title: What we don't know about pain.
mesh_terms: D015670:Acupuncture Therapy; D002490:Central Nervous System / Q000502:physiology; D004723:Endorphins / Q000502:physiology*; D006801:Humans; D009433:Neural Inhibition; D010146:Pain / Q000503:physiopathology*
chemical_list: D004723:Endorphins