(-)-[11C]dihydrotetrabenazine

(-)-[11C]dihydrotetrabenazine ((-)-[11C]DTBZ) is a radiolabeled small molecule used as a positron emission tomography (PET) imaging research tool. It is the levorotary stereoisomer of dihydrotetrabenazine, labeled with the positron-emitting isotope carbon-11. While its structural target is the vesicular monoamine transporter type 2 (VMAT2), the (-)-isomer possesses an extremely low affinity for this transporter (Ki ≈ 2.2 μmol/L) compared to its (+)-enantiomer (Ki ≈ 1 nmol/L). Due to this low affinity, it is primarily utilized in clinical research as an inactive control to quantify and subtract nonspecific binding and free tracer signal, thereby allowing for more precise determination of specific VMAT2 binding when used alongside the active (+)-isomer. It was developed at the University of Michigan and is used to study neurological conditions such as Parkinson's disease and Tourette syndrome.

Other names

(-)-alpha-[11C]dihydrotetrabenazine(-)-9,10-dimethoxy-3-(2-methylpropyl)-1,3,4,6,7,11b-hexahydro-2H-pyrido[2,1-a]isoquinolin-2-ol