Receptor for endocannabinoid N-arachidonyl glycine (NAGly) (By similarity). However, conflicting results about the role of NAGly as an agonist are reported (PubMed:23104136). Can also be activated by plant-derived and synthetic cannabinoid agonists (By similarity). The activity of this receptor is mediated by G proteins which inhibit adenylyl cyclase (By similarity). May contribute to regulation of the immune system (By similarity). Is required for normal homeostasis of CD8+ subsets of intraepithelial lymphocytes (IELs) (CD8alphaalpha and CD8alphabeta IELs) in small intstine by supporting preferential migration of CD8alphaalpha T-cells to intraepithelial compartment over lamina propria compartment, and by mediating their reconstitution into small intestine after bone marrow transplant (PubMed:25348153, PubMed:26197390). Plays a role in hypotensive responses, mediating reduction in intraocular and blood pressure (PubMed:23461720, PubMed:27893106). Mediates NAGly-induced process of reorganization of actin filaments and induction of acrosomal exocytosis (By similarity). Expressed in the eye including cornea, retina, iris and ciliary epithelium (at protein level) (PubMed:23461720). Expressed in spleen, liver and lymphocytes with highest expression levels in intestinal intraepithelial lymphocytes (PubMed:25348153, PubMed:26197390). No visible phenotype (PubMed:26197390). However, reduced number of CD8alphaalpha gammadeltaT IELs has been reported (PubMed:25348153). Belongs to the G-protein coupled receptor 1 family.