Small resistance arteries isolated from animal models of diabetes and obesity exhibit an altered sensitivity to activators of endothelium-dependent vasodilation, including acetylcholine (ACh), bradykinin, and the proteinase-activated receptor 2 (PAR2) ligand Ser-Leu-Ile-Gly-Arg-Leu peptide (SLIGRL) [1], [2], [3], [4], [5], [6]. The gene discussed is F2RL1; the disease is obesity due to melanocortin 4 receptor deficiency.