EnkephalinsReceptor, Cannabinoid, CB1Enkephalin, Ala(2)-MePhe(4)-Gly(5)-Enkephalin, LeucineEnkephalin, MethionineReceptor, Cannabinoid, CB2Receptors, CannabinoidEnkephalin, D-Penicillamine (2,5)-Enkephalin, Leucine-2-AlanineCannabinoidsReceptors, Opioid, muCannabinoid Receptor AgonistsReceptors, OpioidAnalgesicsCannabinoid Receptor ModulatorsEndorphinsReceptors, Opioid, deltaNaloxoneMorphineAnalgesics, OpioidDronabinolCannabinoid Receptor AntagonistsNarcotic AntagonistsBenzoxazinesPiperidinesEndocannabinoidsReceptors, Opioid, kappaPyrazolesPain MeasurementCyclohexanolsNaphthalenesReceptors, Neurokinin-3Injections, SpinalPolyunsaturated AlkamidesNaltrexoneReceptors, DrugPainNeurokinin BDrug ToleranceAnalgesiaCyclazocineEthylketocyclazocineArachidonic AcidsDose-Response Relationship, DrugMorpholinesOpioid PeptidesDynorphinsTachykininsReceptors, TachykininInjections, IntraventricularPain ThresholdPeriaqueductal GrayD-Ala(2),MePhe(4),Met(0)-ol-enkephalinNociceptorsbeta-EndorphinRats, Sprague-DawleySubstance PAnalgesics, Non-NarcoticNeurokinin ACannabidiolSpinal CordMorphinansReceptors, Neurokinin-2BenzomorphansNociceptionNarcoticsMice, Inbred ICRHyperalgesiaOligopeptidesGlyceridesBenzeneacetamidesBehavior, AnimalRNA, Transfer, GlyAdrenergic alpha-2 Receptor AgonistsDrug InteractionsMicroinjectionsCannabisGuinea PigsNeurokinin-1 Receptor AntagonistsPyrrolidinesCannabinolCarboxypeptidase HMorphine DerivativesRats, WistarBrainReceptors, Adrenergic, alpha-2AmidohydrolasesGuanosine 5'-O-(3-Thiotriphosphate)Reaction TimePentazocineClonidineHot TemperatureFormaldehydeNociceptive PainMonoacylglycerol LipasesMedulla OblongataNeuronsAdrenergic alpha-AgonistsDiprenorphineFentanyl