BRAIN'S MARIJUANA-LIKE CHEMICALS POSTPONE PAIN Experts have long known that the brain has the ability to suspend the pain response in times of injury and great stress, even after traumatic incidents such as gunshot wounds. Now, a new study in rats suggests marijuana-like neurochemicals called endocannabinoids may be key to this process. The discovery may lead to a new class of painkillers with fewer side effects than existing pain medications, report researchers at the University of California, Irvine ( UCI ). Their study appears in the June 23 issue of Nature. "This study shows for the first time that natural marijuana-like chemicals in the brain have a link to pain suppression," researcher Daniele Piomelli, a professor of pharmacology and director of the Center for Drug Discovery at the UCI School of Medicine, said in a prepared statement. Stress can provide a delayed pain reaction in certain situations, an effect called stress-induced analgesia. Previous research has identified two kinds of stress-induced analgesia mechanisms in the body -- opioid and non-opioid. This study is the first to offer evidence that the non-opioid form is produced by cannabinoid compounds. "If we design chemicals that can tweak the levels of these cannabinoid compounds in the brain, we might be able to boost their normal effects," Piomeilli explained. "Aside from identifying an important function of these compounds, it provides a template for a new class of pain medications that can possibly replace others shown to have acute side effects," he added.