Cerebrovascular CirculationCerebral ArteriesMiddle Cerebral ArteryPia MaterBlood Circulation TimeBrainCerebral InfarctionBlood Flow VelocityCarbon DioxideCerebral AngiographyUltrasonography, Doppler, TranscranialBrain IschemiaBlood PressureBasilar ArteryHypercapniaPapioCerebral VeinsCerebral PalsyVascular ResistancePartial PressureHypocapniaArteriolesBlood CirculationXenon RadioisotopesHypotensionVasodilationIntracranial PressureBemegrideOxygenEnergy MetabolismHomeostasisIntracranial Embolism and ThrombosisRegional Blood FlowSubarachnoid HemorrhageVasomotor SystemCerebrovascular DisordersLipid MetabolismBlood Gas AnalysisHyperventilationTrimethaphanIschemic Attack, TransientOxygen ConsumptionHemodynamicsVasoconstrictionVertebral ArteryInfarction, Middle Cerebral ArteryHypoxia, BrainVasodilator AgentsIntracranial EmbolismMalaria, CerebralAcetazolamideBlood-Brain BarrierExtracorporeal CirculationLaser-Doppler FlowmetryTime FactorsIntracranial AneurysmEmbolism, AirAnimals, NewbornBlood VolumeCatsMicrocirculationCarotid ArteriesRats, Sprague-DawleySwineIndomethacinDisease Models, AnimalArteriesCerebral HemorrhageNitric OxidePulmonary CirculationMagnetic Resonance ImagingCarotid Artery, InternalAngiography, Digital SubtractionStrokeAnoxiaDogsCarotid StenosisJugular VeinsGlucoseNitroprussideEndothelium, VascularMagnetic Resonance AngiographyCollateral CirculationDose-Response Relationship, DrugTomography, X-Ray ComputedLiverMetabolismAcetylcholineBlood VesselsVasoconstrictor AgentsNitric Oxide SynthaseProstaglandinsRabbitsElectroencephalographyHeart RateCarotid Artery DiseasesHypertensionReference ValuesAnterior Cerebral ArteryPosterior Cerebral Artery