Definition
Stretch-activated ion channels are mechanotransducers which conduct ionic currents by responding to stress in the cell membrane. To be identified as stretch-activated, the ion channel must open and close in response to membrane tension.Mechanotransduction, an electrical signal resulting from a mechanical stimulus, occurs via the opening of stretch-activated ion channels due to membrane deformation. The opening of these channels results in a non-specific ionic flow, which depolarizes the afferent nerve fiber, and may produce action potentials with sufficient depolarization. The opening of these channels is central to a neuron’s response to pressure, often osmotic pressure and blood pressure, to regulate ionic flow in internal environments. There are two mechanisms for which these channels open. The prokaryotic model suggests that stretch-activated channels open directly in response to force to the membrane, whereas the mammalian hair cell model involves a tether bound both to the channel and to the extracellular matrix or cytoskeleton. Force on the membrane then displaces the tether, creating tension which opens the channel.
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