Protein May Determine Addiction, Study Finds
Researchers have found a protein that could determine whether a person becomes addicted to cocaine. Researchers from the Scripps Research Institute’s Florida campus suggest that this protein, called methyl CpG binding protein 2 (MeCP2), interacts with a genetic material called microRNA to control a person’s motivation to use cocaine. The study was published in the journal Nature Neuroscience, and the findings could lead to new treatment methods for addiction.
Paul Kenny, an associate professor in the Department of Molecular Therapeutics at Scripps Florida and lead author of the study, said that their findings show that MeCP2 decreases the amount by which microRNA-212 is increased when cocaine is consumed.
This study is the first to show that MeCP2 is associated with cocaine addiction. The protein has previously been linked with Rett syndrome, which is a common cause of mental retardation in females.
A previous study by Kenny and his colleagues found that microRNA-212 played a role in the drug response in rats. Animals with more microRNA-212 were less likely to use cocaine, which suggests that microRNA-212 protects against cocaine addiction.
Kenny said their findings are important because they show why microRNA-212 doesn’t always protect against addiction because MeCP2 determines the level at which microRNA-212 changes when cocaine is consumed. This suggests that understanding how microRNA-212 is regulated could be an important discovery in understanding addiction.
The researchers analyzed the expression of MeCP2 in the brain after cocaine consumption and found that the expression was increased in animals that were given more access to cocaine. They wanted to find out whether the increase influenced the motivation to continue using cocaine.
After disrupting the expression of MeCP2 with a virus, the researchers found that the rats consumed less and less cocaine, and their microRNA-212 levels were significantly higher. This suggests that disruption of MeCP2 reduces vulnerability to cocaine.
The researchers also found that microRNA-212 could also decrease levels of MeCP2, which suggests that they are connected. Both had opposite effects on a certain growth factor (called BDNF) that controls the “rewarding” aspects of cocaine in the brain.
Kenny noted that they don’t know what influences the levels of MeCP2 and plan to continue their research.
Source: Science Daily, Possible Cocaine Addiction Trigger Uncovered: Protein Linked to Mental Retardation May Be Controlling Factor in Drug's Effect in the Brain, August 16, 2010
