Bradykinins bind and activate two GPCRs, termed B1 and B2 (gene names BDKRB1 and BDKRB2, respectively), which signal through Gq and Gi. B2 is widely expressed in a constitutive fashion, whereas B1 expression is induced during inflammation. B2 appears to mediate much of the activity of kinins in vasodilation, arthritis, edema, and nociception (Leeb-Lundberg et al., 2005). B2 membrane preparations are crude membrane preparations made from our proprietary stable recombinant cell lines to ensure high-level of GPCR surface expression; thus, they are ideal HTS tools for screening of antagonists of B2 interactions with bradykinin. The membrane preparations exhibit a Kd of 0.18 nM for [3H]-bradykinin. With 10 µg/well, B2 Membrane Prep and 0.4 nM [3H]-bradykinin, a greater than 7-fold signal-to-background ratio is obtained.