YohimbineAdrenergic alpha-AntagonistsAdrenergic alpha-2 Receptor AntagonistsPlacebo EffectReceptors, Adrenergic, alphaClonidineDouble-Blind MethodPrazosinReceptors, Adrenergic, alpha-2Adrenergic alpha-AgonistsNorepinephrineIdazoxanAdrenergic AntagonistsDioxanesAdrenergic alpha-2 Receptor AgonistsReceptors, AdrenergicOxymetazolineXylazinePhentolamineCross-Over StudiesDose-Response Relationship, DrugAdrenergic alpha-1 Receptor AntagonistsChlorprothixeneImidazoline ReceptorsSympatholyticsVas DeferensAgmatineTreatment OutcomeEpinephrineMydriasisDrug InteractionsQuinoxalinesElectric StimulationSympathetic Nervous SystemBlood PressureDexmedetomidineDihydroergotoxinePenile ErectionDihydroergotamineAdministration, OralMedetomidineExtinction, PsychologicalPhenylephrineMethysergideRats, Inbred StrainsPropranololAdrenergic AgonistsTetralonesPhenoxybenzamineTolazolineHeart RateAmitriptylineDrug-Seeking BehaviorCatecholaminesNeuroeffector JunctionAzepinesMuscle ContractionTime FactorsAdrenergic NeuronsMethoxaminePain MeasurementNordefrinSerotonin AntagonistsAdrenergic beta-AntagonistsReceptors, Adrenergic, alpha-1Parasympathetic Nervous SystemDrug Therapy, CombinationRandomized Controlled Trials as Topicalpha-MethyltyrosineSingle-Blind MethodRandom AllocationImidazolesGuinea PigsSalivationGuanabenzNaloxoneRats, Sprague-DawleySympathomimeticsDogsProcaterolClinical Trials as TopicPain