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

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

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

PURPOSE: To identify the change of mechanoreceptor of anterior cruciate ligament (ACL) in fixed knee and injured ACL. MATERIALS AND METHODS: Eighteen rabbits were divided into three groups as control, fixed knee, and injured ACL groups. Both knee of all fixed knee group were fixed with K-wire on the first day. The ligaments of the injured ACL group were cut at tibial attatchment site on the first day. Two rabbits of each group were sacrificed for the evaluation of mechanoreceptor at the 1st, 3rd, and 5th week. Histologic studies were performed by modified gold-chloride stain for the mechanoreceptors RESULTS: The types of mechanoreceptor in normal ACL were type I, type II, and type III. There was no difference in the appearance rate of each type. In the fixed knee group, the frequency of appearance decreased significantly at 5th week compared with that of the control group. In the injured ACL group, the frequency of appearance decreased at 1st week and showed no difference at 3rd week in comparison with 1st week, and zero at 5th week. In morphology the degree of degradation of mechanoreceptor increased with time in both experimental group, and showed more severe in the injured ACL group than in the fixed knee group. Most of all mechanoreceptors were located in the subsynovial region, and degraded with synovial degeneration and synovial inflammation. CONCLUSION: Mechanoreceptors were changed with the change of intra-articular condition and ligament itself. Therefore the duration of immobilization shoud be shortened if possible and the torn ACL should be repaired anatomically, if indicated, as soon as possible to preserve the mechanoreceptors.
Anterior Cruciate Ligament* ; Immobilization ; Inflammation ; Knee* ; Ligaments ; Mechanoreceptors* ; Rabbits

PURPOSE: We investigated the therapeutic effect of intravesical electrical stimulation (IVES) in enuretic children who showed refractory response to drug therapy, on the basis that IVES induces direct activation of bladder A delta mechanoreceptor afferents which would result in modulation of a central micturition reflex. MATERIALS AND METHODS: Of 351 enuretic children, the 22 who showed refractory response to drug monotherapy or combination therapy were enrolled in a clinical trial with IVES and then the therapeutic results of IVES and Post-IVES additional drug therapy were evaluated. Therapeutic response was defined when the frequency of bed-wetting was reduced by more than 50%. RESULTS: The rates of therapeutic response to IVES and Post-IVES additional drug therapy were 63.6% and 89.5%, respectively. As compared with Pre-IVES drug therapy, IVES and Post-IVES additional drug therapy showed significant therapeutic effect (p<0.05). Factors such as sex, depth of sleep, attention insufficiency, family history, voiding pattern, frequency of IVES procedure, fecal symptoms and day-time voiding symptoms had no significant impact on therapeutic response to IVES in enuresis (p>0.05). However, there was significant reduction of bed-wetting after IVES in cases with improved day-time voiding symptoms after IVES (p=0.031). CONCLUSIONS: In either a case of enuresis which shows refractory response to drug therapy as a primary modality of treatment or a case of complicated enuresis, IVES and Post-IVES additional drug therapy may produce a therapeutic response.
Child* ; Drug Therapy ; Electric Stimulation Therapy* ; Electric Stimulation* ; Enuresis* ; Humans ; Mechanoreceptors ; Reflex ; Urinary Bladder ; Urination

STUDY DESIGN: Histologic analysis of the ligamentum flavum to determine the distribution of mechanoreceptors in the lumbarspine. OBJECTIVES: To evaluate the distribution of mechanoreceptors in the ligamentum flavum and the quantitative changes according to the presence of degenerative change or segmental instability of the lumbar spine. SUMMARY OF LITERATURE REVIEW: Three types of mechanoreceptors were seen in the ligamentous structures of lumbar spine and they were found mainly in the interspinous/supraspinous ligament complex and the facet joint capsule. The numeric distribution of mechanoreceptors was suggested as the change of proprioception. MATERIALS AND METHODS: The ligamentum flavums were obtained from forty-four patients who underwent surgical decompression for various spinal diseases. The patients were divided into three groups. Group 1(9 cases) was defined as the patients with-out degenerative changes. Group 2(15 cases) included the patients with degenerative changes without instability. In group 3(20cases), the patients had the degenerative changes and instability. The specimens were stained by modified gold-chloride method. The types and numbers of mechanoreceptor were checked in each group and the result was analysed statistically. RESULTS: The total numbers of mechanoreceptors were 2.1+/-1.1, 2.0 +/-1.6, and 0.7+/-0.7 in type 1, 2, and 3. In group 1, the numbers of type 1, 2, and 3 were 2.1+/-0.9, 2.2+/-1.5, and 1.0 +/-0.5, respectively. In group 2, the numbers were 2.0 +/-1.3, 2.0 +/-1.9, and 0.5 +/- 0.6, respectively. In group 3, the numbers were 2.3 +/-1.1, 1.8 +/-1.4, and 0.7 +/-0.8, respectively. Statistically, the numbers of type 1 and type 2 had no difference and were greater than that of type 3. The numbers of type 1, 2, and 3 were not affected according to the presence of degenerative change or instability. CONCLUSION: The mechanoreceptors were seen in ligamentum flavum also as well as interspinous/supraspinous ligament complex and facet joint capsule, and they were mainly slowly or rapidly adapting. The distribution of mechanoreceptors was not affected by the presence of degenerative change or instability. The authors suggest that the degenerative change or instability would not influence to the proprioception of the ligamentum flavum.
Decompression, Surgical ; Humans ; Ligaments ; Ligamentum Flavum* ; Mechanoreceptors* ; Proprioception ; Spinal Diseases ; Spine* ; Zygapophyseal Joint

OBJECTIVE: In inflammation, hyperalgesia is a common phenomenon but its mechanism has not been clarified. Recently some reports suggested substance P might be important factors for inflammatory hyperalgesia in somatic tissue. This study was performed to see whether substance P modulate the activities of uterine afferent fibers in the hypogastric nerve of the cat. METHODS: While recording the electrical activities of nerve fibers, mechanical stimuli were applied as balloon distention using balloon inserted into uterine lumen before and during substance P infusion through uterine artery. RESULTS: Substance P increased the responses to balloon distension of uterus in 14 uterine mechanoreceptive afferent fibers of 24 over 10% compared to before substance P infusion, and decreased the responses of 3. And L-703,606, the neurokinin 1 receptor antagonist failed the modulation of mechano sensitive response by substance P and reduced the spontaneous activities. CONCLUSIONS: These results suggest that substance P modulated the activities of uterine nerve fibers and their responses to mechanical stimulus. It is hypothesized that this kind of modulation of afferent nerve fibers by substance P may be important for the development of inflammatory hyperalgesia.
Animals ; Cats ; Hyperalgesia ; Inflammation ; Mechanoreceptors* ; Nerve Fibers ; Receptors, Neurokinin-1 ; Substance P* ; Uterine Artery ; Uterus

Swallowing is a rare cause of neurally mediated syncope. The mechanism of swallow syncope that contributes to hypotension, bradycardia, or to both is complex. A 59-year-old man had experienced a recurrent loss of consciousness during swallowing of carbonated beverages or sticky foods. Another 59-year-old man had complained of intermittent syncope just after eating foods. These two patients had no significant structural or functional abnormalities in the esophagus or heart. Both cases showed bradycardia when the lower esophagus was stretched by balloon inflation. The activation of mechanoreceptors in the lower esophagus can be regarded as an initiating factor of these cardioinhibitions. The patients were treated with permanent pacemaker implantation and instructed to change eating habits, respectively.
Bradycardia/etiology ; Deglutition/*physiology ; Esophagus/*innervation ; Humans ; Male ; Mechanoreceptors/*physiology ; Middle Aged ; Syncope/*etiology

PURPOSE: The purposes of this study was to evaluate the changes in the mechanoreceptor in the anterior cruciate ligament(ACL) in relation to the healing course following transected posterior cruciate ligament(PCL) MATERIAL AND METHODS: Adult New Zealand White rabbits were used in our study. The PCLs of 40 rabbits were transected at mid-substance on one side. Sham operation was performed on the contralateral side, which served as their own control. At postoperative 2nd, 12th, 24th and 36th week, subsequent changes of the mechanoreceptors were examed histologically with modified gold-chloride staining and arthritic change of cartilage was examed by gross inspection. RESULTS: On gross inspection, the healing process of the transected PCLs began to appear at 6th week, since then the width has steadily increased. There was no evidence of cartilage degeneration from 6th week to 36th week. The number of mechanoreceptor was statistically decreased and morphological degradation was seen as compared with the control side at 6th, 12th and 24th week. The number of type 2 and type 3 mechanoreceptor had been statistically increased over time as the healing of PCL progressed. CONCLUSION: In rabbit model, the mechanoreceptor in ACL changed in response to the stability of the knee with injured PCL. But, further studies are necessary to explain the correlation between the change of mechanoreceptor in ACL and development of arthritis in the knee with injured PCL
Adult ; Anterior Cruciate Ligament* ; Arthritis ; Cartilage ; Humans ; Knee ; Mechanoreceptors* ; Posterior Cruciate Ligament* ; Rabbits

PURPOSE: This study was designed to determine the quantitative changes of the numbers of the mechanoreceptors in the experimentally tenotomized Achilles tendon of rabbits as compared with short-term immobilization and long-term immobilization. MATERIALS AND METHODS: 14 white rabbits were used. After tenotomizing the right Achilles tendon, the subjects were divided into 2 groups according to the periods of immobilizaton. The left side of each Achilles tendon of the rabbits were used as controls. The tendons were stained with a modified gold-chloride method. RESULTS: The number of mechanoreceptor was significantly decreased in the tenotomized Achilles tendon group than the control group (p<0.01). There was no statistical difference between the two experimental groups in the numbers of the mechanoreceptors (p>0.01). CONCLUSION: The injured Achilles tendons may more vulnerable to injury because of the decreased numbers of mechanoreceptors, but no difference between the periods of immobilization. It may suggest that post-operative immobilization period may not affect on the outcome of operative treatment from the viewpoint of mechanoreceptors.
Achilles Tendon ; European Continental Ancestry Group ; Humans ; Immobilization ; Mechanoreceptors ; Rabbits ; Tendons