Figure 2. TH and HA immunostaining in the LC. A, Experimental design for the DREADD study. The AAV-HA tag vector was injected via stereotaxic injections into Ts65Dn or NS mice. Twenty days after surgery, mice were tested for behavior. After a 2 d washout period, mice were given the opposite treatment in a crossover design. B–D, TH immunostaining (B, green), HA staining (C, red), and overlay (D, yellow) in a normosomic mouse LC. E–G, TH (E, green), HA (F, red), and overlay (G, yellow) in the LC of a Ts65Dn mouse. H, Transduction efficiency table, showing range, mean, and SD measured in a total of 19 double-labeled sections. I, FITC-labeled HA immunostaining in the LC region at a higher magnification, with evidence of axonal transport of the DREADD receptors (arrowheads). Scale bars: D, G, 100 μm; I, 40 μm.