Endothelium, VascularNitroprussideVasodilationVasodilator AgentsAcetylcholineCarbacholMuscle RelaxationNitric OxideSodiumEndotheliumVasoconstrictor AgentsVasoconstrictionMuscle, Smooth, VascularNitric Oxide DonorsFerricyanidesDose-Response Relationship, DrugMuscle Relaxants, CentralNitroglycerinMuscle, SmoothNitric Oxide SynthaseCyclic GMPMuscle ContractionGastric FundusNitroarginineArteriesAorta, ThoracicNG-Nitroarginine Methyl EsterGuinea PigsRegional Blood FlowTracheaMethylene BlueArginineNorepinephrineMesenteric ArteriesButoxamineGuanylate CyclaseEndothelium, CornealRats, WistarBrachial ArteryPhenylephrineBiological FactorsIndomethacinEnzyme InhibitorsOxadiazolesElectric StimulationPyrogallolPenisCromakalimRabbitsIsoproterenol15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic AcidPotassium ChlorideBradykininAtropineRats, Sprague-DawleyMuscle TonusSodium ChannelsAortaHydroxocobalaminHistaminePulmonary Arteryomega-N-MethylarginineCholinergic AgonistsReceptors, CholinergicForearmDogsReceptors, NicotinicReceptors, MuscarinicVasoactive Intestinal PeptideCoronary VesselsPotassiumAdrenergic beta-AgonistsSubstance PQuinoxalinesBupranololSwineRats, Inbred WKYReceptors, Adrenergic, betaCells, CulturedPropranololParasympatholyticsAdrenergic AgentsAdenosineCalciumNeuromuscular Nondepolarizing AgentsMuscarinic AgonistsHypotension, ControlledBlood PressureRats, Inbred SHRGuanethidineS-Nitroso-N-Acetylpenicillaminealpha7 Nicotinic Acetylcholine ReceptorTheophyllineCalcitonin Gene-Related PeptideCyclic AMPSerotoninTetrodotoxinColforsinPotassium ChannelsPenicillamine