MecamylamineNicotinic AntagonistsNicotinic AgonistsNicotineDihydro-beta-ErythroidineReceptors, NicotinicAconitineMuscarinic AntagonistsSelf StimulationScopolamine HydrobromideSubstance Withdrawal SyndromeBicyclo Compounds, HeterocyclicTobacco Use DisorderDose-Response Relationship, DrugAcetylcholineRats, Sprague-DawleyPyridinesBehavior, AnimalChlorisondamineGanglionic BlockersCholinergic AntagonistsAzocinesDimethylphenylpiperazinium IodideHexamethonium CompoundsPempidineQuinolizinesGanglionic StimulantsExcitatory Amino Acid AntagonistsAtropineCholinergic AgentsPentolinium TartrateHormone AntagonistsHexamethonium