1-Trifluoromethyl-2,3,4,9-tetrahydro-1H-B-carboline

Mechanism of action

Although βCCE and other β-carbolines are not endogenous BZR ligands (vide supra) and are not currently approved for clinical use, they are used to characterize different GABAA/BZR subtypes (based on a and g subunit composition) and function (e.g., the partial agonist abecarnil) toward the discovery of anxioselective drugs. In this regard, the β-carboline ring system is planar in comparison to the boat conformation of the 1,4-benzodiazepines; thus, β-carbolines have been useful to extend structure–activity relationship information for the agonist, antagonist, and inverse agonist pharmacophores of the various GABAA/BZR subtypes.

Clinical Use

Several β-carbolines have approximately 10-fold higher affinity for the BZR when compared to diazepam. The ethyl ester of β-carboline-3-carboxylic acid (βCCE), identified in human urine extracts as an artifact of the extraction procedure, has very high affinity for the BZR.