Neurobiology and clinical aspects of neuropeptide Y.

Although a large and still increasing number of neuroactive peptides have been discovered in the mammalian brain over the years, it has been difficult to link most of these molecules with specific brain functions and/or brain diseases. A lack of pharmacological tools has hampered the study of brain peptide systems and the elucidation of which among these systems have retained important physiological functions through phylogenesis. Neuropeptide Y (NPY) is one the most abundant neuropeptides in the mammalian brain. A combination of basic and clinical studies has made it possible to circumvent some of these difficulties and provides evidence for a role of NPY in the control of endocrine hypothalamic and pituitary functions, in hypothalamic control of food intake and circadian rhythm, and in limbic emotional integration. Of particular interest is NPY's unique action as an endogenous anxiolytic and its possible role in clinical states of anxiety and depression. Here, we review the biology, anatomy, and physiology of central NPY systems and studies of these systems in various disease states.