N-arachidonyl glycine receptor also known as G-protein coupled receptor 18 (GPR18) is a protein that in humans is encoded by the GPR18gene. Along with the other previously "orphan" receptors GPR55 and GPR119, GPR18 has been found to be a receptor for endogenous lipid neurotransmitters, several of which also bind to cannabinoid receptors.
Resolvin D2 (RvD2), a member of the specialized proresolving mediators (SPM) class of polyunsaturated fatty acid metabolites, is an activating ligand for GPR18; RvD2 and its activation of GPR18 contribute to the resolution of inflammatory responses as well as inflammation-based and other diseases in animal models and are proposed to do so in humans. Furthermore, RvD2 is a metabolite of the omega-3 fatty acid, docosahexaenoic acid (DHA); the metabolism of DHA to RvD2 and RvD2's activation of GPR18 is proposed to one among many other mechanisms for the anti-inflammatory and other beneficial effects attributed to omega-3 fatty acid-rich diets
^Gantz I, Muraoka A, Yang YK, Samuelson LC, Zimmerman EM, Cook H, Yamada T (Sep 1997). "Cloning and chromosomal localization of a gene (GPR18) encoding a novel seven transmembrane receptor highly expressed in spleen and testis". Genomics. 42 (3): 462–6. PMID9205118. doi:10.1006/geno.1997.4752.
^Kohno M, Hasegawa H, Inoue A, Muraoka M, Miyazaki T, Oka K, Yasukawa M (September 2006). "Identification of N-arachidonylglycine as the endogenous ligand for orphan G-protein-coupled receptor GPR18". Biochem. Biophys. Res. Commun. 347 (3): 827–32. PMID16844083. doi:10.1016/j.bbrc.2006.06.175.
^Shinohara M, Serhan CN (2016). "Novel Endogenous Proresolving Molecules:Essential Fatty Acid-Derived and Gaseous Mediators in the Resolution of Inflammation". Journal of Atherosclerosis and Thrombosis. 23 (6): 655–64. PMID27052783. doi:10.5551/jat.33928.
^McHugh D, Page J, Dunn E, Bradshaw HB (May 2011). "Δ(9) -THC and N-arachidonyl glycine are full agonists at GPR18 and cause migration in the human endometrial cell line, HEC-1B". Br J Pharmacol. 165 (8): no. PMID21595653. doi:10.1111/j.1476-5381.2011.01497.x.
^Ashton JC (2012). "The atypical cannabinoid o-1602: Targets, actions, and the central nervous system". Central nervous system agents in medicinal chemistry. 12 (3): 233–239. PMID22831390. doi:10.2174/187152412802430156.
^McHugh D, Bradshaw HB (2012). "GPR18 and NAGly Signaling: New Members of the Endocannabinoid Family or Distant Cousins?". In Abood ME. endoCANNABINOIDS: actions at non-CB1/CB2 cannabinoid receptors. New York: Springer. ISBN978-1-4614-4668-2.
^Rempel, V; et al. (2014). "Bicyclic imidazole-4-one derivatives: a new class of antagonists for the orphan G protein-coupled receptors GPR18 and GPR55". Med. Chem. Commun. 5: 632–649. doi:10.1039/C3MD00394A.
Christian SL, McDonough J, Liu Cy CY, Shaikh S, Vlamakis V, Badner JA, Chakravarti A, Gershon ES (2002). "An evaluation of the assembly of an approximately 15-Mb region on human chromosome 13q32-q33 linked to bipolar disorder and schizophrenia". Genomics. 79 (5): 635–56. PMID11991713. doi:10.1006/geno.2002.6765.
Kohno M, Hasegawa H, Inoue A, Muraoka M, Miyazaki T, Oka K, Yasukawa M (2006). "Identification of N-arachidonylglycine as the endogenous ligand for orphan G-protein-coupled receptor GPR18". Biochem. Biophys. Res. Commun. 347 (3): 827–32. PMID16844083. doi:10.1016/j.bbrc.2006.06.175.