Dentin hypersensitivity is an abrupt intense pain caused by innocuous stimuli to exposed dentinal tubules. Mechanosensitive ion channels have been assessed in dental primary afferent neurons and odontoblasts to explain dentin hypersensitivity. Dentinal fluid dynamics evoked by various stimuli to exposed dentin cause mechanical stress to the structures underlying dentin. This review briefly discusses three hypotheses regarding dentin hypersensitivity and introduces recent findings on mechanosensitive ion channels expressed in the dental sensory system and discusses how the activation of these ion channels is involved in dentin hypersensitivity.
Dental Physiological Phenomena ; Dentin Sensitivity ; Dentin ; Dentinal Fluid ; Hydrodynamics ; Ion Channels ; Mechanoreceptors ; Neurons, Afferent ; Odontoblasts ; Stress, Mechanical

Merkel cell carcinoma (MCC) is a rare and highly aggressive neuroectodermal carcinoma arising from mechanoreceptor Merkel cells. Multiple MCCs are even rarer. We report a case of two independent MCCs simultaneously present in the cheek of a patient, which were effectively and esthetically treated using a cheek flap. Punch biopsy performed in a 60-year-old woman admitted with a chief complaint of two skin-colored hard nodules in her left cheek, accompanied by an itching sensation, was suggestive of MCC. Accordingly, we performed sentinel lymph node biopsy through the modified Blair incision under general anesthesia, in cooperation with the head and neck surgery department. The defect was covered with a cheek flap by slightly extending the existing incision following wide excision with a safety margin of 1 cm. This paper is significant in that it introduces an effective reconstruction technique that maintains function using a cheek flap for the management of this rare case. In addition, this paper is the first to classify multiple MCCs according to the time of onset. We believe that this paper presents an effective alternative reconstruction technique with sentinel node biopsy through the modified Blair incision.
Anesthesia, General ; Biopsy ; Carcinoma, Merkel Cell ; Cheek ; Female ; Head ; Humans ; Mechanoreceptors ; Merkel Cells ; Middle Aged ; Neck ; Neural Plate ; Pruritus ; Sensation ; Sentinel Lymph Node Biopsy ; Surgical Flaps

PURPOSE: The purpose of this study was to resolve, in an efficient manner, the mechanoreceptor problems of the part far from the paretic upper extremity in stroke patients, as well as to provide clinical basic data of an intervention program for efficient neurodynamic in stroke patients, by developing a rhythmic neurodynamic exercise program and verifying functional changes depending on the increase in the upper extremity nerve conduction velocity. METHODS: Samples were extracted from 18 patients with hemiplegia, caused by stroke, and were randomly assigned to either the experimental group I for the general upper extremity neurodynamic (n=9) and the experimental group II for rhythmic upper extremity neurodynamic (n=9). An intervention program was applied ten times per set (three sets one time) and four times a week for two weeks (once a day). As a pre-test, changes in the upper extremity nerve conduction velocity and functions were assessed, and two weeks later, a posttest was conducted to re-measure them in the same manner. RESULTS: The wrist and palm sections of the radial nerve and the wrist and elbow sections of the median nerve, as well as the wrist, lower elbow, upper elbow, and axilla sections of the ulnar nerve had significant differences with respect to the upper extremity nerve conduction velocity between the two groups (p<0.05)(p<0.01), and significant differences were also found in the upper extremity functions (p<0.05). CONCLUSION: Rhythmic neurodynamic accelerated the nerve conduction velocity more in broader neural sections than the general neurodynamic. In conclusion, rhythmic neurodynamic was proven to be effective for improving the functions of upper extremity.
Axilla ; Elbow ; Hemiplegia ; Humans ; Mechanoreceptors ; Median Nerve ; Neural Conduction* ; Radial Nerve ; Stroke* ; Ulnar Nerve ; Upper Extremity* ; Wrist

Cochlear sensory hair cells (HCs) are crucial for hearing as mechanoreceptors of the auditory systems. Clarification of transcriptional regulation for the cochlear sensory HC development is crucial for the improvement of cell replacement therapies for hearing loss. Transcription factor Atoh1 is the key player during HC development and regeneration. In this review, we will focus on Atoh1 and its related signaling pathways (Notch, fibroblast growth factor, and Wnt/β-catenin signaling) involved in the development of cochlear sensory HCs. We will also discuss the potential applicability of these signals for the induction of HC regeneration.
Cochlea ; Fibroblast Growth Factors ; Hair Cells, Auditory ; Hair ; Hearing ; Hearing Loss ; Mechanoreceptors ; Regeneration ; Transcription Factors

The sense of mechanical stimuli (e.g. force or deformation) in the environment underlies several important physiological processes, for example the perception of sound, touch, pain and acceleration. The key step in mechanosensation is to convert the extracellular mechanical stimuli into cellular electrical or chemical signals. This process is termed as mechanotransduction. Based on mechanical and electrophysiological measurements, "Gating-Spring" theory was proposed as a general model to describe the cell biological mechanism of mechanotransduction. However, despite efforts made in several model organisms, the molecular basis of the "Gating-Spring" model remains elusive. In recent years, several key progresses have been made using the mechanoreceptors of Drosophila melanogaster as the models. This article introduces the "Gating-Spring" theory and reviews the recent research progresses on the fly mechanotransduction.
Animals ; Drosophila melanogaster ; Mechanoreceptors ; Mechanotransduction, Cellular

There is growing interest in using food choice/dietary change to influence clinical outcomes in patients with irritable bowel syndrome (IBS). The low fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) diet is an evidence-based approach that is gaining popularity in many Western countries. The low FODMAP diet is based on restricting dietary intake of short chain carbohydrates that are slowly absorbed or indigestible and not absorbed during passage through the small intestine. These are collectively described as "FODMAPs" and comprise oligosaccharides (mostly fructans, galacto-oligosaccharides), sugar polyols, fructose in excess of glucose, and lactose in lactose malabsorbers. The general strategy of the diet is to avoid foods high in FODMAPs and replace them with foods low in FODMAPs, with long-term restriction limited to what is required to control symptoms. The likely mechanism of action is minimisation of the stimulation of mechanoreceptors exerted by distension of the intestinal lumen with water from osmotic effects and gases from bacterial fermentation in those with visceral hypersensitivity. The success of this dietary approach greatly depends on detailed knowledge about the FODMAP composition of food commonly consumed in that country. While the content of foods associated with East and Southeast Asian cuisines has not been fully explored, major high FODMAP sources are frequently used and include onion, garlic, shallots, legumes/pulses, and wheat-based products. Thus, this dietary approach holds great promise in treating IBS patients in East and Southeast Asia. The aim of this review is to highlight how the diet is implemented, its efficacy, and troublesome ingredients frequently used in Asian dishes.
Asia ; Asia, Southeastern* ; Asian Continental Ancestry Group ; Carbohydrates ; Diet* ; Fermentation ; Fructans ; Fructose ; Garlic ; Gases ; Glucose ; Humans ; Hypersensitivity ; Intestine, Small ; Irritable Bowel Syndrome ; Lactose ; Mechanoreceptors ; Oligosaccharides ; Onions ; Shallots ; Water

OBJECTIVES: To map mechanoreceptor response in various regions of the laryngopharynx. METHODS: Five patients with suspected laryngopharyngeal reflux and six healthy control subjects underwent stimulation of mechanoreceptors in the hypopharynx, interarytenoid area, arytenoids, aryepiglottic folds, and pyriform sinuses. The threshold stimuli evoking sensation and eliciting laryngeal adductor reflex were recorded. RESULTS: In controls, an air pulse with 2 mmHg pressure evoked mechanoreceptor response in all regions, except bilateral aryepiglottic folds of one control. In patients, stimulus intensity to elicit mechanoreceptor response ranged between 2 mmHg and 10 mmHg and varied among the regions. Air pulse intensity differed between right and left sides of laryngopharyngeal regions in the majority of patients. CONCLUSION: Laryngopharyngeal mechanoreceptor response was uniform among regions and subjects in the healthy group. Patients with suspected laryngopharyngeal reflux showed inter- and intra-regional variations in mechanoreceptor response. Laryngopharyngeal sensory deficit in patients with suspected laryngopharyngeal reflux is not limited to aryepiglottic folds.
Humans ; Hypopharynx ; Laryngopharyngeal Reflux ; Mechanoreceptors* ; Pyriform Sinus ; Reflex ; Sensation

OBJECTIVETo investigate the density and distribution of nerve endings and neuropeptide Y (NPY) in lumbar facet joints of patients with low back pain.

METHODSFifteen patients without low back pain were selected as control group (group A). Facet joint samples in group A were obtained during the operation or lumbar spinal canal tumor they suffered from. Those patients with low back pain were divided into three groups according to their different origins of pain, such as not from facet joint (group B, 15 patients) ,from facet joint only (group C, 20 patients), or from facet joint partially (group D, 20 patients). Different origins were determined by VAS after facet joint block. The density and distribution of nerve ending and neuropeptide in the capsular tissues were analyzed by a modified gold chloride staining and immunochemistry respectively.

RESULTSCompared with the ones in group A and B, the fact joints in group C and D were more inclined to be degenerated and got more nerve endings. NPY was expressed mainly in the facet joint of patients with low back pain in group C and D. In addition, there was a significant relationship between the distribution of nerve endings and NPY expression,while none of them were related with MRI Fujiwara grade of facet joint.

CONCLUSIONThese results suggest that the number of mechanoreceptors, neural sprouting and secreted peptides in the facet joint capsules vary with the change of mechanical or nociceptive stimulation, which may promote the development of low back pain in return.

Adult ; Aged ; Case-Control Studies ; Chronic Pain ; etiology ; metabolism ; pathology ; Female ; Humans ; Low Back Pain ; etiology ; metabolism ; pathology ; Male ; Mechanoreceptors ; physiology ; Middle Aged ; Nerve Endings ; pathology ; Neuropeptide Y ; analysis

Histone deacetylases are involved in many biological processes and have roles in regulating cell behaviors such as cell cycle entry, cell proliferation and apoptosis. However, the effect of histone deacetylases on the development of hair cells (HCs) has not been fully elucidated. In this study, we examined the influence of histone deacetylases on the early development of neuromasts in the lateral line of zebrafish. Hair cell development was evaluated by fluorescent immunostaining in the absence or presence of histone deacetylase inhibitors. Our results suggested that pharmacological inhibition of histone deacetylases with inhibitors, including trichostatin A, valproic acid and MS-275, reduced the numbers of both HCs and supporting cells in neuromasts. We also found that the treatment of zebrafish larvae with inhibitors caused accumulation of histone acetylation and suppressed proliferation of neuromast cells. Real-time PCR results showed that the expression of both p21 and p27 mRNA was increased following trichostatin A treatment and the increase in p53 mRNA was modest under the same conditions. However, the expression of p53 mRNA was significantly increased by treatment with a high concentration of trichostatin A. A high concentration of trichostatin A also led to increased cell death in neuromasts as detected in a TUNEL assay. Moreover, the nuclei of most of these pyknotic cells were immunohistochemically positive for cleaved caspase-3. These results suggest that histone deacetylase activity is involved in lateral line development in the zebrafish and might have a role in neuromast formation by altering cell proliferation through the expression of cell cycle regulatory proteins.
Animals ; Apoptosis ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor Proteins/genetics/metabolism ; Histone Deacetylase Inhibitors/*pharmacology ; Histone Deacetylases/*metabolism ; Histones/metabolism ; Larva/growth & development/metabolism ; Lateral Line System/cytology/*growth & development/metabolism ; Mechanoreceptors/drug effects/*metabolism/physiology ; RNA, Messenger/genetics/metabolism ; Zebrafish ; Zebrafish Proteins/*metabolism

Dental Occlusion ; Esthetics, Dental ; Humans ; Mechanoreceptors ; Temporomandibular Joint