VasodilationBasilar ArteryEndothelium, VascularMuscle RelaxationParasympathetic Fibers, PostganglionicCerebrovascular CirculationVasodilator AgentsPia MaterCerebral ArteriesHypercapniaArteriolesAcetylcholineArteriesNitroglycerinNitroprussideNitric OxideVasoconstrictionBrachial ArteryRegional Blood FlowVasoconstrictor AgentsCarbon DioxideMuscle, Smooth, VascularEndotheliumVertebrobasilar InsufficiencyNitric Oxide SynthaseDose-Response Relationship, DrugVertebral ArteryMesenteric ArteriesCerebral AngiographyPulmonary ArteryCerebral InfarctionMiddle Cerebral ArteryCarotid ArteriesSubarachnoid HemorrhageDogsVasospasm, IntracranialCoronary VesselsRenal ArteryFemoral ArteryBrain Stem InfarctionsEndothelium, CornealMuscle ContractionNitroarginineCerebral PalsyRabbitsBrainRats, Sprague-DawleyEnzyme InhibitorsNG-Nitroarginine Methyl EsterPotassium ChlorideIntracranial AneurysmVasomotor SystemTime FactorsInfarction, Middle Cerebral ArteryBlood PressureBiological FactorsBrain IschemiaBlood Flow VelocityPapaverineIndomethacinSerotoninForearmAorta, Thoracicomega-N-MethylarginineBradykininArterial Occlusive DiseasesArginineMagnetic Resonance AngiographyIschemic Attack, TransientNitric Oxide Synthase Type IIICarotid Artery, InternalRats, Wistar15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic AcidIliac ArteryRadial ArteryHemodynamicsMammary ArteriesCalciumRelaxationSwineNorepinephrineMicrocirculationRelaxation TherapyTomography, X-Ray ComputedCoronary Artery BypassCells, CulturedDisease Models, AnimalMagnetic Resonance ImagingAortaCarotid Artery DiseasesVascular ResistanceCerebral VeinsMalaria, CerebralCyclic GMPIntracranial Embolism and ThrombosisPosterior Cerebral ArteryNitric Oxide DonorsCoronary CirculationCircle of WillisCerebral Hemorrhage