Tanshinone II-A sodium sulfonate

K_Ca1.1 channel is a large conductance Calcium-activated potassium channel (BK_Ca) known to regulate the repolarization of action potential discharge through molecular association with high voltage activated calcium channels.

Tanshinone II-A sodium sulfonate (TIIAS) is a water soluble derivative of Tanshinone IIA. Tanshinone IIA is an active constituent of the herb Danshen (Salvia miltiorrhiza) widely used in Chinese traditional medicine for coronary artery disease, hypertension and other cardiovascular diseases due to its properties of arterial dilatation. TIIAS is a synthetic opener of K_Ca1.1 channels with an effective concentration 10-200 μM. TIIAS increases the total permeability of BK_Ca in a concentration dependent manner. TIIAS has an EC₅₀ of 111.5 μM at 0.01 μM Ca²⁺ and an EC₅₀ of 68.5 μM at 0.1 μM Ca^{2+ 2}. Similar to Danshen, TIIAS has beneficial effects on cardiac vasodilatation, reduction of oxidative stress and lipid profile. Interestingly, when used in a rat model of preeclampsia TIIAS reduced oxidative stress, however it did not lead to an improvement in pregnancy outcome criteria such as maternal blood pressure and fetal biometrics³. TIIAS was also found to have analgesic properties in neuropathic pain via inhibition of the spinal astrocytic JNK/MCP-1 pathway and the reduction of IL-1β and TNF-α expression⁴.