Ion channels that are selective for chloride ions. There are a range of different types including ligand-gated Cl-channels at synapses (the GABA- and glycine-activated channels), as well as voltage-gated Cl-channels. The voltage-gated channels have ten or twelve transmembrane helices and each protein forms a single pore. They are unrelated to known cation channels or other types of anion channels and there are three CLC subfamilies: CLC-1 is involved in setting and restoring the resting membrane potential of skeletal muscle, whereas other channels are important in solute concentration (mechanisms in the kidney. See also cystic fibrosis (CFTR), Mdr. Mutations in CLCN1 are associated with various forms of myotonia congenita. See chloride intracellular channel proteins. Chloride channels can be blocked by substitution of other anions (I−, Br−, or SO42−) or compounds such as 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), indanyloxyacetic acid 94, niflumic acid, and 4,4-dinitrostilbene-2,2-disulphonic acid (DNDS) as well as some toxins (chlorotoxin, picrotoxin).
Subjects: Medicine and Health — Chemistry.