[Recent progress in sodium channel structures relevant to their functions].

Efforts to reveal specific aspects of protein structure with channel function have been carried out for more than a decade. Recent progresses in this field have been achieved by site-directed mutagenesis of the sodium channel DNA as well as other techniques. Among them I briefly review four topics in this article: (1) extracellular mouth of the ion conducting pore and ion selectivity filter which are correlated to the site of tetrdotoxin binding, (2) cytoplasmic mouth of the ion pore which is correlated with the binding site of local anesthetics, (3) inactivation gate, parts of which are related to periodic paralysis and paramyotonia, and (4) sodium channel blockers as neuprotective drugs.