GPR18, GPR55 and GPR119 in GtoPdb v.2023.1

GPR18, GPR55 and GPR119 (provisional nomenclature), although showing little structural similarity to CB1 CB2 cannabinoid receptors, respond endogenous agents analogous the ligands, as well some natural/synthetic receptor ligands [104]. Although there are multiple reports indicate that can be activated in vitro by N-arachidonoylglycine, lysophosphatidylinositol N-oleoylethanolamide, respectively, is a lack of evidence for activation these lipid messengers vivo. As such, therefore, receptors retain their orphan status.