Phosphodiesterase Inhibitors1-Methyl-3-isobutylxanthine3',5'-Cyclic-AMP PhosphodiesterasesRolipramPhosphoric Diester HydrolasesPurinones4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinoneCyclic AMP3',5'-Cyclic-GMP PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 4TheophyllinePhosphodiesterase 3 InhibitorsPhosphodiesterase 4 InhibitorsCyclic GMPMilrinoneCyclic Nucleotide Phosphodiesterases, Type 3Phosphodiesterase 5 InhibitorsPapaverinePyrrolidinonesCyclic Nucleotide Phosphodiesterases, Type 5Phosphodiesterase ICyclic Nucleotide Phosphodiesterases, Type 12',3'-Cyclic-Nucleotide PhosphodiesterasesColforsinPentoxifyllineBucladesineSulfonesXanthines8-Bromo Cyclic Adenosine MonophosphateNucleotides, CyclicPyridazinesAdenylate CyclasePurinesIsoproterenolEnoximoneVinca AlkaloidsAmrinoneAminophyllineBufo bufoCyclic AMP-Dependent Protein KinasesCyclic Nucleotide Phosphodiesterases, Type 2Dose-Response Relationship, DrugPhotoreceptor CellsCyclic Nucleotide Phosphodiesterases, Type 6KineticsDibutyryl Cyclic GMPPiperazinesCalciumGuanylate CyclaseDipyridamoleErectile DysfunctionAlprostadilPhthalazinesPyridonesThionucleotidesAdenosinePhenylisopropyladenosineCyclic Nucleotide Phosphodiesterases, Type 7Guinea PigsEnzyme ActivationCells, CulturedProstaglandins IPenile ErectionCyclic GMP-Dependent Protein KinasesSecond Messenger SystemsStimulation, ChemicalIsoquinolinesNitric OxideProstaglandins E, SyntheticVasodilator AgentsTransducinRats, Inbred StrainsNitroprussideTetrazolesCattleImidazolesCholera ToxinNicotinic AcidsIloprostIsoenzymesRod Cell Outer SegmentReceptors, Adrenergic, betaTriazinesOxadiazolesAdrenergic beta-AgonistsEnzyme InhibitorsRats, WistarCaffeineAtrial Natriuretic FactorPropranololMuscle, SmoothCardiotonic AgentsDrug SynergismSignal TransductionProstaglandins ERats, Sprague-DawleyTime FactorsAdenosine-5'-(N-ethylcarboxamide)NaphthyridinesMethylene Blue