Mutations have been identified in arginine residues making up the voltage sensor of Na1.4.

The S segments of each domain serve as voltage sensors for activation.

The first four, S1-S4, act as the voltage sensor and allow binding of menthol, icilin and similar channel agonists.

When positive charge builds up on one side of a membrane containing such voltage sensors, it generates an electric force pressing the S4 in the opposite direction.

Changes in membrane potential therefore move the S4 back and forth through the membrane, allowing the voltage sensor to act like a switch.

Conversely, deactivation of the voltage sensor takes place at hyperpolarized potentials, when the membrane collects more negative charge on the inner leaflet.

The highly conserved S4 segment acts as the channel's voltage sensor.

Both ikitoxin and birtoxin are beta toxins, which bind to and trap the voltage sensor of the channel at side 4.

Voltage-gated ion channels have transmembrane voltage sensors.

In hypokalemic periodic paralysis, arginine residues making up the voltage sensor of Na1.4 are mutated.