by Craig Weatherby
Chronic pain is an often-overlooked stepchild of medical science.
Precious little serious research has been devoted to pain, despite the enormous toll it takes on individuals and society.
The available pain drugs remain limited to options with significant drawbacks… opiates, acetaminophen, steroids, aspirin, and aspirin-like drugs such as ibuprofen.
And many people try to downplay pain or even avoid treatment… perhaps due to a misguided sense of stoicism or fear of addiction to synthetic opiates like oxycodone and hydrocodone.
So we hope that the findings of an animal study from the University of California hold when the experiment is repeated in humans.
An Italian-American team gave rodents a drug that raises the levels of a naturally occurring animal and human neurotransmitter called anandamide.
The exciting result was strong, long-lasting pain relief without any apparent side effects… and, as expected, without making the animals “high”.
Anandamide is found in animal and human organs, especially in the brain, and being a cannabinoid-class chemical, it closely resembles the key compounds that make marijuana a psychoactive drug.
The cannabis-like neurotransmitter helps regulate acute pain and inflammatory pain signals, and is needed for appetite regulation and for “working” memory.
Anandamide has also been dubbed—quite misleadingly—“the bliss molecule” for its similarities to the active ingredient in marijuana (delta-9-tetrahydrocannabinol or THC).
Let's take a look at the exciting new findings.
Pot-like body chemical proves a potent pain reliever
American and Italian researchers have found that a novel drug allows anandamide to effectively control pain at the site of an injury (Clapper JR et al. 2010).
Led by Daniele Piomelli, the Louise Turner Arnold Chair in Neurosciences and director of the Center for Drug Discovery at UC Irvine, the study suggests that such compounds could form the basis of pain medications that don't produce sedation, addiction, or other central nervous system side effects common with existing painkillers, such as opiates.
“These findings raise hope that the analgesic properties of marijuana can be harnessed to curb pain,” Piomelli said. “Marijuana itself is sometimes used in clinical settings for pain relief but causes many unwanted effects. However, specific drugs that amplify the actions of natural, marijuana-like chemicals are showing great promise.”
For the study, rats and mice were given a drug created by Piomelli and his colleagues at the Italian universities of Urbino and Parma.
The researchers discovered that the compound, called URB937, did not enter the central nervous system but simply boosted the levels of anandamide in peripheral tissues.
Still, it blocked both acute and chronic pain very effectively. This was surprising, since anandamide had been thought to only work in the brain.
The synthetic drug inhibits FAAH, an enzyme in the body that breaks down anandamide.
A neurotransmitter that's part of the endocannabinoid system, anandamide has been shown in studies by Piomelli and others to play analgesic, anti-anxiety, and antidepressant roles. It's also important in regulating food consumption.
Blocking FAAH activity enhances the effects of anandamide without generating the “high” seen with marijuana.
Piomelli and his team are now collaborating with drug discovery specialists at the Italian Institute of Technology, in Genoa, to develop the new, patented compound into a clinically useful medication.
Researchers from UCI, the University of Georgia, the University of Naples, the University of Parma, the University of Urbino, and the Italian Institute of Technology participated in the study, which was supported by the National Institute on Drug Abuse and the Italian Ministry of Public Education
Clapper JR, Moreno-Sanz G, Russo R, Guijarro A, Vacondio F, Duranti A, Tontini A, Sanchini S, Sciolino NR, Spradley JM, Hohmann AG, Calignano A, Mor M, Tarzia G, Piomelli D. Anandamide suppresses pain initiation through a peripheral endocannabinoid mechanism. Nat Neurosci. 2010 Sep 19. [Epub ahead of print]
University of California Irvine (UCI). Compound boosts marijuana-like chemical in the body to relieve pain at injury site. September 20, 2010. Accessed at http://today.uci.edu/news/2010/09/nr_faah_100920.php