title: Brain endorphins: possible role in long-term memory.
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D004723:Endorphins / Q000502:physiology*; D004745:Enkephalins / Q000494:pharmacology; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D012153:Retention, Psychology / Q000187:drug effects
chemical_list: D004723:Endorphins; D004745:Enkephalins; D009270:Naloxone; D009020:Morphine