Description | Melatonin is a naturally occurring compound found in animals, plants, and microbes [ , ]. In animals melatonin is secreted by the pineal gland during darkness [, ]. It regulates a variety of neuroendocrine functions and is thought to play an essential role in circadian rhythms []. Drugs that modify the action of melatonin, and hence influence circadian cycles, are of clinical interest for example, in the treatment of jet-lag [].Many of the biological effects of melatonin are produced through the activation of melatonin receptors [ ], which are members of rhodopsin-like G protein-coupled receptor family. There are three melatonin receptor subtypes. Melatonin receptor type 1A and melatonin receptor type 1B are present in humans and other mammals [] while melatonin receptor type 1C has been identified in amphibia and birds []. There is also a closely-related orphan receptor, termed melatonin-related receptor type 1X (also known as GPR50) [], is yet to achieve receptor status from the International Union of Basic and Clinical Pharmacology (IUPHAR), since a robust response mediated via the protein has not been reported in the literature. Melatonin receptor type 1C receptors are 80% identical and are distinct from 1A and 1B subtypes. Similar ligand binding and functional characteristics are observed in expressed 1A and 1C receptors. The melatonin receptors inhibit adenylyl cyclase via a pertussis-toxin-sensitive G-protein, probably of the Gi/Go class.This entry represents melatonin receptor 1C, which is found in birds, fish and amphibians, but not in humans [ ]. It has been shown that the widespread distribution of 1C in brain provides a molecular substrate for the profound actions of melatonin in birds []. Also, in amphibians, very low concentrations of melatonin activate the 1C receptor subtype, triggering movement of granules toward the cell centre, thus lightening skin colour. 1C receptor activation reduces intracellular cAMP via a pertussis toxin-sensitive inhibitory G-protein (Gi) []. | Name | Melatonin receptor type 1C |
Short Name | Mel_rcpt_1C | Type | Family |