Phosphodiesterase InhibitorsCyclic Nucleotide Phosphodiesterases, Type 5Phosphodiesterase 5 Inhibitors3',5'-Cyclic-GMP PhosphodiesterasesSulfones3',5'-Cyclic-AMP PhosphodiesterasesCyclic Nucleotide Phosphodiesterases, Type 4PurinesPhosphoric Diester HydrolasesRolipramCyclic Nucleotide Phosphodiesterases, Type 3Phosphodiesterase 3 InhibitorsPhosphodiesterase 4 InhibitorsErectile DysfunctionPiperazines4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinonePurinonesVinca AlkaloidsCyclic Nucleotide Phosphodiesterases, Type 1CarbolinesPenile ErectionCyclic GMPTriazinesPyrrolidinonesMilrinonePhosphodiesterase ICyclic AMPPriapismPenisCounterfeit DrugsPyrimidinonesHypertension, Pulmonary1-Methyl-3-isobutylxanthineCyclic GMP-Dependent Protein KinasesCyclopropanes2',3'-Cyclic-Nucleotide PhosphodiesterasesNitric Oxide DonorsPyridinesVasodilator AgentsGuanylate CyclaseImidazolesHypertrophy, Right VentricularCyclic Nucleotide Phosphodiesterases, Type 2Nitric OxideCyclic Nucleotide Phosphodiesterases, Type 6Dose-Response Relationship, DrugBenzamidesIsoproterenolCyclic Nucleotide Phosphodiesterases, Type 7Muscle RelaxationTheophyllineSulfonamidesTransducinPulmonary ArteryDisease Models, AnimalGuinea PigsEnzyme InhibitorsRod Cell Outer SegmentVasodilationRats, Sprague-DawleyKineticsRats, WistarPapaverinePhotoreceptor CellsCells, CulturedRabbitsAdministration, OralTime FactorsAdenylate CyclasePyrophosphatasesSignal TransductionNucleotides, CyclicCalmodulinBlood PressureDouble-Blind MethodEnzyme ActivationHemodynamicsCattleXanthinesColforsinCyclic AMP-Dependent Protein KinasesTreatment OutcomeIsoenzymesPyridazinesBucladesineRetinal Rod Photoreceptor CellsAmrinoneGlycerylphosphorylcholineMolecular Sequence DataRana catesbeianaCalcium8-Bromo Cyclic Adenosine MonophosphatePentoxifyllineAminophyllineAmino Acid SequenceHydrolysisNucleotidasesThionucleotidesCyclic IMPDictyostelium