Neuropeptide y

Neuropeptide Y (NPY) is a 36 amino-acid neuropeptide that is involved in various physiological and homeostatic processes in both the central and peripheral nervous systems. It is one of the most abundant neuropeptides in the mammalian brain, where it is important in several physiological functions, including: energy balance, memory and learning, epilepsy, anxiety and depression, circadian rhythms, and drug addiction.

Structure

Neuropeptide Y is composed of 36 amino-acid residues and is one of the most abundant peptides in the mammalian nervous system. It belongs to the pancreatic polypeptide family, which also includes pancreatic polypeptide and peptide YY. The structure of NPY is characterized by a hairpin-like (or "pancreatic") fold, stabilized by a helix across the amino-terminal of the molecule.

Function

Neuropeptide Y has been found to be involved in a variety of physiological processes, including:

• Energy balance: NPY is known to influence energy balance by stimulating food intake and conserving energy stores. It is one of the most potent appetite-stimulating factors in the central nervous system.

• Memory and learning: NPY has been implicated in the modulation of memory and learning processes. It is thought to have an inhibitory effect on both short-term and long-term memory formation.

• Epilepsy: NPY has been found to have anti-epileptic properties. It is thought to reduce the excitability of neurons, thereby reducing the likelihood of epileptic seizures.

• Anxiety and depression: NPY is thought to play a role in the regulation of mood and emotion. It has been found to have anxiolytic and antidepressant effects.

• Circadian rhythms: NPY is involved in the regulation of circadian rhythms. It is thought to influence the timing of sleep and wakefulness.

• Drug addiction: NPY has been implicated in the modulation of drug addiction. It is thought to influence the rewarding effects of drugs such as cocaine and alcohol.

Receptors

Neuropeptide Y exerts its effects through binding to a family of G-protein coupled receptors, known as the NPY receptors. There are five known subtypes of NPY receptors: Y1, Y2, Y4, Y5 and y6. Each receptor subtype has a different distribution within the body and has different effects upon activation.

Clinical significance

Due to its involvement in various physiological processes, Neuropeptide Y is a potential target for therapeutic intervention in a variety of conditions, including obesity, epilepsy, anxiety disorders, depression, and drug addiction.