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Kupka JR, Sagheb K, Al-Nawas B, Schiegnitz E. The Sympathetic Nervous System in Dental Implantology. J Clin Med 2023; 12:jcm12082907. [PMID: 37109243 PMCID: PMC10143978 DOI: 10.3390/jcm12082907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/07/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
The sympathetic nervous system plays a vital role in various regulatory mechanisms. These include the well-known fight-or-flight response but also, for example, the processing of external stressors. In addition to many other tissues, the sympathetic nervous system influences bone metabolism. This effect could be highly relevant concerning osseointegration, which is responsible for the long-term success of dental implants. Accordingly, this review aims to summarize the current literature on this topic and to reveal future research perspectives. One in vitro study showed differences in mRNA expression of adrenoceptors cultured on implant surfaces. In vivo, sympathectomy impaired osseointegration in mice, while electrical stimulation of the sympathetic nerves promoted it. As expected, the beta-blocker propranolol improves histological implant parameters and micro-CT measurements. Overall, the present data are considered heterogeneous. However, the available publications reveal the potential for future research and development in dental implantology, which helps to introduce new therapeutic strategies and identify risk factors for dental implant failure.
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Affiliation(s)
- Johannes Raphael Kupka
- Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, 55131 Mainz, Germany
| | - Keyvan Sagheb
- Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, 55131 Mainz, Germany
| | - Bilal Al-Nawas
- Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, 55131 Mainz, Germany
| | - Eik Schiegnitz
- Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, 55131 Mainz, Germany
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Zhan C, Huang M, Yang X, Hou J. Dental nerves: a neglected mediator of pulpitis. Int Endod J 2020; 54:85-99. [PMID: 32880979 DOI: 10.1111/iej.13400] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 08/26/2020] [Indexed: 12/18/2022]
Abstract
As one of the most densely innervated tissues, the dental pulp contains abundant nerve fibres, including sensory, sympathetic and parasympathetic nerve fibres. Studies in animal models and human patients with pulpitis have revealed distinct alterations in protein expression and histological appearance in all types of dental nerve fibres. Various molecules secreted by neurons, such as classical neurotransmitters, neuropeptides and amino acids, not only contribute to the induction, sensitization and maintenance of tooth pain, but also regulate non-neuronal cells, including fibroblasts, odontoblasts, immune cells and vascular endothelial cells. Dental nerves are particularly important for the microcirculatory and immune responses in pulpitis via their release of a variety of functional substances. Further, nerve fibres are found to be involved in dental soft and hard tissue repair. Thus, understanding how dental nerves participate in pulpitis could have important clinical ramifications for endodontic treatment. In this review, the roles of dental nerves in regulating pulpal inflammatory processes are highlighted and their implications for future research on this topic are discussed.
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Affiliation(s)
- C Zhan
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - M Huang
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - X Yang
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - J Hou
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
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3
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Fan W, Zhu X, He Y, Li H, Gu W, Huang F, He H. Peripheral sympathetic mechanisms in orofacial pain. J Pain Res 2018; 11:2425-2431. [PMID: 30425556 PMCID: PMC6200434 DOI: 10.2147/jpr.s179327] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Sympathetic nervous system (SNS) is a part of the autonomic nervous system which involuntarily regulates internal body functions. It appears to modulate the processing of nociceptive information. Many orofacial pain conditions involve inflammation of orofacial tissues and/or injury of nerve, some of which might be attributed to SNS. Thus, the aim of this review was to bring together the data available regarding the peripheral sympathetic mechanisms involved in orofacial pain. A clearer understanding of SNS–sensory interactions in orofacial pain may provide a basis for novel therapeutic strategies for conditions that respond poorly to conventional treatments.
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Affiliation(s)
- Wenguo Fan
- Institute of Stomatological Research, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China, .,Department of Anesthesiology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China
| | - Xiao Zhu
- The Public Service Platform of South China Sea for R&D Marine Biomedicine Resources, Marine Biomedical Research Institute, Guangdong Medical University, Zhanjiang, China
| | - Yifan He
- Institute of Stomatological Research, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China,
| | - Hongmei Li
- Department of Pathology, Guangdong Medical University, Dongguan, China
| | - Wenzhen Gu
- Institute of Stomatological Research, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China,
| | - Fang Huang
- Institute of Stomatological Research, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China,
| | - Hongwen He
- Institute of Stomatological Research, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China,
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4
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Yu CY, Abbott PV. Pulp microenvironment and mechanisms of pain arising from the dental pulp: From an endodontic perspective. AUST ENDOD J 2018. [DOI: 10.1111/aej.12257] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Christine Y. Yu
- Discipline of Endodontics; UWA Dental School; Oral Health Centre of Western Australia; The University of Western Australia (M512); Crawley Western Australia Australia
| | - Paul V. Abbott
- Discipline of Endodontics; UWA Dental School; Oral Health Centre of Western Australia; The University of Western Australia (M512); Crawley Western Australia Australia
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Abstract
Recent findings have indicated that immune responses are subjected to modulation by the sympathetic nervous system (SNS). Moreover, the findings show that the SNS inhibits the production of pro-inflammatory cytokines, while stimulating the production of anti-inflammatory cytokines. The present review is an attempt to summarize the current results on how the SNS affects inflammation in dental tissues. In dental tissues, it has been found that the SNS is significant for recruitment of inflammatory cells such as CD 43+ granulocytes. Sympathetic nerves appear to have an inhibitory effect on osteoclasts, odontoclasts, and on IL-1α production. The SNS stimulates reparative dentin production, since reparative dentin formation was reduced after sympathectomy. Sprouting of sympathetic nerve fibers occurs in chronically inflamed dental pulp, and neural imbalance caused by unilateral sympathectomy recruits immunoglobulin-producing cells to the dental pulp. In conclusion, this article presents evidence in support of interactions between the sympathetic nervous system and dental inflammation.
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Affiliation(s)
- S R Haug
- Department of Biomedicine, Section for Physiology, Faculty of Medicine, University of Bergen, Jonas Lies vei 91, N-5009, Bergen, Norway.
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Raju B, Ibrahim SO. Pathophysiology of oral cancer in experimental animal models: a review with focus on the role of sympathetic nerves. J Oral Pathol Med 2010; 40:1-9. [PMID: 20819130 DOI: 10.1111/j.1600-0714.2010.00928.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Global increase in incidence and mortality as well as poor prognosis of oral cancer (OC) has intensified efforts towards early detection and prevention of this disfiguring disease. Several studies have been conducted using experimental animal models to understand the pathophysiology and molecular events involved in OC. Lack of identification of specific biomarkers during the multifaceted steps of oral carcinogenesis has hindered its diagnosis and treatment. Solid stress generated by growing tumors as well as abnormalities in tumor vasculature lead to increased interstitial fluid pressure, which could obstruct therapeutic drug delivery to tumors. Furthermore, the sympathetic nervous system is known to affect angiogenesis, vessel permeability, immune responses and carcinogenesis. Recent findings indicate that, in addition to angiogenic and lymphangiogenic factors, tumor cells release neurotrophic factors that initiate innervation. Interactions between cytokines and sympathetic neurotransmitters, and their respective receptors expressed by the nerve, immune and tumor cells appear to influence tumor growth. Thus, understanding the complex signaling processes and interrelationships between vascular, nervous and immune systems during oral carcinogenesis may prove vital for successful prevention and treatment of OC. This review aims at outlining the available knowledge on pathophysiology of OC in experimental animal models including evidence from our own findings.
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Affiliation(s)
- Bina Raju
- Department of Biomedicine, Section for Biochemistry and Molecular Biology, University of Bergen, Bergen, Norway
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Rethnam S, Raju B, Fristad I, Berggreen E, Heyeraas KJ. Differential expression of neuropeptide Y Y1 receptors during pulpal inflammation. Int Endod J 2010; 43:492-8. [DOI: 10.1111/j.1365-2591.2010.01704.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wu SX, Wang W, Li H, Wang YY, Feng YP, Li YQ. The synaptic connectivity that underlies the noxious transmission and modulation within the superficial dorsal horn of the spinal cord. Prog Neurobiol 2010; 91:38-54. [DOI: 10.1016/j.pneurobio.2010.01.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 12/10/2009] [Accepted: 01/14/2010] [Indexed: 01/27/2023]
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9
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Moe K, Kettunen P, Kvinnsland IH, Luukko K. Development of the pioneer sympathetic innervation into the dental pulp of the mouse mandibular first molar. Arch Oral Biol 2008; 53:865-73. [DOI: 10.1016/j.archoralbio.2008.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2007] [Revised: 02/18/2008] [Accepted: 03/06/2008] [Indexed: 12/29/2022]
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Shimeno Y, Sugawara Y, Iikubo M, Shoji N, Sasano T. Sympathetic nerve fibers sprout into rat odontoblast layer, but not into dentinal tubules, in response to cavity preparation. Neurosci Lett 2008; 435:73-7. [DOI: 10.1016/j.neulet.2008.02.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Revised: 12/20/2007] [Accepted: 02/05/2008] [Indexed: 10/22/2022]
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Heyeraas KJ, Haug SR, Bukoski RD, Awumey EM. Identification of a Ca2+-sensing receptor in rat trigeminal ganglia, sensory axons, and tooth dental pulp. Calcif Tissue Int 2008; 82:57-65. [PMID: 18175029 DOI: 10.1007/s00223-007-9096-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Accepted: 11/14/2007] [Indexed: 10/22/2022]
Abstract
Extracellular Ca2+ regulates dentin formation, but little information is available on this regulatory mechanism. We have previously reported that sensory denervation reduces dentin formation, suggesting a role for sensory nerves in tooth mineralization. The G protein-coupled Ca2+-sensing receptor (CaR) is expressed in dorsal root ganglia and perivascular sensory nerves in mesenteric arterioles, and activation of these receptors by Ca2+ has been shown to induce vascular relaxation. The present study determined CaR expression in tooth dental pulp (DP), sensory axons, and trigeminal ganglion (TG) as well as the effect of increased [Ca2+]e or a calcimimetic on tooth blood flow. The distribution of CaR, studied by immunochemistry, RT-PCR, and Western blot, indicates abundant expression of CaR in sensory axons in the jaws, TG, and DP. Restriction analysis of PCR products with specific endonucleases showed the presence of CaR message in TG and DP, and Western blotting indicates the expression of mature and immature forms of the receptor in these tissues. Pulpal blood flow, measured by laser-Doppler flowmetry, increased by 67% +/- 6% (n = 12) following receptor stimulation with 5 mM Ca2+, which was completely inhibited by 5 microM IBTx, a high-conductance KCa channel blocker indicating a mechanism involving hyperpolarization. NPS R-467 (10 microM) increased blood flow by 85% +/- 18% (n = 6), suggesting regulation through the CaR. Our results suggest that the CaR is present in sensory nerves, DP, and TG and that an increase in Ca2+ in the DP causes vasodilatation, which may contribute to accumulation of Ca2+ during dentin mineralization.
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Affiliation(s)
- Karin J Heyeraas
- Department of Biomedicine, Section for Physiology, Faculty of Medicine, University of Bergen, Jonas Lies vei 91, N-5009, Bergen, Norway.
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12
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FRISTAD INGE, BLETSA ATHANASIA, BYERS MARGARET. Inflammatory nerve responses in the dental pulp. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1601-1546.2010.00247.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Raju B, Haug SR, Ibrahim SO, Heyeraas KJ. Sympathectomy decreases size and invasiveness of tongue cancer in rats. Neuroscience 2007; 149:715-25. [PMID: 17916410 DOI: 10.1016/j.neuroscience.2007.07.048] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 07/16/2007] [Accepted: 08/08/2007] [Indexed: 01/20/2023]
Abstract
The sympathetic nervous system plays a role in carcinogenesis wherein locally released sympathetic neurotransmitters affect proliferation, angiogenesis, vessel permeability, lymphocyte traffic and cytokine production. The present in vivo study was designed to investigate whether surgical sympathectomy, both unilateral and bilateral, had an effect on tumor growth, interstitial fluid pressure (IFP) and lymphatics in rat tongue cancer. We used 4-nitroquinoline-1-oxide (4-NQO) in drinking water for 19 weeks to induce tongue cancer in 20 Dark Agouti rats. After 11 weeks, one group underwent unilateral sympathectomy and another underwent bilateral sympathectomy, while the third group underwent sham surgery. By 19 weeks, tumors in the bilaterally sympathectomized (BL-SCGx) rats were significantly smaller (P<0.05), more diffuse in appearance and less invasive (P<0.05) compared with the large exophytic tumors in the sham-operated rats. The relative lymphatic area was significantly decreased (P<0.05) in tumors in the BL-SCGx rats compared with the sham group. Interestingly, the tumors in rats that underwent unilateral or bilateral sympathectomy had a significantly lower (P<0.05) IFP than those in sham rats. Lack of tyrosine hydroxylase (TH) immunoreactive nerves and few neuropeptide Y (NPY) positive fibers indicate absence of sympathetic nerve fibers in the bilateral sympathectomized group. The peritumoral lymph vessel area was correlated with the tumor size (P<0.001), depth of invasion (P<0.001), weight of rats (P<0.005) and IFP (P<0.05). In conclusion, the present study presents evidence that deprivation of sympathetic nerves decreases tumor growth in rat tongue, probably caused by decreasing IFP and lymph vessel area.
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Affiliation(s)
- B Raju
- Department of Biomedicine, University of Bergen, 91 Jonas Lies Vei, N-5009, Bergen, Norway.
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Raju B, Haug SR, Ibrahim SO, Heyeraas KJ. High interstitial fluid pressure in rat tongue cancer is related to increased lymph vessel area, tumor size, invasiveness and decreased body weight. J Oral Pathol Med 2007; 37:137-44. [DOI: 10.1111/j.1600-0714.2007.00602.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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15
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Wadachi R, Hargreaves KM. Trigeminal nociceptors express TLR-4 and CD14: a mechanism for pain due to infection. J Dent Res 2006; 85:49-53. [PMID: 16373680 PMCID: PMC2227946 DOI: 10.1177/154405910608500108] [Citation(s) in RCA: 181] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Although certain bacterial species appear to be risk factors for pain due to odontogenic infections, comparatively little is known about the potential mechanisms mediating this effect. In this study, we tested the hypothesis that trigeminal nociceptive neurons express the TLR4 or CD14 receptors, thus enabling sensory neurons to detect and respond to tissue levels of bacterial substances such as lipopolysaccharide (LPS). Immunohistochemical analyses of human and rat trigeminal neurons demonstrated that a capsaicin-sensitive subclass of nociceptors (defined by expression of TRPV1, a capsaicin receptor) expresses both TLR4 and CD14. Moreover, human dental pulp collected from patients with caries lesions demonstrated co-localization of TLR4 and CD14, with markers of peripheral sensory neurons. Collectively, these studies indicate that the capsaicin-sensitive subclass of trigeminal nociceptors expresses TLR4 and CD14. These results indicate that pain due to bacterial infections may result, in part, from direct activation of nociceptors by bacterial products such as LPS.
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Affiliation(s)
- R Wadachi
- Department of Endodontics, UTHSCSA, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
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Zavarella MM, Leblebicioglu B, Claman LJ, Tatakis DN. Unilateral Severe Chronic Periodontitis Associated With Ipsilateral Surgical Resection of Cranial Nerves V, VI, and VII. J Periodontol 2006; 77:142-8. [PMID: 16579716 DOI: 10.1902/jop.2006.77.1.142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The central and peripheral nervous systems participate in several local physiological and pathological processes. There is experimental evidence that the inflammatory, local immune, and wound healing responses of a tissue can be modulated by its innervation. The aim of this clinical report is to present a case of unilateral severe periodontitis associated with ipsilateral surgical resection of the fifth, sixth, and seventh cranial nerves and to discuss the possible contribution of the nervous system to periodontal pathogenesis. METHODS A 39-year-old female patient with a history of a cerebrovascular accident caused by a right pontine arteriovenous malformation and destruction of the right fifth, sixth, and seventh cranial nerves was diagnosed with severe chronic periodontitis affecting only the right maxillary and mandibular quadrants. The patient's oral hygiene was similar for right and left sides of the mouth. Percentages of tooth surfaces carrying dental plaque were 41% and 36% for right and left sides, respectively. Non-surgical and surgical periodontal therapy was performed, and the patient was placed on a regular periodontal maintenance schedule. RESULTS Healing following initial periodontal therapy and osseous periodontal surgery occurred without complications. Follow-up clinical findings at 1 year revealed stable periodontal health. CONCLUSIONS This case report suggests that periodontal innervation may contribute to the regulation of local processes involved in periodontitis pathogenesis. It also suggests that periodontal therapy can be performed successfully at sites and in patients affected by paralysis.
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Affiliation(s)
- Matthew M Zavarella
- Section of Periodontology, College of Dentistry, Ohio State University Health Sciences Center, Columbus, OH 43218-2357, USA
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Haug SR, Heyeraas KJ. Immunoglobulin producing cells in the rat dental pulp after unilateral sympathectomy. Neuroscience 2005; 136:571-7. [PMID: 16198495 DOI: 10.1016/j.neuroscience.2005.08.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 07/30/2005] [Accepted: 08/01/2005] [Indexed: 11/22/2022]
Abstract
Recent studies show that sympathetic nerves participate in immunomodulation. We investigated the effects of unilateral sympathectomy on recruitment of cells expressing kappa and lambda (kappa and lambda) light chains in the rat dental pulp. Superior cervical ganglion was removed in experimental rats (n=10) while control rats (n=8) received sham surgery. Following perfusion 18 days later, mandibular jaws were processed for immunohistochemistry and electron microscopy. Sympathectomy results in recruitment of cells expressing kappa and lambda light chains into the dental pulp (P=0.005). Electron microscopy revealed these cells to be mainly plasma cells and Mott cells. We conclude that neural imbalance caused by unilateral sympathectomy recruits immunoglobulin producing cells in the dental pulp. Our results are in agreement with a model of immune regulation in which the sympathetic nervous system exerts a tonic regulatory effect over lymphocyte proliferation and migration.
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Affiliation(s)
- S R Haug
- Department of Biomedicine, Section for Physiology, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway.
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18
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Haug SR, Heyeraas KJ. Effects of sympathectomy on experimentally induced pulpal inflammation and periapical lesions in rats. Neuroscience 2003; 120:827-36. [PMID: 12895522 DOI: 10.1016/s0306-4522(03)00269-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The role of sympathetic nerves in bone physiology is largely unknown. Recent studies have shown a correlation between sympathectomy and bone remodeling. The present experiments were aimed to study the effects of unilateral sympathectomy on bilateral experimentally induced pulpitis and periapical lesions in the rat maxilla and mandible. Adult male Sprague-Dawley rats were used. Experimental rats (n=11) had the right superior cervical ganglion surgically removed (SCGx) and control rats (n=5) had sham surgery. Pulpal inflammation and periapical bone lesions in the maxilla and mandible were created 14 days later in both experimental and control rats by exposing the dental pulp in the first and second molars and leaving them open to the oral microflora. The rats were perfused 20 days thereafter and the jaws processed for immunohistochemistry with neuropeptide Y (NPY) and ED1 as primary antibodies. Sympathectomy resulted in an almost complete loss of NPY-immunoreactive (IR) fibers in the right SCGx jaws. In the non-sympathectomized (non-SCGx) left side and in the control rats, sprouting of NPY-IR fiber was observed in the inflamed pulp tissue adjacent to reparative dentin formation and in the apical periodontal ligament of the partially necrotic first molars. Significantly more ED1-IR osteoclasts were found in the resorptive lacunae lining the periphery of the periapical lesions on the SCGx side compared with the non-SCGx side (P<0.04) and the controls (P<0.03). The size of the periapical lesions were larger on the SCGx side compared with the non-SCGx side (P<0.03) in the mandible, but not in the maxilla. We conclude that inflammation causes sprouting of NPY-IR nerve fibers and that unilateral removal of the SCG increases both the area of the periapical lesions and the number of osteoclasts in the inflamed region.
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Affiliation(s)
- S R Haug
- Department of Physiology, University of Bergen, Arstadveien 19, 5009 Bergen, Norway.
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Affiliation(s)
- A Brack
- Klinik für Anaesthesiologie und operative Intensivmedizin, Universitätsklinikum Benjamin Franklin, Freie Universität Berlin, Hindenburgdamm 30, D-12200, Berlin, Germany.
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Byers MR, Suzuki H, Maeda T. Dental neuroplasticity, neuro-pulpal interactions, and nerve regeneration. Microsc Res Tech 2003; 60:503-15. [PMID: 12619126 DOI: 10.1002/jemt.10291] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
This review covers current information about the ability of dental nerves to regenerate and the role of tooth pulp in recruitment of regenerating nerve fibers. In addition, the participation of dental nerves in pulpal injury responses and healing is discussed, especially concerning pulp regeneration and reinnervation after tooth replantation. The complex innervation of teeth is highly asymmetric and guided towards specific microenvironments along blood vessels or in the crown pulp and dentin. Pulpal products such as nerve growth factor are distributed in the same asymmetric gradients as the dentinal sensory innervation, suggesting regulation and recruitment of those nerve fibers by those specific factors. The nerve fibers have important effects on pulpal blood flow and inflammation, while their sprouting and cytochemical changes after tooth injury are in response to altered pulpal cytochemistry. Thus, their pattern and neuropeptide intensity are indicators of pulp status, while their local actions continually affect that status. When denervated teeth are injured, either by pulp exposure on the occlusal surface or by replantation, they have more pulpal necrosis than occurs for innervated teeth. However, small pulp exposures on the side of denervated crowns or larger lesions in germ-free animals can heal well, showing the value of postoperative protection from occlusal trauma or from infection. Current ideas about dental neuroplasticity, neuro-pulpal interactions, and nerve regeneration are related to the overall topics of tooth biomimetics and pulp/dentin regeneration.
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Affiliation(s)
- Margaret R Byers
- Department of Anesthesiology, University of Washington, Seattle 98195-6540, USA.
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