Sodium channel

As sodium channel ion channels are referred to in the physiology and cell biology, which have a specific and more or less selective for sodium ion conductivity.

Like other ion channels, sodium channels, voltage- activated or non- activated tension. Currently, nine different subtypes of voltage activated sodium channels are known. They are as Nav1.1 according to the usual nomenclature - called Nav1.9. The index v stands for voltage -activated ( dt, voltage- activated ' ), the first digit identifies the gene family (so far only one known), the second number stands for a known gene (currently 1 to 9, arranged in the order of their discovery ).

Especially tight voltage-activated sodium channels in electrically excitable cells are expressed. Where their activation is responsible for the generation of action potentials. Under physiological conditions, the electrochemical driving force for sodium ions is directed to open the sodium channels by sodium ions to flow from the extracellular space into the cell. The simultaneous opening of many stress- activated sodium channels on reaching the threshold potential is amplified by the inward resulting depolarization, leading to the rapid increase in the membrane potential ( referred to as " spread ").

An example of a non- voltage-activated sodium channel is the epithelial sodium channel ( epithelial Na channel, ENaC). He is, for example, in the manifold and in the proximal tubule cells of the kidney responsible for the reabsorption of sodium ions from the primary. Pharmacological inhibitors of ENaC are used as diuretics therapeutically rid of edema and for the treatment of arterial hypertension. Since they do not lead to increased potassium excretion, such diuretics are also referred to as " potassium-sparing " diuretics.

Antiepileptic drugs and local anesthetics block the sodium channels and thus prevent the triggering of an action potential. Also riluzole is a sodium channel blocker and is neuroprotective.

• Cell Biology
• Membrane channel