This neurotoxin binds at site 3 of insect voltage-activated sodium channels (Nav) and prolongs evoked axonal action potentials by a slowing down of sodium current inactivation (PubMed:12770132). The toxin also inhibits glutamate uptake from rat brain synaptosomes (PubMed:14757211). It reversibly inhibits the N-methyl-D-aspartate (NMDA)-subtype of ionotropic glutamate receptor (GRIN) (By similarity). In addition, the toxin shows antinociceptive effect in all rat pain models tested (inflammatory, neuropathic and nociceptive) (PubMed:27077886). The antinociceptive effect is partially blocked when selective antagonists of both mu- and delta-opioid receptors are administered, revealing that the antinociceptive effect of the toxin involves both opiod and cannabinoid endogenous systems (PubMed:27077886). In vivo, it is highly toxic to house fly (Musca domestica), toxic to cockroach, but has no effect when intracerebroventricularly injected into mice (PubMed:7778132, PubMed:12770132). Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. LD(50) is 3.8 ng/house fly. Does not affect the currents in rat brain Nav1.2/SCN2A or skeletal muscle Nav1.4/SCN4A sodium channels. Belongs to the neurotoxin 03 (Tx2) family. 05 subfamily.