LOCALIZATION OF THE PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR IN THEBRAIN

THIS paper describes the localization of the alpha-type peroxisome pro liferator-activated receptor (PPAR alpha) in the rat brain using immun ocytochemistry and in situ hybridization. Expression of PPAR alpha mRN A was highest in the granular cells of the cerebellar cortex and in th e dentate gyrus, with a somewhat lower expression in areas CA1-CA4 of the hippocampus. PPAR alpha mRNA was also found in some neurones of th e cerebral cortex (layers II-IV) and the molecular layer of the cerebe llar cortex, and in the olfactory tubercle. Immunocytochemistry reveal ed nuclear PPAR alpha-immunoreactivity (-IR) in the same areas as seen with the in situ hybridization. Furthermore, PPAR alpha-IR was also l ocalized in oligodendrocytes, whereas the other glial cell types appea red to lack PPAR alpha. These results suggest that peroxisome prolifer ators and chemicals acting similarly have effects on discrete populati ons of neurones. The presence of PPAR alpha in oligodendrocytes lends further support to the suggestion that peroxisomes are imprortant in t he assembly and degradation of myelin.