SB290157 (SB 290157) trifluoroacetate is a potent, selective nonpeptide antagonist of anaphylatoxin C3a receptor (C3aR) with IC50 of 200 nM. SB 290157 does not antagonize the C5aR or 5 other chemotactic GPCRs on human neutrophils. SB 290157 blocks C3a-induced C3aR internalization and C3a-induced Ca(2+) mobilization in RBL-C3aR cells and human neutrophils with IC50 of 27.7 and 28 nM, respectively. SB 290157 also inhibits C3a-induced Ca2+ mobilization of mouse and guinea pig C3aRS with IC50 of 7 and 12.5 nM, respectively. SB 290157 potently inhibits C3a-mediated ATP release from guinea pig platelets and inhibits C3a-induced potentiation of the contractile response to field stimulation of perfused rat caudal artery, demonstrates antiinflammatory activity in animal models.
