The kinin B-1 receptor: an inducible G protein coupled receptor

The B-1 receptor, selectively stimulated by des-Arg(9) fragments of native kinins, has a place in the vast family of G protein coupled receptors. We discuss a series of six criteria useful for comparing the B-1 receptor with the more prominent and studied bradykinin B-2 receptor. The B-1 receptor has attracted interest because it is rapidly upregulated in biological systems following some types of tissue injury, notably the injection of bacterial materials to rabbits, rats, or pigs. A fast and specific genetic program recruits the expression of what we know now to be a G protein coupled receptor in smooth muscle cells, endothelial cells, fibroblasts, and a few other cell types. The cytokine network has been linked to B-1 receptor expression in functional experiments, and this may be related to the recent finding of potential cytokine response elements in the proposed gene promoter of the human B-1 receptor gene. The experimental approach of B-1 receptor mRNA transcriptional regulation, protein synthesis, and maturation is illustrated, based on the biochemical (Northern blot) and functional analysis of isolated organs from rabbits injected with bacterial lipopolysaccharide or incubated in vitro with or without interleukin-1.