CID 85469571

CID-85469571 is a compound which acts as an antagonist at the former orphan receptor GPR18, and is the first selective antagonist characterised for this receptor, with an IC₅₀ of 279nM, and good selectivity over related receptors (over 36x selectivity vs CB₁ and GPR55, and 14x vs CB₂.) As all previously known antagonists for GPR18 also antagonise GPR55, it has been difficult to separate the effects of these two receptor targets, so the discovery of a selective GPR18 antagonist is expected to be useful in research into the actions of this receptor.