title: The rise and fall of endogenous opioid nomenclature.
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D004723:Endorphins / Q000502:physiology*; D004745:Enkephalins / Q000502:physiology; D006801:Humans; D010455:Peptides / Q000502:physiology; D011957:Receptors, Opioid / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology*; D009626:Terminology as Topic
chemical_list: D004723:Endorphins; D004745:Enkephalins; D010455:Peptides; D011957:Receptors, Opioid