Effect of chronic DORA-22 treatment (100 mg/kg per day for 5 weeks) on amyloid β plaques in 5XFAD mice. Representative photomicrograph of amyloid β plaque staining with 6E10 antibody is shown in the brown staining from a female 5XFAD mouse treated with vehicle (A) or treated with DORA-22 (B). Tissue sections are counterstained with methyl green. An arrow in (A) indicates the location of higher magnification view of the staining shown in (C). (D) The color markup of the positive pixel algorithm (Aperio Image Scope software) demonstrates the ability of the algorithm to quantify the 6E10 immunohistochemical staining accurately. The blue color in the markup indicates negative (unstained) pixels. The yellow, orange, and red color in the markup indicates positive (stained) pixels of increasing intensity, respectively. Orange and red color positive pixels were used in the quantification. Results of the area fraction quantification for the neocortex, hippocampus, and subiculum identified according to the Allen Institute mouse brain atlas (mouse.brain-map.org) on the digital neuropathologic slides, is shown in (E). Levels of PBS soluble and FA soluble Aβ1-40 (F) and Aβ1-42 (G) were measured in cortex homogenates by enzyme-linked immunosorbent assay. Data are plotted as the mean ± SEM (N = 10–12 per group). Abbreviations: FA, formic acid; DORA, dual orexin receptor antagonist; PBS, phosphate-buffered saline; SEM, standard error of the mean.