Delta-conotoxins bind to site 6 of voltage-gated sodium channels and inhibit the inactivation process. This toxin inhibits sodium channel inactivation in neuronal membranes from amphibians and mammals (Nav1.2a/SCN1A, Nav1.3/SCN3A and Nav1.6/SCN8A) upon binding to receptor site 6. Expressed by the venom duct. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. The cysteine framework is VI/VII (C-C-CC-C-C). Dose that produces hyperactivity (ED(50)) is 1.8 pmol/g body mass (native toxin), 1.9 pmol/g body mass (synthetic toxin) and 3.9 pmol/g body mass (P13A mutant). Does not affect rat skeletal muscle (Nav1.4/SCN4A) and human cardiac muscle (Nav1.5/SCN5A) sodium channels. Exists in two forms, due to cis-trans isomerization at 12-Leu-Pro-13. Belongs to the conotoxin O1 superfamily. Another delta-conotoxin was named EVIA in 2001, but this toxin was renamed EVIB (AC P69752).