GPR18

N-arachidonyl glycine receptor also known as G-protein coupled receptor 18 (GPR18) is a is_associated_with::protein that in humans is encoded by the GPR18 is_associated_with::gene. Along with the other previously "orphan" receptors is_associated_with::GPR55 and is_associated_with::GPR119, GPR18 has been found to be a receptor for endogenous lipid neurotransmitters, several of which also bind to is_associated_with::cannabinoid receptors.

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

Ligands
Ligands found to bind to GPR18 as agonists include:
 * Agonists
 * N-Arachidonoylglycine (NAGly)
 * is_associated_with::Abnormal cannabidiol (Abn-CBD)
 * AM-251 - partial agonist
 * is_associated_with::Cannabidiol - partial agonist
 * is_associated_with::O-1602
 * Δ9-Tetrahydrocannabinol (Δ9-THC) - THC is actually a more potent agonist at GPR18 than at CB1 or CB2, with Ki of 0.96nM at GPR18, 8.1nM at GPR55, 25.1nM at CB1 and 35.2nM at CB2.
 * is_associated_with::Anandamide (N-arachidonoyl ethanolamine, AEA)
 * is_associated_with::Arachidonylcyclopropylamide (ACPA)
 * Antagonists
 * is_associated_with::O-1918
 * is_associated_with::CID-85469571