Cerebrovascular CirculationCerebral ArteriesAdrenal InsufficiencyMiddle Cerebral ArteryPia MaterBlood Circulation TimeCerebral InfarctionBrainBlood Flow VelocityRenal InsufficiencyVenous InsufficiencyCerebral AngiographyExocrine Pancreatic InsufficiencyCarbon DioxideUltrasonography, Doppler, TranscranialBrain IschemiaPlacental InsufficiencyBlood PressureBasilar ArteryCerebral VeinsHypercapniaPapioCerebral PalsyVascular ResistancePartial PressureHypocapniaHypotensionXenon RadioisotopesArteriolesBlood CirculationVasodilationIntracranial PressureBemegrideRegional Blood FlowIntracranial Embolism and ThrombosisCerebrovascular DisordersVasomotor SystemSubarachnoid HemorrhageBlood Gas AnalysisOxygenVertebral ArteryHyperventilationHomeostasisHemodynamicsIschemic Attack, TransientTrimethaphanVasoconstrictionInfarction, Middle Cerebral ArteryVasodilator AgentsHypoxia, BrainIntracranial EmbolismMalaria, CerebralAcetazolamideLaser-Doppler FlowmetryBlood-Brain BarrierTime FactorsExtracorporeal CirculationIntracranial AneurysmEmbolism, AirMicrocirculationCarotid ArteriesBlood VolumeArteriesOxygen ConsumptionAnimals, NewbornJugular VeinsCatsDisease Models, AnimalCerebral HemorrhagePulmonary CirculationMagnetic Resonance ImagingAngiography, Digital SubtractionCarotid Artery, InternalPrimary Ovarian InsufficiencyStrokeIndomethacinCarotid StenosisHepatic InsufficiencyNitric OxideSwineTreatment OutcomeNitroprussideTomography, X-Ray ComputedAnoxiaRats, Sprague-DawleyMagnetic Resonance AngiographyCollateral CirculationDogsEndothelium, VascularAddison DiseaseVasoconstrictor AgentsAcetylcholineBlood VesselsRespiratory InsufficiencyHypertensionCarotid Artery DiseasesHeart RateElectroencephalographyAortic Valve InsufficiencyDose-Response Relationship, Drug