AnestheticsReceptors, Opioid, muAnesthetics, LocalAnalgesics, OpioidReceptors, OpioidAnesthetics, InhalationReceptors, Opioid, deltaReceptors, Opioid, kappaAnesthetics, GeneralOpioid PeptidesAnesthetics, IntravenousIsofluraneHalothaneAnesthetics, CombinedNarcotic AntagonistsLidocaineAnesthesia, LocalEnfluraneNaloxoneMethyl EthersOpioid-Related DisordersAnesthesiaBupivacaineNaltrexoneAnesthetics, DissociativePropofolAnesthesia, GeneralMorphineMethoxyfluraneEnkephalinsAnesthesia, InhalationEnkephalin, Ala(2)-MePhe(4)-Gly(5)-BenzocaineNarcoticsFentanylKetamineAnesthesia, DentalTetracaineNerve BlockPrilocaineNitrous OxideProcaineEnkephalin, D-Penicillamine (2,5)-ThiopentalEndorphinsBuprenorphineDynorphinsPain MeasurementEtomidateDose-Response Relationship, DrugPainEtherEnkephalin, LeucineDibucaineMepivacainePentobarbitalAnalgesicsAnesthesiologyEnkephalin, Leucine-2-AlanineAnesthesia, IntravenousAnalgesiaEtidocaineCarticaineDiprenorphineAnesthesia, ConductionAnesthesia, EpiduralPain, PostoperativeAdjuvants, Anesthesiabeta-EndorphinAnesthesia Recovery PeriodXylazineDrug ToleranceRats, Sprague-DawleyChloroformBenzeneacetamidesAnesthesia, ObstetricalEthersAnesthesia, SpinalHypnosis, AnestheticMorphinansHydromorphonePregnanedionesMethadoneXenonTime FactorsDrug InteractionsButorphanolAmidesAmbulatory Surgical ProceduresMedetomidineInjections, SpinalSufentanilMonitoring, IntraoperativePreanesthetic MedicationBenzomorphansHypnotics and SedativesChlorofluorocarbonsOctanolsPyrrolidinesSubstance Withdrawal Syndrome