ATLANTA, Ga. -- Neuroscientists at the Yerkes Primate Research Center of Emory University have discovered in the brain a novel neurotransmitter that helps control food intake and seems to be partially responsible for the feeling of satiety. The finding may eventually be used to develop medications for obesity, a life-threatening, yet common condition that often lies at the root of other serious illnesses such as diabetes and cardiovascular disease. The study will be reported in the journal Synapse (vol 29, No. 4), available in May on the Synapse website.
The neurotransmitter is called CART peptide, for Cocaine and Amphetamine Regulated Transcript, and its role in feeding was found during studies on the effects of cocaine on the brain. Yerkes neuroscientist Pastor Couceyro was one of the first to notice in rodents that CART mRNA increased in a specific area of the brain when cocaine was administered..
"We tested the CART peptide to see if it could be an agent responsible for loss of appetite for two reasons," says Mike Kuhar, Ph.D., Chief of Neuroscience Division at Yerkes. "First, CART is associated with cocaine and cocaine reduces food intake. Also, CART peptides are found in regions of the brain that control food intake."
When the Yerkes research team injected the CART peptide into the brains of normal rats, their food intake was significantly inhibited--by as much as 30 percent, according to Dr. Phil Lambert, who completed the behavioral aspect of the work. In normal rats, CART was present in high levels in the hypothalamus, "meaning that CART is apparently involved in a variety of physiologic processes, not just in cocaine addiction," says Dr. Lambert.
Next Lambert tried the flip side of the experiment-- blocking the brain's naturally-occurring
CART peptides by injecting antibodies (which bind to the CART peptides and render them
non-functional). Without CART peptides to put the brakes on appetite, the rats' feeding
increased. "This antib
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Contact: Kate Egan
kegan@rmy.emory.edu
404-727-7709
Emory University Health Sciences Center
30-Apr-1998