A new study in mice has found that activating a receptor affected by marijuana can dramatically reduce cocaine consumption. The research suggests that new anti-addiction drugs might be developed using synthetic versions of cannabidiol (CBD), the marijuana component that activates the receptor—or even by using the purified natural compound itself.
Researchers formerly believed that the receptor, known as CB2, was not found in the brain and that therefore CBD had no psychoactive effects. But a growing body of research suggests otherwise. After THC, CBD is the second most prevalent active compound in marijuana.
The study found that JWH133, a synthetic drug that activates the CB2 receptor, reduced intravenous cocaine administration in mice by 50-60%.
"It's a very significant reduction,” says Zheng-Xiong Xi, the lead author of the study and a researcher at the National Institute on Drug Abuse.
JWH133 comes with some other features that make it an attractive candidate as a potential anti-addiction treatment. It does not seem to produce either a high or a negative experience, which is critical if it is to become a useful and politically acceptable anti-addiction option. While mice given drugs like cocaine or heroin will spend more time in the place where they got high (apparently hoping for more), mice didn't develop such a “place preference” when given JWH133. Nor did they avoid the spot where they'd been given it, which happens when mice are given drugs they find unpleasant.
"It's extremely exciting,” says Antonello Bonci, scientific director for intramural research at the National Institute on Drug Abuse.
Ethnographic research by Ric Curtis, chair of anthropology at John Jay College in New York suggests that, as is often the case, addicts may have been ahead of the researchers in discovering this potential property of marijuana. National surveys found that as crack use declined in the early 1990's, marijuana use rose— and Curtis found that many crack users reported deliberately substituting marijuana for crack, seeking a cheaper and less disruptive high.
Could successful replacement of crack with marijuana be related to CBD and its activation of CB2 receptors? “That's a very tough question,” says Xi, adding that while we don't really know, he suspects that THC may be more involved. “That sounds more like substitution, using a less addictive drug to replace a more addictive drug,” he says.
The next step to is to figure out what are the side effects of this, to figure out what could limit [development],” says Bonci. Interestingly, other studies suggest that JWH133—and therefore, potentially, CBD—may prevent the development of the brain plaques associated with Alzheimer's disease. It also seems to have antipsychotic effects.
All of which merely adds to the increasingly absurd controversy over medical uses of marijuana.
By MAIA SZALAVITZ Tuesday, July 26, 2011