Stable expression of human kinin B-1 receptor in 293 cells: pharmacological and functional characterization

1 We compared the binding properties of [H-3]-desArg(10)-[Leu(9)]-kallidin, a radiolabelled kinin B-1 receptor antagonist, to membranes from IMR-90 human embryonic fibroblasts and from 293 cells transiently or stably transfected with the human B-1 receptor. 2 The dissociation constant (K-D) of [H-3]-desArg(10)-[Leu(9)]-kallidin and the affinity of several kinin receptor agonists and antagonists were similar between the native and cloned receptor, either transiently or stably expressed in 293 cells. In IMR-90 cells, the rank order of potency was that expected for a kinin B-1 receptor. 3 The receptors transiently or stably expressed in 293 cells were fully functional with respect to their signalling properties. Phosphoinositide hydrolysis was increased in a concentration-dependent manner by the B-1 receptor agonist, desArg(10)-kallidin. Functional coupling to the calcium pathway was also demonstrated for the native and stably expressed human B-1 receptor. 4 In conclusion, the established stable and functional 293 cell clone may provide an important tool for further analysis of the molecular mechanisms involved in binding, activation, and coupling of the kinin B-1 receptor.