Diabetic drug may help treat cocaine addiction

Researchers have found that a US Food and Drug Administration (FDA)-approved drug currently used for obese patients and Type-2 diabetics has the potential to be used in the treatment of cocaine dependence. The drug, trade name Byetta, derives from a naturally occurring hormone called glucagon-like peptide-1, or GLP-1, which regulates feeding behaviour.

In a two-and-a-half year study of rats, the researchers showed that when they activated GLP-1 receptors in the region of the brain that deals with reward behaviour, called the ventral tegmental area, or VTA, the animals self-administered less cocaine.

It is the first time such a role has been shown for the hormone in the brain, the study said. Physiologically, the hormone acts similarly in rat brains and human brains. Rather than injecting cocaine, the scientists modelled the way a human would take the drug by offering the study rats a lever to press for intravenous infusions.

Once the animals stabilised in their drug-taking regimen, the researchers introduced the GLP-1 receptor directly into the brain. "We were looking at what activation of GLP-1 receptors in the VTA does to the animal's self-administration of cocaine," said study lead author Heath Schmidt from the University of Pennsylvania in the US.

"We were able to show a nice decrease in cocaine self-administration," Schmidt noted. The findings were detailed in the journal Neuropsychopharmacology. The drug, whose side effects are known, has already been proven safe for human use and if this research continues to progress successfully, those working to treat cocaine addiction may soon have another option in their toolkit.