Basilar ArteryPonsArteriesVertebrobasilar InsufficiencyVertebral ArteryCerebral ArteriesBrain Stem InfarctionsPulmonary ArteryCarotid ArteriesSubarachnoid HemorrhageCerebral AngiographyVasospasm, IntracranialMesenteric ArteriesRenal ArteryFemoral ArteryVasodilationVasoconstrictionCarotid Artery, InternalIntracranial AneurysmMuscle, Smooth, VascularIliac ArteryCoronary Artery BypassRadial ArteryArterial Occlusive DiseasesMammary ArteriesVasodilator AgentsCerebrovascular CirculationMagnetic Resonance AngiographyDogsCarotid Artery DiseasesSerotoninSubclavian ArteryMiddle Cerebral ArteryBrain StemTomography, X-Ray ComputedSplenic ArteryBrachial ArteryPotassium ChloridePapaverineCircle of WillisCoronary VesselsMuscle ContractionHepatic ArteryVasoconstrictor AgentsCarotid Artery, CommonPicolinesSumatriptanRabbitsAcetylcholineEndothelium, VascularAngiography, Digital SubtractionUltrasonography, Doppler, TranscranialCeliac ArteryIschemic Attack, TransientIntracranial ArteriosclerosisAneurysm, RupturedOphthalmic ArteryTreatment OutcomeMesenteric Artery, SuperiorCerebral InfarctionEmbolization, TherapeuticIntracranial Embolism and ThrombosisAngiographyUmbilical ArteriesRenal Artery ObstructionThoracic ArteriesVasomotor SystemTemporal ArteriesMagnetic Resonance ImagingBronchial ArteriesNitroprussidePosterior Cerebral ArteryPopliteal ArteryMuscle RelaxationUlnar ArteryNitroglycerinSubclavian Steal SyndromeDose-Response Relationship, DrugStentsInfusions, Intra-ArterialUterine ArteryRegional Blood FlowThrombolytic TherapyTime FactorsBrainRats, Sprague-DawleySpasmConstriction, PathologicIntracranial ThrombosisCoronary AngiographyInjections, Intra-ArterialComaCarotid Artery, ExternalBrain IschemiaNorepinephrine15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic AcidNimodipineCerebrovascular DisordersCarotid StenosisDilatation, Pathologic