Measurementent of the efficacy of the compound on the B2 receptor was carried out following the protocol described elsewhere [31]. The method is based on measuring differences in intracellular Ca2+ concentrations produced in diverse conditions on CHO cells expressing recombinant human B2 receptor by fluorometry. Agonism was measured through the capacity of the compound to increase Ca2+ concentration compared to BK (EC50 ~ 2.4 pM). Antagonism was measured through the capacity to antagonize BK based on the reduction of Ca2+ concentration.