The Atypical Cannabinoid O-1602: Targets, Actions, and the Central Nervous System

O-1602 is a cannabidiol analogue that does not bind with high affinity to either the cannabinoid CB1 receptor or CB2 receptor. However, there is evidence that O-1602 has significant effects in the central nervous system as well as other parts of the body. Depending upon the model, O-1602 has anti-inflammatory or pronociceptive effects, mediated through a number of distinct receptors. This article reviews the evidence for functional effects of O-1602, particularly in the CNS, and describes its known targets as they relate to these effects. These include the abnormal cannabidiol (Abn- CBD) receptor and GPR55. The GPR18 receptor has been identified with the Abn-CBD receptor, and therefore the evidence that O-1602 also acts at GPR18 is also reviewed. Finally, the evidence that these receptor targets are expressed in the CNS and the phenotypes of cells expressing these targets is discussed, concluding with a discussion of the prospects for O-1602 as a therapeutic agent in the CNS.