Regional, cellular and subcellular distribution of calcium-activated cyclic nucleotide phosphodiesterase and calcium-dependent regulator in porcine brain.

Abstract— Cyclic nucleotide phosphodiesterase activity (calcium-dependent and calcium-independent) and CDR (calcium-dependent regulator protein of phosphodiesterase) are present in all ten brain regions examined, with the specific activity of both being highest in areas predominating in grey matter and lowest in areas consisting largely of white matter. Fractionation of cerebral cortex into neuronal and glial perikarya shows that cyclic nucleotide phosphodiesterase and CDR are present at approximately equal levels in both cell types. Subcellular fractionation reveals that calcium-sensitive enzyme specific activity, as well as CDR are highly localized in the 100,000 g supernatant fraction. Regional, cellular and subcellular distribution studies indicate that the distribution of CDR closely parallels the distribution of enzyme specific activity, suggesting that the levels of cyclic nucleotide phosphodiesterase and CDR may be synchronized.