Basilar ArteryThrombosisVenous ThrombosisArteriesVertebrobasilar InsufficiencyVertebral ArteryCerebral ArteriesCoronary ThrombosisIntracranial ThrombosisSinus Thrombosis, IntracranialPulmonary ArteryCarotid ArteriesCarotid Artery ThrombosisSubarachnoid HemorrhageBrain Stem InfarctionsCerebral AngiographyFemoral ArteryVasospasm, IntracranialMesenteric ArteriesRenal ArteryIntracranial Embolism and ThrombosisVasodilationCarotid Artery, InternalVasoconstrictionIntracranial AneurysmIliac ArteryArterial Occlusive DiseasesMuscle, Smooth, VascularCoronary Artery BypassTomography, X-Ray ComputedMagnetic Resonance AngiographyAnticoagulantsTreatment OutcomeDogsRadial ArteryCarotid Artery DiseasesVasodilator AgentsMammary ArteriesStentsFibrinolytic AgentsCerebrovascular CirculationSubclavian ArteryHepatic ArterySerotoninCoronary VesselsMiddle Cerebral ArterySplenic ArterySagittal Sinus ThrombosisPhlebographyEndothelium, VascularThrombolytic TherapyBrachial ArteryAngiographyRabbitsCircle of WillisTime FactorsAngiography, Digital SubtractionCarotid Artery, CommonPotassium ChloridePapaverineVasoconstrictor AgentsMuscle ContractionPicolinesFollow-Up StudiesEmbolization, TherapeuticCeliac ArteryPlatelet Aggregation InhibitorsAneurysm, RupturedSumatriptanFemoral VeinUltrasonography, Doppler, TranscranialIliac VeinRisk FactorsIschemic Attack, TransientAcetylcholineIntracranial ArteriosclerosisMesenteric Artery, SuperiorHeparinConstriction, PathologicCerebral InfarctionThrombophiliaRetrospective StudiesCoronary AngiographyThrombectomyOphthalmic ArteryPortal VeinUpper Extremity Deep Vein ThrombosisRenal Artery ObstructionProspective StudiesUmbilical ArteriesPopliteal ArteryAneurysmDose-Response Relationship, DrugPonsDisease Models, AnimalVascular PatencyUlnar ArteryCerebral VeinsThoracic ArteriesVasomotor System