Imidazoline ReceptorsOxazolesReceptors, Adrenergic, alpha-2ImidazolesReceptors, DrugNordefrinClonidineAntihypertensive AgentsIdazoxanAdrenergic alpha-AgonistsAdrenergic alpha-2 Receptor AgonistsGuanabenzDioxanesAdrenergic alpha-2 Receptor AntagonistsYohimbineHeptanesAdrenergic alpha-AntagonistsSympatholyticsSympathetic Nervous SystemBlood PressureHeart RateCisterna MagnaInjections, IntraventricularRats, Inbred SHRBenzofuransAgmatineConsciousnessHypertension, RenovascularDose-Response Relationship, DrugTissue ExtractsIsothiuroniumInfusions, IntraventricularKidneyRats, Sprague-DawleyHypertensionRenal CirculationMedulla OblongataHemodynamicsReflexRabbitsAcrylatesQuinolizinesNatriuresisRats, WistarBicyclo CompoundsThionesGABA-B Receptor AntagonistsAutoreceptorsGlycine AgentsNorepinephrineNaphthyridinesRamiprilNephrectomyInjections, IntravenousChlorineAdministration, OralRats, ZuckerQuinoxalinesPylorusNatriuretic PeptidesBridged CompoundsNitrendipineDogsBenzazepinesSynaptic PotentialsDiuresisPeristalsisAnti-Obesity AgentsMicroinjectionsUrodynamicsPyridazines6-Cyano-7-nitroquinoxaline-2,3-dioneStrychnineHypertension, RenalHypotensionRadioligand AssayGlucuronidesGuanidineGABA-A Receptor AntagonistsBaroreflexAnesthesiaDipeptidesCross-Over StudiesCapillariesDouble-Blind MethodKidney Failure, ChronicRats, Inbred WKYMicrodialysisNifedipineMass SpectrometryAtrial Natriuretic Factor