title: Conditioning of discriminable stimuli produced by morphine.
mesh_terms: D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D051381:Rats
chemical_list: D009020:Morphine