voltage-gated channel

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channel

 [chan´el]
a passage, cut, or groove through which something can pass or flow across a solid structure.
calcium channel (calcium-sodium channel) a slow voltage-gated channel very permeable to calcium ions and slightly permeable to sodium ions, existing in three subtypes designated L, M, and N and located throughout the body; calcium channels are the main cause of action potentials in certain smooth muscles, and the N channels regulate neurotransmitter release.
fast channel a protein channel, such as a sodium channel, that becomes activated relatively quickly; a fast voltage-gated channel has a much lower activation potential than does the slow type. See also slow channel.
ligand-gated channel a protein channel that opens in response to the binding of a molecule (the ligand) to the protein, which causes a conformational change in the protein molecule. See also voltage-gated channel.
potassium channel a slow voltage-gated channel selective for the passage of potassium ions, found on the surface of a wide variety of cells, including nerve, muscle, and secretory cells; its functions include regulation of cell membrane excitability, regulation of repetitive low frequency firing in some neurons, and recovery of the nerve fiber membrane at the end of the action potential.
protein channel a watery pathway through the interstices of a protein molecule by which ions and small molecules can cross a membrane into or out of a cell by diffusion; protein channels play a vital role in depolarization and repolarization of nerve and muscle fibers, and may have physical characteristics such as shape or diameter that particularly attract certain ions.
slow channel a protein channel such as the calcium channel that is slow to become activated; a slow voltage-gated channel has a much higher activation potential than does the fast type. See also fast channel.
sodium channel a type of fast channel selective for the passage of sodium ions. Voltage-gated sodium channels are the main causes of depolarization and repolarization of nerve membranes during the action potential. In cardiac cells they produce phase 0 of the action potential.
voltage-gated channel a protein channel that can be opened or closed in response to changes in the electric potential across a cell membrane. See also ligand-gated channel.
water channel a channel in a cell membrane that permits passage of water molecules; chemical substances such as vasopressin cause the opening of new channels and increase permeability.

vol·tage-gat·ed chan·nel

a class of ion channels that open and close in response to change in the electrical potential across the plasma membrane of the cell; voltage-gated Na+ c.'s are important for conducting action potential along nerve cell processes.

voltage-gated channel

Any of the gated ion channels that open in response to a change in the membrane potential of a cell membrane. These channels give muscle fibers and neurons their ability to generate and propagate impulses.
Synonym: voltage-regulated channel
See also: channel
References in periodicals archive ?
No one had previously reported voltage-gated ion channels in a microbe.
It is well established that voltage-gated ion channels are involved in the control of the excitation-secretion coupling that leads to hormone release in different pituitary hormone-secreting cell types, including somatotropes [3].
The last six chapters of the book focus on the proteins residing in the cell membrane, covering such topics as membrane transporters, sodium-coupled secondary transporters, and voltage-gated ion channels in nerve cells.
With the description of another toxin from shellfish called saxitoxin (possessing two guanidinium moieties), the molecular modeling work of Lipkind and Fozzard (1994) has led to some still-active debates about the three-dimensional structure of voltage-gated ion channels in excitable membranes.
To study the functional properties of voltage-gated ion channels, the voltage-clamp technique first described in 1952 is still the best recognized way to monitor ion channel function.
Taking into account the new structure and several follow-up experiments, all described in the May 1 Nature, MacKinnon's team has offered a proposal for how voltage-gated ion channels work.

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