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Science Advances Dec 2020The skin covering the human palm and other specialized tactile organs contains a high density of mechanosensory corpuscles tuned to detect transient pressure and...
The skin covering the human palm and other specialized tactile organs contains a high density of mechanosensory corpuscles tuned to detect transient pressure and vibration. These corpuscles comprise a sensory afferent neuron surrounded by lamellar cells. The neuronal afferent is thought to be the mechanical sensor, whereas the function of lamellar cells is unknown. We show that lamellar cells within Meissner and Pacinian corpuscles detect tactile stimuli. We develop a preparation of bill skin from tactile-specialist ducks that permits electrophysiological recordings from lamellar cells and demonstrate that they contain mechanically gated ion channels. We show that lamellar cells from Meissner corpuscles generate mechanically evoked action potentials using R-type voltage-gated calcium channels. These findings provide the first evidence for R-type channel-dependent action potentials in non-neuronal cells and demonstrate that lamellar cells actively detect touch. We propose that Meissner and Pacinian corpuscles use neuronal and non-neuronal mechanoreception to detect mechanical signals.
PubMed: 33328243
DOI: 10.1126/sciadv.abe6393 -
Skin Appendage Disorders Mar 2020This article gives an account of the commonest causes of nail pain. The acronyms GIFTED KID and FOMITE will help aid doctors in a busy clinical setting to remember the... (Review)
Review
This article gives an account of the commonest causes of nail pain. The acronyms GIFTED KID and FOMITE will help aid doctors in a busy clinical setting to remember the main causes of onychalgia, respectively, on the fingers and toes. It includes a brief overview of the clinical characteristics and focuses on the type of pain for each condition as well as the mechanisms that cause it.
PubMed: 32258050
DOI: 10.1159/000504347 -
Journal of Anatomy May 2022The human palmar aponeurosis is involved in hand proprioception, and it contains different sensory corpuscle morphotypes that serve this role. In palmar fibromatosis...
The human palmar aponeurosis is involved in hand proprioception, and it contains different sensory corpuscle morphotypes that serve this role. In palmar fibromatosis (classically referred to as Dupuytren's disease), the palmar aponeurosis undergoes fibrous structural changes that, presumably, also affect the nervous system, causing altered perception. We analysed the various sensory nerve formation morphotypes in the palmar aponeuroses of healthy subjects and patients with palmar fibromatosis. To do this, we used immunohistochemistry for corpuscular constituents and the putative mechanoproteins PIEZO2 and acid-sensing ion channel 2. Free nerve endings and Golgi-Mazzoni, Ruffini, paciniform and Pacinian corpuscles were identified in both the healthy and the pathological conditions. The densities of the free nerve endings and Golgi-Mazzoni corpuscles were slightly increased in the pathological tissues. Furthermore, the Pacinian corpuscles were enlarged and displayed an altered shape. Finally, there was also morphological and immunohistochemical evidence of occasional denervation of the Pacinian corpuscles, although no increase in their number was observed. Both PIEZO2 and acid-sensing ion channel 2 were absent from the altered corpuscles. These results indicate that the human palmar aponeurosis is richly innervated, and the free nerve endings and sensory corpuscles within the palmar aponeurosis undergo quantitative and qualitative changes in patients with palmar fibromatosis, which may explain the sensory alterations occasionally reported for this pathology.
Topics: Acid Sensing Ion Channels; Aponeurosis; Dupuytren Contracture; Hand; Humans; Pacinian Corpuscles
PubMed: 34881452
DOI: 10.1111/joa.13609 -
Annals of Anatomy = Anatomischer... Aug 2022Small clear synaptic-like vesicles fill axon terminals of mechanoreceptors. Their functional significance is controversial and probably includes release of...
BACKGROUND
Small clear synaptic-like vesicles fill axon terminals of mechanoreceptors. Their functional significance is controversial and probably includes release of neurotransmitters from afferent axon terminals. Synaptophysin, a major protein of the synaptic vesicle membrane, is present in presynaptic endings of the central and peripheral nervous systems. It is also expressed in mechanosensory neurons which extend into skin forming sensory corpuscles. Nevertheless, synaptophysin occurrence in these structures has never been investigated.
METHODS
Here we used immunohistochemistry to detect synaptophysin in adult human dorsal root ganglia, cutaneous Meissner and Pacinian corpuscles and Merkel cell-neurite complexes from foetal to elderly period. Moreover, we analyzed whether synaptophysin co-localizes with the mechano-gated protein PIEZO2.
RESULTS
Synaptophysin immunoreactivity was observed in primary sensory neurons (36 ± 6%) covering the entire soma size ranges. Axons of Meissner's and Pacinian corpuscles were positive for synaptophysin from 36 and 12 weeks of estimated gestational age respectively, to 72 years old. Synaptophysin was also detected in Merkel cells (from 14 weeks of estimated gestational age to old age). Additionally in adult skin, synaptophysin and PIEZO2 co-localized in the axon of Meissner and Pacinian corpuscles, Merkel cells as well as in some axons of Merkel cell-neurite complexes.
CONCLUSION
Present results demonstrate that a subpopulation of primary sensory neurons and their axon terminals forming cutaneous sensory corpuscles contain synaptophysin, a typical presynaptic vesicle protein. Although the functional relevance of these findings is unknown it might be related to neurotransmission mechanisms linked to mechanotransduction.
Topics: Adult; Aged; Axons; Biomarkers; Humans; Mechanoreceptors; Mechanotransduction, Cellular; Pacinian Corpuscles; Skin; Synaptophysin
PubMed: 35588932
DOI: 10.1016/j.aanat.2022.151955 -
Anatomical Record (Hoboken, N.J. : 2007) Aug 2020Heparan sulfate proteoglycans are pericellular/cell surface molecules involved in somatosensory axon guidance in the peripheral nervous system. However, the distribution...
Heparan sulfate proteoglycans are pericellular/cell surface molecules involved in somatosensory axon guidance in the peripheral nervous system. However, the distribution of heparan sulfate proteoglycans in the extracellular matrix of human cutaneous sensory corpuscles is unknown. Immunohistochemistry and immunofluorescence assays were performed to define the localization of heparan sulfate proteoglycans in human cutaneous Meissner's and Pacinian corpuscles using two anti-heparan sulfate antibodies together with anti-S100 protein, anti-PGP9.5, anti-CD34 (to immunolabel basement membranes, Schwann cells, axon and the intermediate endoneurial layer of Pacinian corpuscles, respectively), anti-Type IV collagen, and anti-chondroitin sulfate antibodies. Heparan sulfate proteoglycans were colocalized with Type IV collagen in Meissner's corpuscles and were located in the outer core lamellae and capsule, but not in the inner core or the intermediate layer, in Pacinian corpuscles. Chondroitin sulfate was observed in the intermediate layer of Pacinian corpuscles but was never colocalized with heparan sulfate proteoglycans. The present results strongly suggest that heparan sulfate proteoglycans are associated with the basement membranes of the lamellar cells in Meissner's corpuscles and with the complex outer core capsule in Pacinian corpuscles. The functional significance of these results, if any, remains to be elucidated.
Topics: Adult; Collagen Type IV; Female; Heparitin Sulfate; Humans; Male; Mechanoreceptors; Middle Aged; Pacinian Corpuscles; S100 Proteins; Skin; Young Adult
PubMed: 31815364
DOI: 10.1002/ar.24328 -
F1000Research 2020Vibrations are all around us. We can detect vibrations with sensitive skin mechanoreceptors, but our conscious awareness of the presence of vibrations is often limited.... (Review)
Review
Vibrations are all around us. We can detect vibrations with sensitive skin mechanoreceptors, but our conscious awareness of the presence of vibrations is often limited. Nevertheless, vibrations play a role in our everyday life. Here, we briefly describe the function of vibration detection and how it can be used for medical applications by way of whole body vibration. Strong vibrations can be harmful, but milder vibrations can be beneficial, although to what extent and how large the clinical relevance is are still controversial. Whole body vibration can be applied via a vibrating platform, used in both animal and human research. Recent findings make clear that the mode of action is twofold: next to the rather well-known exercise (muscle) component, it also has a sensory (skin) component. Notably, the sensory (skin) component stimulating the brain has potential for several purposes including improvements in brain-related disorders. Combining these two components by selecting the optimal settings in whole body vibration has clear potential for medical applications. To realize this, the field needs more standardized and personalized protocols. It should tackle what could be considered the "Big Five" variables of whole body vibration designs: vibration amplitude, vibration frequency, method of application, session duration/frequency, and total intervention duration. Unraveling the underlying mechanisms by translational research can help to determine the optimal settings. Many systematic reviews on whole body vibration end with the conclusion that the findings are promising yet inconclusive. This is mainly because of the large variation in the "Big Five" settings between studies and incomplete reporting of methodological details hindering reproducibility. We are of the opinion that when (part of) these optimal settings are being realized, a much better estimate can be given about the true potential of whole body vibration as a medical application.
Topics: Animals; Brain; Exercise; Humans; Mechanoreceptors; Reproducibility of Results; Vibration
PubMed: 32595943
DOI: 10.12688/f1000research.22649.1 -
BioRxiv : the Preprint Server For... Mar 2023Specialized mechanosensory end organs within mammalian skin-hair follicle-associated lanceolate complexes, Meissner corpuscles, and Pacinian corpuscles-enable our...
Specialized mechanosensory end organs within mammalian skin-hair follicle-associated lanceolate complexes, Meissner corpuscles, and Pacinian corpuscles-enable our perception of light, dynamic touch . In each of these end organs, fast-conducting mechanically sensitive neurons, called Aβ low-threshold mechanoreceptors (Aβ LTMRs), associate with resident glial cells, known as terminal Schwann cells (TSCs) or lamellar cells, to form complex axon ending structures. Lanceolate-forming and corpuscle-innervating Aβ LTMRs share a low threshold for mechanical activation, a rapidly adapting (RA) response to force indentation, and high sensitivity to dynamic stimuli . How mechanical stimuli lead to activation of the requisite mechanotransduction channel Piezo2 and Aβ RA-LTMR excitation across the morphologically dissimilar mechanosensory end organ structures is not understood. Here, we report the precise subcellular distribution of Piezo2 and high-resolution, isotropic 3D reconstructions of all three end organs formed by Aβ RA-LTMRs determined by large volume enhanced Focused Ion Beam Scanning Electron Microscopy (FIB-SEM) imaging. We found that within each end organ, Piezo2 is enriched along the sensory axon membrane and is minimally or not expressed in TSCs and lamellar cells. We also observed a large number of small cytoplasmic protrusions enriched along the Aβ RA-LTMR axon terminals associated with hair follicles, Meissner corpuscles, and Pacinian corpuscles. These axon protrusions reside within close proximity to axonal Piezo2, occasionally contain the channel, and often form adherens junctions with nearby non-neuronal cells. Our findings support a unified model for Aβ RA-LTMR activation in which axon protrusions anchor Aβ RA-LTMR axon terminals to specialized end organ cells, enabling mechanical stimuli to stretch the axon in hundreds to thousands of sites across an individual end organ and leading to activation of proximal Piezo2 channels and excitation of the neuron.
PubMed: 36993253
DOI: 10.1101/2023.03.17.533188 -
Case Reports in Plastic Surgery & Hand... 2019Pacinian corpuscle pathology is a rare clinical entity and an uncommonly reported cause of digital pain. While many prior reports implicate hand trauma, we describe a...
Pacinian corpuscle pathology is a rare clinical entity and an uncommonly reported cause of digital pain. While many prior reports implicate hand trauma, we describe a case of Pacinian hyperplasia found in a patient with Raynaud's phenomenon and propose a potential mechanism of disease.
PubMed: 32002464
DOI: 10.1080/23320885.2019.1698958 -
Anatomical Record (Hoboken, N.J. : 2007) Mar 2022Sea otters (Enhydra lutris) demonstrate rapid, accurate tactile abilities using their paws and facial vibrissae. Anatomical investigations of neural organization in the...
Sea otters (Enhydra lutris) demonstrate rapid, accurate tactile abilities using their paws and facial vibrissae. Anatomical investigations of neural organization in the vibrissal bed and somatosensory cortex coincide with measured sensitivity, but no studies describe sensory receptors in the paws or other regions of glabrous (i.e., hairless) skin. In this study, we use histology to assess the presence, density, and distribution of mechanoreceptors in the glabrous skin of sea otters: paws, rhinarium, lips, and flipper digits, and we use scanning electron microscopy to describe skin-surface texture and its potential effect on the transduction of mechanical stimuli. Our results confirm the presence of Merkel cells and Pacinian corpuscles, but not Meissner corpuscles, in all sea otter glabrous skin. The paws showed the highest density of Merkel cells and Pacinian corpuscles. Within the paw, relative densities of mechanoreceptor types were highest in the distal metacarpal pad and digits, which suggests that the distal paw is a tactile fovea for sea otters. In addition to the highest receptor density, the paw displayed the thickest epidermis. Rete ridges (epidermal projections into the dermis) and dermal papillae (dermal projections into the epidermis) were developed across all glabrous skin. These quantitative and qualitative descriptions of neural organization and physical features, combined with previous behavioral results, contribute to our understanding of how structure relates to function in the tactile modality. Our findings coincide with behavioral observations of sea otters, which use touch to maintain thermoregulatory integrity of their fur, explore objects, and capture visually cryptic prey.
Topics: Animals; Mechanoreceptors; Otters; Skin; Touch; Touch Perception
PubMed: 34425043
DOI: 10.1002/ar.24739 -
Romanian Journal of Morphology and... 2020Lamellar (Pacinian) corpuscle is a cutaneous encapsulated sensory corpuscle, mainly functioning as a rapidly adapting low-threshold mechanoreceptor with characteristic...
Lamellar (Pacinian) corpuscle is a cutaneous encapsulated sensory corpuscle, mainly functioning as a rapidly adapting low-threshold mechanoreceptor with characteristic "onion skin"-like appearance. Even though the Pacinian corpuscle is typically located in the skin, histomorphologically and confirmed by using immunohistochemical methods, we have identified it within the interstitium of the thymus of a newborn with congenital heart defect. To the best of our knowledge, this is the first such account ever to be published. The structure of the thymic Pacinian corpuscle was the same as the Pacinian corpuscle in the skin. The ectopic thymic Pacinian corpuscle can be hypothetically explained as the consequence of impaired migration of neural crest cells, since neural crest-derived cells play an important role in the development of the Pacinian corpuscle, as well as the thymus and heart. In general, the occurrence of ectopic Pacinian corpuscle in different organs is rare. In the scientific literature, there are reports of its sporadic presence in the pancreas, in the lymph nodes, inside the prostate and the urinary bladder wall. Our report presents the first described case of the Pacinian corpuscle in a heterotopic location in the thymus. Similar to other incidental findings of this anatomic structure, explanation of its ectopic development, as well as its local function remains only speculative.
Topics: Humans; Infant, Newborn; Male; Pacinian Corpuscles; Thymus Gland
PubMed: 32747922
DOI: 10.47162/RJME.61.1.33