Putative endocannabinoid receptor (GPR55/GPR18/GPR119)

The putative endocannabinoid receptors are a group of G protein-coupled receptors (GPCRs) that respond to endocannabinoids and related lipid mediators but are distinct from the classical CB1 and CB2 receptors (https://pmc.ncbi.nlm.nih.gov/articles/PMC3062638/). This group primarily includes G protein-coupled receptor 55 (GPR55), G protein-coupled receptor 18 (GPR18), and G protein-coupled receptor 119 (GPR119) (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2931549/). GPR55, often referred to as the 'CB3' receptor, is involved in bone metabolism, inflammatory pain, and cancer cell proliferation (https://pubmed.ncbi.nlm.nih.gov/20133815/). GPR18, also known as the N-arachidonyl glycine receptor, plays significant roles in immune cell trafficking and the regulation of intraocular pressure (https://pubmed.ncbi.nlm.nih.gov/21457036/). GPR119 is predominantly expressed in the pancreas and gastrointestinal tract, where it regulates insulin secretion and GLP-1 release, making it a key target for metabolic disorders like type 2 diabetes (https://pubmed.ncbi.nlm.nih.gov/16723973/). These receptors represent an expansion of the endocannabinoid system and offer novel therapeutic avenues for treating inflammation, obesity, and various cancers (https://www.nature.com/articles/nrd3363). Unlike classical cannabinoid receptors, these putative receptors exhibit unique pharmacological profiles and signaling mechanisms, such as Gq or Gs coupling, which broaden the physiological impact of endocannabinoid signaling (https://pmc.ncbi.nlm.nih.gov/articles/PMC3062638/).

Other names

G protein-coupled receptor 55G protein-coupled receptor 18G protein-coupled receptor 119CB3 receptorNon-classical cannabinoid receptorOrphan cannabinoid receptorN-arachidonylglycine receptor

Modulation of intracellular signaling pathways including Gq-mediated calcium mobilization (GPR55), Gi/o-mediated inhibition of adenylyl cyclase (GPR18), and Gs-mediated stimulation of cAMP production (GPR119) through the binding of endocannabinoids or synthetic ligands (https://pmc.ncbi.nlm.nih.gov/articles/PMC3062638/).