Inhibits all known high-voltage activated calcium channels (L-, P/Q- and R-type currents) (Cav), and most effectively the P/Q- (Cav2.1/CACNA1A) and R-type (Cav2.3/CACNA1E) currents (PubMed:10884557). In rat brain, inhibits glutamate release, neuronal death and loss of neurotransmission in the hippocampus resulting from ischemia. In vivo, induces rapid general flaccid paralysis followed by death in 10-30 minutes at dose levels of 5 ug per mouse. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Belongs to the neurotoxin 02 (plectoxin) family. 01 (Tx3) subfamily.