Figure 5.

Cell type specific expression patterns of cholesterol 24-hydroxylase in murine brain. Coronal sections were subjected to in situ mRNA hybridization analysis using a ³³P-labeled RNA probe (A) or immunohistochemical analyses using an antipeptide antibody probe (B-D). (A) Light pink mRNA hybridization signals reveal an expression pattern consistent with neurons in the cortex (C), hippocampus (HC), dentate gyrus (DG), and thalamus (T). Magnification = ×0.5. (B) A similar pattern of cholesterol 24-hydroxylase protein is revealed at the same magnification by dark purple signal. (C) A photomicrograph of the cortical region of the brain taken at higher magnification (×10). Individual pyramidal neurons in layers I, II, III, and V contain dark red signal indicative of 24-hydroxylase protein. Smaller nonpyramidal cells concentrated in cortical layer IV contain little or no detectable signal. (D) Staining of 24-hydroxylase protein in Purkinje cells of the cerebellum (arrowheads). Signal is also present in the dendritic trees of Purkinje cells. Magnification = ×2.