CID16020046 is a GPR55 inverse agonist that antagonizes GPR55 constitutive activity with an IC50 value of 15 μM.1 It inhibits GPR55-mediated ERK1/2 phosphorylation, LPI-induced Ca2+ signaling (IC50 = 0.21 μM in HEK-GPR55 cells), and GPR55-mediated transcription factor activation.1 It does not affect ERK1/2 phosphorylation or transcription factor activation in CB receptor expressing cells and demonstrates weak activity against a broad spectrum of other GPCRs, ion channels, kinases, and nuclear receptors.1 This compound has been shown to block GPR55-mediated endothelial wound healing and reverse LPI-inhibited platelet aggregation.1
1.Kargl, J., Brown, A.J., Andersen, L., et al.A selective antagonist reveals a potential role of G protein-coupled receptor 55 in platelet and endothelial cell functionJ. Pharmacol. Exp. Ther.346(1)54-66(2013)