3R(A)-PMTX is a mutated form of the (A)-PMTX, originaly isolated from the solitary wasp (Anoplius samariensis) Venom and is a synthetic version of the peptide1.Pompilidotoxins (PMTX, (A) and (B)) are small peptides consisting of 13 amino acids.(A)-PMTX induces a unique pattern of repetitive action potentials previous seen with other neurotoxins and thus facilitate both excitatory and inhibitory synaptic transmission.Recently it was found that this toxin slows the Na+-channel inactivation, without changing the peak current-voltage relationship or the activation time course of the TTX-sensitive Na+ currents in the neuromuscular synapse of the lobster walking leg and in the rat trigeminal ganglion neurons. Effective at concentrations of 10 nM in cultured rat cortical neurons.3R(A)-PMTX is mutated at position 3 with Lysine to Arginine transition, which enhanced its activity on Voltage-Gated Na+ Channels by 5-fold relative to (A)-PMTX.