LOS ANGELES, Aug. 15 (Xinhua) -- A protein linked to mental retardation may act as the trigger controlling the addictive impact of cocaine in the brain, a new study suggests.
The findings may one day lead to new therapies to treat addiction, researchers at the Scripps Research Institute said in the study, appearing in the journal Nature Neuroscience on Sunday.
The results from the study strongly suggest that a protein known as methyl CpG binding protein 2 (MeCP2) interacts with a type of genetic material known as microRNA to control an individual's motivation to consume cocaine.
In the study, the researchers examined the expression of MeCP2 in the brain after exposure to cocaine. They found that expression was increased in those animals given extended access to the drug.
To determine whether this increase influenced the motivation to take cocaine, the researchers used a virus to disrupt expression of MeCP2.
The result showed that rats consumed less and less cocaine. Intriguingly, levels of another protein miR-212 were also far higher in those animals. Because increases in miR-212 suppress attraction to cocaine, the disruption of MeCP2, in essence, put miR-212 in charge and reduced vulnerability to the drug.
"We concluded that MeCP2 may play an important role in addiction by regulating the magnitude by which miR-212 expression is increased in response to cocaine," said Paul Kenny, an associate professor in the Department of Molecular Therapeutics at the institute.
"In other words, MeCP2 seems to control just how much you can protect yourself against the addictive properties of cocaine," Kenny added.
This is the first time that MeCP2 has been shown to play a role in regulating cocaine addiction. Previously, the protein was most linked to Rett syndrome, a progressive neurodevelopmental disorder and one of the most common causes of mental retardation in females.