Researchers have developed a treatment that may help reverse chemical imbalances made to the brain by habitual drug use and could one day help recovering drug addicts avoid future drug use.

When tested on rats, the new treatment was effective in reducing the animals' cravings, according to the findings published in the Journal of Medicinal Chemistry. When someone habitually misuses drugs, their brain chemistry is changed in ways that make it harder for them to quit taking drugs despite negative consequences.Once someone has developed this brain disorder, their mind pays sharper attention to cues that encourage drug use, making it harder for them to abstain.

Serotonin, a brain chemical that transmits information between neural regions, is a key player in these changes. The researchers found that the serotonin 2C receptors in drug addicts do not work as well as they should. The team led by researchers from the University of Texas Medical Branch at Galveston in the US designed, synthesised and pharmacologically evaluated a series of small molecule therapeutics designed to restore the weakened signalling.

The findings showed that the novel therapeutic may help reverse chemical imbalances made to the brain by habitual drug use. In their experiment, the researchers trained rats to press on a lever for cocaine infusions at certain light cues. Once the rats learned this cocaine-seeking behaviour, half of them received the most promising therapeutic and the other half received only saline.

The findings showed that the animals treated with the new therapeutic pressed the lever for cocaine far fewer times than the saline-treated control animals, even when reinforced with the cocaine-associated light cues. "We are the first to show that a serotonin 2C receptor therapeutic of this type can be successfully used to decrease drug-seeking behaviours," said Kathryn Cunningham, Director of Center for Addiction Research at the University of Texas Medical Branch at Galveston.

"Our findings are especially exciting because in addition to someday helping people to recover from drug addiction, impaired functioning of the serotonin 2C receptor is also thought to contribute to other chronic health issues such as depression, impulsivity disorders, obesity and schizophrenia," Cunningham added.