Nature Chem. Biol. doi:10.1038/nchembio.86 (2008)

Marijuana calms people down and relieves pain, but also has the negative effect of promoting memory loss. By blocking the breakdown of two naturally occurring compounds that bind to the same brain receptor as cannabis, scientists in California have found a way to boost the positive effects associated with cannabis use.

THC, the marijuana plant's psychoactive component, binds to a receptor called CB1, as do the brain's own cannabinoids 2-AG and anandamide. John Casida of the University of California, Berkeley, and his colleagues used organophosphorus nerve agents to inhibit the enzymes that catalyse the destruction of these two compounds. Adding one particular nerve agent caused a more than tenfold increase in the levels of these chemicals in the brain. The finding could help pharmacologists design new drugs that relieve pain.