Regional Blood FlowBlood Flow VelocityBlood CirculationPulmonary CirculationCardiac OutputVascular ResistanceHemodynamicsVena Cava, SuperiorMicrospheresCerebrovascular CirculationBlood PressureDogsPulmonary ArterySplanchnic CirculationCoronary CirculationRenal CirculationLaser-Doppler FlowmetryScandiumLiver CirculationHeart RateXenon RadioisotopesOxygenAnesthesiaOxygen ConsumptionMicrocirculationTomography, Emission-ComputedKidneyBlood Gas AnalysisCarbon DioxideBrainOxygen RadioisotopesVasodilationNitrogen RadioisotopesVasodilator AgentsVasoconstrictionRadioisotopesFlow CytometryPhentolamineBlood VolumePartial PressurePulsatile FlowSwineTime FactorsNafronylHindlimbIschemiaNitric OxideVentilation-Perfusion RatioModels, CardiovascularNG-Nitroarginine Methyl EsterRenal ArteryOrganotechnetium CompoundsHeartCollateral CirculationRats, Sprague-DawleyCatsSheepLegPulmonary Gas ExchangeNorepinephrineIliac ArterySympathetic Nervous SystemImmersionMuscle, SkeletalRats, WistarArteriesPropranololSupine PositionAnesthesia, InhalationDose-Response Relationship, DrugNitric Oxide SynthaseMesenteric ArteriesMyocardiumIsofluraneInjections, IntravenousTomography, Emission-Computed, Single-PhotonDisease Models, AnimalRats, Inbred StrainsReference ValuesInfusions, ParenteralRabbitsRetinal ArteryAnoxiaCerebral ArteriesLungRheologyMagnetic Resonance ImagingOphthalmic ArteryCapillariesHyperemiaUltrasonography, DopplerForearmXenonGene FlowEnzyme InhibitorsBlood Circulation TimeUltrasonography, Doppler, ColorCoronary VesselsRetinal VesselsPlethysmography