Receptors, Opioid, muReceptors, OpioidAnalgesics, OpioidReceptors, Opioid, deltaReceptors, Opioid, kappaOpioid PeptidesCell DeathCause of DeathNarcotic AntagonistsNaloxoneOpioid-Related DisordersDeathNaltrexoneEnkephalinsEnkephalin, Ala(2)-MePhe(4)-Gly(5)-MorphineNarcoticsEnkephalin, D-Penicillamine (2,5)-EndorphinsDynorphinsBuprenorphineEnkephalin, LeucineEnkephalin, Leucine-2-AlanineDeath, Sudden, CardiacPainDiprenorphinebeta-EndorphinBrain DeathBenzeneacetamidesAnalgesicsDrug ToleranceMorphinansMethadoneFentanylFetal DeathPain MeasurementHydromorphoneAttitude to DeathBenzomorphansDose-Response Relationship, DrugPyrrolidinesAnalgesiaSubstance Withdrawal SyndromeOpiate Substitution TreatmentTime FactorsHeroinRats, Sprague-DawleyPrescription Drug MisuseChronic PainDrug OverdoseLevorphanolMorphine DependenceCaspasesPrescription DrugsButorphanolOligopeptidesHeroin DependenceDiterpenes, ClerodaneOxymorphoneApoptosisEthylketocyclazocineRisk FactorsMorphine DerivativesCell SurvivalInjections, SpinalPain, IntractableReceptors, Death DomainSignal TransductionBenzylidene CompoundsTreatment OutcomeNeuronsAnalgesics, Non-NarcoticRetrospective StudiesPain ThresholdCyclazocineMortalityPeriaqueductal GrayHydrocodoneD-Ala(2),MePhe(4),Met(0)-ol-enkephalinAutopsyFollow-Up StudiesHyperalgesiaDrug InteractionsCells, CulturedAlfentanilNalbuphineUnited StatesCaspase 3BrainTramadolNecrosisGuanosine 5'-O-(3-Thiotriphosphate)Spinal CordCell LineProspective StudiesLigandsRadioligand AssaySufentanilLoperamideInfant, Newborn