Placebos are inactive treatments that shouldn’t, in some sense, have a real effect. And yet they often do. But the chemical basis of the placebo effect, despite its enormous importance, is still largely a mystery. A study published this week in Nature Medicine shows that cannabinoid receptors are involved in the placebo response to pain, which hasn’t been demonstrated before. The finding implies that the brain’s own endocannabinoids can fight pain, and actually do it via the same pathway as several compounds in the cannabis plant.
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. But studies using living animals yielded inconclusive results because of possible contamination from external sources of morphine in their food or in the environment [Nature]. In addition, the body breaks down and changes morphine, which complicates the task.