Can the Human Body Make Its Own Morphine?

Who needs poppy plants to produce morphine? Last month scientists said they'd isolated the genes those plants use to synthesize the narcotic chemical and made it themselves in a lab. Now, in a study in the Proceedings of the National Academy of Sciences, another team has suggested that we mammals might possess the pathway to create our own morphine. Because we have receptors for the opiate in our brains (which makes it such an effective and addictive painkiller), and because morphine traces show up in our urine, scientists had long wondered if animals could produce the drug themselves.