Excitatory toxin that acts on both calcium and sodium (Nav) channels. It preferentially blocks a subset of calcium channels that is apparently not required for neurotransmitter release, it decreases threshold for sodium channel activation and it slows sodium channel inactivation. As it enhances synaptic transmission by prolonging presynaptic release of neurotransmitter, its effects on sodium and calcium channels may act synergistically to sustain the terminal excitability. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Has no significant effect on voltage-gated potassium current in Drosophila giant neurons. Belongs to the neurotoxin 02 (plectoxin) family. 01 (Tx3) subfamily.