MilrinonePhosphodiesterase Inhibitors3',5'-Cyclic-AMP PhosphodiesterasesPhosphodiesterase 3 InhibitorsPhosphoric Diester HydrolasesCyclic Nucleotide Phosphodiesterases, Type 3Pyridones3',5'-Cyclic-GMP PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 4Phosphodiesterase 4 InhibitorsAmrinoneRolipramPhosphodiesterase 5 InhibitorsPhosphodiesterase ICyclic Nucleotide Phosphodiesterases, Type 1Cardiotonic Agents1-Methyl-3-isobutylxanthineCyclic Nucleotide Phosphodiesterases, Type 5Cyclic AMP4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinoneCyclic GMPPurinones2',3'-Cyclic-Nucleotide PhosphodiesterasesPyridazinesCyclic Nucleotide Phosphodiesterases, Type 2HydrazonesSulfonesCyclic Nucleotide Phosphodiesterases, Type 6TheophyllinePurinesVasodilator AgentsCyclic Nucleotide Phosphodiesterases, Type 7PyrrolidinonesTransducin