A remotely related group of atracotoxins operate by opening sodium channels.

Delta atracotoxin from the venom of the Sydney funnel-web spider produces potentially fatal neurotoxic symptoms in primates by slowing the inactivation of voltage-gated sodium channels.

The beta region contains a cystine knot motif, a feature seen in other neurotoxic polypeptides[2] and other spider toxins, of the CSTX family.

A representative of this group is hanatoxin, a 35 amino acid peptide toxin which was isolated from Chilean rose tarantula (Grammostola rosea, syn.

It inhibits the drk1 voltage-gated potassium channel by altering the energetics of gating.