G Protein Coupled Receptor 55 (GPR55)

GPR55 is activated by the plant cannabinoids Δ⁹-THC and cannabidiol, and the endocannabinoids anandamide, 2-AG, noladin ether in the low nanomolar range. The synthetic cannabinoid CP-55940 is also able to activate the receptor while the structurally unrelated cannabinoid mimic WIN 55,212-2 fails to activate the receptor. Recent research suggests that lysophosphatidylinositol and its 2-arachidonoyl derivative may be the endogenous ligands for GPR55, and the receptor appears likely to be a possible target for treatment of inflammation and pain as with the other cannabinoid receptors.

GPR55 is coupled to the G-protein G₁₃ and activation of the receptor leads to stimulation of rhoA, cdc42 and rac1.GPR55, along with GPR119 and GPR18, have been implicated as novel cannabinoid receptors.