Search Results (107)

Background/Objectives: The male prepuce that covers the glans penis is richly innervated by low-threshold mechanoreceptors, which form cutaneous end-organ complexes (Meissner, Pacinian and Ruffini corpuscles) and mucous end-organ complexes (especially Krause-like corpuscles). The mechanosensory inputs from these formations are the beginning for spinal reflexes that regulate movements of intercourse and erection and, therefore, are required for sexual function. The study was aimed at analyzing the age-dependent changes in prepuce innervation. Methods: Here we used immunohistochemistry to investigate whether the innervation of the male prepuce undergoes age-dependent changes, analyzing subjects aged 4 months to 61 years. Results: Abundant Meissner corpuscles and Krause-like corpuscles were regularly found whose morphology, size, and topography were variable and were not correlated with age; however, Ruffini’s and Pacinian corpuscles were scarcely observed. The earliest evidence of Meissner corpuscles was observed at 4 months, and thereafter they undergo significant age-dependent variations in density. Until the age of 20 years increases progressively, remains stable until 40 years, and then the density decreases. Meissner’s corpuscle index paralleled that of density. Regarding Kause-like corpuscles already resemble the skin of 4-month-old subjects and from the age of 3 years they can be identified at all ages. Its density significantly increased until 10 years and then remained stable. Conclusions: Present results state that the mechanosensory innervation of the human foreskin reaches its maximum value around the age of 20, remains stable during adulthood and decreases with maturity. These findings contribute to a more complete understanding of foreskin innervation and add to the scientific knowledge base surrounding the potential harm of removing a richly innervated structure. Full article

Recently, complementary and alternative medicine have been actively employed for patients experiencing symptoms unresponsive to Western medical treatments like drug therapy. Natural compounds, including polyphenols, carotenoids, and omega fatty acids, have demonstrated various beneficial biological actions for human health in several studies. Given their broad pharmacological activities and reduced toxicity, these compounds possess significant potential as resources for the development of natural analgesic drugs. Given recent studies showing that natural compounds can modulate neuronal excitability (including nociceptive sensory transmission through mechanoreceptors and voltage-gated ion channels) and inhibit the cyclooxygenase-2 cascade, these compounds hold promise as complementary and alternative medicine candidates, particularly as therapeutic agents for nociceptive and pathological pain. This review focuses on elucidating the mechanisms by which natural compounds modulate neuronal electrical signals—including generator potentials, action potentials, and postsynaptic potentials—in nociceptive pathway neurons, potentially leading to local and intravenous anesthetic effects, as well as inflammatory pain relief. Specifically, we discuss the contribution of natural compounds to the relief of nociceptive and/or pathological pain and their potential clinical application, drawing on our recent published in vivo studies. Full article

Among European colubroids, scale sensilla—mechanoreceptors present in the head integument—are more expressed in natricids. The presence of protruded sensilla, observable with the naked eye, is found in the cephalic shields of all species belonging to the genus Natrix. The identification of these sense organs in this genus determines its correlation in aquatic and semi-aquatic species, in which these traits are more developed and recognizable than in terrestrial species. As hypothesized for elapoids, this differentiation could be due to the fact that in natricids, like sea snakes, these can perform a hydrodynamic function in addition to the mechanosensory one. In support of this thesis, within the genus Natrix, the most aquatic species of the five, Natrix tessellata, features the most expressed sensilla. This specificity represents a further analogy in the evolutionary convergences involving the cephalic region that this species shares with marine elapids. Still in the genus Natrix, a second trait involving the shields has been identified, expressing itself in the opposite condition to the protruded sensilla, occurring as a pitting arranged mainly within the shields along the upper portion of the labial arches. In vivo examinations and microscopy were performed on different species of the Natrix genus, and comparative analyses have been carried out on other natricid taxa from the New and Old World, where the presence of protruded scale sensilla has been found in several species. Full article

Vibration sensors are important in many engineering fields, including industry, surgery, space, and mechanics, such as for remote and autonomous driving. We propose a novel, cutting-edge vibratory sensor that mimics human tactile receptors, with a configuration different from current sensors such as strain gauges and piezo materials. The basic principle involves the perception of vibration via touch, with a cutaneous mechanoreceptor that is sensitive to vibration. We investigated the characteristics of the proposed vibratory sensor, in which the mechanoreceptor was covered either in hard rubber (such as silicon oil) or soft rubber (such as urethane), for both low- and high-frequency ranges. The fabricated sensor is based on piezoelectricity with a built-in voltage. It senses applied vibration by means of hairs in the sensor and the hardness of the outer cover. We also investigated two proposed parameters: the sensor response time to stimuli to the vibration aiding the equivalent firing rate (e.f.r.) and the gauge factor (GF_,pe) proposed as treated in piezo-resistivity. The evaluation with the parameters was effective in designing a sensor based on piezoelectricity. These parameters were enhanced by the hairs in the sensor and the hardness of the outer cover. Our results were helpful for designing the present novel vibratory sensor. Full article

Trigeminal somatosensory-evoked potentials (TSEPs) provide valuable insight into neural responses to oral stimuli. This study investigates TSEP recording methods and their impact on interpreting results in clinical settings to improve the development process of neurostimulation-based therapies. The experiments and results presented here aim at identifying appropriate stimulation characteristics to design an active dental prosthesis capable of contributing to restoring the lost neurosensitive connection between the teeth and the brain. Two methods of TSEP acquisition, traditional and occluded, were used, each conducted by a different volunteer. Traditional TSEP acquisition involves stimulation at different sites with varying parameters to achieve a control base. In contrast, occluded TSEPs examine responses acquired under low- and high-force bite conditions to assess the influence of periodontal mechanoreceptors and muscle activation on measurements. Traditional TSEPs demonstrated methodological feasibility with satisfactory results despite a limited subject pool. However, occluded TSEPs presented challenges in interpreting results, with responses deviating from expected norms, particularly under high force conditions, due to the simultaneous occurrence of stimulation and dental occlusion. While traditional TSEPs highlight methodological feasibility, the occluded approach highlights complexities in outcome interpretation and urges caution in clinical application. Previously unreported results were achieved, which underscores the importance of conducting further research with larger sample sizes and refined protocols in order to strengthen the reliability and validity of TSEP assessments. Full article

Cardiovascular diseases such as hypertension alter thoracic aorta structure. The role that the outer layer of the aorta, its perivascular adipose tissue (PVAT), plays in the pathogenesis of these alterations is poorly understood. In the descending thoracic aorta, PVAT is organized into three distinct strips: one located anterior to the aorta (AP) and two positioned laterally (LP). Genetic tracing indicates differences in the ontogeny of LP and AP, but the implications of these developmental differences and PVAT distribution on adipocyte development remain unknown. We hypothesize that the anatomical location of adipocyte progenitors influences their adipogenic potential and vasoactive functions. PVAT from LP and AP was collected from male SD rats at 10 wks of age (n = 7) to harvest adipocyte progenitors that were differentiated to adipocytes in adipogenic media. Adipogenesis was evaluated after induction and we performed next-generation RNA-seq on progenitors and adipocytes. We then employed Gene Set Enrichment Analysis for enrichment and network analyses. LP progenitors exhibited a 1.13-fold higher adipogenesis rate compared to those from AP. DEG analysis revealed LP had higher expression of adipogenic regulators and basal collagens Col4a2 and Col4a4. When challenged with angiotensin-II, adipocyte progenitors from LP maintained their adipogenic capacity and adipocytes from the same site maintained their secretion of adiponectin at higher rates than AP cells. However, treatment with a Piezo1 mechanoreceptor agonist reduced LP’s adipogenic capacity and diminished their adiponectin secretion. These findings highlight site-specific differences in adipogenic activity, extracellular matrix composition, and the secretion of the vasoactive adipokine adiponectin between the LP and AP PVAT strips of the thoracic aorta, suggesting potential functional distinctions in vascular health and disease. Full article

Arthrogenic muscle inhibition (AMI) is a neuromuscular impairment commonly observed following anterior cruciate ligament reconstruction (ACLR). This condition, characterized by persistent quadricep inhibition due to altered afferent feedback, significantly impacts neuromuscular recovery, delaying return to running and sport. Despite advancements in rehabilitation strategies, AMI may persist for months or even years after ACLR, leading to muscle strength asymmetries, altered biomechanics, and an increased risk of reinjury. The mechanisms underlying AMI involve both peripheral (joint effusion, mechanoreceptor dysfunction) and central (corticospinal inhibition, neuroplasticity alterations) components, which collectively hinder voluntary muscle activation and movement control. AMI alters gait mechanics, reduces knee stability, and promotes compensatory patterns that increase injury risk. Current return-to-sport protocols emphasize strength symmetry and functional performance but often neglect neuromuscular deficits. A comprehensive assessment integrating neuromuscular, biomechanical, and proprioceptive evaluations is needed at specific stages to optimize rehabilitation and minimize reinjury risk. Future research should explore targeted interventions such as neuromuscular stimulation, cognitive–motor training, and advanced gait analysis to mitigate AMI’s impact and facilitate a safer, more effective return to sport. Full article

Background/Objectives: Tentonin-3/TMEM150C is a pore-forming protein of a mechanically activated channel recently identified that typically displays rapid activation followed by slow inactivation. It has been detected in murine dorsal root ganglia, nodose ganglion baroreceptors, and muscle spindles. Nevertheless, primary sensory neurons expressing tentonin-3/TMEM150C fall into the categories of nociceptors, mechanoreceptors, and proprioceptors. Methods: We used immunohistochemistry and image analysis (examining the size of the neuronal bodies in the dorsal root ganglia) to investigate the distribution of tentonin-3/TMEM150C in human cervical dorsal root ganglia, sensory nerve formations in the glabrous skin, especially cutaneous end-organ complexes or sensory corpuscles, and muscle spindles. Results: In dorsal root ganglia, 41% of neurons were tentonin-3/TMEM150C-positive, with a distribution of small (12.0%), intermediate (18.1%), and large (10.9%). In the glabrous skin, tentonin-3/TMEM150C was observed in the axon of Meissner, Pacinian, and Ruffini corpuscles as well as in the axon of the Merkel cell–axon complexes. Furthermore, tentonin-3/TMEM150C-positive axons were observed in muscle spindles. No free nerve endings displaying immunoreactivity were found. Conclusions: This is the first report on the distribution of tentonin-3/TMEM150C immunoreactivity in the human peripheral somatosensory system, and although it is a brief preliminary study, it opens new perspectives for the study of this new mechano-gated ion channel. Full article

The carotid sinus and the carotid body are major peripheral chemo- and baro(mechano)receptors that sense changes in arterial wall pressure and in oxygen, carbon dioxide, and pH in arterial blood. Recently, it was demonstrated that the PIEZO1 and PIEZO2 mechanoreceptor/mechanotransducers are responsible for the baroreflex in the murine aortic arch (aortic sinus). Furthermore, some experimental evidence suggests that the carotid body could participate in mechanosensing. In this study, we used immunohistochemistry and immunofluorescence in conjunction with laser confocal microscopy to study the distribution of PIEZO1 and PIEZO2 in the human carotid sinus and carotid body as well as in the petrosal ganglion of the glossopharyngeal nerve and the superior cervical sympathetic ganglion. PIEZO1 and PIEZO2 were detected in different morphotypes of sensory nerve formations in the walls of the carotid sinus and carotid artery walls. In the carotid body, PIEZO1 was present in a small population of type I glomus cells and absent in nerves, whereas PIEZO2 was present in both clusters of type I glomus cells and nerves. The most prominent expression of PIEZO1 and PIEZO2 in the carotid body was found in type II glomus cells. On the other hand, in the petrosal ganglion, around 25% of neurons were PIEZO1-positive, and around 85% were PIEZO2-positive; regarding the superior cervical sympathetic ganglion, around 71% and 86% displayed PIEZO1 and PIEZO2, respectively. The results of this study suggest that PIEZO1 and PIEZO2 could be involved in the detection and/or mechanotransduction of the human carotid sinus, whereas the role of the carotid body is more doubtful since PIEZO1 and PIEZO2 were only detected in some nerves and PIEZO2 was present in a small population of type I glomus cells, with PIEZO1 being absent in these cells. However, since immunoreactivity for PIEZO2 was detected in type II glomus cells, researchers should investigate whether these cells play a role in the detection of mechanical stimuli and/or participate in mechanotransduction. Full article

Human hands have the unique ability to classify material properties, such as hardness, using mechanoreceptors and tactile information. Previous studies have demonstrated hardness classification using Commercial Off-The-Shelf (COTS) sensors but lacked robotic integration considerations. This study explores the integration of multiple COTS sensors, inspired by mechanoreceptors, for classifying material hardness. The sensors were used to classify objects into three categories—hard, soft, and flexible—based on the qualitative Shore hardness scale. The aim was to identify the optimal sensor topology configuration that delivers high accuracy, using machine learning algorithms provided in the literature. The results suggest that the Random Forest Classifier is the most suitable algorithm, showcasing accuracies ranging from 90% to 98.7%, across various sensor topologies. The ‘PFV’ topology, comprising a potentiometer (P), force sensor (F), and vibration sensor (V), achieved the highest accuracy of 98.7%, while the ‘FPV’ and ‘FVP’ recorded accuracies between 96% and 97.5%. The topology of FPV and FVP have the most closely related configuration to that of mechanoreceptors; however, the results show that PFV outperforms this configuration. While the PFV topology marginally outperforms the mechanoreceptor-inspired configurations, the results demonstrate that bio-inspired sensor arrangements provide a robust solution for hardness classification in robotics. The PFV topology performs better than FPV in terms of prediction speed, with an average prediction time of 8.31 ms (millisecond) for PFV versus 13.93 ms for FPV. PFV and FPV achieved 12 and 13 correct predictions, respectively, out of 18 objects. The faster prediction times of PFV make it particularly advantageous for applications requiring quick and accurate decision-making for robotic applications. Full article

Pulmonary hypertension associated with lung diseases and/or hypoxia is classified as group 3 in the clinical classification of pulmonary hypertension. The efficacy of existing selective pulmonary vasodilators for group 3 pulmonary hypertension is still unknown, and it is currently associated with a poor prognosis. The mechanisms by which pulmonary hypertension occurs include hypoxic pulmonary vasoconstriction, pulmonary vascular remodeling, a decrease in pulmonary vascular beds, endothelial dysfunction, endothelial-to-mesenchymal transition, mitochondrial dysfunction, oxidative stress, hypoxia-inducible factors (HIFs), inflammation, microRNA, and genetic predisposition. Among these, hypoxic pulmonary vasoconstriction and subsequent pulmonary vascular remodeling are characteristic factors involving the pulmonary vasculature and are the focus of this review. Several factors have been reported to mediate vascular remodeling induced by hypoxic pulmonary vasoconstriction, such as HIF-1α and mechanosensors, including TRP channels. New therapies that target novel molecules, such as mechanoreceptors, to inhibit vascular remodeling are awaited. Full article

Chemosensation and mechanosensation are vital to insects’ survival and behavior, shaping critical physiological processes such as feeding, metabolism, mating, and reproduction. During feeding, insects rely on diverse chemosensory and mechanosensory receptors to distinguish between nutritious and harmful substances, enabling them to select suitable food sources while avoiding toxins. These receptors are distributed across various body parts, allowing insects to detect environmental cues about food quality and adjust their behaviors accordingly. A deeper understanding of insect sensory physiology, especially during feeding, not only enhances our knowledge of insect biology but also offers significant opportunities for practical applications. This review highlights recent advancements in research on feeding-related sensory receptors, covering a wide range of insect species, from the model organism Drosophila melanogaster to agricultural and human pests. Additionally, this review examines the potential of targeting insect sensory receptors for precision pest control. Disrupting behaviors such as feeding and reproduction emerges as a promising strategy for pest management. By interfering with these essential behaviors, we can effectively control pest populations while minimizing environmental impacts and promoting ecological balance. Full article

Vertebrates’ tongues reflect part of their adaptations to diverse feeding strategies, the types of food items they eat, and the environments where they live. Our contribution was to analyze the macro- and microscopic morphology of the tongues of two porpoise species (Phocoena dioptrica and Phocoena spinipinnis; juveniles and adults), whose biology is little known. Macroscopic and microscopic studies (conventional histology, scanning electron microscopy, immunohistochemistry, and morphometry) were performed. Differences between juvenile and adult individuals of the same species, as well as between juveniles and adults of both species, were found, probably related to their feeding and/or geographical distribution. In addition, novel aspects related to ontogenetic morphological differences, thermoregulation, and immune system components were described. We found a lingual countercurrent vascular system (periarterial venous retia), only mentioned for mysticetes and Physeter macrocephalus (never for smaller odontocetes). In addition, we identified mechanoreceptors (lamellar corpuscles). Both species showed marginal papillae, but only in P. spinipinnis were small (probably vestigial) taste buds observed. Finally, lingual lymphoid aggregates were found. Full article

Hydrogen sulfide (H₂S) donors are emerging as promising candidates for neuroprotective agents. However, H₂S-dependent neuroprotective mechanisms are not yet fully understood. We have demonstrated that an H₂S donor (sodium sulfide, Na₂S) reduces the expression of inducible NO synthase (iNOS) and amyloid-beta precursor protein (APP) in damaged neural tissue at 24 h and 7 days following traumatic brain injury (TBI). The application of aminooxyacetic acid (AOAA), an inhibitor of cystathionine β-synthase (CBS), produced the opposite effect. Seven days after TBI, iNOS expression was observed not only in the cytoplasm but also in some neuronal nuclei, while APP was exclusively localized in the cytoplasm and axons of damaged neurons. It was also shown that iNOS and APP were present in the cytoplasm of mechanoreceptor neurons (MRNs) in the crayfish, in axons, as well as in certain glial cells 8 h after axotomy. Na₂S and AOAA had opposing effects on axotomized MRNs and ganglia in the ventral nerve cord (VNC). Multiple sequence alignments revealed a high degree of identity among iNOS and APP amino acid residues in various vertebrate and invertebrate species. In the final stage of this study, biomodeling identified unique binding sites for H₂S, hydrosulfide anion (HS⁻), and thiosulfate (S₂O₃²⁻) with iNOS and APP. Full article

As one of the most promising electronic devices in the post-Moore era, nanoscale vacuum field emission transistors (VFETs) have garnered significant attention due to their unique electron transport mechanism featuring ballistic transport within vacuum channels. Existing research on these nanoscale vacuum channel devices has primarily focused on structural design for logic circuits. Studies exploring their application potential in other vital fields, such as sensors based on VFET, are more limited. In this study, for the first time, the design of a vacuum field emission transistor (VFET) coupled with a piezoelectric microelectromechanical (MEMS) sensing unit is proposed as the artificial mechanoreceptor for sensing purposes. With a negative threshold voltage similar to an N-channel depletion-mode metal oxide silicon field effect transistor, the proposed VFET has its continuous current tuned by the piezoelectric potential generated by the sensing unit, amplifying the magnitude of signals resulting from electromechanical coupling. Simulations have been conducted to validate the feasibility of such a configuration. As indictable from the simulation results, the proposed piezoelectric VFET exhibits high sensitivity and an electrically adjustable measurement range. Compared to the traditional combination of piezoelectric MEMS sensors and solid-state field effect transistors (FETs), the piezoelectric VFET design has a significantly reduced power consumption thanks to its continuous current that is orders of magnitude smaller. These findings reveal the immense potential of piezoelectric VFET in sensing applications, building up the basis for using VFETs for simple, effective, and low-power pre-amplification of piezoelectric MEMS sensors and broadening the application scope of VFET in general. Full article