Centruroides alpha-neurotoxin (Centruroides α-NaTx)

Centruroides alpha-neurotoxins are a family of potent, basic peptides found in the venom of scorpions from the genus Centruroides, most notably the Arizona bark scorpion (Centruroides sculpturatus) (UniProt, 2024). These toxins exert their effects by binding with high affinity to Site 3 of voltage-gated sodium channels (Nav) in excitable tissues (PubMed, PMID: 15707878). By binding to this site, they physically hinder the movement of the S4 voltage sensor, which is required for the fast inactivation of the channel, leading to prolonged sodium currents and persistent membrane depolarization (StatPearls, 2023). This mechanism results in the over-excitation of the autonomic nervous system and neuromuscular junctions, causing the clinical syndrome known as scorpionism. In a therapeutic context, these toxins are the primary targets for antivenom treatments, such as Anascorp, which utilizes equine-derived F(ab')2 antibody fragments to neutralize the toxins in the systemic circulation (FDA, 2011).

Other names

Centruroides sodium channel alpha-toxinsCentruroides neurotoxinsSite 3 scorpion toxinsCentruroides α-NaTxCentruroides alpha-toxin peptides

The interacting drugs (antivenoms) consist of venom-specific F(ab')2 antibody fragments that bind to and sequester circulating alpha-neurotoxins, preventing them from interacting with voltage-gated sodium channels and facilitating their clearance from the body (FDA, 2011).