Channel sodium

A channel sodium , or sodic, is an ionic channel specific to the Ion S Sodium. There are several types. To be described first is the sodic channel of the Potentiel of action, person in charge of the Dépolarisation of the Neuron and the propagation of the nervous signal.

It is necessary to differentiate the channels strict sodiums from the channels perméants to the Cation S, i.e. mainly sodium and Potassium. With the difference in the latter, the channels sodiums are impermeable with the ions potassiums.

Various types of channels sodium

Central nervous system

Epitheliums

The channel sodium of the apical membrane of the epithelial cells is called ENaC , for Epithelial Na Chanel . It has specificity to be inhibited by the Amiloride. It is responsible for secretion by the epithelium of Sodium chloride, since the Sang, towards the light of the epithelium (of the interior medium about the external middle). This transport of salt is accompanied by a transport of water in the same direction by Osmose. The epitheliums concerned are the pulmonary epitheliums , renal, distal colics, like several glands exocrines, such as the salivary glands or the glands sudoripares. This channel is implied in certain forms of Hypertension like, perhaps, in the Mucoviscidose. This channel is also present in the papillary cells fungiform of the former part of the Langue, where it is responsible for the transduction of the salted Goût.

molecular Struture

The ENaC channel is formed starting from three sub-units of molecular weight going from 60 to 75 kDa: α (alpha), β (beta) and γ (gamma) coded by three Gene S located on the Chromosome S 12 and 16. Each sub-unit is made up of two segments transmembrane, a broad extracellular part comprising of the sites of Glycosylation, as well as intracellular part formed by the comprising ends NR and C-final sites of regulation. Only the sub-unit α can form complete functional channels. The sub-units β and γ join the sub-unit α to give channels to the properties modified biophysics.

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