These include endogenous ligands such as N-arachidonylglycine (NAGly), anandamide, a metabolite of the endocannabinoid anandamide, synthetic ligands such as abnormal-cannabidiol (Abn-CBD), and O-1918, a partial agonist, which can be used as a pharmacological tool to inhibit DRV2/GPR18 signalling (Offertaler et al.