Drug Inverse AgonismReceptors, Opioid, muReceptors, OpioidAnalgesics, OpioidReceptors, Opioid, deltaReceptors, Opioid, kappaOpioid PeptidesNarcotic AntagonistsCarbolinesSerotonin 5-HT2 Receptor AgonistsReceptor, Cannabinoid, CB1NaloxoneHistamine AgonistsPiperidinesNaltrexoneGuanosine 5'-O-(3-Thiotriphosphate)Serotonin 5-HT2 Receptor AntagonistsGABA-A Receptor AgonistsLigandsRadioligand AssayAdrenergic beta-2 Receptor AntagonistsReceptors, Histamine H3Dose-Response Relationship, DrugCannabinoid Receptor AgonistsDopamine AgonistsEnkephalin, LeucinePyrazolesBornanesReceptor, Serotonin, 5-HT2CGABA AgonistsOpioid-Related DisordersEnkephalin, D-Penicillamine (2,5)-CHO CellsReceptors, Adrenergic, beta-2Serotonin AntagonistsSerotonin Receptor AgonistsEnkephalin, Ala(2)-MePhe(4)-Gly(5)-MorphineNarcoticsEnkephalinsBenzomorphansCannabinoidsCricetinaeReceptor, Cannabinoid, CB2FlumazenilDiprenorphineReceptors, CannabinoidReceptors, GABA-ACyclohexanolsHistamine AntagonistsCyclic AMPRats, Sprague-DawleyCannabinoid Receptor AntagonistsBenzylidene CompoundsBinding, CompetitiveReceptor, Serotonin, 5-HT2ANaphthalenesAdrenergic AgonistsDynorphinsEndorphinsBenzodiazepinesCricetulusBuprenorphineCOS CellsReceptors, SerotoninAdrenergic beta-AgonistsReceptors, G-Protein-CoupledMethylhistaminesReceptors, Dopamine D2Enkephalin, Leucine-2-AlanineAdrenergic alpha-1 Receptor AgonistsHistamine H3 AntagonistsDronabinolPropanolaminesBenzoxazinesGTP-Binding ProteinsTetrahydronaphthalenesBenzeneacetamidesCell LineBehavior, AnimalReceptors, DrugPurinergic P1 Receptor AgonistsDrug ToleranceReceptor, Serotonin, 5-HT1BSignal TransductionPainTransfectionAdrenergic beta-2 Receptor AgonistsMuscarinic AgonistsSubstance Withdrawal SyndromePyridinesImidazolesPain MeasurementMorphinansReceptor, Serotonin, 5-HT2BAdrenergic alpha-2 Receptor AgonistsNicotinic AgonistsCells, CulturedDrug InteractionsAdenylate Cyclase