Discovery could yield treatment for cocaine addicts

Scientists have discovered a molecular process in the brain triggered by cocaine use that could provide a target for treatments to prevent or reverse addiction to the drug.

Reporting in the Journal of Neuroscience, Michigan State University neuroscientist A.J. Robison and colleagues say cocaine alters the , the brain's that responds to stimuli such as food, sex and drugs.

"Understanding what happens molecularly to this brain region during long-term exposure to drugs might give us insight into how addiction occurs," said Robison, assistant professor in the Department of Physiology and the Neuroscience Program.

The researchers found that cocaine causes cells in the nucleus accumbens to boost production of two proteins, one associated with addiction and the other related to learning. The proteins have a reciprocal relationship—they increase each other's production and stability in the cells—so the result is a that Robison calls a feed-forward loop.

Robison and colleagues demonstrated that loop's essential role in cocaine responses by manipulating the process in rodents. They found that raising production of the protein linked to addiction made animals behave as if they were exposed to cocaine even when they weren't. They also were able to break the loop, disrupting rodents' response to cocaine by preventing the function of the learning protein.

"At every level that we study, interrupting this loop disrupts the process that seems to occur with long-term exposure to drugs," said Robison, who conducted the study as a postdoctoral fellow at Mount Sinai School of Medicine in New York City before joining the faculty at MSU.

Robison said the study was particularly compelling because it found signs of the same feed-forward loop in the brains of people who died while addicted to cocaine.

"The increased production of these proteins that we found in the animals exposed to drugs was exactly paralleled in a population of human cocaine addicts," he said. "That makes us believe that the further experiments and manipulations we did in the animals are directly relevant to humans."

Robison said the growing understanding of addiction at the molecular level could help pave the way for new treatments for addicts.

"This sort of molecular pathway could be interrupted using genetic medicine, which is what we did with the mice," he said. "Many researchers think that is the future of medicine."

Related Stories

Morphine and cocaine affect reward sensation differently

Oct 05, 2012

(Medical Xpress)—A new study by scientists in the US has found that the opiate morphine and the stimulant cocaine act on the reward centers in the brain in different ways, contradicting previous theories ...

Recommended for you

Steering the filaments of the developing brain

13 hours ago

During brain development, nerve fibers grow and extend to form brain circuits. This growth is guided by molecular cues (Fig. 1), but exactly how these cues guide axon extension has been unclear. Takuro Tojima ...

Do we really only use 10% of our brain?

14 hours ago

As the new film Lucy, starring Scarlett Johansson and Morgan Freeman is set to be released in the cinemas this week, I feel I should attempt to dispel the unfounded premise of the film – that we only use 10% of our brains ...

Birthday matters for wiring-up the brain's vision centers

Jul 31, 2014

Researchers at the University of California, San Diego School of Medicine have evidence suggesting that neurons in the developing brains of mice are guided by a simple but elegant birth order rule that allows them to find ...

User comments