Neuropeptide Y (NPY), a peptide widely expressed in the brain, acts through the protein G-coupled receptors Y1, Y2 and Y5. This peptide modulates many important functions such as the control of energy balance and anxiety. Its involvement in brain development has been less investigated. 

Neuropeptide Y (NPY) receptors are members of a G protein coupled receptor superfamily and they mediate a variety of physiological responses including feeding and vasoconstriction. The endogenous ligands of NPY receptors are a family of structurally related peptides, including NPY, peptide YY (PYY), and pancreatic polypeptide (PP). Increased activity of NPY and its receptors, Y1R, Y2R, and Y5R has been found in the brain in many forms of experimental obesity. Furthermore, several association studies have supported the association between NPY2R and obesity.