What do sodium channels do?
Sodium channels play a central role in physiology: they transmit depolarizing impulses rapidly throughout cells and cell networks, thereby enabling co-ordination of higher processes ranging from locomotion to cognition. These channels are also of special importance for the history of physiology.
What activates a sodium channel?
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.
What drugs block sodium ion channels?
Local anesthetics, antiarrhythmics, and anticonvulsants include both charged and electroneutral compounds that block voltage-gated sodium channels.
What toxins block sodium channels?
Tetrodotoxin (TTX) or saxitoxin (STX) are the two important toxins blocking the entry of Na+ through the Na+ channel (Ritchie and Rogart, 1977). The biochemical analysis of the structural and functional properties of the sodium channel was started with the introduction of tritiated TTX by Hafemann(Hafemann, 1972).
What causes sodium channel inactivation?
Voltage-gated Na(+) channels (VGSCs) initiate action potentials thereby giving rise to rapid transmission of electrical signals along cell membranes and between cells. Depolarization of the cell membrane causes VGSCs to open but also gives rise to a nonconducting state termed inactivation.
How does a sodium channel blocker work?
A class of drugs that act by inhibition of sodium influx through cell membranes. Blockade of sodium channels slows the rate and amplitude of initial rapid depolarization, reduces cell excitability, and reduces conduction velocity.
Where is the sodium channel found?
There are two major classes of sodium channels in mammals: The voltage-gated sodium channel (VGSC) family and the epithelial sodium channel (ESC). Voltage-gated sodium channels exist throughout the body in various cell types, while epithelial sodium channels are located primarily in the skin and kidney.
Is diazepam a sodium channel blocker?
It is concluded that diazepam causes a faster block and unblock of Na+ channels than the other compounds. The effective concentrations of diazepam are, however, higher than the free plasma levels reached therapeutically, e.g., during the treatment of epileptic seizures.
How do sodium channel blockers work?
What happens when you block sodium channels?
The principal effect of reducing the rate and magnitude of depolarization by blocking sodium channels is a decrease in conduction velocity in non-nodal tissue (atrial and ventricular muscle, purkinje conducting system).