Channels within cell membranes control movement of ions due to a voltage-sensitive sensor consisting of four proteins.

“The membranes of living cells, from bacteria to humans, contain macromolecules that behave rather like field-effect transistors. In transistors, the flow of electrons through a semiconductor ‘channel’ is governed by the voltage applied to a ‘gate’ electrode. With the protein equivalents—voltage-gated ion channels—an appropriate voltage, imposed across the cell membrane, causes the channels to open and allows a current of ions to cross the membrane. The control of ion flow through voltage-gated channels is very sensitive to the voltage across the cell membrane. By comparison, an electronic device such as a transistor is much less sensitive to applied voltage.” (Sigworth 2003:21)

Last Updated August 18, 2016