Kidney MedullaRenal CirculationOrnipressinKidney CortexBlood PressureNatriuresisPressureLaser-Doppler FlowmetryRegional Blood FlowArterial PressureKidneyHemodynamicsHypertensionRats, Sprague-DawleyHeart RateDogsNG-Nitroarginine Methyl EsterNitric OxideAngiotensin IISodiumHydrostatic PressureBlood Pressure DeterminationVascular ResistanceSympathetic Nervous SystemCardiac OutputBaroreflexPressoreceptorsHypotensionIntracranial PressureCentral Venous PressureTransducers, PressureVenous PressureIntraocular PressureBlood Pressure Monitoring, AmbulatoryAntihypertensive AgentsDenervationRats, Inbred SHRPulmonary Wedge PressureAtmospheric PressureReflexReninCardiovascular SystemAir PressurePhenylephrineVasoconstrictor AgentsPulseTime FactorsNorepinephrineCarotid SinusVentricular PressureBlood Flow VelocityArteriesHypertension, PulmonaryConsciousness