Acute PainAnalgesiaAnalgesia, EpiduralPainAnalgesia, ObstetricalPain MeasurementPain, PostoperativeAnalgesia, Patient-ControlledPain ManagementAnalgesics, OpioidAnalgesicsPain ThresholdPain ClinicsChronic PainMorphineAnesthetics, LocalPain, IntractablePain PerceptionBupivacaineHyperalgesiaAnalgesics, Non-NarcoticAcupuncture AnalgesiaAnesthesia Department, HospitalInjections, SpinalFentanylFacial PainBack PainLow Back PainNeuralgiaAcute DiseaseNerve BlockLabor PainNociceptorsAbdominal PainAnesthesia, EpiduralNeck PainMeperidineDouble-Blind MethodSufentanilKetorolacPelvic PainUnited States Department of DefenseKetoprofenKetamineLidocaineNaloxoneNarcotic AntagonistsPain, ReferredAnti-Inflammatory Agents, Non-SteroidalLabor, ObstetricAnesthesia, ObstetricalToothacheTramadolRecovery RoomReceptors, Opioid, muAcetaminophenAmidesChronic DiseaseCyclohexanecarboxylic AcidsDexmedetomidineShoulder PainHot TemperatureDiclofenacAnesthesia, SpinalAcupunctureAnesthetics, DissociativeNociceptive PainTreatment OutcomeSpinal CordProspective StudiesBuprenorphineMusculoskeletal PainCryingBehavior, AnimalTranscutaneous Electric Nerve StimulationFormaldehydePostoperative Nausea and VomitingCesarean SectionDose-Response Relationship, DrugRats, Sprague-DawleyInterpleural AnalgesiaCapsaicinDrug ToleranceHydromorphoneGanglia, SpinalTime FactorsAnesthesiologyAnesthesia, GeneralConscious SedationAminesPosterior Horn CellsLabor Stage, FirstPeripheral Nervous System DiseasesCarrageenanAnesthesia, CaudalSkin Physiological PhenomenaClonidineFemoral NervePhysical StimulationReceptors, Opioid