Peripheral mast cells derive the effects of acupuncture in Parkinson's disease.

This research investigates the peripheral mechanisms of acupuncture in treating Parkinson's disease (PD), a progressive neurodegenerative disorder marked by motor impairments. While the central mechanisms of acupuncture have been extensively studied, our focus lies in the peripheral mechanisms at the acupoints, the sites of acupuncture signal initiation. Employing a PD model, we analyzed the local responses to acupuncture stimulation at these points. Our key finding was a significant elevation in both the number and activity of mast cells (MCs) in the peripheral tissues following acupuncture. Intriguingly, pre-treatment with an MC stabilizer diminished the acupuncture's therapeutic effects on PD symptoms. Similarly, local anesthesia with lidocaine at the acupoints attenuated the symptom improvement typically observed with acupuncture. Meanwhile, the augmentation of MC activity induced by acupuncture was significantly impeded by cromolyn, an MC stabilizer, but remained unaffected by lidocaine. This finding suggests that MC activity is a more upstream regulator of acupuncture effects compared to nerve conduction. This study provides groundbreaking insights into the initiation and transmission of acupuncture signals, highlighting the significant role of peripheral MC modulation in PD treatment.

Immunohistochemical localization of proteins involved in exocytosis of glutamate from P2X3 purinoceptor-expressing subserosal afferent nerve endings in the rat gastric antrum.

We previously reported the presence of P2X3 purinoceptors (P2X3)-expressing subserosal afferent nerve endings consisting of net- and basket-like nerve endings in the rat gastric antrum. These nerve endings may morphologically be vagal mechanoreceptors activated by antral peristalsis. The present study investigated immunoreactivities for vesicular glutamate transporter (VGLUT) 1 and VGLUT2 as well as exocytosis-related proteins, i.e., core components of the SNARE complex (SNAP25, Stx1, and VAMP2) and synaptotagmin-1 (Syt1), in whole-mount preparations of the rat gastric antrum using double immunofluorescence. VGLUT1 immunoreactivity was not detected, whereas VGLUT2 immunoreactivity was observed in P2X3-immunoreactive subserosal nerve endings composed of both net- and basket-like endings. In net-like nerve endings, intense VGLUT2 immunoreactivity was localized in polygonal bulges of reticular nerve fibers and peripheral axon terminals. Furthermore, intense immunoreactivities for SNAP25, Stx1, and VAMP2 were localized in net-like nerve endings. Intense immunoreactivities for VAMP2 and Syt1 were observed in VGLUT2-immunoreactive net-like nerve endings. In basket-like nerve endings, VGLUT2 immunoreactivity was localized in pleomorphic terminal structures and small bulges surrounding the subserosal ganglion, whereas immunoreactivities for SNAP25, Stx1, and VAMP2 were weak in these nerve endings. VGLUT2-immunoreactive basket-like nerve endings were weakly immunoreactive for VAMP2 and Syt1. These results suggest that subserosal afferent nerve endings release glutamate by exocytosis mainly from net-like nerve endings to modulate their mechanoreceptor function.

Mentalis nerve branches supplying the lower lip revisited: a study of human fetuses and donated elderly cadavers.

PURPOSE: Little information is known about the mentalis nerve course from the lower lip approximation margin (free margin) to the upper lip. Likewise, no difference in nerve distribution has been observed between the cutaneous and mucosal parts of the lip. Therefore, this study reexamined mentalis nerve morphology. METHODS: For macroscopic observations, three fresh cadavers were dissected (one male and two females; aged 78-93). We also evaluated histological sections obtained from five donated elderly cadavers (two males and three females, aged 82-96 years) and 15 human fetuses (11-40 weeks or crown-rump length 80-372 mm). Immunohistochemical analysis for S100 protein and tyrosine hydroxylase was performed. RESULTS: In both fetuses and adult cadavers, one to three nerve branches ran upward in the submucosal tissue from the mental foramen. Near the free margin of the lip, some branches passed through the orbicularis oris muscle layer toward the lip skin, whereas others followed a reversed J-shaped course along the free margin. Nerve twigs ran in parallel beneath the mucosa, whereas wavy nerve twigs attached to the basal lamina of the lip epidermis. The difference in nerve endings abruptly occurred at the skin-mucosal junction. Tyrosine hydroxylase-positive sympathetic nerve twigs surrounded arteries and formed a branch composed of S100-negative unmyelinated fibers. CONCLUSION: The lower lip skin was innervated by a perforating branch passing through the orbicularis oris muscle, that was different from the lip mucosa. A sudden change in the nerve ending configuration at the mucocutaneous junction seemed to develop postnatally.

The anatomy, neurophysiology, and cellular mechanisms of intradental sensation.

Somatosensory innervation of the oral cavity enables the detection of a range of environmental stimuli including minute and noxious mechanical forces. The trigeminal sensory neurons underlie sensation originating from the tooth. Prior work has provided important physiological and molecular characterization of dental pulp sensory innervation. Clinical dental experiences have informed our conception of the consequence of activating these neurons. However, the biological role of sensory innervation within the tooth is yet to be defined. Recent transcriptomic data, combined with mouse genetic tools, have the capacity to provide important cell-type resolution for the physiological and behavioral function of pulp-innervating sensory neurons. Importantly, these tools can be applied to determine the neuronal origin of acute dental pain that coincides with tooth damage as well as pain stemming from tissue inflammation (i.e., pulpitis) toward developing treatment strategies aimed at relieving these distinct forms of pain.

Periarticular Proprioception: Analyzing the Three-Dimensional Structure of Corpuscular Mechanosensors in the Dorsal Part of the Scapholunate Ligament.

INTRODUCTION: Sensory nerve endings transmit mechanical stimuli into afferent neural signals and form the basis of proprioception, giving rise to the self-perception of dynamic stability of joints. We aimed to analyze the three-dimensional structure of periarticular corpuscular sensory nerve endings in a carpal ligament to enhance our understanding of their microstructure. METHODS: Two dorsal parts of the scapholunate ligament were excised from two human cadaveric wrist specimens. Consecutive cryosections were stained with immunofluorescence markers protein S100B, neurotrophin receptor p75, protein gene product 9.5 (PGP 9.5), and 4',6-diamidino-2-phenylindole. Three-dimensional images of sensory nerve endings were obtained using confocal laser scanning microscopy, and subsequent analysis was performed using Imaris software. RESULTS: Ruffini endings were characterized by a PGP 9.5-positive central axon, with a median diameter of 4.63 µm and a median of 25 cells. The p75-positive capsule had a range in thickness of 0.94 µm and 15.5 µm, consisting of single to three layers of lamellar cells. Ruffini endings were significantly smaller in volume than Pacini corpuscles or Golgi-like endings. The latter contained a median of three intracorpuscular structures. Ruffini endings and Golgi-like endings presented a similar structural composition of their capsule and subscapular space. The central axon of Pacini corpuscles was surrounded by S100-positive cells forming the inner core which was significantly smaller than the outer core, which was immunoreactive for p75 and PGP 9.5. CONCLUSION: This study reports new data regarding the intricate outer and intracorpuscular three-dimensional morphology of periarticular sensory nerve endings, including the volume, number of cells, and structural composition. These results may form a basis to differ between normal and pathological morphological changes in periarticular sensory nerve endings in future studies.

Discontinuity third harmonic generation microscopy for label-free imaging and quantification of intraepidermal nerve fibers.

Label-free imaging methodologies for nerve fibers rely on spatial signal continuity to identify fibers and fail to image free intraepidermal nerve endings (FINEs). Here, we present an imaging methodology-called discontinuity third harmonic generation (THG) microscopy (dTHGM)-that detects three-dimensional discontinuities in THG signals as the contrast. We describe the mechanism and design of dTHGM and apply it to reveal the bead-string characteristics of unmyelinated FINEs. We confirmed the label-free capability of dTHGM through a comparison study with the PGP9.5 immunohistochemical staining slides and a longitudinal spared nerve injury study. An intraepidermal nerve fiber (IENF) index based on a discontinuous-dot-connecting algorithm was developed to facilitate clinical applications of dTHGM. A preliminary clinical study confirmed that the IENF index was highly correlated with skin-biopsy-based IENF density (Pearson's correlation coefficient R = 0.98) and could achieve differential identification of small-fiber neuropathy (p = 0.0102) in patients with diabetic peripheral neuropathy.

Distribution of P2X3 purinoceptor-immunoreactive sensory nerve endings in the carotid body of Japanese macaque (Macaca fuscata).

In the carotid body of laboratory rodents, adenosine 5'-triphosphate (ATP)-mediated transmission is regarded as critical for transmission from chemoreceptor type I cells to P2X3 purinoceptor-expressing sensory nerve endings. The present study investigated the distribution of P2X3-immunoreactive sensory nerve endings in the carotid body of the adult male Japanese monkey (Macaca fuscata) using multilabeling immunofluorescence. Immunoreactivity for P2X3 was detected in nerve endings associated with chemoreceptor type I cells immunoreactive for synaptophysin. Spherical or flattened terminal parts of P2X3-immunoreactive nerve endings were in close apposition to the perinuclear cytoplasm of synaptophysin-immunoreactive type I cells. Immunoreactivity for ectonucleoside triphosphate diphosphohydrolase 2 (NTPDase2), which hydrolyzes extracellular ATP, was localized in the cell body and cytoplasmic processes of S100B-immunoreactive cells. NTPDase2-immunoreactive cells surrounded P2X3-immunoreactive terminal parts and synaptophysin-immunoreactive type I cells, but did not intrude into attachment surfaces between terminal parts and type I cells. These results suggest ATP-mediated transmission between type I cells and sensory nerve endings in the carotid body of the Japanese monkey, as well as those of rodents.

Three-dimensional architecture of the subepithelial corpuscular nerve ending in the rat epiglottis reconstructed by array tomography with scanning electron microscopy.

In the rat laryngeal mucosa, subepithelial corpuscular nerve endings, called laminar nerve endings, are distributed in the epiglottis and arytenoid region and are activated by the pressure changes of the laryngeal cavity. They are also suggested to play a role in efferent regulation because of secretory vesicles in the axoplasm. In the present study, the laminar nerve endings in the rat laryngeal mucosa were analyzed by 3D reconstruction from serial ultrathin sections in addition to immunohistochemistry for synapsin 1. In the light microscopy, synapsin 1-immunoreactive flattened or bulbous terminal parts of the laminar endings were also immunoreactive with VGLUT1, and were surrounded by S100- or S100B-immunoreactive Schwann cells and vimentin-immunoreactive fibroblasts. In the electron microscopy, 3D reconstruction views showed that laminar endings were composed of flattened terminal parts sized 2-5 µm in longitudinal length, overlapping in three to five multiple layers. The terminal parts of the endings were incompletely wrapped by flat cytoplasmic processes of the Schwann cells. In addition, the fibroblast network surrounded the complex of nerve endings and the Schwann cells. Several terminal parts entered through the basement membrane into the epithelial layer and attached to the basal epithelial cells, suggesting that interaction between epithelial cells and laminar nerve endings plays an important role in sensing the pressure changes in the laryngeal cavity. Secretory vesicles were unevenly distributed throughout the terminal part of the laminar nerve endings. The secretory vesicles were frequently observed in the peripheral limb of the terminal parts. It suggests that the laminar nerve endings in the larynx may release glutamate to maintain continuous discharge during the stretching of the laryngeal mucosa.

The size, number, and distribution of nerve endings around and within the human epiglottis, focusing on tracheal intubation maneuvers.

The aim of this study was to examine the distribution of nerve endings in the mucosa, submucosa, and cartilage of the epiglottis and the vallecula area and to quantify them. The findings could inform the choice of laryngoscope blades for intubation procedures. Fourteen neck slices from seven unembalmed, cryopreserved human cadavers were analyzed. The slices were stained, and cross and longitudinal sections were obtained from each. The nerve endings and cartilage were identified. The primary metrics recorded were the number, area, and circumference of nerve endings located in the mucosa and submucosa of the pharyngeal and laryngeal sides of the epiglottis, epiglottis cartilage, and epiglottic vallecula zone. The length and thickness of the epiglottis and cartilage were also measured. The elastic cartilage of the epiglottis was primarily continuous; however, it contained several fragments. It was covered with dense collagen fibers and surrounded by adipose cells from the pharyngeal and laryngeal submucosa. Nerve endings were found within the submucosa of pharyngeal and laryngeal epiglottis and epiglottic vallecula. There were significantly more nerve endings on the posterior surface of the epiglottis than on the anterior surface. The epiglottic cartilage was twice the length of the epiglottis. The study demonstrated that the distribution of nerve endings in the epiglottis differed significantly between the posterior and anterior sides; there were considerably more in the former. The findings have implications for tracheal intubation and laryngoscope blade selection and design.

Study of the nerve endings and mechanoreceptors of the medial meniscotibial ligament of the knee: A structural and distribution analysis.

BACKGROUND: The aim of the present study is to describe the morphology and distribution of the nerve endings of the meniscotibial ligament (MTL) of the knee, in order to understand the interaction between the proprioceptive system and knee mechanics. METHODS: Twenty medial MTLs were obtained from deceased organ donors. The ligaments were measured, weighed and cut. Sections (10 mm) were prepared on hematoxylin and eosin-stained slides for analysis of tissue integrity, and 50 mm sections were submitted to immunofluorescence with the protein gene product (PGP) 9.5 as primary antibody and Alexa Fluor 488 as secondary antibody, followed by microscopic analysis. RESULTS: The medial MTL was identified in 100% of the dissections, with average length, width, thickness and weight of 7.07 ± 1.34 mm, 32.25 ± 3.09 mm, 3.53 ± 0.27 mm and 0.67 ± 0.13 g, respectively. The hematoxylin and eosin-stained histological sections exhibited typical ligament structure, with dense well-organized collagen fibers and vascular tissue. All the specimens analyzed contained type I (Ruffini) mechanoreceptors and free (type IV) nerve endings, varying from parallel to intertwined fibers. Nerve endings not classified with different irregular shapes were also found. Most type I mechanoreceptors were found close to the MTL insertions on the tibial plateau, while the free nerve endings were found adjacent to the capsule. CONCLUSION: The medial MTL showed a peripheral nerve structure, primarily type I and IV mechanoreceptors. These findings suggest that the medial MTL is important for proprioception and medial knee stabilization.

Immunolocalization of vesicular glutamate transporter 2 and exocytosis-related proteins in afferent nerve endings innervating taste buds in the rat incisive papilla.

The present study aimed to investigate the immunolocalization of vesicular glutamate transporter (VGLUT) 1 and 2, and proteins associated with exocytosis, i.e., core components of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor complex (synaptosomal-associated protein of 25 kDa, syntaxin 1, and vesicle-associated membrane protein 2) and synaptotagmin-1 (Syt1), in incisive papillary taste buds of rats using double-indirect immunofluorescence. No VGLUT1 immunoreactivity was observed, whereas VGLUT2-immunoreactive punctate products were closely associated with guanine nucleotide-binding protein G(t) subunit α3-immmunoreactive cells in taste buds. VGLUT2 was immunolocalized in P2X3 purinoceptor-expressing afferent nerve endings. Synaptosomal-associated protein of 25 kDa, syntaxin 1, and vesicle-associated membrane protein 2 were immunolocalized in nerve endings containing VGLUT2-immunoreactive products as well as a few cells in taste buds. VGLUT2 was co-immunolocalized in some intragemmal nerve endings immunoreactive for Syt1, a calcium sensor implicated in vesicle membrane fusion. The present results suggest that afferent nerve endings innervating incisive taste buds release glutamate by exocytosis to modulate taste cell function.

Three-dimensional correlative light and focused ion beam scanning electron microscopy reveals the distribution and ultrastructure of lanceolate nerve endings surrounding terminal hair follicles in human scalp skin.

Lanceolate nerve endings (LNEs) surrounding hair follicles (HFs) play an important role in detecting hair deflection. Complexes of the LNEs form a palisade-like structure along the longitudinal axis of hair roots in which axons are sandwiched between two processes of terminal Schwann cells (tSCs) at the isthmus of HFs. The structure and molecular mechanism of LNEs in animal sinus hair, pelage, and human vellus hairs have been investigated. Despite the high density of HFs in human scalp skin, the LNEs in human terminal HFs have not been investigated. In this study, we aimed to reveal the distribution and ultrastructure of LNEs in terminal HFs of human scalp skin. Using light-sheet microscopy and immunostaining, the LNEs were observed at one terminal HF but not at the other terminal HFs in the same follicular unit. The ultrastructure of the LNEs of terminal HFs in human scalp skin was characterized using correlated light and electron microscopy (CLEM). Confocal laser microscopy and transmission electron microscopy of serial transverse sections of HFs revealed that LNEs were aligned adjacent to the basal lamina outside the outer root sheath (ORS), at the isthmus of terminal HFs, and adjacent to CD200-positive ORS cells in the upper bulge region. Moreover, axons with abundant mitochondria were sandwiched between tSCs. Three-dimensional CLEM, specifically confocal laser microscopy and focused ion beam scanning electron microscopy, of stained serial transverse sections revealed that LNEs were wrapped with type I and type II tSCs, with the processes protruding from the space between the Schwann cells. Moreover, the ultrastructures of LNEs at miniaturized HFs were similar to those of LNEs at terminal HFs. Preembedding immunoelectron microscopy revealed that Piezo-type mechanosensitive ion channel component 2 (Piezo2), a gated ion channel, was in axons and tSCs and adjacent to the cell membrane of axons and tSCs, suggesting that LNEs function as mechanosensors. The number of LNEs increased as the diameter of the ORS decreased, suggesting that LNEs dynamically adapt to the HF environment as terminal HFs miniaturize into vellus-like hair. These findings will provide insights for investigations of mechanosensory organs, aging, and re-innervation during wound healing.

Analysis of Mechanoreceptors and Free Nerve Endings of the Transverse Carpal Ligament.

Background: The treatment of carpal tunnel syndrome (CTS) by sectioning the transverse carpal ligament (TCL) is not exempt from complications. Some nerve branches may be damaged by the incision. The aim of this study is to identify and map the TCL nerve endings, serving as a guide for sectioning this structure in a zone with less nerve ending density. Methods: Ten TCLs were obtained from fresh frozen cadavers. The TCLs were measured, divided into 3 equal bands (radial, central, and ulnar), and submitted to cryostat sectioning. The sections were subjected to immunofluorescence with the protein gene product (PGP) 9.5 and confocal microscopy analysis. Results: All the specimens contained type I and type IV mechanoreceptors. Neural elements occupied 0.695 ± 0.056% of the ligament area. The density of the neural elements was greater in the radial, followed by the ulnar and central bands, with 0.730 ± 0.083%, 0.686 ± 0.009%, and 0.669 ± 0.031%, respectively. Conclusion: The present findings suggest that the region with the least potential for neural element injury during TCL release is the central third near the transition with the ulnar third. When performed distally to proximally with a slight inclination from the radial to the ulnar, this release compromises the lowest nerve element density. Topographically, the proximal limit of the release is the distal wrist crease, while the distal limit is the intersection of Kaplan cardinal line and the axis of the third webspace.

Pathomechanism of the IVDs Degeneration and the Role of Neurotrophic Factors and Concentration of Selected Elements in Genesis of Low Back Pain.

Degenerative disc disease of the lumbosacral spine is a very common medical problem. An episode of sciatica occurs at least once in the life of 60-90% of the human population. A phenomenon that is closely related to the process of lowering the pH of the extracellular matrix degenerating the intervertebral disc (IVD) is the precipitation of calcium salts, especially pyrophosphate dehydrate and hydroxyapatite. In such an altered environment of the IVD, we can observe an increased influx of monocytes, macrophages, T-lymphocytes, as well as non-immunocompetent cells, which are a source of cytokines, e.g., tumor necrosis alpha (TNF-α), interleukin- (IL-1ß, IL-8). The above-mentioned mediators of an inflammatory condition contribute to an increase in the expression of Brain-Derived Neurotrophic Factor (BDNF) and Glial cell Derived Neurotrophic Factor (GDNF) in mast cells and chondrocytes, as well as to the descending transport of these mediators along the nerve endings. In the process of degeneration of the IVD as a result of repeated and even slight injuries, there is damage to the connections of the endplate of the vertebral bodies with the IVD, which results in an impairment of the penetration of nutritional substances and water into the disc. As a consequence, there is an overexpression of the brain-derived neurotrophic factor GDNF, as well as neuromodulin (GAP-43) in the mast cells and chondrocytes of the IVDs, while descending transport of these mediators along the nerve fibers is also observed.

Analysis of Nerve Endings in the Superior Labrum-Biceps Complex by Fluorescence Immunohistochemistry and Confocal Laser Microscopy.

Objectives The capsuloligamentous structures of the shoulder work as static stabilizers, together with the biceps and rotator cuff muscles, increasing the contact surface of the glenoid cavity. Free nerve endings and mechanoreceptors have been identified in the shoulder; however, there are a few studies that describe the presence of these nerves in the biceps' insertion. The present study aimed to describe the morphology and distribution of nerve endings using immunofluorescence with protein gene product 9.5 (PGP 9.5) and confocal microscopy. Methods Six labrum-biceps complexes from six fresh-frozen cadavers were studied. The specimens were coronally cut and prepared using the immunofluorescence technique. In both hematoxylin and eosin (H&E) and immunofluorescence, the organization of the connective tissue with parallel collagen fibers was described. Results In the H&E study, vascular structures and some nerve structures were visualized, which were identified by the elongated presence of the nerve cell. All specimens analyzed with immunofluorescence and confocal microscopy demonstrated poor occurrence of morphotypes of sensory corpuscles and free nerve endings. We identified free nerve endings located in the labrum and in the bicipital insertion, and sparse nerve endings along the tendon. Corpuscular endings with fusiform, cuneiform, and oval aspect were identified in the tendon. Conclusion These findings support the hypothesis that the generation of pain in the superior labral tear from Anterior to posterior (SLAP) lesions derives from the more proximal part of the long biceps cord and even more from the upper labrum. Future quantitative studies with a larger number of specimens may provide more information on these sensory systems.

Analysis of Nerve Endings in the Superior Labrum-Biceps Complex by Fluorescence Immunohistochemistry and Confocal Laser Microscopy / Análise de terminações nervosas no complexo labrum-bíceps superior usando imunohistoquímica de fluorescência e microscopia a laser confocal

Abstract Objectives The capsuloligamentous structures of the shoulder work as static stabilizers, together with the biceps and rotator cuff muscles, increasing the contact surface of the glenoid cavity. Free nerve endings and mechanoreceptors have been identified in the shoulder; however, there are a few studies that describe the presence of these nerves in the biceps' insertion. The present study aimed to describe the morphology and distribution of nerve endings using immunofluorescence with protein gene product 9.5 (PGP 9.5) and confocal microscopy. Methods Six labrum-biceps complexes from six fresh-frozen cadavers were studied. The specimens were coronally cut and prepared using the immunofluorescence technique. In both hematoxylin and eosin (H&E) and immunofluorescence, the organization of the connective tissue with parallel collagen fibers was described. Results In the H&E study, vascular structures and some nerve structures were visualized, which were identified by the elongated presence of the nerve cell. All specimens analyzed with immunofluorescence and confocal microscopy demonstrated poor occurrence of morphotypes of sensory corpuscles and free nerve endings. We identified free nerve endings located in the labrum and in the bicipital insertion, and sparse nerve endings along the tendon. Corpuscular endings with fusiform, cuneiform, and oval aspect were identified in the tendon. Conclusion These findings support the hypothesis that the generation of pain in the superior labral tear from Anterior to posterior (SLAP) lesions derives from the more proximal part of the long biceps cord and even more from the upper labrum. Future quantitative studies with a larger number of specimens may provide more information on these sensory systems.

Resumo Objetivos As estruturas capsulo-ligamentares do ombro funcionam como estabilizadores estáticos, juntamente com os músculos do bíceps e do manguito rotador, aumentando a superfície de contato da cavidade glenoide. Terminações nervosas livres e mecanorreceptores foram identificados no ombro; no entanto, existem alguns estudos que descrevem a presença desses nervos na inserção do bíceps. Este estudo teve como objetivo descrever a morfologia e distribuição de terminações nervosas utilizando imunofluorescência com protein gene product 9.5 (PGP 9.5) e microscopia confocal. Métodos Foram estudados seis complexos labrum-bíceps de seis cadáveres congelados frescos. Os espécimes foram cortados coronalmente e preparados pelo método de imunofluorescência. Tanto em hematoxilina e eosina (H&E) quanto em imunofluorescência, foi descrita a organização do tecido conjuntivo com fibras paralelas de colágeno. Resultados No estudo de H&E, foram visualizadas estruturas vasculares e algumas estruturas nervosas, que foram identificadas pela presença alongada da célula nervosa. Todas as amostras analisadas com imunofluorescência e microscopia confocal demonstraram baixa ocorrência de morfotipos de corpúsculos sensoriais e terminações nervosas livres. Identificamos terminações nervosas livres localizadas no labrum, inserção bicipital e terminações nervosas esparsas ao longo do tendão. Terminais corpusculares com aspecto fusiforme, cuneiforme e oval foram identificados no tendão. Conclusão Esses achados corroboram a hipótese de que a geração de dor nas lesões labrais superiores de anterior a posterior (SLAP, na sigla em inglês) deriva da parte mais proximal do cabo longo do bíceps e ainda mais do labrum superior. Estudos quantitativos futuros com um número maior de espécimes podem fornecer mais informações sobre esses sistemas sensoriais.

Prospective randomized controlled trial comparing fulguration versus fulguration and hydrodistension for Hunner-type interstitial cystitis/bladder pain syndrome.

PURPOSE: In Hunner-type interstitial cystitis/bladder pain syndrome (IC/BPS), it is unclear whether suburothelial afferents underlying normal-appearing background areas contribute to symptom development. We examined whether adding hydrodistension (HD) to transurethral fulguration (TUF) of Hunner lesions, for the purpose of treating the background areas, is superior to TUF alone. METHODS: This randomized controlled trial included 52 patients with Hunner-type IC/BPS allocated at a 1:1 (TUF:TUF+HD) ratio. HD was performed at 80 cmH2O for 8 min before TUF in the TUF+HD group. Thirty-three patients remained until the end of the 6-month observational period. The primary endpoint was the visual analogue scale (VAS) pain score at 1 month. Major secondary endpoints were the treatment-failure rate, VAS pain scores at ≥ 2 months, and frequency-volume chart parameters. RESULTS: Both TUF and TUF+HD showed significant improvement in VAS pain score at 1 month (95% confidence interval [CI]: - 1.62 to 0.16, P = 0.106). VAS pain scores were significantly lower in TUF+HD than TUF at 2 (95% CI: - 1.97 to - 0.28, P = 0.011), 4 (95% CI: - 2.83 to - 0.72, P = 0.002), and 6 (95% CI: - 3.11 to - 0.07, P = 0.040) months. Treatment-failure rate was higher in TUF (36.4%) than TUF+HD (17.4%), without significance (odds ratio: 2.714, 95% CI: 0.68 to 10.84, P = 0.189). Functional capacity and urgency were not significantly different between groups. CONCLUSION: The addition of HD to TUF tended to be superior to TUF monotherapy for controlling pain in Hunner-type IC/BPS. This indicates that not only Hunner lesions but also normal-appearing background areas may have a role in the pain of IC/BPS. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03987594, date of registration: 2019-06-17 (retrospectively registered).

Microscopy of structures surrounding typical acupoints used in clinical practice and electron microscopic evaluation of acupuncture needles.

Although the general functionality and structures of acupoints have been studied, there has been little insight into their underlying morphology and physical characteristics. We describe the microanatomical structures surrounding acupoints, the electron microscopic appearance of the needles, and the physical effects of acupuncture needling on the fascia. We injected heparinized blood solution through thin needles at seven known and commonly used "sweat acupoints" in eight fresh, unembalmed, cryopreserved human cadavers to mark the needle positions, and later, during histological examination, to identify them. After the solution was injected, samples were dissected and prepared for histological examination. We examined 350 cross-sections of five different paraffin wax sections from each acupoint microscopically. Acupuncture needles were photographed and superimposed on the cross-sectioned tissues at similar magnifications. Needles were also examined under a scanning electron microscope to judge the roughness or smoothness of their surfaces. A greater conglomeration of nerve endings surrounded the acupoints than in tissues more than 1-3 cm distant from them. Nerve endings and blood vessels were in close contact with a complex network of membranes formed by interlacing collagen fibers, and were always enclosed within those collagen membranes. Nerve endings were found within hypodermis, muscles, or both. Scanning electron microscopy demonstrated the three-dimensional shapes and sizes of the needles, and the degree of roughness or smoothness of their polished external surfaces. We demonstrate a delicate arrangement of nerve endings and blood vessels enclosed within complex collagen membrane networks at acupoints within the hypodermis and muscle. This arrangement could explain why needling is an essential step in the acupuncture process that provides favorable outcomes in clinical practice.

The morphology of the subacromial and related shoulder bursae. An anatomical and histological study.

Shoulder bursae are essential for normal movement and are also implicated in the pathogenesis of shoulder pain and dysfunction. The subacromial bursa (SAB), within the subacromial space, is considered a primary source of shoulder pain. Several other bursae related to the subcoracoid space, including the coracobrachial (CBB), subcoracoid (SCB) and subtendinous bursa of subscapularis (SSB), are also clinically relevant. The detailed morphology and histological characteristics of these bursae are not well described. Sixteen embalmed cadaveric shoulders from eight individuals (five females, three males; mean age 78.6 ± 7.9 years) were investigated using macro-dissection and histological techniques to describe the locations, dimensions and attachments of the bursae, their relationship to surrounding structures and neurovascular supply. Bursal sections were stained with haematoxylin and eosin to examine the synovium and with antibodies against von Willebrand factor and neurofilament to identify blood vessels and neural structures respectively. Four separate bursae were related to the subacromial and subcoracoid spaces. The SAB was large, with a confluent subdeltoid portion in all except one specimen, which displayed a distinct subdeltoid bursa. The SAB roof attached to the lateral edge and deep surface of the acromion and coracoacromial ligament, and the subdeltoid fascia; its floor fused with the supraspinatus tendon and greater tubercle. The CBB (15/16 specimens) was deep to the conjoint tendon of coracobrachialis and short head of biceps brachii and the tip of the coracoid process, while the inconstant SCB (5/16 specimens) was deep to the coracoid process. Located deep to the subscapularis tendon, the SSB was a constant entity that commonly displayed a superior extension. Synovial tissue was predominantly areolar (SAB and SSB) or fibrous (CBB and SCB), with a higher proportion of areolar synovium in the bursal roofs compared to their floors. Blood vessels were consistently present in the subintima with a median density of 3% of the tissue surface area, being greatest in the SSB and SAB roofs (4.9% and 3.4% respectively) and least in the SAB floor (1.8%) and CBB roof and floor (both 1.6%). Nerve bundles and free nerve endings were identified in the subintima in approximately one-third of the samples, while encapsulated nerve endings were present in deeper tissue layers. The extensive expanse and attachments of the SAB support adoption of the term subacromial-subdeltoid bursa. Morphologically, the strong attachments of the bursal roofs and floors along with their free edges manifest as fixed and mobile portions, which enable movement in relation to surrounding structures. The presence of neurovascular structures demonstrates that these bursae potentially contribute blood supply to surrounding structures and are involved in mechanoreception. The anatomical details presented in this study clarify the morphology of the shoulder bursae, including histological findings that offer further insight into their potential function.

Constitutive Phosphorylation as a Key Regulator of TRPM8 Channel Function.

In mammals, environmental cold sensing conducted by peripheral cold thermoreceptor neurons mostly depends on TRPM8, an ion channel that has evolved to become the main molecular cold transducer. This TRP channel is activated by cold, cooling compounds, such as menthol, voltage, and rises in osmolality. TRPM8 function is regulated by kinase activity that phosphorylates the channel under resting conditions. However, which specific residues, how this post-translational modification modulates TRPM8 activity, and its influence on cold sensing are still poorly understood. By mass spectrometry, we identified four serine residues within the N-terminus (S26, S29, S541, and S542) constitutively phosphorylated in the mouse ortholog. TRPM8 function was examined by Ca2+ imaging and patch-clamp recordings, revealing that treatment with staurosporine, a kinase inhibitor, augmented its cold- and menthol-evoked responses. S29A mutation is sufficient to increase TRPM8 activity, suggesting that phosphorylation of this residue is a central molecular determinant of this negative regulation. Biophysical and total internal reflection fluorescence-based analysis revealed a dual mechanism in the potentiated responses of unphosphorylated TRPM8: a shift in the voltage activation curve toward more negative potentials and an increase in the number of active channels at the plasma membrane. Importantly, basal kinase activity negatively modulates TRPM8 function at cold thermoreceptors from male and female mice, an observation accounted for by mathematical modeling. Overall, our findings suggest that cold temperature detection could be rapidly and reversibly fine-tuned by controlling the TRPM8 basal phosphorylation state, a mechanism that acts as a dynamic molecular brake of this thermo-TRP channel function in primary sensory neurons.SIGNIFICANCE STATEMENT Post-translational modifications are one of the main molecular mechanisms involved in adjusting the sensitivity of sensory ion channels to changing environmental conditions. Here we show, for the first time, that constitutive phosphorylation of the well-conserved serine 29 within the N-terminal domain negatively modulates TRPM8 channel activity, reducing its activation by agonists and decreasing the number of active channels at the plasma membrane. Basal phosphorylation of TRPM8 acts as a key regulator of its function as the main cold-transduction channel, significantly contributing to the net response of primary sensory neurons to temperature reductions. This reversible and dynamic modulatory mechanism opens new opportunities to regulate TRPM8 function in pathologic conditions where this thermo-TRP channel plays a critical role.