VasodilationPulmonary CirculationPulmonary ArteryPersistent Fetal Circulation SyndromeNitric OxideSheepVasodilator AgentsHypertension, Pulmonary15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic AcidVascular ResistanceSydnonesFetusAdministration, InhalationCyclic Nucleotide Phosphodiesterases, Type 5PurinonesNitroprussideOxadiazolesGuanylate CyclaseAnoxiaCyclic GMP3',5'-Cyclic-GMP PhosphodiesterasesAcetylcholineHemodynamicsNitric Oxide DonorsLungEndothelium, VascularNitric Oxide SynthasePhosphodiesterase InhibitorsCharybdotoxinAerosolsVasoconstrictor AgentsVasoconstrictionEnzyme InhibitorsBenzoatesPotassium Channel BlockersQuinoxalinesEpoprostenolForearmMuscle, Smooth, VascularOxygenBlood PressureDose-Response Relationship, DrugDogsArteriolesPotassium ChannelsRegional Blood FlowRats, Sprague-DawleyPregnancyAnimals, NewbornBrachial Arteryomega-N-MethylarginineHyperemiaNitroglycerinCoronary CirculationCoronary VesselsNG-Nitroarginine Methyl EsterBlood Flow VelocityLaser-Doppler FlowmetryAdenosineVasomotor SystemMicrocirculationEndothelium-Dependent Relaxing FactorsMesenteric ArteriesNitric Oxide Synthase Type IIINitroarginineBradykininIndomethacinPlethysmographyPia MaterBiological FactorsInfusions, Intra-ArterialArginineCyclooxygenase InhibitorsSkinBretylium TosylateArteriesHeart RatePapaverineSweatingCerebral ArteriesSkin TemperatureGlyburideMyographyRenal CirculationCalcitonin Gene-Related PeptideBody Temperature RegulationIsosorbide DinitrateCerebrovascular CirculationProstaglandinsFlushingBlood VesselsSwinePurinergic P1 Receptor AntagonistsPhenylephrineNorepinephrineHypertensionPotassium ChlorideRetinal ArteryRats, WistarNitrites