Brachial ArteryVasodilationRegional Blood FlowBlood Flow VelocityArteriesForearmEndothelium, VascularNitroglycerinHyperemiaVasodilator AgentsPulmonary ArteryCarotid ArteriesFemoral ArteryUltrasonography, Doppler, PulsedUltrasonography, DopplerBlood PressureBasilar ArteryCoronary CirculationCerebral ArteriesVascular ResistanceRadial ArteryVertebral ArteryCoronary VesselsPulsatile FlowUmbilical ArteriesMesenteric ArteriesNitric OxideNitroprussideCarotid Artery, CommonOphthalmic ArteryHemodynamicsRenal ArteryLaser-Doppler FlowmetryHepatic ArteryCerebrovascular CirculationCarotid Artery, InternalSubclavian Steal SyndromeMiddle Cerebral ArteryAcetylcholineomega-N-MethylarginineVasoconstrictionPlethysmographyAxillary ArteryUltrasonography, Doppler, ColorCeliac ArteryUlnar ArteryUltrasonography, Doppler, TranscranialSubclavian ArteryMicrocirculationHeart RateTime FactorsArteriolesIliac ArteryCarotid Artery, ExternalInfusions, Intra-ArterialCoronary Artery BypassVasomotor SystemReference ValuesPlacental CirculationMammary ArteriesProspective StudiesComplianceCoronary AngiographyNitric Oxide SynthaseDogsFlow CytometryVasoconstrictor AgentsPulmonary CirculationCarotid Artery DiseasesArmMuscle, Smooth, VascularCross-Over StudiesTreatment OutcomeUltrasonographyCoronary Disease