming for a balanced dietary proline content, as it is involved in the physiology and energy metabolism of eukaryotic plant/human/animal/insect hosts, i.e., in core aspects of this amino acid network, while opening new venues for an efficient treatment of depression that can be adapted to vast groups of consumers and patients. In that regard, the use of artificial intelligence (AI) and molecular biomarkers combined with rapid and non-destructive imaging technologies were also discussed in the scope of enhancing integrative science outcomes, agricultural efficiencies, and diagnostic medical precisions.
Collapse
|
8
|
Benbow T, Teja F, Sheikhi A, Exposto FG, Svensson P, Cairns BE. Peripheral N-methyl-D-aspartate receptor activation contributes to monosodium glutamate-induced headache but not nausea behaviours in rats. Sci Rep 2022; 12:13894. [PMID: 35974090 PMCID: PMC9381496 DOI: 10.1038/s41598-022-18290-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 08/09/2022] [Indexed: 12/29/2022] Open
Abstract
Monosodium glutamate induces behaviors thought to reflect headache and nausea in rats. We explored the effects of the N-methyl-d-aspartate receptor antagonist (2R)-amino-5-phosphonovaleric acid, the inotropic glutamate receptor antagonist kynurenic acid, and the CGRP receptor antagonist olcegepant, on monosodium glutamate-induced increases in nocifensive, headache-like and nausea behaviours. Effects of these antagonists on motor function were examined with a rotarod. The effect of the dopamine receptor antagonist metoclopramide and the serotonin 3 receptor antagonist ondansetron on nausea behaviour was also assessed. (2R)-amino-5-phosphonovaleric acid, and to a lesser extent, kynurenic acid and olcegepant, reduced nocifensive and headache-like behaviours evoked by monosodium glutamate. No alteration in motor function by (2R)-amino-5-phosphonovaleric acid, kynurenic acid or olcegepant was observed. No sex-related differences in the effectiveness of these agents were identified. Nausea behaviour was significantly more pronounced in male than in female rats. Olcegepant, ondansetron and metoclopramide ameliorated this nausea behaviour in male rats. Ondansetron and metoclopramide also reduced headache-like behaviour in male rats. These findings suggest that peripheral N-methyl-d-aspartate receptor activation underlies monosodium glutamate-induced headache-like behaviour but does not mediate the nausea behaviour in rats.
Collapse
Affiliation(s)
- Tarique Benbow
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, V6T 1Z3, Canada
| | - Felisha Teja
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, V6T 1Z3, Canada
| | - Afrooz Sheikhi
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, V6T 1Z3, Canada
| | - Fernando G Exposto
- Section for Orofacial Pain and Jaw Function, Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, 8000, Aarhus C, Denmark
| | - Peter Svensson
- Section for Orofacial Pain and Jaw Function, Department of Dentistry and Oral Health, Aarhus University, Vennelyst Boulevard 9, 8000, Aarhus C, Denmark
| | - Brian E Cairns
- Faculty of Pharmaceutical Sciences, University of British Columbia, 2405 Wesbrook Mall, Vancouver, V6T 1Z3, Canada.
| |
Collapse
|
9
|
Jia L, Wang F, Zhang K, Wang D, Wang X, Li X, Zhang J. l-Theanine Inhibits (-)-Epigallocatechin-3-gallate Oxidation via Chelating Copper. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:7751-7761. [PMID: 35696521 DOI: 10.1021/acs.jafc.2c01379] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Our recent study showed that glutamate can inhibit dopamine oxidation via chelating copper. l-Theanine is an amino acid analogue of glutamate, whereas tea (-)-epigallocatechin-3-gallate (EGCG) is similar to dopamine in avidly undergoing oxidation. We thus hypothesized that l-theanine could also restrain EGCG oxidation via chelating copper. The current study scrutinized influences of l-theanine on EGCG oxidation in vitro and in vivo. The in vitro results showed that l-theanine and copper formed an l-theanine-copper complex with impaired redox activity of copper. Accordingly, l-theanine effectively suppressed copper-facilitated EGCG oxidation, hydroxyl radical production, and DNA damage; inhibited EGCG autoxidation which in essence involves catalysis of transition metals such as copper; and reduced EGCG oxidation-associated formation of a quinone adduct with proteins known as quinoproteins. Consistently, l-theanine significantly increased hepatic EGCG levels and reduced hepatic quinoprotein levels and liver injury in mice treated with EGCG. These lines of evidence together suggest that tea l-theanine can protect against tea catechin oxidation.
Collapse
Affiliation(s)
- Lijie Jia
- The State Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230036, China
| | - Fuming Wang
- The State Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230036, China
| | - Ke Zhang
- The State Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230036, China
| | - Dongxu Wang
- The State Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230036, China
| | - Xiaoxiao Wang
- The State Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230036, China
| | - Xiuli Li
- The State Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230036, China
| | - Jinsong Zhang
- The State Key Laboratory of Tea Plant Biology and Utilization, School of Tea & Food Science, Anhui Agricultural University, Hefei 230036, China
| |
Collapse
|
10
|
Koroleva KS, Svitko SO, Nurmieva DA, Gafurov OS, Buglinina AD, Sitdikova GF. Effects of Nitric Oxide on the Electrical Activity of the Rat Trigeminal Nerve and Mast Cell Morphology. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022030243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
11
|
Guerrero-Toro C, Koroleva K, Ermakova E, Gafurov O, Abushik P, Tavi P, Sitdikova G, Giniatullin R. Testing the Role of Glutamate NMDA Receptors in Peripheral Trigeminal Nociception Implicated in Migraine Pain. Int J Mol Sci 2022; 23:ijms23031529. [PMID: 35163452 PMCID: PMC8835926 DOI: 10.3390/ijms23031529] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/20/2022] [Accepted: 01/26/2022] [Indexed: 01/18/2023] Open
Abstract
The pro-nociceptive role of glutamate in the CNS in migraine pathophysiology is well established. Glutamate, released from trigeminal afferents, activates second order nociceptive neurons in the brainstem. However, the function of peripheral glutamate receptors in the trigeminovascular system suggested as the origin site for migraine pain, is less known. In the current project, we used calcium imaging and patch clamp recordings from trigeminal ganglion (TG) neurons, immunolabelling, CGRP assay and direct electrophysiological recordings from rat meningeal afferents to investigate the role of glutamate in trigeminal nociception. Glutamate, aspartate, and, to a lesser extent, NMDA under free-magnesium conditions, evoked calcium transients in a fraction of isolated TG neurons, indicating functional expression of NMDA receptors. The fraction of NMDA sensitive neurons was increased by the migraine mediator CGRP. NMDA also activated slowly desensitizing currents in 37% of TG neurons. However, neither glutamate nor NMDA changed the level of extracellular CGRP. TG neurons expressed both GluN2A and GluN2B subunits of NMDA receptors. In addition, after removal of magnesium, NMDA activated persistent spiking activity in a fraction of trigeminal nerve fibers in meninges. Thus, glutamate activates NMDA receptors in somas of TG neurons and their meningeal nerve terminals in magnesium-dependent manner. These findings suggest that peripherally released glutamate can promote excitation of meningeal afferents implicated in generation of migraine pain in conditions of inherited or acquired reduced magnesium blockage of NMDA channels and support the usage of magnesium supplements in migraine.
Collapse
Affiliation(s)
- Cindy Guerrero-Toro
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
| | - Kseniia Koroleva
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
| | - Elizaveta Ermakova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
| | - Oleg Gafurov
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
| | - Polina Abushik
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
- Laboratory of Comparative Neurophysiology, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 194223 Saint Petersburg, Russia
| | - Pasi Tavi
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
| | - Guzel Sitdikova
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
- Correspondence: (G.S.); (R.G.); Tel.: +7-9033061092 (G.S.); +358-403553665 (R.G.)
| | - Rashid Giniatullin
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, 70211 Kuopio, Finland; (C.G.-T.); (K.K.); (P.A.); (P.T.)
- Department of Human and Animal Physiology, Institute of Fundamental Medicine and Biology, Kazan Federal University, 420008 Kazan, Russia; (E.E.); (O.G.)
- Correspondence: (G.S.); (R.G.); Tel.: +7-9033061092 (G.S.); +358-403553665 (R.G.)
| |
Collapse
|
12
|
Bhavadharini B, Kavimughil M, Malini B, Vallath A, Prajapati HK, Sunil CK. Recent Advances in Biosensors for Detection of Chemical Contaminants in Food — a Review. FOOD ANAL METHOD 2022. [DOI: 10.1007/s12161-021-02213-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
13
|
Systemic administration of monosodium glutamate induces sexually dimorphic headache- and nausea-like behaviours in rats. Pain 2022; 163:1838-1853. [DOI: 10.1097/j.pain.0000000000002592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 12/17/2021] [Indexed: 11/26/2022]
|
14
|
Benbow T, Cairns BE. Dysregulation of the peripheral glutamatergic system: A key player in migraine pathogenesis? Cephalalgia 2021; 41:1249-1261. [PMID: 34148407 PMCID: PMC8504403 DOI: 10.1177/03331024211017882] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background Although the role of glutamate in migraine pathogenesis remains uncertain, there has been significant interest in the development of drug candidates that target glutamate receptors. Activation of trigeminovascular afferent fibers is now recognized as a crucial step to the onset of a migraine episode. New evidence suggests a dysfunction in peripheral glutamate regulation may play a role in this process. Objective To provide a narrative review of the role of peripheral glutamate dysfunction in migraine. Method A review of recent literature from neurobiological, pharmacological and genomic studies was conducted to support peripheral glutamate dysfunction as a potential element in migraine pathogenesis. Results Studies in rats suggest that elevated blood glutamate mechanically sensitizes trigeminal afferent fibers and stimulates the release of calcitonin-gene related peptide and other neuropeptides to promote and maintain neurogenic inflammation. These effects may be driven by upregulation of glutamate receptors, and modifications to reuptake and metabolic pathways of glutamate. Furthermore, genome wide association studies have found polymorphisms in glutamate receptor and transporter genes that are associated with migraine. Conclusion The role of peripheral glutamate signalling in the onset and maintenance of migraine is not completely elucidated and future studies are still needed to confirm its role in migraine pathogenesis.
Collapse
Affiliation(s)
- Tarique Benbow
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | - Brian E Cairns
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| |
Collapse
|
15
|
Shimada A, Alhilou AM, Svensson P, Ernberg M, Christidis N. Functional Change in Experimental Allodynia After Glutamate-Induced Pain in the Human Masseter Muscle. FRONTIERS IN ORAL HEALTH 2020; 1:609082. [PMID: 35047987 PMCID: PMC8757840 DOI: 10.3389/froh.2020.609082] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 10/23/2020] [Indexed: 11/13/2022] Open
Abstract
Background: Glutamate, as well as nerve growth factor (NGF), is involved in nociception from peripheral tissues, such as muscles. However, the potential interaction between glutamate and NGF still remains unclear. This study investigated the interaction between glutamate-induced masseter muscle pain and NGF-induced allodynia on pain perception and jaw function in healthy individuals, and any possible sex differences in the response. Materials and Methods: Thirty pain-free adult participants (15 men and 15 women, mean age ± SD: 24 ± 4 years) participated in this study consisting of three sessions (Day 0, Day 3, and Day 4). NGF (5 μg/mL, 1.0 mL) was injected into the masseter muscle on Day 0 to induce muscle allodynia. On Day 3, glutamate (1M, 0.2 mL) was injected into the same masseter muscle. Before and after injections on Day 0 and 3, and post-injection (Day 4), spontaneous pain, temporal summation pain, as well as functional pain and fatigue in response to chewing were assessed with validated scales, and the pressure pain threshold (PPT) was recorded. Results: Spontaneous pain intensity was significantly higher after glutamate than NGF (P < 0.001). PPTs, temporal summation pain and functional measures were all reduced 3 days after NGF injection (P's < 0.001). Injection of glutamate on Day 3 did not further affect PPTs or temporal summation pain and there were no sex differences in the effects (P > 0.189). Chewing pain (P = 0.022) and fatigue increased after glutamate injection to a higher degree in the women than men (P = 0.037). Conclusion: Taken together, while glutamate injected into the NGF-sensitized muscle was painful, it did not alter muscle tenderness in women vs. men. However, pain and fatigue evoked by jaw function were higher in women after glutamate injection. This suggest that sex differences reported for masseter myalgia, mimicked by glutamate and NGF mediated pain in this study, may be greater for measures of perceived jaw function, which should be considered in a clinical evaluation.
Collapse
Affiliation(s)
- Akiko Shimada
- Department of Geriatric Dentistry, Osaka Dental University, Osaka, Japan
| | - Abdelrahman M Alhilou
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden.,Department of Restorative Dentistry, College of Dentistry, Umm Al-Qura University, Mecca, Saudi Arabia
| | - Peter Svensson
- Section of Orofacial Pain and Jaw Function, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.,Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Malin Ernberg
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
| | - Nikolaos Christidis
- Division of Oral Diagnostics and Rehabilitation, Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden.,Scandinavian Center for Orofacial Neurosciences (SCON), Huddinge, Sweden
| |
Collapse
|
16
|
Food in Chronic Pain: Friend or Foe? Nutrients 2020; 12:nu12082473. [PMID: 32824467 PMCID: PMC7469060 DOI: 10.3390/nu12082473] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 01/14/2023] Open
|
17
|
Mentana A, Nardiello D, Palermo C, Centonze D. Accurate glutamate monitoring in foodstuffs by a sensitive and interference-free glutamate oxidase based disposable amperometric biosensor. Anal Chim Acta 2020; 1115:16-22. [PMID: 32370865 DOI: 10.1016/j.aca.2020.04.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 02/05/2023]
Abstract
L-Glutamate (L-Glu) is a well-known flavour enhancer that is present in several foodstuffs. Although L-Glu is generally recognized as safe, the use in foodstuffs remains controversial and then its fast and accurate monitoring represents an important issue. In this work a sensitive and interference-free disposable amperometric biosensor for glutamate monitoring in foodstuffs was developed. The biosensor was prepared by immobilizing glutamate oxidase through co-crosslinking with bovine serum albumin and glutaraldehyde onto a screen printed disposable platinum electrode modified with a permselective overoxidized polypyrrole film. The enzyme immobilization was optimized by using different experimental procedures. The optimized glutamate biosensor was integrated in a flow injection system and characterized in terms of linearity (0.005-1.0 mM, r2 = 0.992), limits of detection (1.8 μM) and quantitation (5.4 μM), repeatability (RSD < 3%) and stability of response under operational conditions (up to 50 h, over 400 analysis). The biosensor showed also excellent anti-interference characteristics towards the main electroactive interferents present in food matrices, and this allowed the application to the accurate monitoring of glutamate in different foodstuffs.
Collapse
Affiliation(s)
- Annalisa Mentana
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università degli Studi di Foggia, via Napoli, 25 - 71122, Foggia, Italy
| | - Donatella Nardiello
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università degli Studi di Foggia, via Napoli, 25 - 71122, Foggia, Italy
| | - Carmen Palermo
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università degli Studi di Foggia, via Napoli, 25 - 71122, Foggia, Italy
| | - Diego Centonze
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università degli Studi di Foggia, via Napoli, 25 - 71122, Foggia, Italy.
| |
Collapse
|
18
|
Eid RA, Al-Shraim M, Zaki MS, Kamar SS, Abdel Latif NS, Negm S, Al-Ani B, Haidara MA. Vitamin E protects against monosodium glutamate-induced acute liver injury and hepatocyte ultrastructural alterations in rats. Ultrastruct Pathol 2019; 43:199-208. [PMID: 31599191 DOI: 10.1080/01913123.2019.1673860] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Refaat A. Eid
- Departments of Pathology, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Mubarak Al-Shraim
- Departments of Pathology, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Mohamed Sa. Zaki
- Departments of Anatomy, College of Medicine, King Khalid University, Abha, Saudi Arabia
- Department of Histology, Faculty of Medicine, Zagazig University, Zagazig, Egypt
| | - Samaa S. Kamar
- Departments of Medical HistologyKasr Al-Aini Faculty of Medicine, Cairo University, Giza, Egypt
| | - Noha S. Abdel Latif
- Departments of Medical Pharmacology, Kasr Al-Aini Faculty of Medicine, Cairo University, Giza, Egypt
| | - Sally Negm
- Departments of Microbiology, College of Applied Medical Sciences, Mahail Campus, King Khalid University, Abha, Saudi Arabia
| | - Bahjat Al-Ani
- Departments of Physiology, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Mohamed A. Haidara
- Departments of Physiology, College of Medicine, King Khalid University, Abha, Saudi Arabia
- Physiology Department, Kasr al-Aini Faculty of Medicine, Cairo University, Cairo, Egypt
| |
Collapse
|
19
|
Zhang Y, Zhang L, Venkitasamy C, Pan Z, Ke H, Guo S, Wu D, Wu W, Zhao L. Potential effects of umami ingredients on human health: Pros and cons. Crit Rev Food Sci Nutr 2019; 60:2294-2302. [PMID: 31272187 DOI: 10.1080/10408398.2019.1633995] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Umami taste is the most recent confirmed basic taste in addition to sour, sweet, bitter, and salty. It has been controversial because of its effects on human nutritional benefit. Based on the available literatures, this review categorized 13 positive and negative effects of umami taste on human health. On the positive side, umami taste can improve food flavor and consumption, improve nutrition intake of the elderly and patients, protect against duodenal cancer, reduce ingestion of sodium chloride, decrease consumption of fat, and improve oral functions. On the other hand, umami taste can also induce hepatotoxicity, cause asthma, induce migraine headaches, damage the nervous system, and promote obesity. Due to its novelty, there are many functions and effects of umami taste waiting to be discovered. With further investigation, more information regarding the effects of umami taste on human health will be discerned.
Collapse
Affiliation(s)
- Yin Zhang
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu, China
| | - Longyi Zhang
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu, China
| | - Chandrasekar Venkitasamy
- Department of Biological and Agricultural Engineering, University of California, Davis, Davis, California, USA.,Healthy Processed Foods Research Unit, Western Regional Research Center, USDA-ARS, Albany, California, USA
| | - Zhongli Pan
- Department of Biological and Agricultural Engineering, University of California, Davis, Davis, California, USA.,Healthy Processed Foods Research Unit, Western Regional Research Center, USDA-ARS, Albany, California, USA
| | - Huan Ke
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu, China
| | - Siya Guo
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu, China
| | - Di Wu
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu, China
| | - Wanxia Wu
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu, China
| | - Liming Zhao
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu, China.,State Key Laboratory of Bioreactor Engineering, R&D Center of Separation and Extraction Technology in Fermentation Industry, East China University of Science and Technology, Shanghai, China
| |
Collapse
|
20
|
Kraal AZ, Arvanitis NR, Jaeger AP, Ellingrod VL. Could Dietary Glutamate Play a Role in Psychiatric Distress? Neuropsychobiology 2019; 79:13-19. [PMID: 30699435 PMCID: PMC6667320 DOI: 10.1159/000496294] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 12/18/2018] [Indexed: 12/15/2022]
Abstract
Glutamate is an amino acid that functions as an excitatory neurotransmitter. It has also been associated with somatic and psychiatric distress and is implicated in the pathophysiology of psychiatric disorders such as schizophrenia. Ingestion of dietary glutamate, such as monosodium glutamate (MSG), has been mechanistically linked with greater distress among patients with chronic pain conditions, though findings have been equivocal. Preliminary research suggests that an MSG-restricted diet confers beneficial effects on somatic symptoms and well-being for some individuals with chronic pain conditions. In addition to associations with somatic distress, glutamate has been associated with the onset and progression of psychiatric symptoms. Thus, the role of dietary glutamate in psychiatric distress represents an underdeveloped and potentially important area for future research aimed at clarifying pathophysiological mechanisms and identifying targets for dietary intervention in psychiatric illnesses.
Collapse
Affiliation(s)
- A. Zarina Kraal
- University of Michigan, Department of Psychology, Ann Arbor, MI, USA,University of Michigan, College of Pharmacy, Ann Arbor, MI, USA
| | | | | | - Vicki L Ellingrod
- Department of Psychology, University of Michigan, Ann Arbor, Michigan, USA, .,College of Pharmacy, University of Michigan, Ann Arbor, Michigan, USA,
| |
Collapse
|
21
|
Scourboutakos MJ, Murphy SA, L'Abbé MR. Association between salt substitutes/enhancers and changes in sodium levels in fast-food restaurants: a cross-sectional analysis. CMAJ Open 2018; 6. [PMID: 29514800 PMCID: PMC5878952 DOI: 10.9778/cmajo.20170137] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Restaurant foods have high sodium levels, and efforts have been made to promote reductions. The objective of this study was to understand if salt substitutes and enhancers are associated with changes in sodium levels in fast-food restaurants. METHODS A longitudinal database (MENU-FLIP) containing nutrition information for Canadian chain restaurants with 20 or more locations nationally was created in 2010 and updated in 2013 and 2016. In 2016, when available, ingredient lists were collected from restaurant websites and searched for the presence of salt substitutes/enhancers. Changes in sodium levels (per serving) and the prevalence of salt substitutes/enhancers in 222 foods from 12 of the leading fast-food restaurant chains were compared across 3 time points. RESULTS Sixty-nine percent of foods contained a salt substitute/enhancer. Substitutes/enhancers were found in every restaurant chain (n = 12) for which ingredient data were available. The most common substitutes/enhancers were yeast extracts (in 30% of foods), calcium chloride (28%), monosodium glutamate (14%) and potassium chloride (12%). Sodium levels in foods that contained substitutes/enhancers decreased significantly more (190 ± 42 mg/serving) over the study period than those in foods that did not contain a substitute/enhancer (40 ± 17 mg/serving, p < 0.001). INTERPRETATION Salt substitutes and enhancers are prevalent in restaurant foods and are one means by which restaurants may be lowering sodium levels in their foods. At this time, the potential consequences of these findings, if any, are uncertain.
Collapse
Affiliation(s)
- Mary J Scourboutakos
- Affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ont
| | - Sarah A Murphy
- Affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ont
| | - Mary R L'Abbé
- Affiliation: Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ont
| |
Collapse
|
22
|
Update on food safety of monosodium l -glutamate (MSG). PATHOPHYSIOLOGY 2017; 24:243-249. [DOI: 10.1016/j.pathophys.2017.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/18/2017] [Accepted: 08/21/2017] [Indexed: 12/22/2022] Open
|
23
|
Yuasa M, Koe M, Maeda A, Eguchi A, Abe H, Tominaga M. Characterization of flavor component in Japanese instant soup stocks ‘dashi’. Int J Gastron Food Sci 2017. [DOI: 10.1016/j.ijgfs.2017.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
|
24
|
Mortensen A, Aguilar F, Crebelli R, Di Domenico A, Dusemund B, Frutos MJ, Galtier P, Gott D, Gundert-Remy U, Leblanc JC, Lindtner O, Moldeus P, Mosesso P, Parent-Massin D, Oskarsson A, Stankovic I, Waalkens-Berendsen I, Woutersen RA, Wright M, Younes M, Boon P, Chrysafidis D, Gürtler R, Tobback P, Altieri A, Rincon AM, Lambré C. Re-evaluation of glutamic acid (E 620), sodium glutamate (E 621), potassium glutamate (E 622), calcium glutamate (E 623), ammonium glutamate (E 624) and magnesium glutamate (E 625) as food additives. EFSA J 2017; 15:e04910. [PMID: 32625571 PMCID: PMC7009848 DOI: 10.2903/j.efsa.2017.4910] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of glutamic acid-glutamates (E 620-625) when used as food additives. Glutamate is absorbed in the intestine and it is presystemically metabolised in the gut wall. No adverse effects were observed in the available short-term, subchronic, chronic, reproductive and developmental studies. The only effect observed was increased kidney weight and increased spleen weight; however, the increase in organ weight was not accompanied by adverse histopathological findings and, therefore, the increase in organ weight was not considered as an adverse effect. The Panel considered that glutamic acid-glutamates (E 620-625) did not raise concern with regards to genotoxicity. From a neurodevelopmental toxicity study, a no observed adverse effect level (NOAEL) of 3,200 mg monosodium glutamate/kg body weight (bw) per day could be identified. The Panel assessed the suitability of human data to be used for the derivation of a health-based guidance value. Although effects on humans were identified human data were not suitable due to the lack of dose-response data from which a dose without effect could be identified. Based on the NOAEL of 3,200 mg monosodium glutamate/kg bw per day from the neurodevelopmental toxicity study and applying the default uncertainty factor of 100, the Panel derived a group acceptable daily intake (ADI) of 30 mg/kg bw per day, expressed as glutamic acid, for glutamic acid and glutamates (E 620-625). The Panel noted that the exposure to glutamic acid and glutamates (E 620-625) exceeded not only the proposed ADI, but also doses associated with adverse effects in humans for some population groups.
Collapse
|
25
|
Martin VT, Vij B. Diet and Headache: Part 1. Headache 2016; 56:1543-1552. [DOI: 10.1111/head.12953] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 08/31/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Vincent T. Martin
- Department of Internal Medicine; University of Cincinnati College of Medicine; Cincinnati OH USA
| | - Brinder Vij
- Department of Neurology; University of Cincinnati College of Medicine; Cincinnati OH USA
| |
Collapse
|
26
|
Martin VT, Vij B. Diet and Headache: Part 2. Headache 2016; 56:1553-1562. [DOI: 10.1111/head.12952] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 08/31/2016] [Indexed: 12/28/2022]
Affiliation(s)
- Vincent T. Martin
- Department of Internal Medicine; University of Cincinnati College of Medicine; Cincinnati OH USA
| | - Brinder Vij
- Department of Neurology; University of Cincinnati College of Medicine; Cincinnati OH USA
| |
Collapse
|
27
|
O’Brien M, Cairns BE. Monosodium glutamate alters the response properties of rat trigeminovascular neurons through activation of peripheral NMDA receptors. Neuroscience 2016; 334:236-244. [DOI: 10.1016/j.neuroscience.2016.08.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 01/03/2023]
|
28
|
Affiliation(s)
- Kathleen Holton
- Department of Health Studies, Center for Behavioral Neuroscience, American University, 4400 Massachusetts Avenue NW, Gray Hall 119, Washington, DC 20016, USA
| |
Collapse
|
29
|
Obayashi Y, Nagamura Y. Does monosodium glutamate really cause headache? : a systematic review of human studies. J Headache Pain 2016; 17:54. [PMID: 27189588 PMCID: PMC4870486 DOI: 10.1186/s10194-016-0639-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/14/2016] [Indexed: 01/03/2023] Open
Abstract
Although monosodium glutamate (MSG) is classified as a causative substance of headache in the International Classification of Headache Disorders 3rd edition (ICHD-III beta), there is no literature in which causal relationship between MSG and headache was comprehensively reviewed. We performed systematic review of human studies which include the incidence of headache after an oral administration of MSG. An analysis was made by separating the human studies with MSG administration with or without food, because of the significant difference of kinetics of glutamate between those conditions (Am J Clin Nutr 37:194-200, 1983; J Nutr 130:1002S-1004S, 2000) and there are some papers which report the difference of the manifestation of symptoms after MSG ingestion with or without food (Food Chem Toxicol 31:1019-1035, 1993; J Nutr 125:2891S-2906S, 1995). Of five papers including six studies with food, none showed a significant difference in the incidence of headache except for the female group in one study. Of five papers including seven studies without food, four studies showed a significant difference. Many of the studies involved administration of MSG in solution at high concentrations (>2 %). Since the distinctive MSG is readily identified at such concentrations, these studies were thought not to be properly blinded. Because of the absence of proper blinding, and the inconsistency of the findings, we conclude that further studies are required to evaluate whether or not a causal relationship exists between MSG ingestion and headache.
Collapse
Affiliation(s)
- Yoko Obayashi
- />International Glutamate Technical Committee (IGTC), Avenue Jules Bordet 142, B-1140 Brussels, Belgium
| | - Yoichi Nagamura
- />Faculty of Health Science, Department of Clinical Nurition, Suzuka University of Medical Science, 1001-1 Kishioka-cho, Suzuka-city, Mie 510-0293 Japan
| |
Collapse
|
30
|
Shimada A, Castrillon EE, Baad-Hansen L, Ghafouri B, Gerdle B, Wåhlén K, Ernberg M, Cairns BE, Svensson P. Increased pain and muscle glutamate concentration after single ingestion of monosodium glutamate by myofascial temporomandibular disorders patients. Eur J Pain 2016; 20:1502-12. [PMID: 27091318 DOI: 10.1002/ejp.874] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND A randomized, double-blinded, placebo-controlled study was conducted to investigate if single monosodium glutamate (MSG) administration would elevate muscle/serum glutamate concentrations and affect muscle pain sensitivity in myofascial temporomandibular disorders (TMD) patients more than in healthy individuals. METHODS Twelve myofascial TMD patients and 12 sex- and age-matched healthy controls participated in two sessions. Participants drank MSG (150 mg/kg) or NaCl (24 mg/kg; control) diluted in 400 mL of soda. The concentration of glutamate in the masseter muscle, blood plasma and saliva was determined before and after the ingestion of MSG or control. At baseline and every 15 min after the ingestion, pain intensity was scored on a 0-10 numeric rating scale. Pressure pain threshold, pressure pain tolerance (PPTol) and autonomic parameters were measured. All participants were asked to report adverse effects after the ingestion. RESULTS In TMD, interstitial glutamate concentration was significantly greater after the MSG ingestion when compared with healthy controls. TMD reported a mean pain intensity of 2.8/10 at baseline, which significantly increased by 40% 30 min post MSG ingestion. At baseline, TMD showed lower PPTols in the masseter and trapezius, and higher diastolic blood pressure and heart rate than healthy controls. The MSG ingestion resulted in reports of headache by half of the TMD and healthy controls, respectively. CONCLUSION These findings suggest that myofascial TMD patients may be particularly sensitive to the effects of ingested MSG. WHAT DOES THIS STUDY ADD?': Elevation of interstitial glutamate concentration in the masseter muscle caused by monosodium glutamate (MSG) ingestion was significantly greater in myofascial myofascial temporomandibular disorders (TMD) patients than healthy individuals. This elevation of interstitial glutamate concentration in the masseter muscle significantly increased the intensity of spontaneous pain in myofascial TMD patients.
Collapse
Affiliation(s)
- A Shimada
- Section of Orofacial Pain and Jaw Function, Department of Dentistry, Faculty of Health Sciences, Aarhus University, Denmark. .,Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark.
| | - E E Castrillon
- Section of Orofacial Pain and Jaw Function, Department of Dentistry, Faculty of Health Sciences, Aarhus University, Denmark.,Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark
| | - L Baad-Hansen
- Section of Orofacial Pain and Jaw Function, Department of Dentistry, Faculty of Health Sciences, Aarhus University, Denmark.,Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark
| | - B Ghafouri
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, County Council of Östergötland, Linköping University, Sweden
| | - B Gerdle
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, County Council of Östergötland, Linköping University, Sweden
| | - K Wåhlén
- Division of Community Medicine, Department of Medical and Health Sciences, Faculty of Health Sciences, Pain and Rehabilitation Center, Anaesthetics, Operations and Specialty Surgery Center, County Council of Östergötland, Linköping University, Sweden
| | - M Ernberg
- Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark.,Section of Orofacial Pain and Jaw Function, Department of Dental Medicine, Karolinska Institute, Huddinge, Sweden
| | - B E Cairns
- Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, Canada
| | - P Svensson
- Section of Orofacial Pain and Jaw Function, Department of Dentistry, Faculty of Health Sciences, Aarhus University, Denmark.,Scandinavian Center for Orofacial Neurosciences (SCON), Aarhus, Denmark
| |
Collapse
|
31
|
Abstract
This paper examines current knowledge about putative "pro-algesic" dietary components, and discusses whether limiting the intake of these substances can help improve chronic pain. Although there is a common impression that numerous food components, natural and synthetic, can cause or worsen pain symptoms, very few of these substances have been investigated. This article focuses on four substances, monosodium glutamate, aspartame, arachidonic acid, and caffeine, where research shows that overconsumption may induce or worsen pain. For each substance, the mechanism whereby it may act to induce pain is examined, and any clinical trials examining the effectiveness of reducing the intake of the substance discussed. While all four substances are associated with pain, decreased consumption of them does not consistently reduce pain.
Collapse
Affiliation(s)
- Brian Edwin Cairns
- a Faculty of Pharmaceutical Sciences , The University of British Columbia , Vancouver , Canada.,b Center for Neuroplasticity and Pain, SMI, Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg East , Denmark
| |
Collapse
|
32
|
Shimada A, Castrillon E, Baad-Hansen L, Ghafouri B, Gerdle B, Ernberg M, Cairns B, Svensson P. Muscle pain sensitivity after glutamate injection is not modified by systemic administration of monosodium glutamate. J Headache Pain 2015. [PMID: 26197975 PMCID: PMC4510106 DOI: 10.1186/s10194-015-0546-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Background Monosodium glutamate (MSG) is often thought to be associated with headache and craniofacial pains like temporomandibular disorders. This randomized, double-blinded, placebo-controlled study was performed to investigate how ingestion of MSG affects muscle pain sensitivity before and after experimentally induced muscle pain. Methods Sixteen healthy adult subjects participated in 2 sessions with at least 1-week interval between sessions. In each session, two injections of glutamate (Glu, 0.5 M, 0.2 ml) and two injections of saline (0.9 %, 0.2 ml) into the masseter and temporalis muscles, respectively, were undertaken, with a 15 min interval between each injection. Injections of saline were made contralateral to Glu injections and done in a randomized order. Participants drank 400 mL of soda mixed with either MSG (150 mg/kg) or NaCl (24 mg/kg, placebo) 30 min before the intramuscular injections. Pressure pain thresholds (PPT), autonomic parameters and pain intensity were assessed prior to (baseline) and 30 min after ingestion of soda, as well as 5 min and 10 min after the intramuscular injections and at the end of the session. Whole saliva samples were collected prior to and 30, 45, 60, and 75 min after the ingestion of soda. Results MSG administration resulted in a significantly higher Glu level in saliva than administration of NaCl and was associated with a significant increase in systolic blood pressure. Injections of Glu were significantly more painful than injections of NaCl. However, ingestion of MSG did not change the intensity of Glu-evoked pain. Glu injections also significantly increased systolic and diastolic blood pressure, but without an additional effect of MSG ingestion. Glu injections into the masseter muscle significantly reduced the PPT. However, pre-injection MSG ingestion did not significantly alter this effect. Interestingly, PPT was significantly increased in the trapezius after MSG ingestion and intramuscular injection of Glu in the jaw muscles. Conclusion The main finding in this study was that systemic intake of a substantial amount of MSG does not influence either pain intensity or pressure pain sensitivity in the masseter and temporalis muscles into which Glu injections were made.
Collapse
Affiliation(s)
- Akiko Shimada
- Section of Orofacial Pain and Jaw Function, Department of Dentistry, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark, Vennelyst Boulevard 9, 8000, Aarhus C, Denmark,
| | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Migraine is a neurovascular disorder that is associated with severe headache and neurologic symptoms. The pathogenesis of migraine is believed to involve trigeminovascular system activation with the primary dysfunction located in brainstem. Glutamate, the major excitatory neurotransmitter in the central nervous system, and its receptors have since long been suggested in migraine pathophysiology. Different preclinical studies have confirmed their potential role in migraine. Moreover, several glutamate receptor modulators have been studied in clinical studies, some with promising results. In this review, we will give an overview of what is known about the role of glutamate in the pathogenesis of migraine, which will be followed by an overview of available efficacy, safety and tolerability data for glutamate receptor inhibitors in clinical development for the treatment of migraine.
Collapse
|
34
|
Curto M, Lionetto L, Fazio F, Mitsikostas DD, Martelletti P. Fathoming the kynurenine pathway in migraine: why understanding the enzymatic cascades is still critically important. Intern Emerg Med 2015; 10:413-21. [PMID: 25708356 DOI: 10.1007/s11739-015-1208-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 01/27/2015] [Indexed: 12/11/2022]
Abstract
Kynurenine pathway, the quantitatively main branch of tryptophan metabolism, has been long been considered a source of nicotinamide adenine dinucleotide, although several of its products, the so-called kynurenines, are endowed with the capacity to activate glutamate receptors, thus potentially influencing a large group of functions in the central nervous system (CNS). Migraine, a largely unknown pathology, is strictly related to the glutamate system in the CNS pathologic terms. Despite the large number of studies conducted on migraine etio-pathology, the kynurenine pathway has been only recently linked to this disease. Nonetheless, some evidence suggests an intriguing role for some kynurenines, and an exploratory study on the serum kynurenine level might be helpful to better understand possible alterations of the kynurenine pathway in patients suffering from migraine.
Collapse
Affiliation(s)
- Martina Curto
- Psychiatric Unit, Neurosciences, Mental Health and Sensory Organs (NESMOS) Department, Sant'Andrea Hospital, Sapienza University of Rome, Rome, Italy
| | | | | | | | | |
Collapse
|
35
|
Shimada A, Baad-Hansen L, Castrillon E, Ghafouri B, Stensson N, Gerdle B, Ernberg M, Cairns B, Svensson Odont P. Differential effects of repetitive oral administration of monosodium glutamate on interstitial glutamate concentration and muscle pain sensitivity. Nutrition 2015; 31:315-23. [DOI: 10.1016/j.nut.2014.07.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 07/01/2014] [Accepted: 07/24/2014] [Indexed: 10/24/2022]
|
36
|
Abstract
It is evident that chronic pain can modify the excitability of central nervous system which imposes a specific challenge for the management and for the development of new analgesics. The central manifestations can be difficult to quantify using standard clinical examination procedures, but quantitative sensory testing (QST) may help to quantify the degree and extend of the central reorganization and effect of pharmacological interventions. Furthermore, QST may help in optimizing the development programs for new drugs.Specific translational mechanistic QST tools have been developed to quantify different aspects of central sensitization in pain patients such as threshold ratios, provoked hyperalgesia/allodynia, temporal summation (wind-up like pain), after sensation, spatial summation, reflex receptive fields, descending pain modulation, offset analgesia, and referred pain areas. As most of the drug development programs in the area of pain management have not been very successful, the pharmaceutical industry has started to utilize the complementary knowledge obtained from QST profiling. Linking patients QST profile with drug efficacy profile may provide the fundamentals for developing individualized, targeted pain management programs in the future. Linking QST-assessed pain mechanisms with treatment outcome provides new valuable information in drug development and for optimizing the management regimes for chronic pain.
Collapse
Affiliation(s)
- Lars Arendt-Nielsen
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, School of Medicine, Aalborg University, Fredrik Bajers Vej 7-D3, 9220, Aalborg, Denmark,
| |
Collapse
|
37
|
Pyun K, Son JS, Kwon YB. Chronic activation of sigma-1 receptor evokes nociceptive activation of trigeminal nucleus caudalis in rats. Pharmacol Biochem Behav 2014; 124:278-83. [PMID: 24992726 DOI: 10.1016/j.pbb.2014.06.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2014] [Revised: 06/16/2014] [Accepted: 06/24/2014] [Indexed: 10/25/2022]
Abstract
Primary headache disorders, including migraine, are thought to be mediated by prolonged nociceptive activation of the trigeminal nucleus caudalis (TNC), but the precise mechanisms are poorly understood. Our past studies demonstrated that sigma-1 receptors (Sig-1R) facilitate spinal nociceptive transmission in several pain models. Based on these findings, this study asked if chronic activation of Sig-1R by intracisternal administration of the selective Sig-1R agonist, PRE084, produced TNC neuronal activation as a migraine trigger in rats. A single infusion of PRE084 (10, 50, 100, 500 nmol) significantly increased the number of Fos immunoreactive neurons (Fos-IR) in TNC, which BD1047 (a Sig-1R antagonist) reversed. Chronic infusion of PRE084 (100 nmol for 1, 3, 7 and 14 days) time-dependently elevated Fos-IR in TNC. The number of Fos-IR elevation from day 7 of infusion was comparable with a single capsaicin infusion as a headache model. Increase in face grooming/scratching behavior was evident from day 7, and peaked at day 14 of chronic PRE084 infusion, which was correlated with ΔFosB elevation and phosphorylation of extracellular signal-regulated kinase, and the NMDA receptor NR1 subunit in TNC. Following 14 days of PRE084 infusion, the number of Fos-IR increased until day 7 after final infusion. Moreover, by day 14, Fos-IR associated with PRE084 infusion was significantly reversed by NMDA receptor antagonist MK801, rather than BD1047. These findings indicated that chronic activation of Sig-1R could evoke prolonged neuronal activation in the trigeminovascular system.
Collapse
Affiliation(s)
- Kihyun Pyun
- Department of Computer Science and Engineering, Chonbuk National University, Jeonju 561-180, Republic of Korea
| | - Ji Seon Son
- Department of Anesthesiology and Pain Medicine, Chonbuk National University Medical School, Jeonju 561-180, Republic of Korea
| | - Young Bae Kwon
- Department of Pharmacology, Institute for Medical Science, Chonbuk National University Medical School, Jeonju, Republic of Korea.
| |
Collapse
|
38
|
Glutamate dysregulation in the trigeminal ganglion: a novel mechanism for peripheral sensitization of the craniofacial region. Neuroscience 2013; 256:23-35. [PMID: 24144624 DOI: 10.1016/j.neuroscience.2013.10.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 09/24/2013] [Accepted: 10/07/2013] [Indexed: 10/26/2022]
Abstract
In the trigeminal ganglion (TG), satellite glial cells (SGCs) form a functional unit with neurons. It has been proposed that SGCs participate in regulating extracellular glutamate levels and that dysfunction of this SGC capacity can impact nociceptive transmission in craniofacial pain conditions. This study investigated whether SGCs release glutamate and whether elevation of TG glutamate concentration alters response properties of trigeminal afferent fibers. Immunohistochemistry was used to assess glutamate content and the expression of excitatory amino acid transporter (EAAT)1 and EAAT2 in TG sections. SGCs contained glutamate and expressed EAAT1 and EAAT2. Potassium chloride (10 mM) was used to evoke glutamate release from cultured rat SGCs treated with the EAAT1/2 inhibitor (3S)-3-[[3-[[4-(trifluoromethyl)ben zoyl]amino]phenyl]methoxy]-L-aspartic acid (TFB-TBOA) or control. Treatment with TFB-TBOA (1 and 10 μM) significantly reduced the glutamate concentration from 10.6 ± 1.1 to 5.8 ± 1.4 μM and 3.0 ± 0.8 μM, respectively (p<0.05). Electrophysiology experiments were conducted in anaesthetized rats to determine the effect of intraganglionic injections of glutamate on the response properties of ganglion neurons that innervated either the temporalis or masseter muscle. Intraganglionic injection of glutamate (500 mM, 3 μl) evoked afferent discharge and significantly reduced muscle afferent mechanical threshold. Glutamate-evoked discharge was attenuated bythe N-methyl-D-aspartate receptor antagonist 2-amino-5-phosphonovalerate (APV) and increased by TFB-TBOA, whereas mechanical sensitization was only sensitive to APV. Antidromic invasion of muscle afferent fibers by electrical stimulation of the caudal brainstem (10 Hz) or local anesthesia of the brainstem with lidocaine did not alter glutamate-induced mechanical sensitization. These findings provide a novel mechanism whereby dysfunctional trigeminal SGCs could contribute to cranial muscle tenderness in craniofacial pain conditions such as migraine headache.
Collapse
|