Diabetes Drug Decreases Psychostimulant Addiction Behavior

In a study of cocaine addiction, animals were injected with the diabetes drug Exendin-4, a longer-lasting analog of the natural hormone glucagon-like peptide-1 (GLP-1), which is released in response to nutrient ingestion and is a regulator of energy metabolism and feeding behavior. The resulting behavior showed significant reduction of the rewarding effects of cocaine and the findings were consistent over a broad range of Exendin-4 dosage. The study reported no evidence of negative side effects or addiction to Exendin-4 treatment.

“We suspect that this is a general mechanism that will translate to additional drugs of abuse, especially other stimulants, like amphetamine and methamphetamine,” said Gregg Stanwood, PhD, assistant professor of Pharmacology and an investigator in the Vanderbilt Kennedy Center and Vanderbilt Brain Institute. "I think the power of this research is that it is so easily translatable to humans because [Extendin-4] is already FDA approved [for diabetes]," said Aurelio Galli, PhD, professor of Molecular Physiology and Biophysics, Vanderbilt Brain Institute investigator, and codirector of the Neuroscience Program in Substance Abuse. "Any disease that is based on dysregulated dopamine can be potentially targeted. There is a lot of comorbidity between metabolic disorders like diabetes and obesity and psychiatric disease like addiction and schizophrenia."

Prof. Stanwood noted that although it is important to be very cautious in extrapolating the results to humans, these are encouraging data. “There are no medically based therapies for stimulant addiction that have been successful in the clinic, although there are a variety of psychosocial and behavioral therapies that are somewhat effective in some people,” said Prof. Stanwood. “The beauty of this is that it targets a completely new mechanism so we are cautiously hopeful [...]. We don’t expect this to be a magic bullet where one can simply take this drug and their addiction goes away, but hopefully a medicine like this, in combination with social and behavioral support, will help an addict on the road to recovery.”

The findings were published early online October 23, 2012, in the journal Molecular Psychiatry.

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