CB13 is an agonist of both CB1 and CB2, with poor penetration of the central nervous system.81 However, this compound was not effective in murine TNBS or DSS colitis when administered intraperitoneally, but was effective when injected intracerebroventricularly.79 Equally ineffective was the peripherally restricted, non-selective agonist, SAB378.76 This evidence concerns the gene CNR2 and colitis.