AnalgesicsAnalgesics, OpioidReceptors, Opioid, muAnalgesics, Non-NarcoticDexmedetomidineAnalgesiaPainReceptors, OpioidPain MeasurementAnti-Inflammatory Agents, Non-SteroidalMorphineNaloxoneReceptors, Opioid, deltaPain ThresholdReceptors, Opioid, kappaHypnotics and SedativesHyperalgesiaOpioid PeptidesKetamineDose-Response Relationship, DrugPlant ExtractsRats, Sprague-DawleyNarcotic AntagonistsIbuprofenBehavior, AnimalDiclofenacOpioid-Related DisordersAcetaminophenCyclooxygenase 2 InhibitorsNaltrexoneNaproxenPain, PostoperativeCyclooxygenase InhibitorsKetoprofenAspirinFlurbiprofenSulindacEnkephalinsPiroxicamTramadolTolmetinNarcoticsEnkephalin, Ala(2)-MePhe(4)-Gly(5)-Drug ToleranceBuprenorphineEndorphinsEnkephalin, D-Penicillamine (2,5)-FentanylKetorolacIndomethacinProstaglandin-Endoperoxide SynthasesThiazinesDynorphinsPhenacetinCyclooxygenase 2PyrazolesCyclooxygenase 1HydromorphoneEnkephalin, LeucinePain ManagementMorphinansInjections, SpinalDextropropoxypheneSulfonamidesCodeineDipyroneEnkephalin, Leucine-2-AlanineDouble-Blind MethodPain, IntractableEtodolacbeta-EndorphinMeperidineAnti-Inflammatory AgentsPentazocineMethadoneDrug InteractionsBenzeneacetamidesStereoisomerismAnalgesia, Patient-ControlledDiprenorphineButorphanolCarrageenanAnesthetics, LocalHydrocodoneChronic PainFenoprofenGrowth Differentiation Factor 15Ketorolac TromethamineOxymorphoneMorphine DerivativesAnalgesia, EpiduralPhenylbutazoneLevorphanolStomach UlcerKidney Papillary NecrosisSulfonesDiflunisalBenzomorphansGastrointestinal DiseasesBupivacaine