MethadoneNarcoticsOpiate Substitution TreatmentOpioid-Related DisordersHeroin DependenceMethadyl AcetateBrain ChemistryAnalgesics, OpioidBuprenorphineBrain InjuriesNeonatal Abstinence SyndromeBrain NeoplasmsHeroinBrain MappingBrainSubstance Abuse DetectionPyrrolidinesBrain EdemaDrug OverdoseBrain StemDose-Response Relationship, DrugMorphineBrain IschemiaTime FactorsSubstance Withdrawal SyndromeNarcotic AntagonistsStreet DrugsSubstance-Related DisordersSubstance Abuse, IntravenousDextropropoxypheneMagnetic Resonance ImagingCocaine-Related DisordersRats, Sprague-DawleyNeuronsOpiumMolecular Sequence DataStereoisomerismBrain AbscessNaloxoneOxidoreductases, N-DemethylatingDrug InteractionsCells, CulturedMice, Inbred C57BLSignal TransductionMeconiumCerebral CortexCell LineTherapeutic CommunityRNA, MessengerKineticsBlood-Brain BarrierCocaineHypoxia, BrainAmino Acid SequenceDirectly Observed TherapyPrisonersNaltrexoneMice, KnockoutCalciumCytochrome P-450 CYP3ACodeinePainReceptors, Opioid, muPupil