Modulation of tolerance to the lethal effect of morphine by extinction.
D000818:Animals; D003463:Cues; D004361:Drug Tolerance; D005108:Extinction, Psychological; D008297:Male; D009020:Morphine / Q000506:poisoning*; D051381:Rats; D012119:Respiration / Q000187:drug effects
D009020:Morphine