Ames et al. (1999) identified GPR14 as a urotensin II receptor. GPR14 mRNA was most abundant in the heart and pancreas, with no expression detected in 15 discrete brain regions. Additional RT-PCR experiments revealed expression in human cardiac (atria and ventricle) and arterial (aorta) tissue, endothelial (coronary artery and umbilical vein) cells, and smooth muscle (coronary artery in aortic) cell lines, but not in vena cava nor in the renal vein smooth muscle cell line. Human GPR14 was subcloned into a mammalian expression vector and transfected into HEK293 cells; using a reverse pharmacologic approach, the cells were used to search for a ligand activating GPR14 using a calcium-mobilization assay. Transiently transfected cells were exposed to over 700 known and putative GPCR agonists. Only goby urotensin II elicited a response.