Blocks contraction of smooth muscle elicited by high potassium-induced depolarization, but does not block caffeine-stimulated contraction. Since high potassium-treatment activates voltage-gated channels and caffeine exposure activates ryanodine receptors, this toxin may target L-type voltage-gated calcium channels (Cav) (and not ryanodine receptors) on smooth muscle (PubMed:12047379). This toxin also shows a little inhibition on cyclic nucleotide-gated CNGA1 channel (PubMed:12646276). Expressed by the venom gland. Belongs to the CRISP family.