Phosphodiesterase InhibitorsCyclic Nucleotide Phosphodiesterases, Type 5Phosphodiesterase 5 InhibitorsSulfonesCyclic Nucleotide Phosphodiesterases, Type 43',5'-Cyclic-GMP Phosphodiesterases3',5'-Cyclic-AMP PhosphodiesterasesPurinesRolipramPhosphoric Diester HydrolasesCyclic Nucleotide Phosphodiesterases, Type 3Phosphodiesterase 3 InhibitorsPhosphodiesterase 4 InhibitorsPiperazinesErectile Dysfunction4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinonePurinonesCyclic Nucleotide Phosphodiesterases, Type 1Vinca AlkaloidsCyclic GMPCarbolinesPenile ErectionTriazinesPyrrolidinonesCyclic AMPMilrinonePhosphodiesterase IPriapismPenisCounterfeit DrugsCyclic GMP-Dependent Protein KinasesPyrimidinones1-Methyl-3-isobutylxanthine2',3'-Cyclic-Nucleotide PhosphodiesterasesCyclopropanesPyridinesHypertension, PulmonaryNitric Oxide DonorsEnzyme InhibitorsImidazolesDose-Response Relationship, DrugVasodilator AgentsGuanylate CyclaseNitric OxideCyclic Nucleotide Phosphodiesterases, Type 2SulfonamidesHypertrophy, Right VentricularBenzamidesCyclic Nucleotide Phosphodiesterases, Type 6Cyclic Nucleotide Phosphodiesterases, Type 7Muscle RelaxationIsoproterenolTheophyllineIsoenzymesRats, Sprague-DawleyCells, CulturedKineticsRats, WistarDisease Models, AnimalSignal TransductionPulmonary ArteryCyclooxygenase 2 InhibitorsGuinea PigsVasodilationTransducinEnzyme ActivationAdministration, OralRabbitsTime FactorsCyclooxygenase InhibitorsRod Cell Outer SegmentPapaverinePhotoreceptor CellsAdenylate CyclaseBlood PressureDouble-Blind MethodCalmodulinCattlePyrophosphatasesCyclic AMP-Dependent Protein KinasesNucleotides, CyclicCyclooxygenase 2HemodynamicsPyridazinesColforsinMolecular Sequence DataPyrazolesProstaglandin-Endoperoxide SynthasesCalciumAmino Acid SequenceSubstrate SpecificityXanthinesTreatment OutcomePhosphorylationBucladesineCyclooxygenase 1AminopyridinesHydrolysisNitrobenzenesStructure-Activity Relationship