Inhibits many voltage-gated sodium channels and one voltage-gated calcium channel (Cav2.2/CACNA1B (IC(50)=400 nM), Nav1.2/SCN2A (IC(50)=3-70 nM), Nav1.1/SCN1A (IC(50)=523-1060 nM), Nav1.7/SCN9A (IC(50)=129.1-5120 nM), Nav1.4/SCN4A (IC(50)=263-888 nM or >10 uM) and Nav1.5/SCN5A (IC(50)=188-323 nM or >10 uM)) (PubMed:16267209, PubMed:27129258, PubMed:28880874, PubMed:29703751). It acts by shifting the voltage dependence of channel activation to more depolarized potentials and by blocking the inward component of the sodium current (PubMed:16267209). It shows moderate affinity for lipid bilayers (PubMed:29703751). On Nav1.7/SCN9A, it has been shown to interact with the S3-S4 loop of domain DII (site 4) (PubMed:27129258). Is significantly more potent against Nav1.2/SCN2A than the other Nav channel subtypes (PubMed:16267209). In vivo, this toxin causes general ataxia, lack of response to stimuli, and semiparalysis (PubMed:16267209). After a few minutes, the mice are unable to stand, and breathing is reduced in rhythm and intensity (PubMed:16267209). Symptoms gradually increase with progressive slowing of breathing and flaccid paralysis, death occurred within 10 to 20 minutes post injection (PubMed:16267209). Animals remain totally flaccid, and no symptoms of excitatory neurotoxicity are observed (PubMed:16267209). Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Derivatives such as D1Z/M5I/K18Y/R24Ka or D1Z/M5I/R27Na are under preclinical trial by Pfizer to treat pain. Synthetic variant D1Z/M5I/K18Y/R24Ka has a N-terminal pyroglutamate and a C-terminal amidation. It shows an IC(50)=2.7 nM on Nav1.7/SCN9A and IC(50)>3 uM on Nav1.4/SCN4A and Nav1.5/SCN5A. Synthetic variant D1Z/M5I/R27Na has a N-terminal pyroglutamate and a C-terminal amidation. It shows an IC(50)=2.8 nM on Nav1.7/SCN9A and IC(50)>3 uM on Nav1.4/SCN4A and Nav1.5/SCN5A. Does not inhibit Cav1.3/CACNA1D and Cav3.1/CACNA1G (PubMed:28880874). Does not inhibit Nav1.3/SCN3A, Nav1.6/SCN8A, Nav1.8/SCN10A (PubMed:16267209, PubMed:28880874). Belongs to the neurotoxin 10 (Hwtx-1) family. 04 (CcoTx1) subfamily.