Can ingredients in rosemary extract fight cocaine addiction?

Researchers have discovered that an antioxidant found in rosemary extract can reduce cocaine use by dampening the brain's reward response, providing a new therapeutic target for the treatment of addiction.

The study in the journal Neuron describes the researchers' focus on a region of the brain called the globus pallidus externus, which acts as a gatekeeper and regulates how we respond to cocaine.

They discovered that parvalbumin-positive neurons in the GPe play a crucial role in controlling the response to cocaine by altering the activity of neurons that release the pleasure molecule dopamine.

“There are currently no effective therapies for addiction to psychostimulants such as cocaine, which, along with opioids, pose a significant health burden,” says corresponding author Kevin Beier, associate professor of physiology and biophysics at the University of California, Irvine.

“Our study deepens our understanding of the fundamental brain mechanisms that increase vulnerability to substance-related disorders and provides a basis for the development of new interventions.”

Results in mice showed that globus pallidus externus parvalbumin-positive cells, which indirectly affect the release of dopamine, become more excitable after exposure to cocaine. This led to a decrease in the expression of certain proteins encoding membrane channels that normally help keep the activity of globus pallidus cells under control. The researchers found that carnosic acid, an isolate from rosemary extract, selectively binds to the affected channels, offering a way to reduce the response to the drug in a relatively specific way.

“Only a subset of people are vulnerable to developing a substance use disorder, but we cannot yet determine who these individuals are. If globus pallidus cell activity can effectively predict response to cocaine, it could be used to measure likely responses and thus serve as a biomarker for those most at risk,” says Beier. “In addition, it is possible that high-risk individuals could be given carnosic acid to reduce response to cocaine.”

The next steps of this research include a thorough evaluation of the negative side effects of carnosic acid and determining the ideal dosage and timing. The team is also interested in testing its effectiveness in reducing cravings for other drugs and developing more effective and targeted variants.

Scientists from the University of West Virginia and the University of Colorado were involved in the study.

Support for this work came from the National Institutes of Health, One Mind, the Alzheimer's Association, New Vision Research, the BrightFocus Foundation, and the Brain & Behavior Research Foundation.

Source: UC Irvine