High affinity, selective KCa2.2 (SK2) channel blocker (Kd = 3.8 nM). Exhibits >200-fold selectivity for KCa2.2 over KCa2.1, KCa2.3, KCa3.1, IK, Kv and Kir2.1. Increases theta-burst responses and increases LTP in rat hippocampal slices in vitro. Convulsive
OSK-1 is a potent potassium channel blocker belonging to the α-KTx3 toxins. It exhibits IC50 values of 0.6 nM, 5.4 nM, and 0.014 nM for Kv1.1, Kv1.2, and Kv1.3 channels, respectively. Additionally, OSK-1 acts as a moderate blocker of the calcium-activated KCa3.1 channel, with an IC50 of 225 nM. Consequently, OSK-1 finds application as an immunosuppressive drug.