BaroreflexHeart RatePressoreceptorsBlood PressurePhenylephrineAutonomic Nervous SystemSympathetic Nervous SystemSensitivity and SpecificityValsalva ManeuverVagus NerveReflexNitroprussideTilt-Table TestCardiovascular SystemBradycardiaSupine PositionVasoconstrictor AgentsCarotid SinusAutonomic Nervous System DiseasesReflex, AbnormalHeartTachycardiaParasympathetic Nervous SystemElectrocardiographyHead-Down TiltDizzinessSolitary NucleusHypertensionSignal Processing, Computer-AssistedHemodynamicsConsciousnessPulseTelemetryPosturePeroneal NerveCardiovascular Physiological PhenomenaPhotoplethysmographyCarotid ArteriesSyncope, VasovagalDenervationLower Body Negative PressureArteriesVasodilator AgentsSympathomimeticsHypovolemiaNorepinephrineRespirationHypotension, OrthostaticExerciseBlood Pressure DeterminationMedulla OblongataChemoreceptor CellsPhysical Conditioning, AnimalRats, Sprague-DawleyVasomotor SystemHeart FailureTime FactorsRespiratory MechanicsAgingRats, Inbred SHRNitroglycerinBreathing ExercisesVascular ResistanceCardiotonic AgentsAntihypertensive AgentsSystoleMuscle, SkeletalReninReproducibility of ResultsAtropineNervous System Physiological PhenomenaArterial PressureReference ValuesAngiotensin IICardiac OutputSinoatrial NodeInjections, IntraventricularElectrocardiography, AmbulatoryAtenololCircadian RhythmMathematical ComputingRats, WistarPredictive Value of TestsDogsReceptor, Angiotensin, Type 1RestPropranololDiabetic NeuropathiesMicroinjectionsComplianceAdrenergic alpha-AgonistsCase-Control StudiesVentricular DysfunctionAdrenergic beta-AntagonistsKidneyAngiotensin IRats, Inbred WKYPhysical ExertionAnalysis of VarianceMuscarinic Antagonists