Fig. 2.

CB₂ mRNA expression in VTA DA neurons by ISH assays. (A, a) CB_2A mRNA and the location detected by a CB₂-riboprobe. (A, b) The antisense, but not the sense (control), riboprobe detected CB₂ mRNA in midbrain neurons in WT and CB₁^−/− mice, but not in CB₂^−/− mice. (A, c) Double-label fluorescent images of CB₂ mRNA (by ISH) and TH (by IHC) staining, illustrating CB₂ mRNA staining in individual TH-positive VTA DA neurons in WT mice, but not in CB₂^−/− mice (Zimmer strain). (B, a) CB_2A mRNA and the location detected by a CB₂-RNAscope probe. (B, b and c) CB₂-RNAscope probe-detected CB₂ mRNA in VTA DA neurons in WT and CB₂^−/− mice. This probe detected CB₂ mRNA in CB₂^−/− mice because it targets the downstream UTR region rather than the upstream gene-deleted region. Scales are shown in the figures. Also see Fig. S1.