Iberiotoxin (IbTx)

Iberiotoxin (IbTx) is a toxin that was originally isolated from Buthus tamulus scorpion venom. Iberiotoxin inhibits selectively the high conductance Ca2+-activated K+ channel (KCa1.1) at nanomolar concentrations (IC50 ~2 nM). This toxin does not affect other types of calcium-dependent or voltage-dependent K+ channels. Iberiotoxin is a valuable tool to study specifically Maxi-K channels.