Paralyzes but does not kill U.thayeri crabs. Partially and reversibly inhibits glutamate-evoked peak currents (IC(50)=4.7 uM) but not voltage-gated potassium channel currents in cultured isolated neurons from the land snail H.aspersa. Weakly inhibits voltage-gated potassium peak currents (IC(50)=6.4 uM) and steady-state currents (IC(50)=8.2 uM) in rat dorsal root ganglion (DRG) neurons. Weakly inhibits voltage-gated sodium currents in rat DRG neurons (IC(50)=0.9 uM). PD(50) is 707 ug/kg in U.thayeri crabs. Has no inhibitory effect on voltage-gated ion channels Kv1.1/KCNA1, Kv1.2/KCNA2, Kv1.3/KCNA3, Kv1.4/KCNA4, Kv1.6/KCNA6, Kv2.1/KCNB1, Kv3.1/KCNC1, Kv4.2/KCND2, Kv10.1/KCNH1/EAG1, Shaker IR (with the inactivation domain removed), Nav1.4/SCN4A, Nav1.5/SCN5A, Nav1.6/SCN8A or D.melanogaster Nav1/para. Belongs to the sea anemone type 3 (BDS) potassium channel toxin family.