BaroreflexSensitivity and SpecificityHeart RatePressoreceptorsSympathetic Nervous SystemBlood PressurePhenylephrineCarotid SinusVagus NerveAutonomic Nervous SystemReflexNitroprussideSolitary NucleusBradycardiaValsalva ManeuverDenervationCardiovascular SystemSupine PositionConsciousnessArteriesDeciduomaVasoconstrictor AgentsTrimethaphanReflex, AbnormalCardiovascular Physiological PhenomenaLower Body Negative PressureTilt-Table TestParasympathetic Nervous SystemHypertensionCarotid ArteriesVasomotor SystemContrast SensitivityRats, Sprague-DawleyGanglionic BlockersHead-Down TiltNeurotransmitter AgentsPostureTachycardiaTime FactorsPeroneal NerveDizzinessAutonomic Nervous System DiseasesReproducibility of ResultsElectrocardiographyAmidinotransferasesCentral Venous PressureAutonomic DenervationSympathomimeticsMedulla OblongataVagus Nerve DiseasesVasodilator AgentsKidneyModels, CardiovascularMuscle, SkeletalPhotoplethysmographyChemoreceptor CellsPulseAntihypertensive AgentsMicroinjectionsPredictive Value of TestsNorepinephrineExerciseCardiovascular DeconditioningDogsVascular ResistanceAngiotensin IIGravity SuitsRabbitsRats, Inbred SHRSympathetic Fibers, PostganglionicDose-Response Relationship, DrugFourth VentricleArterial PressureRespirationInfusions, IntraventricularReference ValuesSignal Processing, Computer-AssistedAtropine DerivativesPure Autonomic FailureInsulin ResistanceRespiratory MechanicsReceptor, Muscarinic M3Syncope, VasovagalNeckRats, WistarTelemetryNitroglycerinHypotensionAgingPhysical Conditioning, AnimalSinus of ValsalvaVagotomyROC CurveElectric StimulationAdrenergic FibersLosartanAlgorithmsResistinSuctionSinoatrial Node