Researchers found that repeated exposure to cocaine causes a genetic change that leads to altered levels of a specific brain protein called cyclin-dependent kinase 5 (Cdk5). Previous research found that Cdk5 regulates the action of dopamine, a chemical messenger in the brain associated with cocaine’s pleasurable ‘rush’ and with addiction to cocaine and other drugs. Scientists discovered that delta-FosB, a protein, triggers increases in Cdk5 levels. These results suggest that delta-FosB-mediated changes in Cdk5 levels and the resulting alterations in dopamine signalling in brain cells contribute to adaptive changes in the brain related to cocaine addiction,’ said Dr. James Bibb of Rockefeller University in New York City, N.Y., who was involved in the study.

“This research provides a valuable insight into the step-by-step molecular adaptations that the brain makes in response to drugs,” said Dr. Alan I. Leshner, director of NIDA. “These adaptations result in long-term changes at the cellular level that are involved in the development of addiction.”

Source: Dr James Bibb et al Rockefeller University New York city published in Nature March 2001