Compound 26, a GPR55 agonist, exhibits potent activity with EC50 values of 0.239 nM for hGPR55 and 1.76 nM for rGPR55. It also induces β-arrestin recruitment to human GPR55 with an EC50 of 6.2 nM [1].

GPR55 agonist 4 (Compound 28), with an EC50 of 131 nM for hGPR55 and 1.41 nM for rGPR55, effectively induces β-arrestin recruitment to human GPR55 [1].

AM251 is a effective CB1 receptor antagonist (IC50/Ki: 8 /7.49 nM) that displays 306-fold selectivity over CB2 receptors; also effective GPR55 agonist (EC50: 39 nM).

L-α-Lysophosphatidylinositol Soy Sodium, an endogenous ligand of GPR55, is an endocannabinoid neurotransmitter and lysophospholipid. This compound falls within the class of lysophospholipids [1].

PSB-SB-487 is antagonist of GPR55.

GPR55 cannabinoid receptor agonist

CID 16020046 (C390-0219) is a selective GPR55 antagonist, inhibiting GPR55 constitutive activity with IC50 of 0.15 μM in yeast.

S-Geranylgeranyl-L-glutathione acts as a ligand for the orphan G protein-coupled receptor (GPCR) P2RY8, displaying selective affinity by inducing internalization of P2RY8 in preference to the sphingosine-1-phosphate receptor 2 (S1P2), GPR55, cysteinyl leukotriene receptor 1 (CysLT1 receptor), and the CysLT2 receptor at a concentration of 100 nM. Additionally, at a lower concentration of 10 nM, S-Geranylgeranyl-L-glutathione inhibits the chemokine (C-X-C motif) ligand 12-induced migration of both P2RY8-expressing WEHI-231 B cell lymphoma cells and human tonsil germinal center B cells.

Potent and selective CB2 receptor agonist (Ki = 12.8 nM; EC50 = 38.67 nM). Exhibits negligible affinity for the CB1 receptor (Ki > 40,000 nM) and no activity at the GPR55. Suppresses neuroinflammation by reducing microglial activation in a multiple sclerosis mouse model. BBB permeable; anti-inflammatory and neuroprotective.

GSK494581A is a GPR55 agonist and glycine transporter subtype 1 inhibitor.

PSB-KD107 is an agonist of the Cannabinoid-Activated Orphan G‑Protein-Coupled Receptor GPR18. PSB-KD107 displayed significantly higher potency and efficacy than THC, determined in a GPR18-dependent β-arrestin recruitment assay, and were found to be selective versus the CB-sensitive receptors CB1, CB2, and GPR55.

ML-184 (CID2440433) is a potent synthetic agonist of GPR55 with EC50 of 0.26 μM.

GSK575594A is a selective agonist of GPR55.

ML-191 is an inhibitor of LPI-induced phosphorylation of ERK1/2.

Anandamide ((5Z,8Z,11Z,14Z)-N-(2-Hydroxyethyl)icosa-5,8,11,14-tetraenamide), an immune modulator, acts via not only cannabinoid receptors (CB1 and CB2) but also other targets (e.g., GPR18/GPR55) in the central nervous system.

CID1792197 is a selective agonist of GPR55.

ML192 (CID1434953) is a selective GPR55 ligand antagonist. ML192 is an inhibitor that inhibits β-arrestin transport, ERK1/2 phosphorylation, and PKCβII translocation.

ML-193 (CID 1261822) is a potent and selective GPR55 antagonist( IC50 : 221 nM). It shows more than 27-fold selectivity for GPR55 over GPR35, CB1 and CB2, and can improve the motor and the sensorimotor deficits of Parkinson’s disease (PD) rats.

Tetrahydromagnolol can activate cannabinoid (CB) receptors.

O-1602 is a novel GPR55 agonist, an atypical cannabinoid associated with the central nervous system and obesity, and is a candidate compound for the treatment of cystitis.O-1602 promotes hepatic steatosis through GPR55 and PI3 kinase / Akt / SREBP-1c signalling in mice.O-1602 induces, in a GPR3-independent manner, in Hep55B cells with elevated intracellular calcium.

Virodhamine trifluoroacetate is an antagonist of endogenous cannabinoid receptor mixed that acts by being a full agonist at GPR55 and CB2 and partial antagonist at CB1.

CID-1792579 is a selective agonist of GPR55.

CID1172084, a novel high-potent GPR55 agonist, interacts with cannabinoid receptors.

PSB-KD477 is an Agonist of the Cannabinoid-Activated Orphan G-Protein-Coupled Receptor GPR18. PSB-KD477 displayed significantly higher potency and efficacy than THC, determined in a GPR18-dependent β-arrestin recruitment assay, and were found to be selective versus the CB-sensitive receptors CB1, CB2, and GPR55. Structure-activity relationships were steep, and indole substitution was crucial for biological activity. These first selective agonists, which are structurally distinct from the lipidic agonist(s), will allow target validation studies and may eventually contribute to the deorphanization of GPR18.