EnkephalinsSubstance PEnkephalin, MethionineEnkephalin, LeucineEnkephalin, Ala(2)-MePhe(4)-Gly(5)-Enkephalin, Leucine-2-AlanineEnkephalin, D-Penicillamine (2,5)-Receptors, Neurokinin-1EndorphinsTachykininsReceptors, OpioidNeurokinin-1 Receptor AntagonistsReceptors, Opioid, deltaNaloxoneReceptors, Opioid, muNeurokinin ADynorphinsPhysalaeminReceptors, TachykininMorphineEledoisinEthylketocyclazocineCyclazocineReceptors, Neurokinin-2Narcotic AntagonistsCalcitonin Gene-Related PeptideCapsaicinSubstance-Related DisordersThiorphanGuinea PigsCarboxypeptidase Hbeta-EndorphinAnalgesics, OpioidBenzomorphansNaltrexoneOpioid PeptidesReceptors, NeurotransmitterD-Ala(2),MePhe(4),Met(0)-ol-enkephalinNeprilysinNeuropeptidesQuinuclidinesNeurokinin BNarcoticsVasoactive Intestinal PeptideReceptors, Opioid, kappaAnalgesicsProtein PrecursorsIleumSpinal CordDiprenorphineDose-Response Relationship, DrugOligopeptidesIsoindolesRats, Sprague-DawleySomatostatinRats, Inbred StrainsReceptors, Neurokinin-3Neurotransmitter AgentsEtorphineInjections, SpinalNeuronsTioproninElectric StimulationSubstance Abuse Treatment CentersNeurons, AfferentMyenteric PlexusMuscle, SmoothBrainKassininMuscle ContractionNeurotensinMorphinansNeurogenic InflammationPyrrolidinesAdrenal MedullaGanglia, SpinalDrug ToleranceCorpus StriatumPeptidesRadioimmunoassayBradykininBiphenyl CompoundsGalaninAtropineGlobus PallidusVas DeferensBinding, CompetitiveNerve FibersPainChromaffin GranulesAcetylcholineInjections, IntraventricularPiperidinesGlycopeptidesNeuropeptide YKineticsRats, WistarBombesinThiobarbituric Acid Reactive SubstancesNociceptive Pain