Regional distribution of PPAR beta in the cerebellum of the rat

Peroxisome proliferator-activated I receptors (PPARs) are nuclear receptors belonging to the superfamily of steroid hormone receptors. Different subty pes of PPARs (alpha, beta and gamma) have been described, PPAR alpha and PP AR gamma presenting a more tissue specific distribution than PPAR beta. Spe cific polyclonal antibodies directed against each subtype of PPARs were pro duced and characterized. The general expression of PPAR proteins was invest igated in rat brain and cerebellar extracts by Western blotting. In order t o localize the PPAR proteins and transcripts in the cerebellum, immunocytoc hemical and in situ hybridization assays were performed. Our Western blot a nalysis revealed a 52 kDa band with the anti-PPAR beta antibody in brain an d cerebellar homogenates, but no band with the anti-PPAR alpha, gamma1/gamm a2 and gamma2. By immunocytochemistry, a high expression of PPAR beta appea red in the nucleus of Purkinje cells. The in situ hybridization assays show ed that PPAR beta transcripts were localized in the cytoplasm of the Purkin je cells. No labeling was observed for the other PPAR isoforms in the cereb ellum. Purkinje cells represent the only efferent way from the cerebellar c ortex and modulate spinal cord activity. The regional distribution of PPAR beta in these cells suggests some fundamental role for this subtype in this pathway. (C) 2000 Elsevier Science B.V. All rights reserved.