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Neural signalling of gut mechanosensation in ingestive and digestive processes. Nat Rev Neurosci 2022; 23:135-156. [PMID: 34983992 DOI: 10.1038/s41583-021-00544-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2021] [Indexed: 12/29/2022]
Abstract
Eating and drinking generate sequential mechanosensory signals along the digestive tract. These signals are communicated to the brain for the timely initiation and regulation of diverse ingestive and digestive processes - ranging from appetite control and tactile perception to gut motility, digestive fluid secretion and defecation - that are vital for the proper intake, breakdown and absorption of nutrients and water. Gut mechanosensation has been investigated for over a century as a common pillar of energy, fluid and gastrointestinal homeostasis, and recent discoveries of specific mechanoreceptors, contributing ion channels and the well-defined circuits underlying gut mechanosensation signalling and function have further expanded our understanding of ingestive and digestive processes at the molecular and cellular levels. In this Review, we discuss our current understanding of the generation of mechanosensory signals from the digestive periphery, the neural afferent pathways that relay these signals to the brain and the neural circuit mechanisms that control ingestive and digestive processes, focusing on the four major digestive tract parts: the oral and pharyngeal cavities, oesophagus, stomach and intestines. We also discuss the clinical implications of gut mechanosensation in ingestive and digestive disorders.
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Bogdanov V, Reinhard J, McGlone F, Haehner A, Simons CT, Hummel T. Oral Somatosensory Sensitivity in Patients With Taste Disturbance. Laryngoscope 2021; 131:2572-2577. [PMID: 34435674 DOI: 10.1002/lary.29843] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/30/2021] [Accepted: 08/10/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The significance of the human sense of taste is typically underestimated until it is altered or even lost. Hypogeusia, a diminished capacity to taste, has an adverse influence on a patient's quality of life. Similar to interactions between the oral senses and between olfaction and intranasal trigeminal sensitivity, taste disturbance may also affect the mechanosensitivity of the tongue. In this study, we investigated the lingual tactile sensitivity of patients with subjective taste disturbance and people with normogeusia. STUDY DESIGN Prospective case-control study. METHODS Forty-six patients with subjective taste disturbance (mean age 60 years) and 43 participants with normogeusia (mean age 55 years) were enrolled and underwent a stereognostic test of edge and point sensitivity based on 3D-printed letters sized from 2 to 8 mm. Gustatory function and salivary production were also tested. RESULTS Patients with dysgeusia needed significantly bigger letters to recognize them compared with controls (P = .01). Apart from this, patients with dysgeusia had no significant association between gustatory function and salivary production. Duration of dysgeusia and age were not associated with the presently obtained measures of gustatory or oral mechanosensory function. CONCLUSIONS The results of this study indicate that taste dysfunction has a negative impact on oral mechanosensitivity and hence possibly on oral texture perception. LEVEL OF EVIDENCE 3 Laryngoscope, 131:2572-2577, 2021.
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Affiliation(s)
- Vasyl Bogdanov
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany.,Department of Otorhinolaryngology, Head and Neck Surgery, Carl-Thiem-Klinikum Cottbus gGmbH, Cottbus, Germany
| | - Jule Reinhard
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany
| | - Francis McGlone
- Faculty of Health, School of Psychology, Liverpool John Moores University, Liverpool, United Kingdom
| | - Antje Haehner
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany
| | - Chris T Simons
- CFAES Department of Food Science & Technology, Columbus, Ohio, U.S.A
| | - Thomas Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany
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Somatosensory innervation of the oral mucosa of adult and aging mice. Sci Rep 2018; 8:9975. [PMID: 29967482 PMCID: PMC6028454 DOI: 10.1038/s41598-018-28195-2] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 06/18/2018] [Indexed: 02/06/2023] Open
Abstract
Oral mechanoreception is implicated in fundamental functions including speech, food intake and swallowing; yet, the neuroanatomical substrates that encode mechanical stimuli are not well understood. Tactile perception is initiated by intricate mechanosensitive machinery involving dedicated cells and neurons. This signal transduction setup is coupled with the topology and mechanical properties of surrounding epithelium, thereby providing a sensitive and accurate system to detect stress fluctuations from the external environment. We mapped the distribution of anatomically distinct neuronal endings in mouse oral cavity using transgenic reporters, molecular markers and quantitative histomorphometry. We found that the tongue is equipped with an array of putative mechanoreceptors that express the principal mechanosensory channel Piezo2, including end bulbs of Krause innervating individual filiform papillae and a novel class of neuronal fibers innervating the epithelium surrounding taste buds. The hard palate and gums are densely populated with three classes of sensory afferents organized in discrete patterns including Merkel cell-neurite complexes, Meissner’s corpuscles and glomerular corpuscles. In aged mice, we find that palatal Merkel cells reduce in number at key time-points that correlate with impaired oral abilities, such as swallowing and mastication. Collectively, this work identifies the mechanosensory architecture of oral tissues involved in feeding.
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Moayedi Y, Duenas-Bianchi LF, Lumpkin EA. Somatosensory innervation of the oral mucosa of adult and aging mice. Sci Rep 2018. [PMID: 29967482 DOI: 10.1038/s41598‐018‐28195‐2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Oral mechanoreception is implicated in fundamental functions including speech, food intake and swallowing; yet, the neuroanatomical substrates that encode mechanical stimuli are not well understood. Tactile perception is initiated by intricate mechanosensitive machinery involving dedicated cells and neurons. This signal transduction setup is coupled with the topology and mechanical properties of surrounding epithelium, thereby providing a sensitive and accurate system to detect stress fluctuations from the external environment. We mapped the distribution of anatomically distinct neuronal endings in mouse oral cavity using transgenic reporters, molecular markers and quantitative histomorphometry. We found that the tongue is equipped with an array of putative mechanoreceptors that express the principal mechanosensory channel Piezo2, including end bulbs of Krause innervating individual filiform papillae and a novel class of neuronal fibers innervating the epithelium surrounding taste buds. The hard palate and gums are densely populated with three classes of sensory afferents organized in discrete patterns including Merkel cell-neurite complexes, Meissner's corpuscles and glomerular corpuscles. In aged mice, we find that palatal Merkel cells reduce in number at key time-points that correlate with impaired oral abilities, such as swallowing and mastication. Collectively, this work identifies the mechanosensory architecture of oral tissues involved in feeding.
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Affiliation(s)
- Yalda Moayedi
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA
| | - Lucia F Duenas-Bianchi
- SPURS Biomedical Research Program, Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, 10032, USA
| | - Ellen A Lumpkin
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, 10032, USA. .,Department of Dermatology, Columbia University, New York, NY, 10032, USA. .,Program in Neurobiology and Behavior, Columbia University, New York, NY, 10032, USA.
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Valach J, Foltán R, Vlk M, Szabo P, Smetana K. Phenotypic characterization of oral mucosa: what is normal? J Oral Pathol Med 2017; 46:834-839. [DOI: 10.1111/jop.12556] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/27/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Jaroslav Valach
- Department of Dental Medicine; 1st Faculty of Medicine; Charles University and General University Hospital in Prague; Prague Czech Republic
| | - René Foltán
- Department of Dental Medicine; 1st Faculty of Medicine; Charles University and General University Hospital in Prague; Prague Czech Republic
| | - Marek Vlk
- Department of Dental Medicine; 1st Faculty of Medicine; Charles University and General University Hospital in Prague; Prague Czech Republic
| | - Pavol Szabo
- Institute of Anatomy; 1st Faculty of Medicine; Charles University; Prague Czech Republic
- Department of Biomedical Research; East-Slovak Institute of Cardiovascular Diseases; Košice Slovakia
- BIOCEV; 1st Faculty of Medicine; Charles University; Vestec Czech Republic
| | - Karel Smetana
- Institute of Anatomy; 1st Faculty of Medicine; Charles University; Prague Czech Republic
- BIOCEV; 1st Faculty of Medicine; Charles University; Vestec Czech Republic
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Straka M, Polák Š, Straková Trapezanlidis M, Varga I. What we know about the cellular microenvironment of clinically healthy human gingiva? An immunohistochemical and histological study. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Loss of Aβ-nerve endings associated with the Merkel cell-neurite complex in the lesional oral mucosa epithelium of lichen planus and hyperkeratosis. Int J Oral Sci 2016; 8:32-8. [PMID: 27025263 PMCID: PMC4822177 DOI: 10.1038/ijos.2015.31] [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] [Accepted: 07/15/2015] [Indexed: 11/27/2022] Open
Abstract
The Merkel cell-neurite complex initiates the perception of touch and mediates Aβ slowly adapting type I responses. Lichen planus is a chronic inflammatory autoimmune disease with T-cell-mediated inflammation, whereas hyperkeratosis is characterized with or without epithelial dysplasia in the oral mucosa. To determine the effects of lichen planus and hyperkeratosis on the Merkel cell-neurite complex, healthy oral mucosal epithelium and lesional oral mucosal epithelium of lichen planus and hyperkeratosis patients were stained by immunohistochemistry (the avidin-biotin-peroxidase complex and double immunofluorescence methods) using pan cytokeratin, cytokeratin 20 (K20, a Merkel cell marker), and neurofilament 200 (NF200, a myelinated Aβ- and Aδ-nerve fibre marker) antibodies. NF200-immunoreactive (ir) nerve fibres in healthy tissues and in the lesional oral mucosa epithelium of lichen planus and hyperkeratosis were counted and statistically analysed. In the healthy oral mucosa, K20-positive Merkel cells with and without close association to the intraepithelial NF200-ir nerve fibres were detected. In the lesional oral mucosa of lichen planus and hyperkeratosis patients, extremely rare NF200-ir nerve fibres were detected only in the lamina propria. Compared with healthy tissues, lichen planus and hyperkeratosis tissues had significantly decreased numbers of NF200-ir nerve fibres in the oral mucosal epithelium. Lichen planus and hyperkeratosis were associated with the absence of Aβ-nerve endings in the oral mucosal epithelium. Thus, we conclude that mechanosensation mediated by the Merkel cell-neurite complex in the oral mucosal epithelium is impaired in lichen planus and hyperkeratosis.
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Mishra SK, Chowdhary R, Chrcanovic BR, Brånemark PI. Osseoperception in Dental Implants: A Systematic Review. J Prosthodont 2016; 25:185-95. [PMID: 26823228 DOI: 10.1111/jopr.12310] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2014] [Indexed: 11/28/2022] Open
Abstract
PURPOSE Replacement of lost teeth has significant functional and psychosocial effects. The capability of osseointegrated dental implants to transmit a certain amount of sensibility is still unclear. The phenomenon of developing a certain amount of tactile sensibility through osseointegrated dental implants is called osseoperception. The aim of this article is to evaluate the available literature to find osseoperception associated with dental implants. MATERIALS AND METHODS To identify suitable literature, an electronic search was performed using Medline and PubMed database. Articles published in English and articles whose abstract is available in English were included. The articles included in the review were based on osseoperception, tactile sensation, and neurophysiological mechanoreceptors in relation to dental implants. Articles on peri-implantitis and infection-related sensitivity were not included. Review articles without the original data were excluded, although references to potentially pertinent articles were noted for further follow-up. The phenomenon of osseoperception remains a matter of debate, so the search strategy mainly focused on articles on osseoperception and tactile sensibility of dental implants. This review presents the histological, neurophysiological, and psychophysical evidence of osseoperception and also the role of mechanoreceptors in osseoperception. RESULTS The literature on osseoperception in dental implants is very scarce. The initial literature search resulted in 90 articles, of which 81 articles that fulfilled the inclusion criteria were included in this systematic review. CONCLUSION Patients restored with implant-supported prostheses reported improved tactile and motor function when compared with patients wearing complete dentures.
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Affiliation(s)
- Sunil Kumar Mishra
- Department of Maxillofacial Prosthodontics and Implantology, Peoples Dental Academy, Bhopal, India
| | - Ramesh Chowdhary
- Department of Prosthodontics and Maxillofacial Implantology, Rajarajeshwari Dental College and Hospital, Bangalore, India
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Abstract
Neuroendocrine cells of the oral mucosa constitute an under-recognized component of the diffuse neuroendocrine system with diverse subpopulations and elusive biologic roles in the oral cavity. Primary malignant oral tumors that show a neuroendocrine phenotype display histomorphologic heterogeneity thereby giving rise to a spectrum of lesions in this rare category of oral malignancy. These lesions can be divided into neuroendocrine carcinomas (NECs) of small cell or non-small cell type. The former is further subdivided into the Merkel cell type or the pulmonary type while the latter includes atypical carcinoid tumor and large cell NEC. All histologic subtypes of oral NEC appear to have a strong predilection for men in their fifth or sixth decade and arise predominantly in the non-keratinized oral mucosa. The biologic behavior of oral Merkel cell carcinomas appears to be more aggressive than those of skin. It remains to be determined whether histologic categorization of the remaining tumor subtypes is predictive of patient survival in oral neuroendocrine tumors.
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Affiliation(s)
- Farzana Mahomed
- Division of Oral Pathology, School of Oral Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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Habre-Hallage P, Abboud-Naaman NB, Reychler H, van Steenberghe D, Jacobs R. Perceptual changes in the peri-implant soft tissues assessed by directional cutaneous kinaesthesia and graphaesthesia: a prospective study. Clin Implant Dent Relat Res 2009; 13:296-304. [PMID: 19673925 DOI: 10.1111/j.1708-8208.2009.00215.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The innervation of skin and oral mucosa plays a major physiological role in exteroception. This innervation is also clinically relevant as sensory changes occur after neurosurgical procedures. PURPOSE The goal of this study was to compare the perception of mechanical stimuli applied to the buccal mucosa in the vicinity of osseointegrated oral implants with that in the controlateral dentate side. The role of the previously reported increased innervation in the peri-implant soft tissues in the oral sensorimotor function was thus examined. MATERIALS AND METHODS Seventeen subjects with 20 implants were tested. Directional cutaneous kinaesthesia (DCK) and graphesthesia (G) were performed on the buccal side of the alveolar mucosa before and at planned intervals after implant placement. The observation was pursued until 6 months after the prosthetic rehabilitation. In each subject, the contralateral mucosa served as a control to the implant sites. Average percentages of correct responses in a four-choice task for DCK and a three-choice task for G were calculated. RESULTS Despite an intersubject variation in both the DCK and G, high intraindividual correlations were found (p < .005). The implant sites showed a significant difference toward the control sites at the four interval test for both tests. For DCK and G, the average of correct responses decreased after abutment connection (i.e., after the implant uncovering surgery) to increase afterwards to reach a level close to, but still lower than, the control sites 3 to 6 months after the prosthetic rehabilitation. CONCLUSION The DCK and G are simple but reliable sensory tests that can be easily applied in the oral region. This prospective study indicates that tooth loss reduces tactile function compared with implant-supported prostheses. The peri-implant soft tissues could be partially involved in the osseoperception function.
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Affiliation(s)
- Pascale Habre-Hallage
- Department of Prosthodontics, Faculty of Dentistry, Saint-Joseph University, Campus of Medical Sciences, Damascus Road, Beirut, Lebanon.
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Righi A, Betts CM, Marchetti C, Marucci G, Montebugnoli L, Prati C, Eusebi LHU, Muzzi L, Ragazzini T, Foschini MP. Merkel cells in the oral mucosa. Int J Surg Pathol 2006; 14:206-11. [PMID: 16959700 DOI: 10.1177/1066896906290053] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ninety-eight consecutive surgical biopsies of oral mucosa from 96 patients were evaluated immunohistochemically with an anti-cytokeratin 20 (CK 20) anti-body to evidence Merkel cells (MC). Fifteen cases, showing the highest number of MC, were additionally studied with chromogranin A, S-100 protein, neuro filaments, epithelial membrane antigen, and double immunostaining for CK 20 and Ki67 antibodies to evaluate MC proliferation. Electron microscopy was performed in 2 cases. MC were observed in 58 cases. The highest number of MC was found in the gingival, buccal, and palate mucosa, especially in chronically damaged oral mucosa (lichen and chronic aspecific inflammation) as well as in the mucosa overlying tumors rather than in normal or acute inflammation. MC were not observed in dysplastic or neoplastic epithelium. MC showed evidence of proliferation, as demonstrated by Ki67 positivity, in 3 cases. In conclusion, MC appear to play a role in the reparative processes of oral mucosa.
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Affiliation(s)
- Alberto Righi
- Section of Anatomic Pathology, Bellaria Hospital, University of Bologna, Bologna, Italy
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