Regional Blood FlowMicrospheresBlood Flow VelocityCardiac OutputCerebrovascular CirculationHemodynamicsBlood CirculationVascular ResistanceDogsCoronary CirculationSplanchnic CirculationBlood PressureScandiumRenal CirculationLiver CirculationPulmonary CirculationLaser-Doppler FlowmetryXenon RadioisotopesHeart RateAnesthesiaOxygenBlood Gas AnalysisRadioisotopesOxygen ConsumptionNafronylNitrogen RadioisotopesTomography, Emission-ComputedPhentolamineOxygen RadioisotopesVentilation-Perfusion RatioBrainKidneySwineHindlimbCarbon DioxideMicrocirculationOrganotechnetium CompoundsVasoconstrictionModels, CardiovascularPartial PressureTime FactorsImmersionBlood VolumeIliac ArteryRenal ArteryIschemiaVasodilationPulmonary Gas ExchangeVasodilator AgentsSupine PositionAnesthesia, InhalationHeartNG-Nitroarginine Methyl EsterCollateral CirculationMyocardiumIsofluraneLegInfusions, ParenteralCatsNitric OxideMesenteric ArteriesRats, Sprague-DawleyFlow CytometryMuscle, SkeletalSympathetic Nervous SystemPropranololForearmTomography, Emission-Computed, Single-PhotonSheepNorepinephrineDose-Response Relationship, DrugRats, WistarRats, Inbred StrainsRabbitsInjections, IntravenousPulsatile FlowNitric Oxide SynthaseMagnetic Resonance ImagingCoronary VesselsDisease Models, AnimalReference ValuesArteriesLungMyocardial ContractionCapillariesBlood DonorsEnzyme InhibitorsMyocardial InfarctionCoronary DiseaseRheologyAnoxiaHyperemiaUltrasonography, DopplerPostureXenonGene FlowBlood Circulation TimeUltrasonography, Doppler, ColorPlethysmographyCerebral Arteries