NitroglycerinNitrate ReductaseVasodilator AgentsDrug ToleranceAdministration, CutaneousNitrate Reductase (NADH)Silver NitrateVasodilationAdministration, SublingualNicorandilPentaerythritol TetranitrateCoronary VesselsNitric OxideIsosorbide DinitrateAldehyde DehydrogenaseDogsBlood PressureAngina PectorisNitrate Reductase (NAD(P)H)Tilt-Table TestSpasmNitric Oxide DonorsOintmentsCoronary CirculationFerricyanidesChloratesHemodynamicsPeripheral Nervous System AgentsHeart RateVascular ResistanceCoronary VasospasmAnion Transport ProteinsEndothelium, VascularCyclic GMPBrachial ArteryAcetylcholineNitroprussideDiltiazemNitratesGuanylate CyclaseSyncope, VasovagalNitrogenPapaverineMuscle RelaxationMethylene BlueRegional Blood FlowS-NitrosothiolsInfusions, IntravenousDouble-Blind MethodMolybdenumInjections, Intra-ArterialQuaternary Ammonium CompoundsGalliumFissure in AnoHydralazineCoronary DiseaseAortaDose-Response Relationship, DrugVasoconstrictionBlood Flow VelocityScorpion StingsCoronary AngiographyRadial ArteryTime FactorsCyanamideMuscle, Smooth, VascularPotassium CompoundsErgonovineSodium NitriteChloral HydrateOxidation-Reduction