Sodium channel

Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na⁺) through a cell's membrane.^[1]^[2] They belong to the superfamily of cation channels.

Function[edit]

In excitable cells such as neurons, myocytes, and certain types of glia, sodium channels are responsible for the rising phase of action potentials. These channels go through three different states called resting, active and inactive states. Even though the resting and inactive states would not allow the ions to flow through the channels the difference exists with respect to their structural conformation.

Selectivity[edit]

Sodium channels are highly selective for the transport of ions across cell membranes. The high selectivity with respect to the sodium ion is achieved in many different ways. All involve encapsulation of the sodium ion in a cavity of specific size within a larger molecule.^[3]

Ligand-gated sodium channels [edit]

Ligand-gated sodium channels are activated by binding of a ligand instead of a change in membrane potential.

They are found, e.g. in the neuromuscular junction as nicotinic receptors, where the ligands are acetylcholine molecules. Most channels of this type are permeable to potassium to some degree as well as to sodium.

Alkaloid

aconitine

at the U.S. National Library of Medicine Medical Subject Headings (MeSH)

Sodium+Channels

. IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2021-12-09. Retrieved 2008-12-18.