title: Endogenous opioids and pain: status of human studies and new treatment concepts.
authors.forename: R C
authors.initials: RC
authors.lastname: Frederickson
authors.forename: R E
authors.initials: RE
authors.lastname: Chipkin
mesh_terms: D000698:Analgesia; D004723:Endorphins / Q000008:administration & dosage / Q000502:physiology* / Q000627:therapeutic use; D006801:Humans; D007278:Injections, Spinal; D010146:Pain / Q000188:drug therapy* / Q000378:metabolism; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology*
chemical_list: D004723:Endorphins; D011957:Receptors, Opioid