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Ronan EA, Nagel M, Emrick JJ. The anatomy, neurophysiology, and cellular mechanisms of intradental sensation. FRONTIERS IN PAIN RESEARCH 2024; 5:1376564. [PMID: 38590718 PMCID: PMC11000636 DOI: 10.3389/fpain.2024.1376564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 03/11/2024] [Indexed: 04/10/2024] Open
Abstract
Somatosensory innervation of the oral cavity enables the detection of a range of environmental stimuli including minute and noxious mechanical forces. The trigeminal sensory neurons underlie sensation originating from the tooth. Prior work has provided important physiological and molecular characterization of dental pulp sensory innervation. Clinical dental experiences have informed our conception of the consequence of activating these neurons. However, the biological role of sensory innervation within the tooth is yet to be defined. Recent transcriptomic data, combined with mouse genetic tools, have the capacity to provide important cell-type resolution for the physiological and behavioral function of pulp-innervating sensory neurons. Importantly, these tools can be applied to determine the neuronal origin of acute dental pain that coincides with tooth damage as well as pain stemming from tissue inflammation (i.e., pulpitis) toward developing treatment strategies aimed at relieving these distinct forms of pain.
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Affiliation(s)
- Elizabeth A. Ronan
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, MI, United States
| | - Maximilian Nagel
- Sensory Cells and Circuits Section, National Center for Complementary and Integrative Health, Bethesda, MD, United States
| | - Joshua J. Emrick
- Department of Biologic and Materials Sciences & Prosthodontics, School of Dentistry, University of Michigan, Ann Arbor, MI, United States
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Kunioku Y, Kimura M, Ouchi T, Fukuda K, Shibukawa Y. Intracellular cAMP Signaling Pathway via G s Protein-Coupled Receptor Activation in Rat Primary Cultured Trigeminal Ganglion Cells. Biomedicines 2023; 11:2347. [PMID: 37760789 PMCID: PMC10525138 DOI: 10.3390/biomedicines11092347] [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: 06/09/2023] [Revised: 08/13/2023] [Accepted: 08/17/2023] [Indexed: 09/29/2023] Open
Abstract
G protein-coupled receptors in trigeminal ganglion (TG) neurons are often associated with sensory mechanisms, including nociception. We have previously reported the expression of P2Y12 receptors, which are Gi protein-coupled receptors, in TG cells. Activating P2Y12 receptors decreased the intracellular free Ca2+ concentration ([Ca2+]i). This indicated that intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels can mediate Ca2+ signaling in TG cells. Here, we report more extensive-expression patterns of Gs protein-coupled receptors in primary cultured TG neurons isolated from 7-day-old newborn Wistar rats and further examine the roles of these receptors in cAMP signaling using the BacMam sensor in these neurons. To identify TG neurons, we also measured [Ca2+]i using fura-2 in TG cells and measured intracellular cAMP levels. TG neurons were positive for Gαs protein-coupled receptors, beta-2 adrenergic (β2), calcitonin gene-related peptide (CGRP), adenosine A2A (A2A), dopamine 1 (D1), prostaglandin I2 (IP), and 5-hydroxytriptamine 4 (5-HT4) receptor. Application of forskolin (FSK), an activator of adenylyl cyclase, transiently increased intracellular cAMP levels in TG neurons. The application of a phosphodiesterase inhibitor augmented the FSK-elicited intracellular cAMP level increase. These increases were significantly suppressed by the application of SQ22536, an adenylyl cyclase inhibitor, in TG neurons. Application of agonists for β2, CGRP, A2A, D1-like, IP, and 5-HT4 receptors increased intracellular cAMP levels. These increases were SQ22536-sensitive. These results suggested that TG neurons express β2, CGRP, A2A, D1, IP, and 5-HT4 receptors, and the activations of these Gαs protein-coupled receptors increase intracellular cAMP levels by activating adenylyl cyclase.
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Affiliation(s)
- Yuki Kunioku
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (Y.K.); (T.O.); (Y.S.)
- Division of Special Needs Dentistry and Orofacial Pain, Department of Oral Health and Clinical Science, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan;
| | - Maki Kimura
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (Y.K.); (T.O.); (Y.S.)
| | - Takehito Ouchi
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (Y.K.); (T.O.); (Y.S.)
| | - Kenichi Fukuda
- Division of Special Needs Dentistry and Orofacial Pain, Department of Oral Health and Clinical Science, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan;
| | - Yoshiyuki Shibukawa
- Department of Physiology, Tokyo Dental College, 2-9-18, Kanda-Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan; (Y.K.); (T.O.); (Y.S.)
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Grover V, Kumar A, Jain A, Chatterjee A, Grover HS, Pandit N, Satpathy A, Madhavan Pillai BR, Melath A, Dhruvakumar D, Thakur R, Joshi NV, Deshpande N, Dadlani H, Meenakshi AA, Ashok KP, Reddy KV, Bhasin MT, Salaria SK, Verma A, Gaikwad RP, Darekar H, Amirisetty R, Phadnaik M, Karemore V, Dhulipalla R, Mody D, Rao TS, Chakarpani S, Ranganath V. ISP Good Clinical Practice Recommendations for the management of Dentin Hypersensitivity. J Indian Soc Periodontol 2022; 26:307-333. [PMID: 35959314 PMCID: PMC9362809 DOI: 10.4103/jisp.jisp_233_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 05/11/2022] [Accepted: 05/11/2022] [Indexed: 11/24/2022] Open
Abstract
Dentin hypersensitivity (DH) is a rising concern in clinical dentistry that causes pain and discomfort and negatively affects the quality of life of patients. Indian Society of Periodontology conducted a nationwide survey, involving 3000 dentists in December 2020, which revealed significant knowledge gaps regarding DH, viz., under-diagnosis, incorrect differential diagnosis, and treatment strategies/recommendations for the management of DH patients in daily clinical practice. The current paper has been envisioned and conceptualized to update the practicing Indian dentists regarding the so-called enigma of dentistry “Dentin Hypersensitivity,” based on the best available contemporary evidence. An expert panel was constituted comprising 30 subject experts from across the country, which after extensive literature review and group discussions formulated these recommendations. The panel advocated routine screening of all dentate patients for exposed dentin areas and DH to avoid under-diagnosis of the condition and suggested an early preventive management. Consensus guidelines/recommendations for the use of desensitizing agents (DAs) at home, including the use of herbal agents, are also provided within the backdrop of the Indian context. The guidelines recommend that active management of DH shall be accomplished by a combination of at home and in-office therapies, starting with the simplest and cost-effective home use of desensitizing toothpastes. A diagnostic decision tree and a flowchart for application in daily practice are designed to manage the patients suffering from DH or presenting with exposed dentin areas in dentition. Various treatment methods to manage DH have been discussed in the paper, including the insights from previously published treatment guidelines. Further, a novel system of classification of DH patients based on specific case definitions has been developed for the first time. Explicit charts regarding the available treatment options and the chronology of institution of the agent, for the management in different case categories of DH, have been provided for quick reference. The management strategy takes into account a decision algorithm based on hierarchy of complexity of treatment options and intends to improve the quality of life of the patient by long-term maintenance with an innovatively defined triple C's or 3Cs approach.
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Affiliation(s)
- Vishakha Grover
- Department of Periodontology, Dr. H. S. J. Institute of Dental Sciences, Panjab University, Chandigarh, India
| | - Ashish Kumar
- Department of Periodontology, Dental College, Regional Institute of Medical Sciences, Imphal, Manipur, India
| | - Ashish Jain
- Department of Periodontology, Dental Institute, Regional Institute of Medical Sciences, Ranchi, Jharkhand, India
| | - Anirban Chatterjee
- Department of Periodontology, Renupriya Dental Health Care, Bengaluru, Karnataka, India
| | | | - Nymphea Pandit
- Department of Periodontology, D. A. V Dental College and Hospital, Yamunanagar, Haryana, India
| | - Anurag Satpathy
- Department of Periodontics and Oral Implantology, Institute of Dental Sciences, Siksha "O" Anusandhan (Deemed to be University), Bhubaneswar, Odisha, India
| | | | - Anil Melath
- Department of Periodontics, Mahe Institute of Dental Sciences and Hospital, Mahe, Puducherry, India
| | - Deepa Dhruvakumar
- Department of Periodontology, Teerthanker Mahaveer Dental College and Research Centre, Teerthanker Mahaveer University, Moradabad, Uttar Pradesh, India
| | - Roshani Thakur
- Department of Periodontics, Saraswati Dhanvantari Dental College and Hospital, Parbhani, India
| | - Nilesh V Joshi
- Department of Periodontology, Dental College and Hospital, Bharati Vidyapeeth (Deemed to be) University, Navi Mumbai, India
| | - Neeraj Deshpande
- Department of Periodontology, K. M. Shah Dental College, Sumandeep Vidyapeeth Deemed to be University, Vadodara, Gujarat, India
| | - Himanshu Dadlani
- Department of Periodontology, Kalka Dental College, Meerut, Uttar Pradesh, India
| | - A Archana Meenakshi
- Department of Periodontology, Ragas Dental College and Hospitals, Chennai, Tamil Nadu, India
| | - K P Ashok
- Department of Periodontics, GSL Dental College, Rajahmundry, India
| | - K Vinathi Reddy
- Department of Periodontics, Sri Sai College of Dental Surgery, Kaloji Narayana Rao University of Health Sciences, Vikarabad, Telangana, India
| | - Meenu Taneja Bhasin
- Department of Periodontics, Sudha Rustagi Dental College, Faridabad, Haryana, India
| | | | - Abhishek Verma
- Department of Periodontics, Sri Sai College of Dental Surgery, Kaloji Narayana Rao University of Health Sciences, Vikarabad, Telangana, India
| | | | | | - Ramesh Amirisetty
- Department of Periodontology, G. Pulla Reddy Dental College and Hospital, Dr. NTR University of Health Sciences, Kurnool, Andhra Pradesh, India
| | - Mangesh Phadnaik
- Department of Periodontology, Government Dental College and Hospital, Guntur, Andhra Pradesh, India
| | - Vaibhav Karemore
- Department of Periodontology, Government Dental College and Hospital, Guntur, Andhra Pradesh, India
| | - Ravindranath Dhulipalla
- Department of Periodontology, Sibar Institute of Dental Sciences, Dr. NTR University of Health Sciences, Guntur, Andhra Pradesh, India
| | - Dhawal Mody
- VSPM Dental College and Research Centre, Nagpur, Maharashtra, India
| | - Tushar Shri Rao
- Department of Periodontics and Implantology, VSPM Dental College and Research Centre, Nagpur, Maharashtra, India
| | - Swarna Chakarpani
- Department of Periodontics, Sibar Institute of Dental Sciences, Dr. NTR University of Health Sciences, Guntur, Andhra Pradesh, India
| | - V Ranganath
- Department of Periodontics, AECS Maaruti Dental College and Research Center, Bengaluru, Karnataka, India
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Mitochondrial Reactive Oxygen Species Elicit Acute and Chronic Itch via Transient Receptor Potential Canonical 3 Activation in Mice. Neurosci Bull 2022; 38:373-385. [PMID: 35294713 PMCID: PMC9068852 DOI: 10.1007/s12264-022-00837-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 12/13/2021] [Indexed: 02/08/2023] Open
Abstract
Mitochondrial reactive oxygen species (mROS) that are overproduced by mitochondrial dysfunction are linked to pathological conditions including sensory abnormalities. Here, we explored whether mROS overproduction induces itch through transient receptor potential canonical 3 (TRPC3), which is sensitive to ROS. Intradermal injection of antimycin A (AA), a selective inhibitor of mitochondrial electron transport chain complex III for mROS overproduction, produced robust scratching behavior in naïve mice, which was suppressed by MitoTEMPO, a mitochondria-selective ROS scavenger, and Pyr10, a TRPC3-specific blocker, but not by blockers of TRPA1 or TRPV1. AA activated subsets of trigeminal ganglion neurons and also induced inward currents, which were blocked by MitoTEMPO and Pyr10. Besides, dry skin-induced chronic scratching was relieved by MitoTEMPO and Pyr10, and also by resveratrol, an antioxidant. Taken together, our results suggest that mROS elicit itch through TRPC3, which may underlie chronic itch, representing a potential therapeutic target for chronic itch.
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Immunohistochemistry as a detection tool for ion channels involved in dental pain signaling. Saudi Dent J 2022; 34:155-166. [PMID: 35935722 PMCID: PMC9346947 DOI: 10.1016/j.sdentj.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 11/21/2022] Open
Abstract
Background Despite advances in pain detection, diagnosis, and management, the prevalence of dental pain is still on the rise. Although dental pain is not directly related to fatal outcomes, the two most common types of dental pain—dental caries and dentin hypersensitivity—have a significant impact on an individual’s quality of life. Understanding the mechanism of the pain pathway is one of the crucial steps in providing better treatment for these patients. Ion channels are critical biomolecules that have been the subject of dental study owing to their roles in the transmission and transduction of external stimuli, as well as in the control and perception of pain. Numerous immunohistochemical (IHC) staining approaches have also been used to identify the many ion channels implicated in peripheral pain signaling in dental pulp. Highlight This review highlights the critical steps in IHC and its role in the detection of ion channels involved in the dental pain signaling pathway. Conclusion The key ion channels identified using IHC and whose functions have been widely researched in dental tissues are addressed in this review article.
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Current Concepts of Dentinal Hypersensitivity. J Endod 2021; 47:1696-1702. [PMID: 34302871 DOI: 10.1016/j.joen.2021.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Although many clinical studies have reported on the prevalence of dental pain, far fewer studies have focused on the mechanisms of dental pain. This is an important gap because increased understanding of dental pain mechanisms may lead to improved diagnostic tests or therapeutic interventions. The aim of this study was to comprehensively review the literature on the mechanisms of dentinal sensitivity. METHODS PubMed and Ovid were searched for articles that addressed dentinal pain and or pulpal sensitivity. Because of the breadth of research ranging from cellular/molecular studies to clinical trials, a narrative review on the mechanisms of dentinal sensitivity was constructed based on the literature. RESULTS Five various mechanisms for dentinal sensitivity have been proposed: (1) the classic hydrodynamic theory, (2) direct innervation of dentinal tubules, (3) neuroplasticity and sensitization of nociceptors, (4) odontoblasts serving as sensory receptors, and (5) algoneurons. CONCLUSIONS These theories are not mutually exclusive, and it is possible that several of them contribute to dentinal sensitivity. Moreover, pulpal responses to tissue injury may alter the relative contribution of these mechanisms. For example, pulpal inflammation may lead to neuronal sprouting and peripheral sensitization. Knowledge of these mechanisms may prompt the development of therapeutic drugs that aim to disrupt these mechanisms, leading to more effective treatments for pulpal pain.
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Joshi HP, Jo HJ, Kim YH, An SB, Park CK, Han I. Stem Cell Therapy for Modulating Neuroinflammation in Neuropathic Pain. Int J Mol Sci 2021; 22:ijms22094853. [PMID: 34063721 PMCID: PMC8124149 DOI: 10.3390/ijms22094853] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 04/28/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023] Open
Abstract
Neuropathic pain (NP) is a complex, debilitating, chronic pain state, heterogeneous in nature and caused by a lesion or disease affecting the somatosensory system. Its pathogenesis involves a wide range of molecular pathways. NP treatment is extremely challenging, due to its complex underlying disease mechanisms. Current pharmacological and nonpharmacological approaches can provide long-lasting pain relief to a limited percentage of patients and lack safe and effective treatment options. Therefore, scientists are focusing on the introduction of novel treatment approaches, such as stem cell therapy. A growing number of reports have highlighted the potential of stem cells for treating NP. In this review, we briefly introduce NP, current pharmacological and nonpharmacological treatments, and preclinical studies of stem cells to treat NP. In addition, we summarize stem cell mechanisms—including neuromodulation in treating NP. Literature searches were conducted using PubMed to provide an overview of the neuroprotective effects of stem cells with particular emphasis on recent translational research regarding stem cell-based treatment of NP, highlighting its potential as a novel therapeutic approach.
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Affiliation(s)
- Hari Prasad Joshi
- Department of Neurosurgery, School of Medicine, CHA University, CHA Bundang Medical Center, Seongnam-si 13496, Gyeonggi-do, Korea; (H.P.J.); (S.-B.A.)
- Spinal Cord Research Centre, Regenerative Medicine Program, Department of Physiology and Pathophysiology, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E 0W2, Canada
| | - Hyun-Jung Jo
- Gachon Pain Center, Department of Physiology, College of Medicine, Gachon University, Incheon 21999, Gyeonggi-do, Korea; (H.-J.J.); (Y.-H.K.)
| | - Yong-Ho Kim
- Gachon Pain Center, Department of Physiology, College of Medicine, Gachon University, Incheon 21999, Gyeonggi-do, Korea; (H.-J.J.); (Y.-H.K.)
| | - Seong-Bae An
- Department of Neurosurgery, School of Medicine, CHA University, CHA Bundang Medical Center, Seongnam-si 13496, Gyeonggi-do, Korea; (H.P.J.); (S.-B.A.)
| | - Chul-Kyu Park
- Gachon Pain Center, Department of Physiology, College of Medicine, Gachon University, Incheon 21999, Gyeonggi-do, Korea; (H.-J.J.); (Y.-H.K.)
- Correspondence: (C.-K.P.); (I.H.)
| | - Inbo Han
- Department of Neurosurgery, School of Medicine, CHA University, CHA Bundang Medical Center, Seongnam-si 13496, Gyeonggi-do, Korea; (H.P.J.); (S.-B.A.)
- Correspondence: (C.-K.P.); (I.H.)
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Transient Receptor Potential (TRP) Ion Channels in Orofacial Pain. Mol Neurobiol 2021; 58:2836-2850. [PMID: 33515176 DOI: 10.1007/s12035-021-02284-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/05/2021] [Indexed: 02/07/2023]
Abstract
Orofacial pain, including temporomandibular joint disorders pain, trigeminal neuralgia, dental pain, and debilitating headaches, affects millions of Americans each year with significant population health impact. Despite the existence of a large body of information on the subject, the molecular underpinnings of orofacial pain remain elusive. Two decades of research has identified that transient receptor potential (TRP) ion channels play a crucial role in pathological pain. A number of TRP ion channels are clearly expressed in the trigeminal sensory system and have critical functions in the transduction and pathogenesis of orofacial pain. Although there are many similarities, the orofacial sensory system shows some distinct peripheral and central pain processing and different sensitivities from the spinal sensory system. Relative to the extensive review on TRPs in spinally-mediated pain, the summary of TRPs in trigeminally-mediated pain has not been well-documented. This review focuses on the current experimental evidence involving TRP ion channels, particularly TRPV1, TRPA1, TRPV4, and TRPM8 in orofacial pain, and discusses their possible cellular and molecular mechanisms.
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Polymodal Activation and Desensitization of TRPV1 Receptor in Human Odontoblasts-Like Cells with Eugenol. Int J Dent 2021; 2020:8813979. [PMID: 33456468 PMCID: PMC7785394 DOI: 10.1155/2020/8813979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/10/2020] [Accepted: 12/21/2020] [Indexed: 11/23/2022] Open
Abstract
Dentinal hypersensitivity is a frequent reason for dental consultation, and its pathophysiology has not been fully clarified. Previous findings have made it possible to establish a relationship between the cellular sensory capacity and the activation of the polymodal transient receptor potential vanilloid 1 (TRPV1), which is responsible for the nociceptive response and whose desensitization could cause analgesia. Thus, the objective of this study was to determine the expression, localization, and functional activity of TRPV1 in human odontoblasts-like-cells (hOLCs) and the effect of eugenol (EUG) on its activation and desensitization. Human dental pulp stem cells (hDPSCs) were obtained from third molars and were characterized using flow cytometry, and their differentiation potential toward the osteoblastic, chondrogenic, and adipogenic lineages was investigated. Subsequently, the hDPSCs underwent odontogenic differentiation for 7, 14, and 21 days, and their phenotype (odontogenic markers dentin matrix protein-1 (DMP-1) and dentin sialoprotein (DSP)) was evaluated using immunofluorescence. The TRPV1 gene expression in hOLCs was estimated using RT-qPCR, and its localization was analyzed using immunofluorescence. Half-maximal effective concentration (EC50) from both eugenol (EUG) and capsaicin (CAP) was determined; in addition, receptor activation was evaluated against chemical, thermal, and pH stimuli. For the statistical analysis, a one-way ANOVA with a Tukey post hoc test (p < 0.05) was used. After establishing the in vitro model of hOLCs and the membrane location of TRPV1, its chemical activation with EUG and CAP was demonstrated, as well as its thermal activation at ≥ 43°C and with an acidic (<6) or basic pH (between 9 and 12). Receptor desensitization was achieved after 20 min of exposure to two concentrations of EUG (603.5 and 1000 µM). These findings represent a stepping-stone for the construction of a pulp pain study model oriented toward a therapeutic alternative for the treatment of dentinal hypersensitivity.
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Pei F, Liu J, Zhang L, Pan X, Huang W, Cen X, Huang S, Jin Y, Zhao Z. The functions of mechanosensitive ion channels in tooth and bone tissues. Cell Signal 2020; 78:109877. [PMID: 33296740 DOI: 10.1016/j.cellsig.2020.109877] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/02/2020] [Accepted: 12/03/2020] [Indexed: 02/08/2023]
Abstract
Tooth and bone are independent tissues with a close relationship. Both are composed of a highly calcified outer structure and soft inner tissue, and both are constantly under mechanical stress. In particular, the alveolar bone and tooth constitute an occlusion system and suffer from masticatory and occlusal force. Thus, mechanotransduction is a key process in many developmental, physiological and pathological processes in tooth and bone. Mechanosensitive ion channels such as Piezo1 and Piezo2 are important participants in mechanotransduction, but their functions in tooth and bone are poorly understood. This review summarizes our current understanding of mechanosensitive ion channels and their roles in tooth and bone tissues. Research in these areas may shed new light on the regulation of tooth and bone tissues and potential treatments for diseases affecting these tissues.
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Affiliation(s)
- Fang Pei
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Jialing Liu
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Lan Zhang
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Xuefeng Pan
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Wei Huang
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China
| | - Xiao Cen
- Department of the Temporomandibular Joint, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Shishu Huang
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital, Sichuan University, Chengdu, PR China.
| | - Ying Jin
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China.
| | - Zhihe Zhao
- State Key Laboratory of Oral Diseases, Department of Orthodontics, West China School of Stomatology, Sichuan University, Chengdu, PR China.
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Co-Application of Eugenol and QX-314 Elicits the Prolonged Blockade of Voltage-Gated Sodium Channels in Nociceptive Trigeminal Ganglion Neurons. Biomolecules 2020; 10:biom10111513. [PMID: 33167484 PMCID: PMC7694476 DOI: 10.3390/biom10111513] [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: 10/05/2020] [Revised: 10/31/2020] [Accepted: 11/02/2020] [Indexed: 12/11/2022] Open
Abstract
Local anesthetics (LAs) can completely block nociception by inhibiting voltage-gated sodium channels (VGSCs), and thus, blocking action potentials (APs) within sensory neurons. As one of the several LAs, eugenol is used for dental pain treatment. It reportedly features multiple functions in regulating diverse ion channels. This study aimed to investigate the long-lasting analgesic effect of eugenol alone, as well as that of the combination of eugenol as a noxious-heat-sensitive transient receptor potential vanilloid 1 (TRPV1) channel agonist and a permanently charged sodium channel blocker (QX-314), on neuronal excitability in trigeminal ganglion (TG) neurons. Eugenol alone increased inward current in a dose-dependent manner in capsaicin-sensitive TG neurons. Eugenol also inhibited the VGSC current and AP. These effects were reversed through wash-out. The combination of eugenol and QX-314 was evaluated in the same manner. The combination completely inhibited the VGSC current and AP. However, these effects were not reversed and were continuously blocked even after wash-out. Taken together, our results suggest that, in contrast to the effect of eugenol alone, the combination of eugenol and QX-314 irreversibly and selectively blocked VGSCs in TG neurons expressing TRPV1.
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Ghosh A, Mazumder D. Comparative evaluation of treatment of noncarious cervical hypersensitivity by a fluoride varnish, a dentin bonding agent, and Er, Cr:YSGG laser: An in vivo study. J Conserv Dent 2020; 22:516-521. [PMID: 33088057 PMCID: PMC7542079 DOI: 10.4103/jcd.jcd_215_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/28/2020] [Accepted: 07/03/2020] [Indexed: 12/04/2022] Open
Abstract
Context: Dentin hypersensitivity is one of the most common dental problems encountered regularly. This commonly appearing condition is quite difficult to treat satisfactorily, and so, a large number of techniques and therapeutic alternatives constantly are being proposed to relieve it. However, till date, the search for an ideal agent is on. Various laser systems have been discussed as a new treatment option for dentin hypersensitivity. Researchers are claiming good prognosis with lasers. Treatment with soft tissue lasers is being practiced for some time and is well documented. However, the use of Er, Cr:YSGG laser for desensitization purpose is new, and the available data on clinical outcome are limited. Aims: The purpose of this study was to test and compare the efficacy of a fluoride varnish, a dentin bonding agent, and Er, Cr: YSGG laser in treating noncarious cervical hypersensitivity, in vivo. Settings and Design: Fifty patients aged between 25 and 55 years complaining of dentinal hypersensitivity who reported to the Department of Conservative Dentistry and Endodontics, Dr. R. Ahmed Dental College and Hospital, Kolkata, participated in this study. Subjects and Methods: Sensitive teeth in each patient were randomly divided into three treatment groups: Group 1 treated with fluoride varnish Group 2 treated with dentin bonding agent Group 3 treated with Er, Cr: YSGG laser.
Hypersensitivity assessment was done pretreatment, immediately posttreatment, and 1 day, 1, 2, 3, and 4 weeks postoperatively. Statistical Analysis Used: The data obtained were tabulated and subjected to statistical analysis using the paired and unpaired t-test. Results: In all the treatment groups, there was significant decrease in mean hypersensitivity scores from pretreatment values after 4 weeks. The posttreatment hypersensitivity scores of Group 3 were minimum for all three test stimuli followed by Group 2 and Group 1, respectively. Conclusions: All the three treatment agents, namely fluoride varnish, dentin bonding agent, and Er, Cr:YSGG laser, were effective in treating dentin hypersensitivity. Least recurrence in hypersensitivity occurred in the laser-treated group. Even where recurrences did occur, hypersensitivity did not return to pretreatment value and occurred more in those cases exhibiting high pretreatment sensitivity.
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Affiliation(s)
- Amrita Ghosh
- Department of Conservative Dentistry and Endodontics, Dr. R. Ahmed Dental College and Hospital, Kolkata, West Bengal, India
| | - Dibyendu Mazumder
- Department of Conservative Dentistry and Endodontics, Dr. R. Ahmed Dental College and Hospital, Kolkata, West Bengal, India
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13
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Allison JR, Stone SJ, Pigg M. The painful tooth: mechanisms, presentation and differential diagnosis of odontogenic pain. ACTA ACUST UNITED AC 2020. [DOI: 10.1111/ors.12481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- J. R. Allison
- School of Dental Sciences Faculty of Medical Sciences Newcastle University Newcastle upon Tyne UK
| | - S. J. Stone
- School of Dental Sciences Faculty of Medical Sciences Newcastle University Newcastle upon Tyne UK
| | - M. Pigg
- Department of Endodontics Faculty of Odontology Scandinavian Centre for Orofacial Neurosciences (SCON) Malmö University Malmö Sweden
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14
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Emrick JJ, von Buchholtz LJ, Ryba NJP. Transcriptomic Classification of Neurons Innervating Teeth. J Dent Res 2020; 99:1478-1485. [PMID: 32702253 DOI: 10.1177/0022034520941837] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Toothache is a common painful consequence of damage to the teeth, particularly when coupled to infection. Clinical restoration of tooth integrity, sometimes involving physical and chemical sterilization of the tooth with nerve fiber ablation (i.e., endodontic therapy), generally alleviates pain and allows long-lasting dental function. These observations raise questions regarding the biological role of tooth-innervating fibers. Here, we determined the transcriptomic diversity of the sensory neurons that can be retrogradely labeled from mouse molar teeth. Our results demonstrate that individual molars are each targeted by a dedicated population of about 50 specialized trigeminal neurons. Transcriptomic profiling identifies the majority of these as expressing markers of fast-conducting neurons, with about two-thirds containing nociceptive markers. Our data provide a new view of dental innervation, extending previous reports that used candidate gene approaches. Importantly, almost all retrogradely labeled neurons, including nociceptors, express the recently characterized mechanosensor Piezo2, an ion channel that endows cells with sensitivity to gentle touch. Intriguingly, about a quarter of the labeled neurons do not appear to be nociceptors, perhaps insinuating a role for them in discriminative touch. We hypothesize that dental neurons are capable of providing mechanosensitive information to drive rapid behavioral responses and protect teeth from damage. Damage to the teeth and exposure of the large population of molar nociceptors may trigger prolonged or abnormal activation driving toothache. Future studies examining the responses of these transcriptomically defined classes of neurons will help define their significance in oral sensation.
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Affiliation(s)
- J J Emrick
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - L J von Buchholtz
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - N J P Ryba
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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15
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Lee PR, Lee JY, Kim HB, Lee JH, Oh SB. TRPM8 Mediates Hyperosmotic Stimuli-Induced Nociception in Dental Afferents. J Dent Res 2019; 99:107-114. [PMID: 31718465 DOI: 10.1177/0022034519886847] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Hyperosmolar sweet foods onto exposed tooth dentin evoke sudden and intense dental pain, called dentin hypersensitivity. However, it remains unclear how hyperosmolar stimuli excite dental primary afferent (DPA) neurons and thereby lead to dentin hypersensitivity. This study elucidated whether TRPM8, which is well known as a cold temperature- or menthol-activated receptor, additionally mediates nociception in response to hyperosmolar stimuli in adult mouse DPA neurons, which are identified by a fluorescent retrograde tracer: DiI. Single-cell reverse transcription polymerase chain reaction revealed that TRPM8 was expressed in subsets of DPA neurons and that TRPM8 was highly colocalized with TRPV1 and Piezo2. Immunohistochemical analysis also confirmed TRPM8 expression in DPA neurons. By using Fura-2-based calcium imaging, application of hyperosmolar sucrose solutions elicited calcium transients in subsets of the trigeminal ganglion neurons, which was significantly abolished by a selective TRPM8 antagonist: N-(3-Aminopropyl)-2-[(3-methylphenyl)methoxy]-N-(2-thienylmethyl)benzamide (AMTB) hydrochloride. When we further examined changes of c-fos expression (a neuronal activation marker) in the spinal trigeminal nucleus after hyperosmolar stimulation onto exposed tooth dentin, c-fos mRNA and protein expression were increased and were also significantly reduced by AMTB, especially in the spinal trigeminal interpolaris-caudalis transition zone (Vi/Vc). Taken together, our results provide strong evidence that TRPM8 expressed in DPA neurons might mediate dental pain as a hyperosmosensor in adult mice.
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Affiliation(s)
- P R Lee
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - J Y Lee
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - H B Kim
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - J H Lee
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - S B Oh
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.,Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
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16
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Bista P, Imlach WL. Pathological Mechanisms and Therapeutic Targets for Trigeminal Neuropathic Pain. MEDICINES (BASEL, SWITZERLAND) 2019; 6:E91. [PMID: 31443547 PMCID: PMC6789505 DOI: 10.3390/medicines6030091] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/15/2019] [Accepted: 08/16/2019] [Indexed: 12/31/2022]
Abstract
Trigeminal neuropathic pain is a chronic pain condition caused by damage or inflammation of the trigeminal nerve or its branches, with both peripheral and central nervous system dysfunction contributing to the disorder. Trigeminal pain conditions present with diagnostic and therapeutic challenges to healthcare providers and often require multiple therapeutic approaches for pain reduction. This review will provide the overview of pathophysiology in peripheral and central nociceptive circuits that are involved in neuropathic pain conditions involving the trigeminal nerve and the current therapeutics that are used to treat these disorders. Recent advances in treatment of trigeminal pain, including novel therapeutics that target ion channels and receptors, gene therapy and monoclonal antibodies that have shown great promise in preclinical studies and clinical trials will also be described.
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Affiliation(s)
- Pawan Bista
- Department of Physiology & Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia
| | - Wendy L Imlach
- Department of Physiology & Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3800, Australia.
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17
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Lee K, Lee BM, Park CK, Kim YH, Chung G. Ion Channels Involved in Tooth Pain. Int J Mol Sci 2019; 20:ijms20092266. [PMID: 31071917 PMCID: PMC6539952 DOI: 10.3390/ijms20092266] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 05/03/2019] [Accepted: 05/03/2019] [Indexed: 01/05/2023] Open
Abstract
The tooth has an unusual sensory system that converts external stimuli predominantly into pain, yet its sensory afferents in teeth demonstrate cytochemical properties of non-nociceptive neurons. This review summarizes the recent knowledge underlying this paradoxical nociception, with a focus on the ion channels involved in tooth pain. The expression of temperature-sensitive ion channels has been extensively investigated because thermal stimulation often evokes tooth pain. However, temperature-sensitive ion channels cannot explain the sudden intense tooth pain evoked by innocuous temperatures or light air puffs, leading to the hydrodynamic theory emphasizing the microfluidic movement within the dentinal tubules for detection by mechanosensitive ion channels. Several mechanosensitive ion channels expressed in dental sensory systems have been suggested as key players in the hydrodynamic theory, and TRPM7, which is abundant in the odontoblasts, and recently discovered PIEZO receptors are promising candidates. Several ligand-gated ion channels and voltage-gated ion channels expressed in dental primary afferent neurons have been discussed in relation to their potential contribution to tooth pain. In addition, in recent years, there has been growing interest in the potential sensory role of odontoblasts; thus, the expression of ion channels in odontoblasts and their potential relation to tooth pain is also reviewed.
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Affiliation(s)
- Kihwan Lee
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 406-799, Korea.
| | - Byeong-Min Lee
- Department of Oral Physiology and Program in Neurobiology, School of Dentistry, Seoul National University, Seoul 08826, Korea.
| | - Chul-Kyu Park
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 406-799, Korea.
| | - Yong Ho Kim
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon 406-799, Korea.
| | - Gehoon Chung
- Department of Oral Physiology and Program in Neurobiology, School of Dentistry, Seoul National University, Seoul 08826, Korea.
- Dental Research Institute, Seoul National University, Seoul 03080, Korea.
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18
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Hossain MZ, Bakri MM, Yahya F, Ando H, Unno S, Kitagawa J. The Role of Transient Receptor Potential (TRP) Channels in the Transduction of Dental Pain. Int J Mol Sci 2019; 20:ijms20030526. [PMID: 30691193 PMCID: PMC6387147 DOI: 10.3390/ijms20030526] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 12/18/2022] Open
Abstract
Dental pain is a common health problem that negatively impacts the activities of daily living. Dentine hypersensitivity and pulpitis-associated pain are among the most common types of dental pain. Patients with these conditions feel pain upon exposure of the affected tooth to various external stimuli. However, the molecular mechanisms underlying dental pain, especially the transduction of external stimuli to electrical signals in the nerve, remain unclear. Numerous ion channels and receptors localized in the dental primary afferent neurons (DPAs) and odontoblasts have been implicated in the transduction of dental pain, and functional expression of various polymodal transient receptor potential (TRP) channels has been detected in DPAs and odontoblasts. External stimuli-induced dentinal tubular fluid movement can activate TRP channels on DPAs and odontoblasts. The odontoblasts can in turn activate the DPAs by paracrine signaling through ATP and glutamate release. In pulpitis, inflammatory mediators may sensitize the DPAs. They could also induce post-translational modifications of TRP channels, increase trafficking of these channels to nerve terminals, and increase the sensitivity of these channels to stimuli. Additionally, in caries-induced pulpitis, bacterial products can directly activate TRP channels on DPAs. In this review, we provide an overview of the TRP channels expressed in the various tooth structures, and we discuss their involvement in the development of dental pain.
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Affiliation(s)
- Mohammad Zakir Hossain
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Marina Mohd Bakri
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Farhana Yahya
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur 50603, Malaysia.
| | - Hiroshi Ando
- Department of Biology, School of Dentistry, Matsumoto Dental University, 1780 Gobara, Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Shumpei Unno
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
| | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
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19
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Abstract
The trigeminal sensory nerve fiber branches supply afferent information from the skin and mucous membranes of the face and head and the oral cavity regarding information on temperature, touch, and pain. Under normal conditions, the trigeminal nerve serves to provide important information from nerve fibers and tissues using specialized receptors sensitive for irritant and painful stimuli. The current scientific consensus indicates that nerve endings responsible for chemical and thermal sensitivity of the skin and mucous membranes are the same nerves responsible for nociception. This "chemesthetic sense" allows many vertebrates to detect chemical agonists that induce sensations such as touch, burning, stinging, tingling, or changes in temperature. Research has been under way for many years to determine how exposure of the oral and/or nasal cavity to compounds that elicit pungent or irritant sensations can produce these sensations. In addition, these chemicals can alter other sensory information such as taste and smell to affect the flavor of foods and beverages. We now know that these 'chemesthetic molecules' are agonists of molecular receptors, which exist on primary afferent nerve fibers that innervate the orofacial area. However, under pathophysiologic conditions, over- or underexpression or activity of these receptors may lead to painful orotrigeminal syndromes. Some of these individual receptors are discussed in detail, including transient receptor potential channels and acid sensing ion channels, among others.
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Affiliation(s)
- Amanda H Klein
- Department of Pharmacy Practice and Pharmaceutical Sciences, University of Minnesota, Duluth, MN, United States. //
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20
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Michot B, Lee CS, Gibbs JL. TRPM8 and TRPA1 do not contribute to dental pulp sensitivity to cold. Sci Rep 2018; 8:13198. [PMID: 30181551 PMCID: PMC6123413 DOI: 10.1038/s41598-018-31487-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 08/15/2018] [Indexed: 01/17/2023] Open
Abstract
Sensory neurons innervating the dental pulp have unique morphological and functional characteristics compared to neurons innervating other tissues. Stimulation of dental pulp afferents whatever the modality or intensity of the stimulus, even light mechanical stimulation that would not activate nociceptors in other tissues, produces an intense pain. These specific sensory characteristics could involve receptors of the Transient Receptor Potential channels (TRP) family. In this study, we compared the expression of the cold sensitive receptors TRPM8 and TRPA1 in trigeminal ganglion neurons innervating the dental pulp, the skin of the cheek or the buccal mucosa and we evaluated the involvement of these receptors in dental pulp sensitivity to cold. We showed a similar expression of TRPM8, TRPA1 and CGRP in sensory neurons innervating the dental pulp, the skin or the mucosa. Moreover, we demonstrated that noxious cold stimulation of the tooth induced an overexpression of cFos in the trigeminal nucleus that was not prevented by the genetic deletion of TRPM8 or the administration of the TRPA1 antagonist HC030031. These data suggest that the unique sensory characteristics of the dental pulp are independent to TRPM8 and TRPA1 receptors expression and functionality.
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Affiliation(s)
- Benoit Michot
- Department of Endodontics, New York University College of Dentistry, New York, USA.
| | - Caroline S Lee
- Department of Endodontics, New York University College of Dentistry, New York, USA
| | - Jennifer L Gibbs
- Department of Endodontics, New York University College of Dentistry, New York, USA
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21
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An S. The emerging role of extracellular Ca
2+
in osteo/odontogenic differentiation and the involvement of intracellular Ca
2+
signaling: From osteoblastic cells to dental pulp cells and odontoblasts. J Cell Physiol 2018; 234:2169-2193. [DOI: 10.1002/jcp.27068] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 06/25/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Shaofeng An
- Department of Operative Dentistry and EndodonticsGuanghua School of Stomatology, Hospital of Stomatology, Sun Yat‐sen UniversityGuangzhou China
- Guangdong Province Key Laboratory of StomatologySun Yat‐Sen UniversityGuangzhou China
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22
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Del Fiacco M, Serra MP, Boi M, Poddighe L, Demontis R, Carai A, Quartu M. TRPV1-Like Immunoreactivity in the Human Locus K, a Distinct Subregion of the Cuneate Nucleus. Cells 2018; 7:cells7070072. [PMID: 29986526 PMCID: PMC6071077 DOI: 10.3390/cells7070072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 06/30/2018] [Accepted: 07/05/2018] [Indexed: 01/02/2023] Open
Abstract
The presence of transient receptor potential vanilloid type-1 receptor (TRPV1)-like immunoreactivity (LI), in the form of nerve fibres and terminals, is shown in a set of discrete gray matter subregions placed in the territory of the human cuneate nucleus. We showed previously that those subregions share neurochemical and structural features with the protopathic nuclei and, after the ancient name of our town, collectively call them Locus Karalis, and briefly Locus K. TRPV1-LI in the Locus K is codistributed, though not perfectly overlapped, with that of the neuropeptides calcitonin gene-related peptide and substance P, the topography of the elements immunoreactive to the three markers, in relation to each other, reflecting that previously described in the caudal spinal trigeminal nucleus. Myelin stainings show that myelinated fibres, abundant in the cuneate, gracile and trigeminal magnocellular nuclei, are scarce in the Locus K as in the trigeminal substantia gelatinosa. Morphometric analysis shows that cell size and density of Locus K neurons are consistent with those of the trigeminal substantia gelatinosa and significantly different from those of the magnocellular trigeminal, solitary and dorsal column nuclei. We propose that Locus K is a special component of the human dorsal column nuclei. Its functional role remains to be determined, but TRPV1 appears to play a part in it.
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Affiliation(s)
- Marina Del Fiacco
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
| | - Maria Pina Serra
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
| | - Marianna Boi
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
| | - Laura Poddighe
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
| | - Roberto Demontis
- Department of Medical Sciences and Public Health, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
| | - Antonio Carai
- Department of Medical Sciences and Public Health, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
| | - Marina Quartu
- Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato (CA), Italy.
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23
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Sato M, Ogura K, Kimura M, Nishi K, Ando M, Tazaki M, Shibukawa Y. Activation of Mechanosensitive Transient Receptor Potential/Piezo Channels in Odontoblasts Generates Action Potentials in Cocultured Isolectin B 4-negative Medium-sized Trigeminal Ganglion Neurons. J Endod 2018; 44:984-991.e2. [PMID: 29709295 DOI: 10.1016/j.joen.2018.02.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 02/15/2018] [Accepted: 02/20/2018] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Various stimuli to the dentin surface elicit dentinal pain by inducing dentinal fluid movement causing cellular deformation in odontoblasts. Although odontoblasts detect deformation by the activation of mechanosensitive ionic channels, it is still unclear whether odontoblasts are capable of establishing neurotransmission with myelinated A delta (Aδ) neurons. Additionally, it is still unclear whether these neurons evoke action potentials by neurotransmitters from odontoblasts to mediate sensory transduction in dentin. Thus, we investigated evoked inward currents and evoked action potentials form trigeminal ganglion (TG) neurons after odontoblast mechanical stimulation. METHODS We used patch clamp recordings to identify electrophysiological properties and record evoked responses in TG neurons. RESULTS We classified TG cells into small-sized and medium-sized neurons. In both types of neurons, we observed voltage-dependent inward currents. The currents from medium-sized neurons showed fast inactivation kinetics. When mechanical stimuli were applied to odontoblasts, evoked inward currents were recorded from medium-sized neurons. Antagonists for the ionotropic adenosine triphosphate receptor (P2X3), transient receptor potential channel subfamilies, and Piezo1 channel significantly inhibited these inward currents. Mechanical stimulation to odontoblasts also generated action potentials in the isolectin B4-negative medium-sized neurons. Action potentials in these isolectin B4-negative medium-sized neurons showed a short duration. Overall, electrophysiological properties of neurons indicate that the TG neurons with recorded evoked responses after odontoblast mechanical stimulation were myelinated Aδ neurons. CONCLUSIONS Odontoblasts established neurotransmission with myelinated Aδ neurons via P2X3 receptor activation. The results also indicated that mechanosensitive TRP/Piezo1 channels were functionally expressed in odontoblasts. The activation of P2X3 receptors induced an action potential in the Aδ neurons, underlying a sensory generation mechanism of dentinal pain.
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Affiliation(s)
- Masaki Sato
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Kazuhiro Ogura
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Maki Kimura
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Koichi Nishi
- Removable Prosthodontics and Gerodontology, Tokyo Dental College, Tokyo, Japan
| | - Masayuki Ando
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
| | - Masakazu Tazaki
- Department of Physiology, Tokyo Dental College, Tokyo, Japan
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24
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Bakri MM, Yahya F, Munawar KMM, Kitagawa J, Hossain MZ. Transient receptor potential vanilloid 4 (TRPV4) expression on the nerve fibers of human dental pulp is upregulated under inflammatory condition. Arch Oral Biol 2018; 89:94-98. [PMID: 29499561 DOI: 10.1016/j.archoralbio.2018.02.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/27/2017] [Accepted: 02/15/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVE Transient receptor potential vanilloid 4 (TRPV4) has been considered as a mechano-, thermo- and osmo-receptor. Under inflammatory conditions in dental pulp, teeth can become sensitive upon exposure to a variety of innocuous stimuli. The objective of the present study was to investigate the expression of the TRPV4 channel on nerve fibers in human dental pulp of non-symptomatic and symptomatic teeth associated with inflammatory conditions. DESIGN Dental pulp from extracted human permanent teeth was processed for fluorescence immunohistochemistry. Ten asymptomatic (normal) and 10 symptomatic (symptoms associated with pulpitis) teeth were used in this study. Nerve fibers were identified by immunostaining for a marker, protein gene product 9.5, and the cells were counterstained with 4',6-diamidino-2-phenylindole. An anti-TRPV4 antibody was used to trace TRPV4 expression. RESULTS TRPV4 expression was co-localized with the nerve fiber marker. Immunoreactivity for TRPV4 was more intense (p < 0.05) in the nerves of symptomatic teeth than those of normal teeth. The number of co-localization spots was increased significantly (p < 0.05) in the dental pulp of symptomatic teeth compared with that of asymptomatic (normal) teeth. CONCLUSIONS There is expression of TRPV4 channels on the nerve fibers of human dental pulp. Our findings suggest upregulation of TRPV4 expression under inflammatory conditions in the pulp. The upregulation of TRPV4 channels may be associated with the exaggerated response of dental pulp to innocuous mechanical, thermal and osmotic stimuli under inflammatory conditions.
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Affiliation(s)
- Marina M Bakri
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Farhana Yahya
- Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | | | - Junichi Kitagawa
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan
| | - Mohammad Zakir Hossain
- Department of Oral Physiology, School of Dentistry, Matsumoto Dental University, 1780 Gobara Hirooka, Shiojiri, Nagano 399-0781, Japan.
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25
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Ogata K, Tsumuraya T, Oka K, Shin M, Okamoto F, Kajiya H, Katagiri C, Ozaki M, Matsushita M, Okabe K. The crucial role of the TRPM7 kinase domain in the early stage of amelogenesis. Sci Rep 2017; 7:18099. [PMID: 29273814 PMCID: PMC5741708 DOI: 10.1038/s41598-017-18291-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 12/07/2017] [Indexed: 12/15/2022] Open
Abstract
Transient receptor potential melastatin-7 (TRPM7) is a bi-functional protein containing a kinase domain fused to an ion channel. TRPM7 is highly expressed in ameloblasts during tooth development. Here we show that TRPM7 kinase-inactive knock-in mutant mice (TRPM7 KR mice) exhibited small enamel volume with opaque white-colored incisors. The TRPM7 channel function of ameloblast-lineage cells from TRPM7 KR mice was normal. Interestingly, phosphorylation of intracellular molecules including Smad1/5/9, p38 and cAMP response element binding protein (CREB) was inhibited in ameloblasts from TRPM7 KR mice at the pre-secretory stage. An immunoprecipitation assay showed that CREB was bound to TRPM7, suggesting that direct phosphorylation of CREB by TRPM7 was inhibited in ameloblast-lineage cells from TRPM7 KR mice. These results indicate that the function of the TRPM7 kinase domain plays an important role in ameloblast differentiation, independent of TRPM7 channel activity, via phosphorylation of CREB.
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Affiliation(s)
- Kayoko Ogata
- Section of Cellular Physiology, Department of Physiological Sciences and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan.,Section of Pediatric Dentistry, Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka, Japan
| | - Tomoyuki Tsumuraya
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Kyoko Oka
- Section of Pediatric Dentistry, Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka, Japan.
| | - Masashi Shin
- Section of Cellular Physiology, Department of Physiological Sciences and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan
| | - Fujio Okamoto
- Section of Cellular Physiology, Department of Physiological Sciences and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan
| | - Hiroshi Kajiya
- Section of Cellular Physiology, Department of Physiological Sciences and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan
| | - Chiaki Katagiri
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Masao Ozaki
- Section of Pediatric Dentistry, Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka, Japan
| | - Masayuki Matsushita
- Department of Molecular and Cellular Physiology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Koji Okabe
- Section of Cellular Physiology, Department of Physiological Sciences and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan
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Relevance of TRPA1 and TRPM8 channels as vascular sensors of cold in the cutaneous microvasculature. Pflugers Arch 2017; 470:779-786. [PMID: 29164310 PMCID: PMC5942358 DOI: 10.1007/s00424-017-2085-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 10/16/2017] [Accepted: 10/30/2017] [Indexed: 01/22/2023]
Abstract
Cold exposure is directly related to skin conditions, such as frostbite. This is due to the cold exposure inducing a vasoconstriction to reduce cutaneous blood flow and protect against heat loss. However, a long-term constriction will cause ischaemia and potentially irreversible damage. We have developed techniques to elucidate the mechanisms of the vascular cold response. We focused on two ligand-gated transient receptor potential (TRP) channels, namely, the established “cold sensors” TRP ankyrin 1 (TRPA1) and TRP melastin (TRPM8). We used the anaesthetised mouse and measured cutaneous blood flow by laser speckle imaging. Two cold treatments were used. A generalised cold treatment was achieved through whole paw water immersion (10 °C for 5 min) and a localised cold treatment that will be potentially easier to translate to human studies was carried out on the mouse paw with a copper cold probe (0.85-cm diameter). The results show that TRPA1 and TRPM8 can each act as a vascular cold sensor to mediate the vasoconstrictor component of whole paw cooling as expected from our previous research. However, the local cooling-induced responses were only blocked when the TRPA1 and TRPM8 antagonists were given simultaneously. This suggests that this localised cold probe response requires both functional TRPA1 and TRPM8.
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Kadala A, Sotelo-Hitschfeld P, Ahmad Z, Tripal P, Schmid B, Mueller A, Bernal L, Winter Z, Brauchi S, Lohbauer U, Messlinger K, Lennerz JK, Zimmermann K. Fluorescent Labeling and 2-Photon Imaging of Mouse Tooth Pulp Nociceptors. J Dent Res 2017; 97:460-466. [PMID: 29130364 DOI: 10.1177/0022034517740577] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Retrograde fluorescent labeling of dental primary afferent neurons (DPANs) has been described in rats through crystalline fluorescent DiI, while in the mouse, this technique was achieved with only Fluoro-Gold, a neurotoxic fluorescent dye with membrane penetration characteristics superior to the carbocyanine dyes. We reevaluated this technique in the rat with the aim to transfer it to the mouse because comprehensive physiologic studies require access to the mouse as a model organism. Using conventional immunohistochemistry, we assessed in rats and mice the speed of axonal dye transport from the application site to the trigeminal ganglion, the numbers of stained DPANs, and the fluorescence intensity via 1) conventional crystalline DiI and 2) a novel DiI formulation with improved penetration properties and staining efficiency. A 3-dimensional reconstruction of an entire trigeminal ganglion with 2-photon laser scanning fluorescence microscopy permitted visualization of DPANs in all 3 divisions of the trigeminal nerve. We quantified DPANs in mice expressing the farnesylated enhanced green fluorescent protein (EGFPf) from the transient receptor potential cation channel subfamily M member 8 (TRPM8EGFPf/+) locus in the 3 branches. We also evaluated the viability of the labeled DPANs in dissociated trigeminal ganglion cultures using calcium microfluorometry, and we assessed the sensitivity to capsaicin, an agonist of the TRPV1 receptor. Reproducible DiI labeling of DPANs in the mouse is an important tool 1) to investigate the molecular and functional specialization of DPANs within the trigeminal nociceptive system and 2) to recognize exclusive molecular characteristics that differentiate nociception in the trigeminal system from that in the somatic system. A versatile tool to enhance our understanding of the molecular composition and characteristics of DPANs will be essential for the development of mechanism-based therapeutic approaches for dentine hypersensitivity and inflammatory tooth pain.
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Affiliation(s)
- A Kadala
- 1 Klinik für Anästhesiologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - P Sotelo-Hitschfeld
- 1 Klinik für Anästhesiologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
- 2 Instituto de Fisiología, Facultad de Medicina, Escuela de Graduados, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Z Ahmad
- 1 Klinik für Anästhesiologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - P Tripal
- 3 Optical Imaging Centre Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - B Schmid
- 3 Optical Imaging Centre Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - A Mueller
- 1 Klinik für Anästhesiologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - L Bernal
- 1 Klinik für Anästhesiologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Z Winter
- 1 Klinik für Anästhesiologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - S Brauchi
- 2 Instituto de Fisiología, Facultad de Medicina, Escuela de Graduados, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - U Lohbauer
- 4 Klinik für Zahnerhaltung und Parodontologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - K Messlinger
- 5 Institut für Physiologie und Pathophysiologie, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - J K Lennerz
- 6 Center for Integrated Diagnostics, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - K Zimmermann
- 1 Klinik für Anästhesiologie, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
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Solé-Magdalena A, Martínez-Alonso M, Coronado CA, Junquera LM, Cobo J, Vega JA. Molecular basis of dental sensitivity: The odontoblasts are multisensory cells and express multifunctional ion channels. Ann Anat 2017; 215:20-29. [PMID: 28954208 DOI: 10.1016/j.aanat.2017.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 08/22/2017] [Accepted: 09/10/2017] [Indexed: 12/26/2022]
Abstract
Odontoblasts are the dental pulp cells responsible for the formation of dentin. In addition, accumulating data strongly suggest that they can also function as sensory cells that mediate the early steps of mechanical, thermic, and chemical dental sensitivity. This assumption is based on the expression of different families of ion channels involved in various modalities of sensitivity and the release of putative neurotransmitters in response to odontoblast stimulation which are able to act on pulp sensory nerve fibers. This review updates the current knowledge on the expression of transient-potential receptor ion channels and acid-sensing ion channels in odontoblasts, nerve fibers innervating them and trigeminal sensory neurons, as well as in pulp cells. Moreover, the innervation of the odontoblasts and the interrelationship been odontoblasts and nerve fibers mediated by neurotransmitters was also revisited. These data might provide the basis for novel therapeutic approaches for the treatment of dentin sensibility and/or dental pain.
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Affiliation(s)
- A Solé-Magdalena
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - M Martínez-Alonso
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain
| | - C A Coronado
- Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile
| | - L M Junquera
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Servicio de Cirugía Maxilofacial, Hospital Universitario Central de Asturias, Oviedo, Spain
| | - J Cobo
- Departamento de Especialidades Médico-Quirúrgicas, Universidad de Oviedo, Spain; Instituto Asturiano de Odontología, Oviedo, Spain
| | - J A Vega
- Departamento de Morfología y Biología Celular Universidad de Oviedo, Spain; Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Temuco, Chile.
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29
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Araya EI, Nones CFM, Ferreira LEN, Kopruszinski CM, Cunha JMD, Chichorro JG. Role of peripheral and central TRPV1 receptors in facial heat hyperalgesia in streptozotocin-induced diabetic rats. Brain Res 2017; 1670:146-155. [PMID: 28606782 DOI: 10.1016/j.brainres.2017.06.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/10/2017] [Accepted: 06/03/2017] [Indexed: 01/08/2023]
Abstract
There is increasing evidence that diabetes may be related to sensory changes in the trigeminal system. Long lasting facial heat hyperalgesia has been described in diabetic rats, but the mechanisms remain to be elucidated. Herein, the contribution of peripheral and central TRPV1 receptors to facial heat hyperalgesia in diabeticrats was investigated. Diabetes was induced in male Wistar rats by streptozotocin (60mg/kg, i.p) and facial heat hyperalgesia was assessed once a week up to four weeks. The role of TRPV1 receptors in the heat hyperalgesia in diabetic rats was evaluated through: 1) the ablation of TRPV1 receptors by resiniferatoxin (RTX) treatment and 2) injection of the TRPV1 antagonist, capsazepine, into the upper lip, trigeminal ganglion or medullary subarachnoid space, at doses that completed prevented the heat hyperalgesia induced by capsaicin in naïve rats. Western blot was used to estimate the changes in TRPV1 expression in diabetic rats. Diabetic rats exhibited facial heat hyperalgesia from the first up to the fourth week after streptozotocin injection, which was prevented by insulin treatment. Ablation of TRPV1-expressing fibers prevented facial hyperalgesia in diabetic rats. Capsazepine injection in all sites resulted in significant reduction of facial heat hyperalgesia in diabetic rats. Diabetic rats exhibited a significant decrease in TRPV1 expression in the trigeminal nerve, increased expression in the trigeminal ganglion and no changes in subnucleus caudalis when compared to normoglycemic ones. In conclusion, our results suggest that facial heat hyperalgesia in diabetic rats is maintained by peripheral and central TRPV1 receptors activation.
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Affiliation(s)
- Erika Ivanna Araya
- Department of Pharmacology, Federal University of Parana, Curitiba, Parana, Brazil
| | | | - Luiz Eduardo Nunes Ferreira
- Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP - Piracicaba, São Paulo, Brazil
| | | | - Joice Maria da Cunha
- Department of Pharmacology, Federal University of Parana, Curitiba, Parana, Brazil
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Alexandrino LD, Alencar CDM, Silveira ADSD, Alves EB, Silva CM. Randomized clinical trial of the effect of NovaMin and CPP-ACPF in combination with dental bleaching. J Appl Oral Sci 2017; 25:335-340. [PMID: 28678953 PMCID: PMC5482257 DOI: 10.1590/1678-7757-2016-0408] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/29/2016] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE This randomized, controlled, double-blind clinical study evaluated the effect of calcium sodium phosphosilicate (NovaMin) and casein phosphopeptide-amorphous calcium phosphate with fluoride (CPP-ACPF) on the prevention of post-operative sensitivity and on the effects of clinical bleaching treatment. MATERIAL AND METHODS Sixty volunteers were selected according to inclusion and exclusion criteria and were randomly assigned into three groups (n=20): CG (control group) patients, who were treated with 35% hydrogen peroxide; NOVAG (NovaMin group) patients, who were treated with 35% hydrogen peroxide followed by the application of NovaMin; and CPPG (CPP group) patients, who were treated with 35% hydrogen peroxide followed by the application of CPP-ACPF. Both bioactive agents were applied for five minutes. An evaporative stimulus associated with a modified visual scale was used to analyze sensitivity 24 hours after each bleaching session. The color evaluation was performed on the maxillary central incisors using a spectrophotometer. Associations between the intervention group, bleaching session, and reported sensitivity were tested using Chi-square partitioning. RESULTS Color change values (ΔE) were analyzed using analysis of variance (ANOVA). The significance level used for both tests was 5%. In the intragroup assessment, the Friedman test showed that only the CPP-ACPF group showed no statistically significant difference (p<0.05) between baseline and first bleaching session. In the intergroup assessment, the Kruskal-Wallis test showed that the CPPG had less postoperative sensitivity after the first session, when compared to the other groups (p<0.05). Color change analysis (ΔE) showed a significant difference between the means obtained in the different bleaching sessions in all groups (p<0.05). CONCLUSIONS This study showed that the combination of CPP-ACPF with 35% hydrogen peroxide significantly reduced post-operative sensitivity in the first session, compared with the other evaluated treatments. The association of CPP-ACPF and NovaMin did not affect the color change induced by tooth bleaching.
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Won J, Vang H, Lee P, Kim Y, Kim H, Kang Y, Oh S. Piezo2 Expression in Mechanosensitive Dental Primary Afferent Neurons. J Dent Res 2017; 96:931-937. [DOI: 10.1177/0022034517702342] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mechanosensitive ion channels have been suggested to be expressed in dental primary afferent (DPA) neurons to transduce the movement of dentinal fluid since the proposal of hydrodynamic theory. Piezo2, a mechanosensitive, rapidly inactivating (RI) ion channel, has been recently identified in dorsal root ganglion (DRG) neurons to mediate tactile transduction. Here, we examined the expression of Piezo2 in DPA neurons by in situ hybridization, single-cell reverse transcriptase polymerase chain reaction, and whole-cell patch-clamp recordings. DPA neurons with Piezo2 messenger RNA (mRNA) or Piezo2-like currents were further characterized based on their neurochemical and electrophysiological properties. Piezo2 mRNA was found mostly in medium- to large-sized DPA neurons, with the majority of these neurons also positive for Nav1.8, CGRP, and NF200, whereas only a minor population was positive for IB4 and peripherin. Whole-cell patch-clamp recordings revealed Piezo2-like, RI currents evoked by mechanical stimulation in a subpopulation of DPA neurons. RI currents were pharmacologically blocked by ruthenium red, a compound known to block Piezo2, and were also reduced by small interfering RNA-mediated Piezo2 knockdown. Piezo2-like currents were observed almost exclusively in IB4-negative DPA neurons, with the current amplitude larger in capsaicin-insensitive DPA neurons than the capsaicin-sensitive population. Our findings show that subpopulation of DPA neurons is indeed mechanically sensitive. Within this subpopulation of mechanosensitive DPA neurons, we have identified the Piezo2 ion channel as a potential transducer for mechanical stimuli, contributing to RI inward currents. Piezo2-positive DPA neurons were characterized as medium- to large-sized neurons with myelinated A-fibers, containing nociceptive peptidergic neurotransmitters.
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Affiliation(s)
- J. Won
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - H. Vang
- Dental Research Institute and Department of Neurobiology & Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - P.R. Lee
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Y.H. Kim
- Dental Research Institute and Department of Neurobiology & Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
- Department of Physiology, College of Medicine, Gachon University, Incheon, Republic of Korea (present address)
| | - H.W. Kim
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Y. Kang
- Dental Research Institute and Department of Neurobiology & Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, Osaka, Japan
| | - S.B. Oh
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
- Dental Research Institute and Department of Neurobiology & Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
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Yilmaz HG, Albaba MR, Caygur A, Cengiz E, Boke-Karacaoglu F, Tumer H. Treatment of recurrent aphthous stomatitis with Er,Cr:YSGG laser irradiation: A randomized controlled split mouth clinical study. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 170:1-5. [PMID: 28359996 DOI: 10.1016/j.jphotobiol.2017.03.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/07/2017] [Accepted: 03/16/2017] [Indexed: 11/28/2022]
Abstract
The present randomized controlled split mouth clinical study aimed to investigate the efficacy of Er,Cr:YSGG laser irradiation on pain reduction and healing rate of recurrent aphthous stomatitis. 40 patients with RAS were recruited for this study and RAS ulcerations of each patient were randomly assigned to the control or test group. In the test group, Er,Cr:YSGG laser with non-contact mode was used to irradiate RAS lesions. In the placebo group, RAS lesions were irradiated with the same device without laser emission. Pain was evaluated with visual analog scale (VAS) while a clinician graded healing of RAS (HRAS). In the placebo group at immediate; scores of VAS presented no statistically significance; in the test group, laser application showed significant pain reducing, at 1st day control. In the test group, a significantly healing effect at 1st day control was observed and this effect was maintained throughout the study. In the placebo group, scores of HRAS were statistically significant at controls on 3, 7, 10days. Statistically significant difference between the scores of VAS and HRAS was found for all control days except day 10 according to the intergroup comparisons. Based on these findings, Er,Cr:YSGG laser application at 0.25W without water may be appropriate to reduce pain and also accelerate the healing of RAS.
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Affiliation(s)
- Hasan Guney Yilmaz
- Department of Periodontology, Faculty of Dentistry, Near East University, Mersin, Turkey.
| | - Mohammed Rateb Albaba
- Department of Periodontology, Faculty of Dentistry, Near East University, Mersin, Turkey
| | - Ayse Caygur
- Department of Periodontology, Faculty of Dentistry, Near East University, Mersin, Turkey
| | - Esra Cengiz
- Department of Restorative Dentistry, Faculty of Dentistry, Mersin University, Mersin, Turkey
| | - Fatma Boke-Karacaoglu
- Department of Periodontology, Faculty of Dentistry, Ankara University, Ankara, Turkey
| | - Hayriye Tumer
- Department of Periodontology, Faculty of Dentistry, Near East University, Mersin, Turkey
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Kun J, Perkecz A, Knie L, Sétáló G, Tornóczki T, Pintér E, Bán Á. TRPA1 receptor is upregulated in human oral lichen planus. Oral Dis 2016; 23:189-198. [PMID: 27718297 DOI: 10.1111/odi.12593] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/14/2016] [Accepted: 10/04/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVE Oral lichen planus (OLP) is a chronic inflammatory disease of unknown etiology with antigen-specific and non-specific mechanisms. Transient receptor potential ankyrin 1 (TRPA1) is a non-selective cation channel activated by noxious stimuli such as oxidative stress products evoking pain and release of proinflammatory mediators from sensory nerve endings culminating in neurogenic inflammation. Extraneuronal TRPA1s, for example, on immune cells possess yet unknown functions. SUBJECTS AND METHODS We studied the buccal mRNA expression (qPCR) and protein localization (immunohistochemistry) of TRPA1 receptors and key OLP mediator transcripts in oral mucosa samples of healthy volunteers (n = 9), OLP patients (n = 43), and OLP-like hyperkeratotic patients (n = 12). RESULTS We measured 27.7- and 25.5-fold TRPA1 mRNA increase in OLP and OLP-like hyperkeratotic patients compared to healthy controls. TRPA1 transcripts elevated 2.4-fold in hypertensive OLP but not in hyperkeratotic patients compared to counterparts, reduced by 1.6-fold by angiotensin-convertase inhibitor intake. TRPA1 messenger RNA was more coexpressed with transcripts of tumor necrosis factor α than with interferon γ. Keratinocytes, macrophages but not T cells expressed TRPA1. CONCLUSIONS We provided evidence for the extraneuronal presence and upregulation of the proinflammatory TRPA1 receptor in buccal samples of patients with OLP. This may implicate the ion channel in the pathomechanism of OLP.
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Affiliation(s)
- J Kun
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, Pécs, Hungary.,Molecular Pharmacology Group, Szentágothai Research Center, University of Pecs, Pécs, Hungary.,MTA-PTE NAP B Chronic Pain Research Group, University of Pécs, Pécs, Hungary
| | - A Perkecz
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, Pécs, Hungary
| | - L Knie
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pécs Medical School, Pécs, Hungary
| | - G Sétáló
- Department of Medical Biology, University of Pécs Medical School, Pécs, Hungary
| | - T Tornóczki
- Oral Pathology Unit, Department of Pathology, University of Pécs Medical School, Hungary
| | - E Pintér
- Department of Pharmacology and Pharmacotherapy, University of Pécs Medical School, Pécs, Hungary.,Molecular Pharmacology Group, Szentágothai Research Center, University of Pecs, Pécs, Hungary
| | - Á Bán
- Department of Dentistry, Oral and Maxillofacial Surgery, University of Pécs Medical School, Pécs, Hungary
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Mickle AD, Shepherd AJ, Mohapatra DP. Nociceptive TRP Channels: Sensory Detectors and Transducers in Multiple Pain Pathologies. Pharmaceuticals (Basel) 2016; 9:ph9040072. [PMID: 27854251 PMCID: PMC5198047 DOI: 10.3390/ph9040072] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 11/07/2016] [Accepted: 11/09/2016] [Indexed: 02/07/2023] Open
Abstract
Specialized receptors belonging to the transient receptor potential (TRP) family of ligand-gated ion channels constitute the critical detectors and transducers of pain-causing stimuli. Nociceptive TRP channels are predominantly expressed by distinct subsets of sensory neurons of the peripheral nervous system. Several of these TRP channels are also expressed in neurons of the central nervous system, and in non-neuronal cells that communicate with sensory nerves. Nociceptive TRPs are activated by specific physico-chemical stimuli to provide the excitatory trigger in neurons. In addition, decades of research has identified a large number of immune and neuromodulators as mediators of nociceptive TRP channel activation during injury, inflammatory and other pathological conditions. These findings have led to aggressive targeting of TRP channels for the development of new-generation analgesics. This review summarizes the complex activation and/or modulation of nociceptive TRP channels under pathophysiological conditions, and how these changes underlie acute and chronic pain conditions. Furthermore, development of small-molecule antagonists for several TRP channels as analgesics, and the positive and negative outcomes of these drugs in clinical trials are discussed. Understanding the diverse functional and modulatory properties of nociceptive TRP channels is critical to function-based drug targeting for the development of evidence-based and efficacious new generation analgesics.
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Affiliation(s)
- Aaron D Mickle
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
| | - Andrew J Shepherd
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
| | - Durga P Mohapatra
- Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
- Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
- Siteman Cancer Center, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
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Resolvin E1 Inhibits Substance P-Induced Potentiation of TRPV1 in Primary Sensory Neurons. Mediators Inflamm 2016; 2016:5259321. [PMID: 27738388 PMCID: PMC5055963 DOI: 10.1155/2016/5259321] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 08/24/2016] [Accepted: 08/31/2016] [Indexed: 11/18/2022] Open
Abstract
The neuropeptide substance P (SP) is expressed in primary sensory neurons and is commonly regarded as a “pain” neurotransmitter. Upon peripheral inflammation, SP activates the neurokinin-1 (NK-1) receptor and potentiates activity of transient receptor potential vanilloid subtype 1 (TRPV1), which is coexpressed by nociceptive neurons. Therefore, SP functions as an important neurotransmitter involved in the hypersensitization of inflammatory pain. Resolvin E1 (RvE1), derived from omega-3 polyunsaturated fatty acids, inhibits TRPV1 activity via activation of the chemerin 23 receptor (ChemR23)—an RvE1 receptor located in dorsal root ganglion neurons—and therefore exerts an inhibitory effect on inflammatory pain. We demonstrate here that RvE1 regulates the SP-induced potentiation of TRPV1 via G-protein coupled receptor (GPCR) on peripheral nociceptive neurons. SP-induced potentiation of TRPV1 inhibited by RvE1 was blocked by the Gαi-coupled GPCR inhibitor pertussis toxin and the G-protein inhibitor GDPβ-S. These results indicate that a low concentration of RvE1 strongly inhibits the potentiation of TRPV1, induced by the SP-mediated activation of NK-1, via a GPCR signaling pathway activated by ChemR23 in nociceptive neurons. RvE1 might represent a new therapeutic target for the treatment of inflammatory pain as a prospective endogenous inhibitor that strongly inhibits TRPV1 activity associated with peripheral inflammation.
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Quartu M, Serra MP, Boi M, Poddighe L, Picci C, Demontis R, Del Fiacco M. TRPV1 receptor in the human trigeminal ganglion and spinal nucleus: immunohistochemical localization and comparison with the neuropeptides CGRP and SP. J Anat 2016; 229:755-767. [PMID: 27456865 DOI: 10.1111/joa.12529] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/30/2016] [Indexed: 01/02/2023] Open
Abstract
This work presents new data concerning the immunohistochemical occurrence of the transient receptor potential vanilloid type-1 (TRPV1) receptor in the human trigeminal ganglion (TG) and spinal nucleus of subjects at different ontogenetic stages, from prenatal life to postnatal old age. Comparisons are made with the sensory neuropeptides calcitonin gene-related peptide (CGRP) and substance P (SP). TRPV1-like immunoreactive (LI) material was detected by western blot in homogenates of TG and medulla oblongata of subjects at prenatal and adult stages of life. Immunohistochemistry showed that expression of the TRPV1 receptor is mostly restricted to the small- and medium-sized TG neurons and to the caudal subdivision of the spinal trigeminal nucleus (Sp5C). The extent of the TRPV1-LI TG neuronal subpopulation was greater in subjects at early perinatal age than at late perinatal age and in postnatal life. Centrally, the TRPV1 receptor localized to fibre tracts and punctate elements, which were mainly distributed in the spinal tract, lamina I and inner lamina II of the Sp5C, whereas stained cells were rare. The TRPV1 receptor colocalized partially with CGRP and SP in the TG, and was incompletely codistributed with both neuropeptides in the spinal tract and in the superficial laminae of the Sp5C. Substantial differences were noted with respect to the distribution of the TRPV1-LI structures described in the rat Sp5C and with respect to the temporal expression of the receptor during the development of the rat spinal dorsal horn. The distinctive localization of TRPV1-LI material supports the concept of the involvement of TRPV1 receptor in the functional activity of the protopathic compartment of the human trigeminal sensory system, i.e. the processing and neurotransmission of thermal and pain stimuli.
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Affiliation(s)
- Marina Quartu
- Department of Biomedical Sciences, Cytomorphology Section, University of Cagliari, Monserrato (CA), Italy
| | - Maria Pina Serra
- Department of Biomedical Sciences, Cytomorphology Section, University of Cagliari, Monserrato (CA), Italy
| | - Marianna Boi
- Department of Biomedical Sciences, Cytomorphology Section, University of Cagliari, Monserrato (CA), Italy
| | - Laura Poddighe
- Department of Biomedical Sciences, Cytomorphology Section, University of Cagliari, Monserrato (CA), Italy
| | - Cristina Picci
- Department of Biomedical Sciences, Cytomorphology Section, University of Cagliari, Monserrato (CA), Italy
| | - Roberto Demontis
- Department of Public Health, Clinical and Molecular Medicine, University of Cagliari, Cagliari, Italy
| | - Marina Del Fiacco
- Department of Biomedical Sciences, Cytomorphology Section, University of Cagliari, Monserrato (CA), Italy
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Hargreaves KM, Ruparel S. Role of Oxidized Lipids and TRP Channels in Orofacial Pain and Inflammation. J Dent Res 2016; 95:1117-23. [PMID: 27307050 DOI: 10.1177/0022034516653751] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Acute or chronic inflammation comprises a highly prevalent type of orofacial pain and is mediated by the generation of endogenous agonists that activate numerous receptors expressed on terminals of trigeminal (TG) nociceptive afferent neurons. One such studied receptor is transient receptor potential vanilloid subtype 1 (TRPV1). TRPV1 is a ligand-gated cation channel that is expressed on a major subclass of nociceptors and is found in many orofacial tissues, including dental pulp. Antagonists to TRPV1 reveal an important role for this channel in mediating hypersensitivity in preclinical models of inflammatory or neuropathic pain. Recent studies have demonstrated that endogenous TRPV1 agonists are generated by oxidation of omega-6 polyunsaturated fatty acids, including both linoleic acid and arachidonic acid. A major mechanism triggering the release of oxidative linoleic acid metabolites (OLAMs) and oxidative arachidonic acid metabolites (OAAMs) is the action of oxidative enzymes. Oxidative enzymes such as cytochrome P450 isozymes are rapidly upregulated in TG neurons after orofacial inflammation and increase the capacity of TG neurons to generate OLAMs. Cytochrome P450 isozymes are also increased in immune cells in irreversibly inflamed human dental pulp, and extracts of this tissue have significantly increased capacity to generate OLAMs. Together, these studies point to a novel pain mechanism involving the enzymatic generation of endogenous OLAM and OAAM agonists of TRPV1. This finding provides a rationale for an entirely new class of analgesics by inhibition of oxidative enzyme activity.
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Affiliation(s)
- K M Hargreaves
- Department of Endodontics, University of Texas Health Science Center at San Antonio, TX, USA
| | - S Ruparel
- Department of Endodontics, University of Texas Health Science Center at San Antonio, TX, USA
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El Karim IA, McCrudden MT, McGahon MK, Curtis TM, Jeanneau C, Giraud T, Irwin CR, Linden GJ, Lundy FT, About I. Biodentine Reduces Tumor Necrosis Factor Alpha–induced TRPA1 Expression in Odontoblastlike Cells. J Endod 2016; 42:589-95. [DOI: 10.1016/j.joen.2015.12.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/26/2015] [Accepted: 12/21/2015] [Indexed: 02/04/2023]
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Marshall-Gradisnik S, Huth T, Chacko A, Johnston S, Smith P, Staines D. Natural killer cells and single nucleotide polymorphisms of specific ion channels and receptor genes in myalgic encephalomyelitis/chronic fatigue syndrome. APPLICATION OF CLINICAL GENETICS 2016; 9:39-47. [PMID: 27099524 PMCID: PMC4821384 DOI: 10.2147/tacg.s99405] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
AIM The aim of this paper was to determine natural killer (NK) cytotoxic activity and if single nucleotide polymorphisms (SNPs) and genotypes in transient receptor potential (TRP) ion channels and acetylcholine receptors (AChRs) were present in isolated NK cells from previously identified myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS) patients. SUBJECTS AND METHODS A total of 39 ME/CFS patients (51.69±2 years old) and 30 unfatigued controls (47.60±2.39 years old) were included in this study. Patients were defined according to the 1994 Centers for Disease Control and Prevention criteria. Flow cytometry protocols were used to examine NK cytotoxic activity. A total of 678 SNPs from isolated NK cells were examined for 21 mammalian TRP ion channel genes and for nine mammalian AChR genes via the Agena Bioscience iPlex Gold assay. SNP association and genotype was determined using analysis of variance and Plink software. RESULTS ME/CFS patients had a significant reduction in NK percentage lysis of target cells (17%±4.68%) compared with the unfatigued control group (31%±6.78%). Of the 678 SNPs examined, eleven SNPs for TRP ion channel genes (TRPC4, TRPC2, TRPM3, and TRPM8) were identified in the ME/CFS group. Five of these SNPs were associated with TRPM3, while the remainder were associated with TRPM8, TRPC2, and TRPC4 (P<0.05). Fourteen SNPs were associated with nicotinic and muscarinic AChR genes: six with CHRNA3, while the remainder were associated with CHRNA2, CHRNB4, CHRNA5, and CHRNE (P<0.05). There were sixteen genotypes identified from SNPs in TRP ion channels and AChRs for TRPM3 (n=5), TRPM8 (n=2), TRPC4 (n=3), TRPC2 (n=1), CHRNE (n=1), CHRNA2 (n=2), CHRNA3 (n=1), and CHRNB4 (n=1) (P<0.05). CONCLUSION We identified a number of SNPs and genotypes for TRP ion channels and AChRs from isolated NK cells in patients with ME/CFS, suggesting these SNPs and genotypes may be involved in changes in NK cell function and the development of ME/CFS pathology. These anomalies suggest a role for dysregulation of Ca(2+) in AChR and TRP ion channel signaling in the pathomechanism of ME/CFS.
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Affiliation(s)
- Sonya Marshall-Gradisnik
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia; National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Teilah Huth
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia; National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Anu Chacko
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia; National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Samantha Johnston
- School of Medical Science, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia; National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Pete Smith
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
| | - Donald Staines
- National Centre for Neuroimmunology and Emerging Diseases, Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia
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Variability in Capsaicin-stimulated Calcitonin Gene-related Peptide Release from Human Dental Pulp. J Endod 2016; 42:542-6. [PMID: 26898566 DOI: 10.1016/j.joen.2015.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 12/16/2022]
Abstract
INTRODUCTION The unique innervation and anatomic features of dental pulp contribute to the remarkable finding that any physical stimulation of pulpal tissue is painful. Furthermore, when pathological processes such as caries affect teeth and produce inflammation of the pulp, the pain experienced can be quite intense and debilitating. To better understand these underlying neurobiological mechanisms and identify novel analgesic targets for pulpally derived pain, we have developed a powerful ex vivo model using human tooth slices. METHODS Noncarious, freshly extracted teeth were collected and sectioned longitudinally into 1-mm-thick slices containing both dental pulp and the surrounding mineralized tissues. Tooth slices from 36 patients were exposed to 60 μmol/L capsaicin to stimulate the release of calcitonin gene-related peptide (CGRP) from nerve terminals in the pulp. Patient factors were analyzed for their effects on capsaicin-stimulated CGRP release using a mixed model analysis of variance. RESULTS Approximately one third of the variability observed in capsaicin-evoked CGRP release was attributable to differences between individuals. In terms of individual factors, there was no effect of anesthesia type, sex, or age on capsaicin-stimulated CGRP release. Using a within-subject study design, a significant effect of capsaicin on CGRP release was observed. CONCLUSIONS Capsaicin-stimulated CGRP release from dental pulp is highly variable between individuals. A within-subject study design improves the variability and maximizes the potential of this powerful translational model to test the efficacy of novel pharmacotherapeutic agents on human peripheral nociceptors.
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Jin Y. La(3+) Alters the Response Properties of Neurons in the Mouse Primary Somatosensory Cortex to Low-Temperature Noxious Stimulation of the Dental Pulp. BIOCHEMISTRY INSIGHTS 2015; 8:9-20. [PMID: 26604777 PMCID: PMC4640426 DOI: 10.4137/bci.s30752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 10/12/2015] [Accepted: 10/14/2015] [Indexed: 12/31/2022]
Abstract
Although dental pain is a serious health issue with high incidence among the human population, its cellular and molecular mechanisms are still unclear. Transient receptor potential (TRP) channels are assumed to be involved in the generation of dental pain. However, most of the studies were conducted with molecular biological or histological methods. In vivo functional studies on the role of TRP channels in the mechanisms of dental pain are lacking. This study uses in vivo cellular electrophysiological and neuropharmacological method to directly disclose the effect of LaCl3, a broad spectrum TRP channel blocker, on the response properties of neurons in the mouse primary somatosensory cortex to low-temperature noxious stimulation of the dental pulp. It was found that LaCl3 suppresses the high-firing-rate responses of all nociceptive neurons to noxious low-temperature stimulation and also inhibits the spontaneous activities in some nonnociceptive neurons. The effect of LaCl3 is reversible. Furthermore, this effect is persistent and stable unless LaCl3 is washed out. Washout of LaCl3 quickly revitalized the responsiveness of neurons to low-temperature noxious stimulation. This study adds direct evidence for the hypothesis that TRP channels are involved in the generation of dental pain and sensation. Blockade of TRP channels may provide a novel therapeutic treatment for dental pain.
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Affiliation(s)
- Yanjiao Jin
- Department of Stomatology, Tianjin Medical University General Hospital, Heping District, Tianjin, People's Republic of China
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Wang K, He T, Luo YI, Bentsen B, Arendt-Nielsen L. Quantitative sensory testing of dentinal sensitivity in healthy humans. Acta Odontol Scand 2015; 74:259-64. [PMID: 26542888 DOI: 10.3109/00016357.2015.1110248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The study was to provide information on quantitative sensory testing (QST) of normal teeth to establish a sensory profile and investigate the possible gender and regional differences. MATERIALS AND METHODS A modified QST protocol was applied on both left and right upper-jaw incisors and pre-molar sof 14 healthy men and 14 age-matched healthy women (18-25 years). Mechanical stimulus sensitivity (MSS), cold detection threshold (CDT), cold pain threshold (CPT), warm detection threshold (WDT), heat pain threshold (HPT), electrical detection threshold (EDT) and electrical pain threshold (EPT) were determined from the four teeth (labial side of incisor and buccal side of the first premolar). The QST parameters were analysed by ANOVA. RESULTS The applied mechanical or thermal stimuli did not evoke any pain sensation. A normal tooth did not seem to be able to distinguish between the warm or cold stimuli applied. No significant differences were found between genders (p > 0.099) or teeth (p > 0.053) regarding mechanical and thermal stimuli. The EDT and EPT were significantly higher in the pre-molar compared with incisor (p < 0.002) without gender differences (p > 0.573). CONCLUSION The established methods and results provided important information on diagnosis and treatment evaluation of dentinal hypersensitivity.
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Affiliation(s)
- Kelun Wang
- a Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
| | - Tao He
- b The Procter & Gamble Company , Global Oral Care Clinical , Mason , Ohio USA
| | - Y I Luo
- a Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
| | - Bo Bentsen
- a Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
| | - Lars Arendt-Nielsen
- a Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Faculty of Medicine , Aalborg University , Aalborg , Denmark
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Maresin 1 Inhibits TRPV1 in Temporomandibular Joint-Related Trigeminal Nociceptive Neurons and TMJ Inflammation-Induced Synaptic Plasticity in the Trigeminal Nucleus. Mediators Inflamm 2015; 2015:275126. [PMID: 26617436 PMCID: PMC4651643 DOI: 10.1155/2015/275126] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/20/2015] [Indexed: 12/21/2022] Open
Abstract
In the trigeminal system, disruption of acute resolution processing may lead to uncontrolled inflammation and chronic pain associated with the temporomandibular joint (TMJ). Currently, there are no effective treatments for TMJ pain. Recently, it has been recognized that maresin 1, a newly identified macrophage-derived mediator of inflammation resolution, is a potent analgesic for somatic inflammatory pain without noticeable side effects in mice and a potent endogenous inhibitor of transient receptor potential vanilloid 1 (TRPV1) in the somatic system. However, the molecular mechanisms underlying the analgesic actions of maresin 1 on TMJ pain are unclear in the trigeminal system. Here, by performing TMJ injection of a retrograde labeling tracer DiI (a fluorescent dye), I showed that maresin 1 potently inhibits capsaicin-induced TRPV1 currents and neuronal activity via Gαi-coupled G-protein coupled receptors in DiI-labeled trigeminal nociceptive neurons. Further, maresin 1 blocked TRPV1 agonist-evoked increases in spontaneous excitatory postsynaptic current frequency and abolished TMJ inflammation-induced synaptic plasticity in the trigeminal nucleus. These results demonstrate the potent actions of maresin 1 in regulating TRPV1 in the trigeminal system. Thus, maresin 1 may serve as a novel endogenous inhibitor for treating TMJ-inflammatory pain in the orofacial region.
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Mori Y, Takahashi N, Polat OK, Kurokawa T, Takeda N, Inoue M. Redox-sensitive transient receptor potential channels in oxygen sensing and adaptation. Pflugers Arch 2015; 468:85-97. [PMID: 26149285 PMCID: PMC4700073 DOI: 10.1007/s00424-015-1716-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022]
Abstract
Regulation of ion channels is central to the mechanisms that underlie immediate acute physiological responses to changes in the availability of molecular oxygen (O2). A group of cation-permeable channels that are formed by transient receptor potential (TRP) proteins have been characterized as exquisite sensors of redox reactive species and as efficient actuators of electric/ionic signals in vivo. In this review, we first discuss how redox-sensitive TRP channels such as TRPA1 have recently emerged as sensors of the relatively inert oxidant O2. With regard to the physiological significance of O2 sensor TRP channels, vagal TRPA1 channels are mainly discussed with respect to their role in respiratory regulation in comparison with canonical pathways in glomus cells of the carotid body, which is a well-established O2-sensing organ. TRPM7 channels are discussed regarding hypoxia-sensing function in ischemic cell death. Also, ubiquitous expression of TRPA1 and TRPM7 together with their physiological relevance in the body is examined. Finally, based upon these studies on TRP channels, we propose a hypothesis of “O2 remodeling.” The hypothesis is that cells detect deviation of O2 availability from appropriate levels via sensors and adjust local O2 environments in vivo by controlling supply and consumption of O2 via pathways comprising cellular signals and transcription factors downstream of sensors, which consequently optimize physiological functions. This new insight into O2 adaptation through ion channels, particularly TRPs, may foster a paradigm shift in our understanding in the biological significance of O2.
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Affiliation(s)
- Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
- Laboratory of Environmental Systems Biology, Department of Technology and Ecology, Hall of Global Environmental Studies, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
| | - Nobuaki Takahashi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Onur Kerem Polat
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Tatsuki Kurokawa
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Norihiko Takeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Masahiro Inoue
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari-ku, Osaka, 537-8511, Japan
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Mickle AD, Shepherd AJ, Mohapatra DP. Sensory TRP channels: the key transducers of nociception and pain. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 131:73-118. [PMID: 25744671 DOI: 10.1016/bs.pmbts.2015.01.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Peripheral detection of nociceptive and painful stimuli by sensory neurons involves a complex repertoire of molecular detectors and/or transducers on distinct subsets of nerve fibers. The majority of such molecular detectors/transducers belong to the transient receptor potential (TRP) family of cation channels, which comprise both specific receptors for distinct nociceptive stimuli, as well as for multiple stimuli. This chapter discusses the classification, distribution, and functional properties of individual TRP channel types that have been implicated in various nociceptive and/or painful conditions.
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Affiliation(s)
- Aaron D Mickle
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Andrew J Shepherd
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Durga P Mohapatra
- Department of Pharmacology, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesia, The University of Iowa Roy J. and Lucile A. Carver College of Medicine, Iowa City, Iowa, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA.
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Lehto SG, Weyer AD, Zhang M, Youngblood BD, Wang J, Wang W, Kerstein PC, Davis C, Wild KD, Stucky CL, Gavva NR. AMG2850, a potent and selective TRPM8 antagonist, is not effective in rat models of inflammatory mechanical hypersensitivity and neuropathic tactile allodynia. Naunyn Schmiedebergs Arch Pharmacol 2015; 388:465-76. [PMID: 25662185 PMCID: PMC4359714 DOI: 10.1007/s00210-015-1090-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 01/13/2015] [Indexed: 01/05/2023]
Abstract
TRPM8 has been implicated in pain and migraine based on dorsal root- and trigeminal ganglion-enriched expression, upregulation in preclinical models of pain, knockout mouse studies, and human genetics. Here, we evaluated the therapeutic potential in pain of AMG2850 ((R)-8-(4-(trifluoromethyl)phenyl)-N-((S)-1,1,1-trifluoropropan-2-yl)-5,6-dihydro-1,7-naphthyridine-7(8H)-carboxamide), a small molecule antagonist of TRPM8 by in vitro and in vivo characterization. AMG2850 is potent in vitro at rat TRPM8 (IC90 against icilin activation of 204 ± 28 nM), highly selective (>100-fold IC90 over TRPV1 and TRPA1 channels), and orally bioavailable (F po > 40 %). When tested in a skin-nerve preparation, AMG2850 blocked menthol-induced action potentials but not mechanical activation in C fibers. AMG2850 exhibited significant target coverage in vivo in a TRPM8-mediated icilin-induced wet-dog shake (WDS) model in rats (at 10 mg/kg p.o.). However, AMG2850 did not produce a significant therapeutic effect in rat models of inflammatory mechanical hypersensitivity or neuropathic tactile allodynia at doses up to 100 mg/kg. The lack of efficacy suggests that either TRPM8 does not play a role in mediating pain in these models or that a higher level of target coverage is required. The potential of TRPM8 antagonists as migraine therapeutics is yet to be determined.
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Affiliation(s)
- Sonya G. Lehto
- Department of Neuroscience, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
| | - Andy D. Weyer
- Department of Cell Biology, Neurobiology and Anatomy Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226 USA
| | - Maosheng Zhang
- Department of Neuroscience, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
| | - Beth D. Youngblood
- Department of Neuroscience, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
| | - Judy Wang
- Department of Neuroscience, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
| | - Weiya Wang
- Department of Neuroscience, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
| | - Patrick C. Kerstein
- Department of Cell Biology, Neurobiology and Anatomy Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226 USA
| | - Carl Davis
- Department of Pharmacokinetics and Drug Metabolism, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
| | - Kenneth D. Wild
- Department of Neuroscience, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
| | - Cheryl L. Stucky
- Department of Cell Biology, Neurobiology and Anatomy Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226 USA
| | - Narender R. Gavva
- Department of Neuroscience, Amgen Inc, One Amgen Center Dr, Thousand Oaks, CA 91320-1799 USA
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Tokuda M, Tatsuyama S, Fujisawa M, Morimoto-Yamashita Y, Kawakami Y, Shibukawa Y, Torii M. Dentin and pulp sense cold stimulus. Med Hypotheses 2015; 84:442-4. [PMID: 25665859 DOI: 10.1016/j.mehy.2015.01.039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/23/2015] [Indexed: 11/26/2022]
Abstract
Dentin hypersensitivity is a common symptom, and recent convergent evidences have reported transient receptor potential (TRP) channels in odontoblasts act as mechanical and thermal molecular sensor, which detect stimulation applied on the exposed dentin surface, to drive multiple odontoblastic cellular functions, such as sensory transduction and/or dentin formation. In the present study, we confirmed expression of TRP melastatin subfamily member-8 (TRPM8) channels in primary cultured cells derived from human dental pulp cells (HPCs) and mouse odontoblast-lineage cells (OLCs) as well as in dentin matrix protein-1 (DMP-1) and dentin sialoprotein (DSP) positive acutely isolated rat odontoblasts from dental pulp tissue slice culture by immunohistochemical analyses. In addition, we detected TRPM8 channel expression on HPCs and OLCs by RT-PCR and Western blotting analyses. These results indicated that both odontoblasts and dental pulp cells express TRPM8 channels in rat, mouse and human, and therefore we hypothesize they may contribute as cold sensor in tooth.
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Affiliation(s)
- Masayuki Tokuda
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
| | - Shoko Tatsuyama
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Mari Fujisawa
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Yoko Morimoto-Yamashita
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | - Yoshiko Kawakami
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
| | | | - Mistuso Torii
- Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
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Kwon M, Baek SH, Park CK, Chung G, Oh SB. Single-cell RT-PCR and immunocytochemical detection of mechanosensitive transient receptor potential channels in acutely isolated rat odontoblasts. Arch Oral Biol 2014; 59:1266-71. [PMID: 25150531 DOI: 10.1016/j.archoralbio.2014.07.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 07/15/2014] [Accepted: 07/19/2014] [Indexed: 01/25/2023]
Abstract
OBJECTIVE Hydrostatic force applied to tooth pulp has long been suspected to be the direct cause of dental pain. However, the molecular and cellular identity of the transducer of the mechanical force in teeth is not clear. Growing number of literatures suggested that odontoblasts, secondary to its primary role as formation of tooth structure, might function as a cellular mechanical transducer in teeth. DESIGN In order to determine whether odontoblasts could play a crucial role in transduction of hydrostatic force applied to dental pulp into electrical impulses, current study investigated the expression of stretch-activated transient receptor potential (TRP) channels in acutely isolated odontoblasts from adult rats by single cell reverse transcriptase polymerase chain reaction and immunocytochemical analysis. RESULTS As the result, expression of TRPM7 (melastatin 7) was observed in majority (87%) of odontoblasts while mRNAs for TRPC1 (canonical 1), TRPC6 (canonical 6) and TRPV4 (vanilloid 4) were detected in small subpopulations of odontoblasts. TRPM3 (melastatin 3) was not detected in our experimental set-up. Immunocytochemical analysis further revealed TRPM7 expression at protein level. CONCLUSION Expression of the mechanosensitive TRP channels provides additional evidence that supports the sensory roles of odontoblasts. Given that TRPM7 is a mechanosensitive ion channel with a kinase activity that plays a role in Mg(2+) homeostasis, it is possible that TRPM7 expressed in odontoblasts might play a central role in mineralization during dentin formation.
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Affiliation(s)
- Minsoo Kwon
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Sang Hoon Baek
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Chul-Kyu Park
- Department of Physiology, Graduate School of Medicine, Gachon University, Incheon 406-799, Republic of Korea
| | - Gehoon Chung
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea; Pain Cognitive Function Research Center, Seoul National University, Seoul, Republic of Korea.
| | - Seog Bae Oh
- Dental Research Institute and Department of Neurobiology and Physiology, School of Dentistry, Seoul National University, Seoul, Republic of Korea; Pain Cognitive Function Research Center, Seoul National University, Seoul, Republic of Korea; Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea.
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Hwang H, Min H, Kim D, Yu SW, Jung SJ, Choi SY, Lee SJ. Imiquimod induces a Toll-like receptor 7-independent increase in intracellular calcium via IP3 receptor activation. Biochem Biophys Res Commun 2014; 450:875-9. [DOI: 10.1016/j.bbrc.2014.06.084] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 06/17/2014] [Indexed: 11/28/2022]
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Nilius B, Szallasi A. Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine. Pharmacol Rev 2014; 66:676-814. [DOI: 10.1124/pr.113.008268] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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