Helplessness, LearnedEscape ReactionSynapsesDendritic SpinesHippocampusTestosterone PropionateSpineDendritesImmunological SynapsesFeminizationGonadal HormonesCA1 Region, HippocampalPyramidal CellsSynaptic TransmissionExcitatory Postsynaptic PotentialsPhencyclidineNeuronal PlasticityRats, Sprague-DawleyPresynaptic TerminalsOvariectomyElectrical SynapsesNeuronsDihydrotestosteroneMicroscopy, Electron, TransmissionOrchiectomyMicroscopy, ElectronPrefrontal CortexReceptors, AMPASynaptic Vesicles