title: Brain endorphins and the sense of well-being: a psychobiological hypothesis.
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects; D001923:Brain Chemistry; D003216:Conditioning, Operant / Q000187:drug effects; D004361:Drug Tolerance; D004644:Emotions / Q000502:physiology*; D004723:Endorphins / Q000502:physiology*; D004745:Enkephalins / Q000008:administration & dosage / Q000494:pharmacology; D008568:Memory / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D012646:Self Administration; D012653:Self Stimulation / Q000187:drug effects; D013997:Time Factors
chemical_list: D004723:Endorphins; D004745:Enkephalins; D009270:Naloxone