Daniele Piomelli, professor of pharmacology and director of the Center for Drug Discovery in the UCI School of Medicine, and colleagues have found that marijuana-like chemicals called endocannabinoids play a key role in stress-induced analgesia -- the body's way of initially blocking pain after an injury during periods of intense stress. In addition, the researchers have developed a novel inhibitor molecule that boosts the analgesic effect of the specific cannabinoid compound most directly related to pain relief.

Study results appear in the June 23 issue of the journal Nature.

"This study shows for the first time that natural marijuana-like chemicals in the brain have a link to pain suppression," Piomelli said. "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."

Scientists have long known that stress gives injured athletes or even gunshot victims a period of time in which the body's pain reaction is delayed, an effect called stress-induced analgesia. Researchers along the way have found two kinds of stress-induced analgesia mechanisms, opioid and non-opioid, and this study offers the first evidence that the non-opioid form is produced by cannabinoid compounds.

Piomelli and study co-author, Andrea Hohmann, a neuroscientist at the University of Georgia, found one specific cannabinoid compound, 2-AG, provided profound and immediate response to the body's pain reaction during stress. The researchers found that when blocking 2-AG response in test rat
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Contact: Tom Vasich
tmvasich@uci.edu
949-824-6455
University of California - Irvine
22-Jun-2005