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Neuron Oct 2023Touch and proprioception rely on the discriminative abilities of distinct classes of mechanosensory neurons. In this issue of Neuron, two studies provide evidence that...
Touch and proprioception rely on the discriminative abilities of distinct classes of mechanosensory neurons. In this issue of Neuron, two studies provide evidence that biomechanical mechanisms and ultrastructural cellular specializations are key contributors in defining mechanoreceptor stimulus threshold and selectivity.
Topics: Mechanoreceptors; Neurons; Touch; Proprioception; Touch Perception
PubMed: 37857088
DOI: 10.1016/j.neuron.2023.09.033 -
Neuropharmacology Jul 2015It is well established that some members of the Deg/ENaC super family of amiloride sensitive ion channels can participate directly in the transduction of mechanical... (Review)
Review
It is well established that some members of the Deg/ENaC super family of amiloride sensitive ion channels can participate directly in the transduction of mechanical stimuli by sensory neurons in invertebrates. A large body of work has also implicated the acid sensing ion channels family (ASIC1-4) as participants in regulating mechanoreceptor sensitivity in vertebrates. In this review we provide an overview of the physiological and genetic evidence for involvement of ASICs in mechanosensory function. On balance, the available evidence favors the idea that these channels have an important regulatory role in mechanosensory function. It is striking how diverse the consequences of Asic gene deletion are on mechanosensory function with both gain and loss of function effects being observed depending on sensory neuron type. We conclude that other, as yet unknown, molecular partners of ASIC proteins may be decisive in determining their precise physiological role in mechanosensory neurons. This article is part of the Special Issue entitled 'Acid-Sensing Ion Channels in the Nervous System'.
Topics: Acid Sensing Ion Channels; Animals; Humans; Mechanoreceptors
PubMed: 25528740
DOI: 10.1016/j.neuropharm.2014.12.007 -
Spine Jan 1998Histologic analysis of normal human facet capsules to determine the density and distribution of encapsulated nerve endings in the thoracic and lumbar spine. (Review)
Review
STUDY DESIGN
Histologic analysis of normal human facet capsules to determine the density and distribution of encapsulated nerve endings in the thoracic and lumbar spine.
OBJECTIVES
To quantify the extent of mechanoreceptor innervation in normal facet tissues and determine the relative distribution of three specific receptor types with respect to thoracic and lumbar segments.
SUMMARY OF BACKGROUND DATA
Ongoing studies of spinal innervation have shown that human facet tissues contain mechanoreceptive endings capable of detecting motion and tissue distortion. The hypothesis has been advanced that spinal proprioception may play a role in modulating protective muscular reflexes that prevent injury or facilitate healing.
METHODS
Whole facet capsules harvested from seven healthy adult patients were processed using a gold chloride staining method and cut into 35-micron sections for histologic analysis. No sampling was performed; all sections were analyzed. Receptor endings were classified by the method of Freeman and Wyke if they met the following three criteria: 1) encapsulation, 2) identifiable morphometry, and 3) consistent morphometry on serial sections.
RESULTS
One Type 1 and four Type 2 endings were identified among 10 thoracic facet capsules. Five Type 1, six Type 2, and one Type 3 ending were identified among 13 lumbar facet capsules. Occasional atypical receptive endings were noted that did not fit the established classification. Unencapsulated free nerve endings were seen in every specimen, but were not quantified.
CONCLUSIONS
Encapsulated nerve endings are believed to be primarily mechanosensitive and may provide proprioceptive and protective information to the central nervous system regarding joint function and position. A consistent, but small population of receptors has been found previously in cervical facets, but innervation of the thoracic and lumbar levels is less consistent. This suggests that proprioceptive function in the thoracic and lumbar spine is less refined and, perhaps, less critical than in the cervical spine.
Topics: Adolescent; Adult; Humans; Joint Capsule; Lumbosacral Region; Male; Mechanoreceptors; Middle Aged; Nerve Endings; Spine; Thorax
PubMed: 9474721
DOI: 10.1097/00007632-199801150-00004 -
Scientific Reports Mar 2022Most biological sensors preferentially encode changes in a stimulus rather than the steady components. However, intrinsically phasic artificial mechanoreceptors have not...
Most biological sensors preferentially encode changes in a stimulus rather than the steady components. However, intrinsically phasic artificial mechanoreceptors have not yet been described. We constructed a phasic mechanoreceptor by encapsulating carbon nanotube film in a viscoelastic matrix supported by a rigid substrate. When stimulated by a spherical indenter the sensor response resembled the response of fast-adapting mammalian mechanoreceptors. We modelled these sensors from the properties of percolating conductive networks combined with nonlinear contact mechanics and discussed the implications of this finding.
Topics: Animals; Electric Conductivity; Mammals; Mechanoreceptors; Nanotubes, Carbon
PubMed: 35264589
DOI: 10.1038/s41598-021-04483-2 -
Cell Aug 2023The properties of dorsal root ganglia (DRG) neurons that innervate the distal colon are poorly defined, hindering our understanding of their roles in normal physiology...
The properties of dorsal root ganglia (DRG) neurons that innervate the distal colon are poorly defined, hindering our understanding of their roles in normal physiology and gastrointestinal (GI) disease. Here, we report genetically defined subsets of colon-innervating DRG neurons with diverse morphologic and physiologic properties. Four colon-innervating DRG neuron populations are mechanosensitive and exhibit distinct force thresholds to colon distension. The highest threshold population, selectively labeled using Bmpr1b genetic tools, is necessary and sufficient for behavioral responses to high colon distension, which is partly mediated by the mechanosensory ion channel Piezo2. This Aδ-HTMR population mediates behavioral over-reactivity to colon distension caused by inflammation in a model of inflammatory bowel disease. Thus, like cutaneous DRG mechanoreceptor populations, colon-innervating mechanoreceptors exhibit distinct anatomical and physiological properties and tile force threshold space, and genetically defined colon-innervating HTMRs mediate pathophysiological responses to colon distension, revealing a target population for therapeutic intervention.
Topics: Ganglia, Spinal; Mechanoreceptors; Colon; Neurons; Skin
PubMed: 37541195
DOI: 10.1016/j.cell.2023.07.007 -
ACS Nano Oct 2021Mechanoreceptors endow humans with the sense of touch by translating the external stimuli into coded spikes, inspiring the rise of artificial mechanoreceptor systems....
Mechanoreceptors endow humans with the sense of touch by translating the external stimuli into coded spikes, inspiring the rise of artificial mechanoreceptor systems. However, to incorporate slow adaptive receptors-like pressure sensors with artificial neurons remains a challenge. Here we demonstrate an artificial mechanoreceptor by rationally integrating a polypyrrole-based resistive pressure sensor with a volatile NbO memristor, to mimic the tactile sensation and perception in natural skin, respectively. The artificial mechanoreceptor enables the tactile sensory coding by converting the external mechanical stimuli into strength-modulated electrical spikes. Also, tactile sensation enhancement is achieved by processing the spike frequency characteristics with the pulse coupled neural network. Furthermore, the artificial mechanoreceptor can integrate signals from parallel sensor channels and encode them into unified electrical spikes, resembling the coding of intensity in tactile neural processing. These results provide simple and efficient strategies for constructing future bio-inspired electronic systems.
Topics: Humans; Mechanoreceptors; Polymers; Pyrroles; Skin; Touch
PubMed: 34597014
DOI: 10.1021/acsnano.1c05836 -
Progress in Brain Research 1988
Review
Topics: Animals; Biomechanical Phenomena; Mechanoreceptors; Physical Stimulation; Skin Physiological Phenomena; Species Specificity; Time Factors
PubMed: 3055048
DOI: 10.1016/s0079-6123(08)63023-x -
Advanced Science (Weinheim,... Mar 2022A self-powered artificial mechanoreceptor module is demonstrated with a triboelectric nanogenerator (TENG) as a pressure sensor with sustainable energy harvesting and a...
A self-powered artificial mechanoreceptor module is demonstrated with a triboelectric nanogenerator (TENG) as a pressure sensor with sustainable energy harvesting and a biristor as a neuron. By mimicking a biological mechanoreceptor, it simultaneously detects the pressure and encodes spike signals to act as an input neuron of a spiking neural network (SNN). A self-powered neuromorphic tactile system composed of artificial mechanoreceptor modules with an energy harvester can greatly reduce the power consumption compared to the conventional tactile system based on von Neumann computing, as the artificial mechanoreceptor module itself does not demand an external energy source and information is transmitted with spikes in a SNN. In addition, the system can detect low pressures near 3 kPa due to the high output range of the TENG. It therefore can be advantageously applied to robotics, prosthetics, and medical and healthcare devices, which demand low energy consumption and low-pressure detection levels. For practical applications of the neuromorphic tactile system, classification of handwritten digits is demonstrated with a software-based simulation. Furthermore, a fully hardware-based breath-monitoring system is implemented using artificial mechanoreceptor modules capable of detecting wind pressure of exhalation in the case of pulmonary respiration and bending pressure in the case of abdominal breathing.
Topics: Mechanoreceptors; Monitoring, Physiologic; Neural Networks, Computer; Robotics; Touch
PubMed: 35032113
DOI: 10.1002/advs.202105076 -
Journal of Applied Physiology... Aug 2007Airway sensors play an important role in control of breathing. Recently, it was found that pulmonary slowly adapting stretch receptors (SARs) cease after a brief...
Airway sensors play an important role in control of breathing. Recently, it was found that pulmonary slowly adapting stretch receptors (SARs) cease after a brief excitation following sodium pump blockade by ouabain. This deactivation can be explained by overexcitation. If this is true, mechanical stimulation of the SARs should also lead to a deactivation. In this study, we recorded unit activity of the SARs in anesthetized, open-chest, and mechanically ventilated rabbits and examined their responses to lung inflation at different constant pressures. Forty-seven of 137 units had a clear deactivation during the lung inflation. The deactivation threshold varied from unit to unit. For a given unit, the higher the inflation pressure, the sooner the deactivation occurs. For example, the SARs deactivated at 3.0 +/- 0.3 and 4.8 +/- 0.4 s when the lungs were inflated to constant pressures of 30 and 20 cmH(2)O, respectively (n = 25, P < 0.0001). The units usually ceased after a brief intense discharge. In some units, their activity shifted to a lower level, indicating a pacemaker switching. Our results support the notion that SARs deactivate due to overexcitation.
Topics: Action Potentials; Animals; Lung; Mechanoreceptors; Mechanotransduction, Cellular; Muscle, Smooth; Pulmonary Stretch Receptors; Rabbits
PubMed: 17525293
DOI: 10.1152/japplphysiol.01286.2006 -
Neirofiziologiia = Neurophysiology 1992The paper is concerned with the study of localization, firing properties, methods of activation and projection into the neuronal structures of the medulla oblongata as... (Review)
Review
The paper is concerned with the study of localization, firing properties, methods of activation and projection into the neuronal structures of the medulla oblongata as well as the reflex action of two types of mechanoreceptors of the lungs: slow- and rapid-adapting stretch receptors. Data on the first relay neurons monosynaptically connected with slow-adapting pulmonary stretch receptor afferents are presented.
Topics: Afferent Pathways; Animals; Lung; Mechanoreceptors; Nerve Fibers; Neurons; Respiration; Respiratory Center; Synapses
PubMed: 1513412
DOI: No ID Found