PhenylephrineNorepinephrineNorepinephrine Plasma Membrane Transport ProteinsAdrenergic alpha-AgonistsVasoconstrictor AgentsAdrenergic alpha-1 Receptor AgonistsReceptors, Adrenergic, alpha-1Receptors, Adrenergic, alphaEpinephrineAdrenergic alpha-AntagonistsSympathetic Nervous SystemPrazosinVasoconstrictionEphedrineCatecholaminesBlood PressureReceptors, AdrenergicSympathomimeticsAdrenergic AgonistsDesipramineDose-Response Relationship, DrugPropranololIsoproterenolClonidineHeart RateAdrenergic Uptake InhibitorsPhentolamineRats, Sprague-DawleyAdrenergic alpha-1 Receptor AntagonistsYohimbineAorta, ThoracicNitroprussideReceptors, Adrenergic, alpha-2Muscle, Smooth, VascularMesenteric ArteriesBaroreflexVasodilator AgentsMethoxamineMuscle ContractionReceptors, Adrenergic, betaDogsMydriaticsDopamine beta-HydroxylaseVasodilationTyraminePressoreceptorsRats, Inbred StrainsAcetylcholinePotassium ChlorideRats, WistarAdrenergic AgentsHemodynamicsVascular ResistanceHypotensionArteriesDopamineHeartAdrenergic beta-AgonistsAdrenergic AntagonistsTropicamideAngiotensin IIDioxanesVasopressinsLocus CoeruleusCalciumAdrenergic beta-AntagonistsMyocardiumNitric OxideSerotoninAdrenergic alpha-2 Receptor AgonistsRegional Blood FlowRabbitsHypertensionElectric StimulationAdrenergic FibersAdrenergic alpha-2 Receptor AntagonistsAnesthesia, ObstetricalSympatholyticsMethoxyhydroxyphenylglycolAortaMuscle RelaxationAnesthesia, SpinalEndothelium, VascularStimulation, ChemicalOxymetazolineVasomotor SystemTrimethaphanBiogenic MonoaminesTailNG-Nitroarginine Methyl EsterEnzyme InhibitorsPerfusionHydroxydopaminesRats, Inbred WKYRats, Inbred SHRNormetanephrineNeurotransmitter Uptake InhibitorsGanglionic BlockersDrug InteractionsTime Factors