3',5'-Cyclic-AMP PhosphodiesterasesCyclic AMPCyclic Nucleotide Phosphodiesterases, Type 4Cyclic Nucleotide Phosphodiesterases, Type 3Phosphoric Diester HydrolasesCyclic Nucleotide Phosphodiesterases, Type 1Cyclic Nucleotide Phosphodiesterases, Type 23',5'-Cyclic-GMP PhosphodiesterasesPhosphodiesterase Inhibitors2',3'-Cyclic-Nucleotide PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 5RolipramCyclic GMPCyclic Nucleotide Phosphodiesterases, Type 71-Methyl-3-isobutylxanthineNucleotides, CyclicPurinones