| Primary Identifier | IPR000393 | Type | Family |
| Short Name | NPY5_rcpt |
| description | Neuropeptide Y (NPY) acts as a neurotransmitter in the brain and in the autonomic nervous system. In the brain it is thought to have several functions, including increasing food intake and storage of energy as fat [, , , ], facilitation of learning and memory via the modulation of hippocampal activity [, , ], inhibition of anxiety [, , ], presynaptic inhibition of neurotransmitter release in the CNS and periphery [], and modulation of circadian rhythm [, ]. In the periphery, NPY stimulates vascular smooth muscle contraction [, ], modulates the release of pituitary hormones [, ], pain transmission [], inhibition of insulin release [, , ]and modulation of renal function []. NPY has also been implicated in the pathophysiology of hypertension [], congestive heart failure and appetite regulation [, , , ]and controlling epileptic seizures []. Signalling responses appear to be restricted to certain cell types and in the autonomic system it is mainly produced by neurons of the sympathetic nervous system and serves as a strong vasoconstrictor and also causes growth of fat tissue []. These include inhibition of Ca2+ channels, such as in neurones [], and activation and inhibition of K+ channels, such as in cardiomyocytes []and vascular smooth muscle cells [].The various functions of NPY are mediated by neuropeptide Y receptors, which are members of rhodopsin-like G-protein coupled receptors, they are also activated by peptide YY and the pancreatic polypeptide []. There are five pharmacologically distinct neuropeptide Y receptor subtypes []; neuropeptide Y receptor Y1 (Y1), neuropeptide Y receptor Y2 (Y2), neuropeptide Y receptor Y4 (Y4), neuropeptide Y receptor Y5 (Y5) and neuropeptide Y receptor Y6 (Y6). Four of the neuropeptide Y receptors have been identified in humans (Y1, Y2, Y4, Y5), which represent therapeutic targets for obesity and other disorders [, , ], as they are also involved in the control of circadian rhythm and anxiety [, , , , , ]. The pharmacological profile of the Y6 receptor is controversial, since the 'receptor' is non-functional in primates including humans [, ]and is absent from the rat genome []. All NPY receptors couple to pertussis toxin-sensitive Gi proteins via the inhibition of adenylate cyclase []. Activated neuropeptide receptors release the Gi subunit which inhibits the production of the second messenger cAMP from ATP []. Studies with endogenously expressed receptors have mainly been performed with Y1 receptors and Y2 receptors, whereas investigations of the signal transduction of other natively expressed NPY receptors has as yet, not beendemonstrated.This entry represents the neuropeptide Y5 receptor, which has less than 35% overall identity to known Y-type receptors []. It is found primarily in the central nervous system [], including the paraventricular nucleus of the hypothalamus []. The Y5 receptor has been postulated to be the 'feeding' receptor, and may provide new approaches for the study and treatment of obesity and eating disorders [, , , ]. |
