Neuropeptide Y is a vasoactive peptide and is widely distributed throughout the central and peripheral nervous systems. Neuropeptide Y is coreleased with noradrenaline by perivascular nerve endings. At high concentrations, it has a direct vasoconstrictor effect. In addition, it enhances the vascular effect of various agonists, including noradrenaline and angiotensin II. Moreover, neuropeptide Y has an inhibitory effect on renin secretion. This peptide may have an important role in cardiovascular regulation.