GPR91 is a class A G-protein coupled receptor that binds selectively to succinate, an intermediate in the citric acid cycle, and couples to both the Gi/Go and Gq pathways. Renal proximal tubules are a major site of GPR91 expression, and succinate-mediated activation of renal GPR91 stimulates the release of renin to cause vasoconstriction and hypertension. In addition, GPR91 in retinal neurons mediates retinal vascularization induced by succinate, which accumulates in response to hypoxia. Dendritic cells also highly express GPR91, which mediates succinate-induced immune cell migration and activation in vitro and in vivo. Therefore, suppression of GPR91 is a potential strategy for treatment of vascular retinopathies, hypertension, and inflammation.