In vivo assessment of adenoviral vector‐mediated gene expression of dopamine D2 receptors in the rat striatum by positron emission tomography

Abstract
For functional assessment of gene therapy in experimental animals, in vivo assessment of transferred genes will provide a major advance over an in vitro analysis which must be done post‐hoc. In the current study we conducted positron emission tomography (PET) analysis in rats following injection of the adenoviral vector encoding the cDNA for the rat dopamine D2 receptors (D2R) (AdCMV.DopD2R) into rat brain to provide a quantitative evaluation of D2R overexpression. Quantitative measurements as well as images by PET and ex vivo autoradiography demonstrated the significant increase of D2R binding of [11C]raclopride, a specific D2R radioligand, in the AdCMV.DopD2R‐injected rat striatum 2 or 3 days after vector injection. Longitudinal in vivo assessment of the gene expression by PET demonstrated decreased binding of [11C]raclopride with time, which was in agreement with the observation in a cross‐sectional autoradiographic study. The results of the current study demonstrate that PET can be used for longitudinal in vivo assessment of D2R expression mediated by adenoviral vector in rat brain. Synapse 43:195–200, 2002.