VasoconstrictionStrokeVasoconstrictor AgentsBrain IschemiaCerebrovascular DisordersVascular ResistanceRegional Blood FlowPulmonary CirculationBlood PressureAnoxiaArteriolesPulmonary ArteryVasodilationEndothelin-1NorepinephrineHemodynamicsShiveringForearmSkin TemperaturePhenylephrineRenal CirculationMesenteric ArteriesVasomotor SystemCerebral HemorrhageBody Temperature RegulationIschemic Attack, TransientVasodilator AgentsMuscle, Smooth, VascularReceptors, EndothelinAdrenergic alpha-AgonistsCerebral InfarctionAdrenergic alpha-1 Receptor AgonistsTime FactorsSympathetic Nervous SystemNitric OxideRisk FactorsPerfusionEndothelinsDose-Response Relationship, DrugDogsReceptor, Endothelin ARats, Sprague-DawleyAdrenergic alpha-AntagonistsArteriesAngiotensin IIReceptor, Endothelin BNG-Nitroarginine Methyl Ester15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic AcidHeart RateReceptors, Adrenergic, alphaAcute DiseaseHeadache Disorders, PrimaryStroke VolumeProspective StudiesCoronary VesselsCardiac OutputHypertensionMethoxamineFibrinolytic AgentsEndothelium, VascularCerebral ArteriesMicrocirculationTyramineParesisTreatment OutcomeStroke, LacunarSplanchnic CirculationCerebrovascular CirculationViper VenomsTissue Plasminogen ActivatorPrazosinRats, WistarBlood Flow VelocityFollow-Up StudiesNitric Oxide SynthaseRecovery of FunctionOxygenBrain InfarctionLaser-Doppler FlowmetryInfarction, Middle Cerebral ArteryMeclofenamic AcidInjections, Intra-ArterialPeptides, CyclicEnzyme InhibitorsPotassium ChlorideKidneyBlood VesselsThrombolytic TherapyHypertension, PulmonaryAcetylcholinePhentolamineReceptors, Adrenergic, alpha-1NitroprussideIntracranial HemorrhagesThromboxane A2IndomethacinReceptors, ThromboxanePlethysmographyLower Body Negative PressureIncidence