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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]
Persistent sodium current generation is hypothesized to occur by the incomplete inactivation of the voltage-gated sodium channel current (INa), where the channel becomes constitutively active and conducts sodium, creating a "persistently active" inward sodium current. Upon depolarization, the four identical motifs of the sodium channel (which ...
Voltage-gated sodium channels (VGSCs), also known as voltage-dependent sodium channels (VDSCs), are a group of voltage-gated ion channels found in the membrane of excitable cells (e.g., muscle, glial cells, neurons, etc.) with a permeability to the sodium ion Na +. They are the main channels involved in action potential of excitable cells.
Voltage-gated ion channels are often specific to ions, including Na +, K +, Ca 2+, and Cl −. Each of these ions plays an important role in the electrical behavior of the cell. [9] The gates also have unique properties with important physiological implications. For example, Na + channels open and close rapidly, while K + gates open and close ...
Ion channels may be classified by gating, i.e. what opens and closes the channels. For example, voltage-gated ion channels open or close depending on the voltage gradient across the plasma membrane, while ligand-gated ion channels open or close depending on binding of ligands to the channel. [14]
A positively charged region between the III and IV domains of sodium channels is thought to act in a similar way. [9] The essential region for inactivation in sodium channels is four amino acid sequence made up of isoleucine, phenylalanine, methionine and threonine (IFMT). [13] The T and F interact directly with the docking site in the channel ...
Ion channels are typically categorised by gating mechanism and by the ion they conduct. Note that an ion channel may overlap between different categories. Some channels conduct multiple ion currents and some are gated by multiple mechanisms. Examples of targets for modulators include: Voltage-gated ion channels. Calcium channel: see also ...
Voltage-gated ion-channels are usually ion-specific, and channels specific to sodium (Na +), potassium (K +), calcium (Ca 2+), and chloride (Cl −) ions have been identified. [1] The opening and closing of the channels are triggered by changing ion concentration, and hence charge gradient, between the sides of the cell membrane.