Cutaneous mechanoreceptors are physiologically classified with respect to conduction velocity, which is directly related to the diameter and myelination of the axon.
D-hair receptors have large receptive fields and very low mechanical thresholds, and have been shown to be the most sensitive of known cutaneous mechanoreceptors.
C fibers are activated by both mechanical and thermal stimuli, and also respond to algesic chemicals, such as capsaicin.
C-fiber nociceptors which respond to both mechanical and thermal stimuli include C-mechanoheat (C-MH), C-mechanocold (C-MC), and C-mechanoheatcold (C-MHC).
Other groups of C fibers include C-fiber low threshold mechanoreceptors (C-LT), which are involved in nondiscriminative touch, and mechanically insensitive afferents (MIA), which lack mechanosensitivity and are also known as "silent" or "sleeping" nociceptors.
It is believed, however, that sensory neurons employ fast, mechanically gated cation channels, and that the depolarization that results across the membrane is followed by the generation of a sodium-dependent action potential at the transduction site.
It is believed that rapid, mechanically gated cation channels are characteristic of all sensory neurons.
[1] Mechanosensation also contributes to cell growth and development through extracellular matrix (ECM) interaction and traction of integrin receptors which facilitate adhesion.
[8] The mechanosensitivity of TREK-1 channels in a biological membrane was directly attributed to the generation of phosphatidic acid in a fast two step process (<3 ms).
[12] The stereocilia of functional hair cells have the ability to convert mechanical deflections to neural signals.
Because the tip links are composed of cadherin molecules, computer modeling using steered molecular dynamics can estimate the stiffness.
It has been found that the tip links are relatively stiff, so it is thought that there has to be something else in the hair cells that is stretchy which allows the stereocilia to move back and forth.
These mice have been recognized for several decades as potential for identifying the mutation that caused this deafness and balance problems.
The mechanism of the hair cell might contribute to the understanding other mechanosensory systems such as the sense of touch.
Normally the tip links grow back in about half a day, but for some people they are more fragile, making those individuals more susceptible to hearing loss.
Within the biological and medical disciplines, recent discoveries[citation needed] have noted that primary cilia in many types of cells within eukaryotes serve as cellular antennae.
The current scientific understanding of primary cilia organelles views them as "sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation.
"[16] Some primary cilia on epithelial cells in eukaryotes act as cellular antennae, providing chemosensation, thermosensation, and mechanosensation of the extracellular environment.
These cilia then play a role in mediating specific signalling cues, including soluble factors in the external cell environment, a secretory role in which a soluble protein is released to have an effect downstream of the fluid flow, and mediation of fluid flow if the cilia are motile.
A high-level-abstraction summary is that, "in effect, the cilium is a biological machine composed of perhaps over 600 proteins in molecular complexes, many of which also function independently as nanomachines.
Studies suggest that hyperalgesia and allodynia are set off and sustained by certain groups of mechanosensitive sensory neurons.
There is a general consensus among the scientific community that neuropeptides and NMDA receptors are crucial to the initiation of sensitization states such as hyperalgesia and allodynia.
Pain associated with allodynia can be attributed to myelinated A-fibers as a result of a change in their central functional connectivity.
There is a general consensus that continuous C-fiber activity at the location of the initial stimulus is responsible for maintaining allodynia.