A, In situ hybridization against the transgenic D2 mRNA. Expression was detected in the striatum and olfactory tubercle of D2OE mice and was completely absent in D2OE-Dox and control mice. B, In situ hybridization of two adjacent 16 μm sections hybridized with an antisense oligonucleotide against the mouse D2 receptor coding sequence (top) or an antisense oligonucleotide directed against the transgenic D2 mRNA (bottom). Whereas endogenous D2 receptors are expressed in dopaminergic midbrain neurons, transgenic D2 receptors are absent. C, Double in situ hybridization using cRNA probes against acetylcholinesterase (AChE; left) and the transgenic D2 receptor (trD2R; middle). The right panel shows the overlay (with DAPI nuclear stain).
