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Objective: To investigate the effect of sodium tanshinone Ⅱ-A sulfonate (DS-201) on large conductance Ca2-sensitive K+ channels (BKCa) and to further study by focusing on the kinetics of DS-201 on BKCa.Methods:we addressed the effect of DS-201 on BKCa heterogenetic expressed in HEK-293 cells.HEK293 cell strain with stable expression of BKCa was constructed through transfecting the plasmid pcDNA3.1-BKCa(α).The currents were recorded by patch clamp technique.Results: In the absence of β1 subunit, 80 μM DS-201 increased the macroscopic current density from 28.87±2.50 pA/pF to 39.14 ±1.90 pA/pF (P<0.05).In insideout configuration, 80μM DS-201 increased the NPo from 0.0183±0.007 to 0.45±0.17 (P<0.01).80 and 160 μM DS-201 increased the voltage dependence of BKCa by decreasing the half activated voltage (V1/2) from 102±20 mV to 54±8 mV (P<0.05)and to 30.64 mV, respectively.It also delayed the deactivation time constant from 0.27 ms to 0.91 ms (80 μM DS201) and to 10.72 ms (160 μM DS-201) by analyzing the tail currents.However, 80 and 160 μM DS-201 had no effect on the activation time constant.Conclusions: DS-201 activated BKCa without β1 subunit dependence.It increased the voltage dependence and delayed the transition of channel from open to closed states without affecting the activation kinetics.