Boosting the amounts of a marijuana-like brain transmitter called anandamide produces antidepressant effects in test rats, according to American and Italian researchers.
The researchers, led by Daniele Piomelli, the Louise Turner Arnold Chair in Neurosciences and director of the Center for Drug Discovery at the University of California, Irvine, used a drug they created, called URB597, which blocks anandamide degradation in the brain, thereby increasing the levels of this chemical.
“These findings raise the hope that the mood-elevating properties of marijuana can be harnessed to treat depression,” Piomelli said. “Marijuana itself has shown no clinical use for depression. However, specific drugs that amplify the actions of natural marijuana-like transmitters in the brain are showing great promise.”
The researchers administered URB597 to chronically-stressed rats that demonstrated behaviors similar to those seen in depressed human patients. The stressed rats treated with the drug, after five weeks of treatment, were behaving similarly to a comparison group of unstressed animals.
URB597 works by inhibiting an enzyme in the body FAAH that breaks down anandamide. Anandamide, dubbed as “the bliss molecule” for its similarities to the active ingredient in marijuana is a neurotransmitter that is part of the brain’s endocannabinoid system. In studies by Piomelli and others, anandamide has been shown to play analgesic, anti-anxiety, and antidepressant roles besides being involved in the regulation of feeding and obesity. Inhibiting FAAH activity boosts the effects of anandamide without producing the “high” seen with marijuana.
Piomelli and colleagues at the Universities of Urbino and Parma in Italy created URB597.
The study appears in an issue of Biological Psychiatry.
University of California