Association between Kinin B1 Receptor Expression and Leukocyte Trafficking across Mouse Mesenteric Postcapillary Venules

Using intravital microscopy, we examined the role played by B1 receptors in leukocyte trafficking across mouse mesenteric postcapillary venules in vivo. B1 receptor blockade attenuated interleukin (IL)-1β–induced (5 ng intraperitoneally, 2 h) leukocyte–endothelial cell interactions and leukocyte emigration (∼50% reduction). The B1 receptor agonist des-Arg9bradykinin (DABK), although inactive in saline- or IL-8–treated mice, caused marked neutrophil rolling, adhesion, and emigration 24 h after challenge with IL-1β (when the cellular response to IL-1β had subsided). Reverse transcriptase polymerase chain reaction and Western blot revealed a temporal association between the DABK-induced response and upregulation of mesenteric B1 receptor mRNA and de novo protein expression after IL-1β treatment. DABK-induced leukocyte trafficking was antagonized by the B1 receptor antagonist des-arg10HOE 140 but not by the B2 receptor antagonist HOE 140. Similarly, DABK effects were maintained in B2 receptor knockout mice. The DABK-induced responses involved the release of neuropeptides from C fibers, as capsaicin treatment inhibited the responses. Treatment with the neurokinin (NK)1 and NK3 receptor