BaroreflexHeart RatePressoreceptorsSympathetic Nervous SystemBlood PressurePhenylephrineCarotid SinusGene FrequencyVagus NerveAutonomic Nervous SystemReflexNitroprussideSolitary NucleusBradycardiaValsalva ManeuverDenervationCardiovascular SystemConsciousnessSupine PositionArteriesTrimethaphanHeartReflex, AbnormalVasoconstrictor AgentsCardiovascular Physiological PhenomenaLower Body Negative PressureParasympathetic Nervous SystemTilt-Table TestPostureGanglionic BlockersVasomotor SystemCarotid ArteriesHypotension, OrthostaticHead-Down TiltHypertensionRats, Sprague-DawleyTachycardiaAutonomic Nervous System DiseasesPeroneal NerveDizzinessTime FactorsElectrocardiographyHemodynamicsCentral Venous PressureAutonomic DenervationMedulla OblongataElectric StimulationVagus Nerve DiseasesSympathomimeticsModels, CardiovascularSignal Processing, Computer-AssistedPhotoplethysmographyRespirationVasodilator AgentsMicroinjectionsKidneyPulseAntihypertensive AgentsCardiovascular DeconditioningChemoreceptor CellsExerciseGravity SuitsSympathetic Fibers, PostganglionicMuscle, SkeletalRespiratory MechanicsFourth VentricleArterial PressureVascular ResistanceNorepinephrineAngiotensin IIRats, Inbred SHRPure Autonomic FailureInfusions, IntraventricularAtropine DerivativesSyncope, VasovagalRabbitsInjections, IntraventricularCase-Control StudiesNeckTelemetryHypotensionVagotomySinus of ValsalvaAllelesAtropineNitroglycerinAdrenergic FibersDogsReference ValuesGenotypeRats, WistarSuctionSinoatrial NodeRestAgingAutonomic PathwaysLosartanPhysical Exertion