PhenylephrineVeinsSaphenous VeinAdrenergic alpha-AgonistsPortal VeinVaricose VeinsAdrenergic alpha-1 Receptor AgonistsVasoconstrictor AgentsFemoral VeinPulmonary VeinsReceptors, Adrenergic, alpha-1Jugular VeinsReceptors, Adrenergic, alphaEphedrinePrazosinVasoconstrictionMesenteric VeinsRenal VeinsAdrenergic alpha-AntagonistsUmbilical VeinsIliac VeinHepatic VeinsPopliteal VeinMydriaticsSympathomimeticsAorta, ThoracicAdrenergic alpha-1 Receptor AntagonistsMuscle, Smooth, VascularNorepinephrineSubclavian VeinBlood PressureBaroreflexAdrenergic AgonistsSplenic VeinIsoproterenolNitroprussideVasodilator AgentsCerebral VeinsClonidineReceptors, AdrenergicDose-Response Relationship, DrugTropicamideMuscle ContractionVasodilationMesenteric ArteriesRetinal VeinMethoxamineEndothelium, VascularAzygos VeinBrachiocephalic VeinsRats, Sprague-DawleyPropranololPressoreceptorsAnesthesia, ObstetricalPotassium ChlorideHeart RateAxillary VeinRats, WistarPhentolamineRetinal Vein OcclusionAnesthesia, SpinalArteriesAcetylcholineEpinephrineYohimbineSympathetic Nervous SystemNitric OxideHypotensionDioxanesMuscle RelaxationRabbitsAortaRegional Blood FlowRats, Inbred StrainsCalciumDogsAdrenergic beta-AgonistsNG-Nitroarginine Methyl EsterPhenoxybenzamineTailEnzyme InhibitorsVasopressinsVenous ThrombosisPupilNitric Oxide SynthaseHemodynamicsOxymetazolineVascular ResistanceAngiotensin IIStimulation, ChemicalPenisTime FactorsVena Cava, InferiorHeartPhlebographyVenous InsufficiencyReceptors, Adrenergic, alpha-2Cells, CulturedNitroarginineQuinoxalines