Regional Blood FlowBlood VolumeBlood PressureBlood Flow VelocityHemorrhageHeart RateHypertensionCerebrovascular CirculationLaser-Doppler FlowmetryFlow CytometryVascular ResistancePulsatile FlowXenon RadioisotopesMicrospheresHemodynamicsDogsMicrocirculationRenal CirculationOxygenVasodilationLiver CirculationOxygen ConsumptionPulmonary CirculationTomography, Emission-ComputedRheologySplanchnic CirculationCarbon DioxideHyperemiaOxygen RadioisotopesBrainUltrasonography, DopplerXenonGene FlowBlood Circulation TimeUltrasonography, Doppler, ColorPlethysmographyVasodilator AgentsCollateral CirculationCerebral ArteriesTime FactorsArteriesVasoconstrictionModels, CardiovascularUltrasonography, Doppler, TranscranialCapillariesNitric OxideHindlimbPartial PressureIschemiaBlood Gas AnalysisLegMiddle Cerebral ArteryRetinal VesselsAntipyrinePerfusionMuscle, SkeletalChoroidSkin TemperatureVasomotor SystemFemoral ArteryBrain IschemiaSkinAdenosineRats, Sprague-DawleyNitrogen RadioisotopesTomography, Emission-Computed, Single-PhotonSheepTechnetium Tc 99m ExametazimeReference ValuesOximesArteriolesOphthalmic ArteryKryptonNitroprussideAcetazolamideSwineEndothelium, VascularHomeostasisRetinal ArteryBlood ViscosityNG-Nitroarginine Methyl EsterHypercapniaUltrasonography, Doppler, PulsedPhysical ExertionMagnetic Resonance ImagingKidneyAnoxiaAnesthesiaHeartBlood VesselsUterusIntracranial PressureCoronary CirculationCatsHematocritNitric Oxide SynthaseDisease Models, AnimalInfusions, Intra-ArterialInjections, Intra-ArterialRest