![]() These mechanosensitivity modalities depend on Aβ, Aδ and C nerve fibers (distinguished according to axon diameter, degree of myelination, and axonal conduction velocity) connected to low-threshold mechanoreceptors (LTMRs). The sensory corpuscles are the receptors responsible for tactile modalities including light brush, touch, pressure sensation, stretch, and vibration. Tactile sensation is one of the most important components of mechanosensation, and originates in nerve fibers that can be distinguished based on the morphology of their skin terminals (i.e., free nerve endings and sensory corpuscles), as well as on the conduction speed of their action potentials. Most of those putative ion channels belong to the degenerin/epithelial sodium channel (especially the family of acid-sensing ion channels), the transient receptor potential channel superfamilies, and the Piezo family. The process of mechanotransduction requires the conversion of a mechanical stimulus into electrical signals (action potentials) through the activation of mechanosensible ion channels present both in the axon and the periaxonal cells of sensory corpuscles (i.e., Schwann-, endoneurial- and perineurial-related cells). ![]() Furthermore, low-threshold mechanoreceptors associated with Aδ and C nerve fibers have been identified in hairy skin. These specialized sensory organs are linked anatomically and functionally to mechanosensory neurons, which function as low-threshold mechanoreceptors connected to peripheral skin through Aβ nerve fibers. The vertebrate skin contains sensory corpuscles that are receptors for different qualities of mechanosensitivity like light brush, touch, pressure, stretch or vibration. The structure of sensory corpuscles is formed by an axon, non-myelinating Schwann-like cells, a capsule of endoneurial and/or perineurial origin and extracelullar matrix molecules. Aβ nerve fibers end at the dermis level forming several morphotypes of sensory corpuscles with capacity of detecting different stimuli: Merkel cell–neurite complexes, Ruffini corpuscles, Meissner’s corpuscles and Pacinian corpuscles are present in the glabrous skin while pilo-neural complexes are found in hairy skin. The afferent innervation of vertebrate skin is supplied by nerve fibers (Aβ, Aδ, C) which are originated from peripheral neurons localized in the dorsal root ganglia (DRG). Functionally, they are mechanoreceptors transducing external mechanical stimuli into electrical signals which will be later led to the Central Nervous System. Vertebrate cutaneous sensory corpuscles are specialized sensory nerve formations located in the skin of all vertebrates and responsible for tactile sensation.
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