title: Endogenous opioids and pain: a review.
mesh_terms: D000818:Animals; D004723:Endorphins / Q000037:antagonists & inhibitors / Q000502:physiology*; D006168:Guinea Pigs; D006801:Humans; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D010146:Pain / Q000378:metabolism*
chemical_list: D004723:Endorphins; D009270:Naloxone