Voltage-gated Na+ channels in glia: properties and possible functions.
Glial cells are nervous-system cells that have classically been considered to be inexcitable. Despite their lack of electrical excitability, they can express voltage-activated Na+ channels with properties similar to the Na+ channels used by excitable cells to generate action potentials. The functional role that these voltage-activated Na+ channels play in glia is unclear. Three functions have been proposed: (1) glial cells might synthesize Na+ channels and donate them to adjacent neurons, thereby reducing the biosynthetic load of neurons; (2) Na+ channels might endow glial cells with the ability to sense electric activity of neighboring neurons, and might thus play a role in neuro-glial communication; and (3) Na+ influx through voltage-gated Na+ channels could be important to fuel the glial (Na+,K+)-ATPase, thereby facilitating and possibly modulating K+ uptake from the extracellular space.
Sontheimer
H
H
Neurobiology Research Center, University of Alabama at Birmingham 35294-0021, USA.
Black
J A
JA
Waxman
S G
SG
D000818:Animals; D004594:Electrophysiology; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology*; D009457:Neuroglia / Q000201:enzymology / Q000378:metabolism / Q000502:physiology*; D015222:Sodium Channels / Q000502:physiology*
D015222:Sodium Channels