SKA-121 is a KCa3.1 (IKCa1, IK1, KCa4, SKCa4, SK4) subtype-selective small conductance Ca2+-activated K+ channel (SK channel) positive-gating modulator (EC50 = 109 nM/KCa3.1 vs. 8.7 μM/KCa2.1, 6.8 μM/KCa2.2, 4.4 μM/KCa2.3) with 200- to 400-fold selectivity over CaV1.2 as well as representative KVs (KV1.3, KV2.1, KV3.1, and KV11.1) and NaV (NaV1.2, NaV1.4, NaV1.5, and NaV1.7) channels. When applied in vivo, SKA-121 significantly lowers mean arterial blood pressure in wild-type, but not KCa3.1(-/-), normotensive and hypertensive mice (100 mg/kg i.p.). SKA-121 is a more potent and selective KCa3.1 activator than SKA-31 (EC50 = 260 nM/KCa3.1, 2.9 μM/KCa2.1, 1.9 μM/KCa2.2, 2.9 μM/KCa2.3).
