Phosphodiesterase InhibitorsRolipram4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinoneMilrinonePurinonesPyrrolidinones3',5'-Cyclic-AMP PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 41-Methyl-3-isobutylxanthinePhosphoric Diester Hydrolases3',5'-Cyclic-GMP PhosphodiesterasesPhosphodiesterase 3 InhibitorsPhosphodiesterase 4 InhibitorsCyclic AMPCyclic Nucleotide Phosphodiesterases, Type 5Cyclic GMPSulfonesTheophyllineCyclic Nucleotide Phosphodiesterases, Type 3PyridazinesPhosphodiesterase 5 InhibitorsPapaverinePurinesCyclopropanesPhosphodiesterase IAminopyridinesCyclic Nucleotide Phosphodiesterases, Type 12',3'-Cyclic-Nucleotide PhosphodiesterasesColforsinPentoxifyllineBucladesineXanthinesPiperazines8-Bromo Cyclic Adenosine MonophosphateNucleotides, CyclicDose-Response Relationship, DrugAdenylate CyclaseGuinea PigsIsoproterenolPyridinesEnoximoneVinca AlkaloidsBenzamidesAmrinoneAminophyllineBufo bufoCyclic AMP-Dependent Protein KinasesCyclic Nucleotide Phosphodiesterases, Type 2Photoreceptor CellsCyclic Nucleotide Phosphodiesterases, Type 6KineticsDibutyryl Cyclic GMPCalciumGuanylate CyclaseDipyridamoleErectile DysfunctionAlprostadilPhthalazinesPyridonesThionucleotidesAdenosinePhenylisopropyladenosineCyclic Nucleotide Phosphodiesterases, Type 7Enzyme 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-Dawley