Regional Blood FlowCollateral CirculationMicrospheresBlood Flow VelocityCerebrovascular CirculationHemodynamicsCardiac OutputDogsVascular ResistanceBlood CirculationCoronary CirculationSplanchnic CirculationBlood PressureScandiumRenal CirculationLiver CirculationCollateral LigamentsLaser-Doppler FlowmetryPulmonary CirculationXenon RadioisotopesHeart RateOxygenAnesthesiaHindlimbMedial Collateral Ligament, KneeRadioisotopesBlood Gas AnalysisNitrogen RadioisotopesOxygen ConsumptionNafronylIschemiaTomography, Emission-ComputedPhentolamineBrainVentilation-Perfusion RatioOxygen RadioisotopesSwineKidneyMicrocirculationCarbon DioxideIliac ArteryOrganotechnetium CompoundsModels, CardiovascularVasoconstrictionTime FactorsVasodilator AgentsBlood VolumeVasodilationImmersionPartial PressureRenal ArteryPulmonary Gas ExchangeHeartNG-Nitroarginine Methyl EsterSupine PositionAnesthesia, InhalationCatsMyocardiumIsofluraneLegRats, Sprague-DawleyNitric OxideMesenteric ArteriesInfusions, ParenteralMuscle, SkeletalFlow CytometryTomography, Emission-Computed, Single-PhotonSympathetic Nervous SystemDisease Models, AnimalPropranololSheepRats, WistarForearmRabbitsArteriesNorepinephrineNitric Oxide SynthaseMagnetic Resonance ImagingRats, Inbred StrainsDose-Response Relationship, DrugInjections, IntravenousCoronary DiseasePulsatile FlowReference ValuesCoronary VesselsCapillariesMyocardial InfarctionLungMyocardial ContractionLigationCircle of WillisFemoral ArteryCerebral ArteriesHyperemiaBlood DonorsEnzyme InhibitorsArterial Occlusive DiseasesUltrasonography, DopplerRheologyUltrasonography, Doppler, Color