Receptors, OpioidDihydromorphineNaloxoneSigma FactorEnkephalin, Leucine-2-AlanineEnkephalinsEndorphinsEtorphineEnkephalin, LeucineEthylketocyclazocineEnkephalin, MethionineDiprenorphineMorphineCyclazocineNarcoticsReceptors, sigmaReceptors, Opioid, muLevorphanolBenzomorphansNaltrexoneNarcotic AntagonistsPhenazocineEnkephalin, Ala(2)-MePhe(4)-Gly(5)-Morphine DerivativesReceptors, Opioid, deltaRNA Polymerase Sigma 54MorphinansOpiate AlkaloidsDynorphinsFentanylReceptors, Opioid, kappaDextrorphanAnalgesics, Opioidbeta-EndorphinLevallorphanEnkephalin, D-Penicillamine (2,5)-Hybrid CellsOpioid-Related DisordersAnalgesiaAnalgesicsBrainBinding, CompetitiveLoperamideNeuroblastomaGuanylyl ImidodiphosphateBrain ChemistryOpioid PeptidesRats, Inbred StrainsDNA-Directed RNA PolymerasesGene Expression Regulation, BacterialPentazocineCodeineHeroinIleumKineticsMethadoneGliomaDrug TolerancePyrrolidinesBacterial ProteinsMolecular Sequence DataGuinea PigsClonidineReceptors, DrugKetamineDose-Response Relationship, DrugHeroin DependenceOpiumAdenylate CyclaseSubstance Withdrawal SyndromeSubstance Abuse DetectionPainBase SequenceReceptors, AdrenergicBacillus subtilisMorphine DependenceReceptors, Adrenergic, alphaStereoisomerismBuprenorphineBrain StemAmino Acid SequenceThalamusAutoradiographyCorpus StriatumSpinal CordStructure-Activity Relationship14-3-3 ProteinsCell MembraneLigandsOligopeptidesPromoter Regions, GeneticTranscription, GeneticRats, Sprague-DawleyGuanosine TriphosphateNeuronsEscherichia coliCatsGenes, BacterialCerebral CortexCell Line