ABSTRACT
The method used for identifying the Phosphodiesterase 9A (PDE9A) inhibitor involved a unique assay system for monitoring intracellular 3',5'-cyclic adenosinemonophosphate signaling. Subcellular localization of the PDE9A splice variants PDE9A1 and PDE9A6 has been investigated using recombinant proteins produced in HEK293 cells. The tissue-expression pattern of PDE9A mRNA is relatively broad in humans with some variants exhibiting unique tissue-expression patterns. cDNAs for the ninth PDE family were retrieved from the Incyte human expressed sequence tag (EST) database and the mouse EST database using human PDE4B cDNA and mouse PDE1A2 cDNA sequences as queries, respectively. PDE9A mRNA is also expressed in all regions of the cerebellum, especially in Purkinje cells where PDE9A mRNA expression is highly abundant. To determine which cell types express PDE9A mRNA in the brain, double staining of PDE9A antisense probe with anti–neuronal nuclei or anti–glial fibrillary acidic protein antibody was performed.
