Charybdotoxin blocks dendrotoxin-sensitive voltage-activated K+ channels.

Charybdotoxin, a short scorpion venom neurotoxin, which was thought to be specific for the blockade of Ca2+-activated K+ channels also blocks a class of voltage-sensitive K+ channels that are known to be the target of other peptide neurotoxins from snake and bee venoms such as dendrotoxin and MCD peptide. Charybdotoxin also inhibits 125I-dendrotoxin and 125I-MCD peptide binding to their receptors. All these effects are observed with an IC50 of about 30 nM.