IsofluraneAnesthetics, InhalationHalothaneAnesthesia, InhalationEnfluraneMethyl EthersAnestheticsNitrous OxideEthersAnesthesiaAnesthetics, IntravenousPropofolAnesthetics, GeneralDose-Response Relationship, DrugAnesthesia, GeneralXenonFentanylAnesthesia Recovery PeriodHemodynamicsDogsMethoxyfluraneBlood Gas AnalysisRats, Sprague-DawleyDepression, ChemicalThiopentalIschemic Preconditioning, MyocardialPulmonary AlveoliElectroencephalographyAnesthetics, CombinedEtherDrug InteractionsPentobarbital