PhenylephrineAdrenergic alpha-AgonistsAdrenergic alpha-1 Receptor AgonistsVasoconstrictor AgentsReceptors, Adrenergic, alpha-1Receptors, Adrenergic, alphaEphedrinePrazosinVasoconstrictionAdrenergic alpha-AntagonistsOphthalmic SolutionsMydriaticsAorta, ThoracicSympathomimeticsAdrenergic alpha-1 Receptor AntagonistsTropicamideBlood PressureBaroreflexAdrenergic AgonistsIsoproterenolNorepinephrineNitroprussideClonidineVasodilator AgentsReceptors, AdrenergicMuscle, Smooth, VascularDose-Response Relationship, DrugMuscle ContractionMethoxamineMesenteric ArteriesVasodilationRats, Sprague-DawleyAnesthesia, ObstetricalPropranololPressoreceptorsHeart RatePotassium ChlorideAnesthesia, SpinalRats, WistarHypotensionPhentolamineEpinephrineSympathetic Nervous SystemAcetylcholineYohimbineNitric OxideDioxanesRats, Inbred StrainsMuscle RelaxationRabbitsCalciumPupilAortaArteriesAdrenergic beta-AgonistsEndothelium, VascularNG-Nitroarginine Methyl EsterVasopressinsTailEnzyme InhibitorsPhenoxybenzamineRegional Blood FlowOxymetazolineDogsVascular ResistanceNitric Oxide SynthaseAngiotensin IIStimulation, ChemicalHemodynamicsPenisHeartQuinoxalinesMetaproterenolReceptors, Adrenergic, alpha-2CardiomegalyMyographyNitroarginineCardiotonic AgentsMuscle, SmoothMuscle TonusReceptors, Adrenergic, betaAdrenergic alpha-2 Receptor AgonistsPerfusionCesarean SectionTime FactorsMyocardiumNasal DecongestantsEndothelin-1RitodrineAdrenergic beta-AntagonistsGanglionectomyPhenylmercury CompoundsAdministration, TopicalMyocardial ContractionCatecholaminesErgonovineIndomethacinMethylene BlueGanglionic BlockersIsometric Contraction