Functions
Stretch-activated ion channels are of use in the initial formation of an action potential from a mechanical stimulus, for example by the mechanoreceptors in an animal's vibrissae (whiskers).
Afferent nerve fibers responsible for sensory stimulus detection and feedback are especially sensitive to stimulation. This results from the specialized mechanoreceptor cells that are superimposed upon the afferent nerve fibers. Stretch-activated ion channels are located on these mechanoreceptor cells and serve to lower the action potential threshold, thus making the afferent nerves more sensitive to stimulation. Afferent nerve endings without mechanoreceptor cells are called free nerve endings. They are less sensitive than the encapsulated afferent fibers and generally function in the perception of pain.
Stretch-activated ion channels are responsible for many bodily functions in mammals. In the skin they are responsible for sensing vibration, pressure sensation, stretch, touch, and light touch. They are expressed in sensory modalities including taste, hearing, smell, heat sensation, volume control, and vision. They can also regulate internal functions of our body including, but not limited to, osmotic pressure in cells, blood pressure in veins and arteries, micturition, and heart contractility. In addition to these functionalities, stretch-activated ion channels have also been found to be involved with balance and proprioceptive sensation.
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