Inhibits mammalian voltage-gated sodium channel subtypes Nav1.5/SCN5A and Nav1.8/SCN10A by shifting the voltage dependence of channel activation to more depolarized potentials and by blocking the inward component of the sodium current. In vivo, this toxin causes erect, elevated tail, initial partial ataxia, followed by recovery over approximately 1 hour after injection and the progressive development of shaking. Although paralysis subsides, the body tremors never cease and persist until the end of the experiment. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Belongs to the neurotoxin 10 (Hwtx-1) family. 47 subfamily.