Phosphodiesterase type 4 isozymes expression in human brain examined by insitu hybridization histochemistry and [H-3]rolipram binding autoradiography - Comparison with monkey and rat brain

We have examined the distribution of Four different cyclic AMP-specific pho sphodiesterase isozyme (PDE4A, PDE4B. PDE4C and PDE4D) mRNAs in the brain o f different species by in situ hybridization histochemistry and by autoradi ography with [H-3]rolipram. We have compared the localization of each isozy me in human brain with that in rat and monkey brain. We have Found that the four PDE4 isoforms display a differential expression pattern at both regio nal and cellular level in the three species. PDE4A. PDE4B and PDE4D are wid ely distributed in human brain, with the two latter appearing more abundant . In contrast, PDE4C in human brain, presents a more restricted distributio n, limited to cortex, some thalamic nuclei and cerebellum. This is at varia nce with the distribution of PDE4C in rat brain, where it is found exclusiv ely in olfactory bulb. In monkey brain, the highest expression for this iso form is found in the claustrum, and at lower levels in cortical areas and c erebellum PDE4B presented a broad distribution, being expressed in both neu ronal and non neuronal cell populations. In general, the distribution of bi nding sites visualized with [H-3]rolipram correlated well with the expressi on of each PDE4 isozyme. (C) 2000 Elsevier Science B.V. All rights reserved .