By Jill ElishMarch 2001
THIS IS YOUR BRAIN ON COCAINE: FSU RESEARCHER IDENTIFIES CHEMICAL RESPONSE TO CHRONIC USE
TALLAHASSEE, Fla.--A Florida State University researcher is helping shed light on the addictive powers of cocaine.
Professor Charles Ouimet, a neuroscientist in FSU's psychology department, joined about a dozen other researchers from universities across the country to determine the brain's chemical response to chronic cocaine use. The results of that study, "Effects of chronic exposure to cocaine are regulated by the neuronal protein Cdk5," are published in the March 15 issue of Nature.
"This study gets us one step closer to understanding the process by which addiction happens and the mechanisms you might use to tap into and interfere with the process," he said. "Ultimately, we may be able to develop pharmaceutical agents that could help treat cocaine addiction, much in the way that we use methadone to treat heroin addiction."
The authors of the paper theorize that Cdk5, a chemical normally present in the brain, increases in concentration with repeated use of cocaine in an attempt to counter its effects. Ouimet's role was to show that the chemical Cdk5 is present in the cells that respond to cocaine. To do this, he studied the brains of rats and mice who were given cocaine for five successive days.
"The brain produces more Cdk5 when you take cocaine in order to try to keep it in a normal state," Ouimet explained. "But the brain cannot cope with the insult of putting cocaine in the system. If the brain were able to keep up, then we wouldn't have cocaine addiction."
To prove the theory, Ouimet's colleagues at Yale University gave a group of cocaine-induced rats the drug Roscovatine, a Cdk5 inhibitor. With the Cdk5 inhibited by the drug, the cocaine-induced locomotor activity of the rats markedly increased.
"If you gave them the Roscovatine, it made the effects of cocaine worse, showing that Cdk5 at least partially mitigated the compensatory effects," he said.
This is among the first studies to show the effects of chronic cocaine use on the brain enzymes, according to Ouimet. Identifying Cdk5 as one of the chemicals that changes drastically with the exposure to cocaine gives researchers insight into the process of addiction.
This type of research is not just significant for treatment of cocaine addiction but may ultimately help researchers understand how the brain changes with other kinds of addictions, such as gambling and smoking, Ouimet said.
"I suspect, and others suspect, that similar mechanisms could be in place with other addictions," he said. "If we could find that out, we could help a lot of people."
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