PregnanedionesAnestheticsPregnenesPentobarbitalMethohexitalReceptors, GABA-AEtomidateHydroxysteroidsPregnanoloneAnesthesia, Intravenousgamma-Aminobutyric AcidGABA ModulatorsReceptors, GABAPicrotoxinPyridazinesXenopus laevisChloridesPatch-Clamp TechniquesElectrophysiologyOocytesMembrane PotentialsNeurons