As can be seen in Figure 1a, raloxifene antagonizes BK with an IC50 ~16 µM with an apparent dissociation constant KB = 1.8 µM, computed using the modified Cheng Prusoff equation [32]:KB=IC501+AEC50 where, IC50 = 16 µM corresponds to raloxifene and EC50 = 2.4 pM corresponds to BK, and A = 0.03 nM is the concentration of BK that was used in the experiments. We also tested its activity as an agonist on CHO cells stably transfected with the B2 receptor. Present results also showed (Figure 1b) that the compound exhibited a partial agonistic profile, with a maximum effect of 20% of BK that was achieved at around 20 µM.