Wakefulness-Promoting AgentsClonidineReceptors, Adrenergic, alpha-2Adrenergic alpha-AgonistsAdrenergic alpha-2 Receptor AgonistsReceptors, Adrenergic, alphaYohimbineAdrenergic alpha-AntagonistsPreanesthetic MedicationSympatholyticsalpha 1-AntitrypsinImidazoline ReceptorsGuanfacineInjections, SpinalPrazosinHypoxia-Inducible Factor 1, alpha SubunitAnalgesicsAdrenergic alpha-2 Receptor AntagonistsIdazoxanNorepinephrineOxymetazoline