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Aliases GPR18, G protein-coupled receptor 18
External IDs MGI: 107859 HomoloGene: 18814 GeneCards: GPR18
RNA expression pattern
PBB GE GPR18 210279 at fs.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC) Chr 13: 99.25 – 99.26 Mb Chr 14: 121.91 – 121.92 Mb
PubMed search [1] [2]
View/Edit Human View/Edit Mouse

N-arachidonyl glycine receptor also known as G-protein coupled receptor 18 (GPR18) is a protein that in humans is encoded by the GPR18 gene.[3][4] 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.[5][6][7]

Research supports the hypothesis that GPR18 is the abnormal cannabidiol receptor and N-arachidonoyl glycine, the endogenous lipid metabolite of anandamide, initiates directed microglial migration in the CNS through activation of GPR18,[8] though recent evidence demonstrates that NAGly was not shown to be a GPR18 agonist in rat sympathetic neurons.[9]

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.[10] 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[11]



Ligands found to bind to GPR18 as agonists include:[8][12]



  1. ^ "Human PubMed Reference:". 
  2. ^ "Mouse PubMed Reference:". 
  3. ^ 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. PMID 9205118. doi:10.1006/geno.1997.4752. 
  4. ^ "Entrez Gene: GPR18 G protein-coupled receptor 18". 
  5. ^ 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. PMID 16844083. doi:10.1016/j.bbrc.2006.06.175. 
  6. ^ Burstein S (December 2008). "The elmiric acids: biologically active anandamide analogs". Neuropharmacology. 55 (8): 1259–64. PMC 2621443Freely accessible. PMID 18187165. doi:10.1016/j.neuropharm.2007.11.011. 
  7. ^ Bradshaw HB, Lee SH, McHugh D (September 2009). "ORPHAN ENDOGENOUS LIPIDS AND ORPHAN GPCRS: A GOOD MATCH". Prostaglandins Other Lipid Mediat. 89 (3–4): 131–4. PMC 2740803Freely accessible. PMID 19379823. doi:10.1016/j.prostaglandins.2009.04.006. 
  8. ^ a b McHugh D, Hu SS, Rimmerman N, Juknat A, Vogel Z, Walker JM, Bradshaw HB (2010). "N-arachidonoyl glycine, an abundant endogenous lipid, potently drives directed cellular migration through GPR18, the putative abnormal cannabidiol receptor". BMC Neurosci. 11: 44. PMC 2865488Freely accessible. PMID 20346144. doi:10.1186/1471-2202-11-44. 
  9. ^ Lu VB, Puhl HL, Ikeda SR (Jan 2013). "N-Arachidonyl glycine does not activate G protein-coupled receptor 18 signaling via canonical pathways.". Molecular Pharmacology. 83 (1): 267–82. PMC 3533477Freely accessible. PMID 23104136. doi:10.1124/mol.112.081182. 
  10. ^ 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. PMID 27052783. doi:10.5551/jat.33928. 
  11. ^ Calder PC (2015). "Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance". Biochimica et Biophysica Acta. 1851 (4): 469–84. PMID 25149823. doi:10.1016/j.bbalip.2014.08.010. 
  12. ^ 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. PMID 21595653. doi:10.1111/j.1476-5381.2011.01497.x. 
  13. ^ 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. PMID 22831390. doi:10.2174/187152412802430156. 
  14. ^ 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. ISBN 978-1-4614-4668-2. 
  15. ^ Chiang N, Dalli J, Colas RA, Serhan CN (2015). "Identification of Resolvin D2 Receptor Mediating Resolution of Infections and Organ Protection". J. Exp. Med. 212 (8): 1203–1217. PMC 4516788Freely accessible. PMID 26195725. doi:10.1084/jem.20150225. 
  16. ^ 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. 

Further reading[edit]

  • 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. PMID 11991713. 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. PMID 16844083. doi:10.1016/j.bbrc.2006.06.175.