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----------------------------------------------------------------------- Brain receptor role links Alzheimer's and smoking ----------------------------------------------------------------------- WASHINGTON (November 4, 1997 4:16 p.m. EST http://www.nando.net) - U.S. government scientists said Tuesday they had found a new function for a brain receptor that could link smoking, Alzheimer's and epilepsy. They found the receptor, known as the nicotinic receptor, on a brain cell in rats and said this shed light on the function of chemicals in the brain. The brain cells are known as interneurons and are found in the hippocampus, the part of the brain linked with learning and memory, Susan Jones and Jerrel Yakel of the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina, reported. Each interneuron can affect thousands of "excitatory" neurons -- the workhorses of the brain -- so Jones and Yakel theorize that finding the receptor on these means a broader role in the brain. "We are not exactly sure what role it plays," Yakel said in a telephone interview. "This class of neuron previously was not thought to have functional receptors." Receptors are a kind of chemical doorway on the outside of a cell. This particular receptor is designed to let acetylcholine -- a neurotransmitter or message-carrying chemical -- deliver its information into the cell. It is also the receptor that nicotine acts on -- thus its name and its role in smoking. Yakel said the receptor could shed light on studies that show nicotine can sometimes help the memories of people with Alzheimer's. Alzheimer's patients have been shown to have fewer nicotinic receptors in their brains. "There is pretty good evidence that some of the symptoms of Alzheimer's could be mitigated a bit by nicotine or nicotinic-type drugs," Yakel added. "That's a pretty good clue." A rare form of epilepsy known as autosomal dominant nocturnal frontal lobe epilepsy is known to result from a mutation in the gene for one part of this receptor -- thus the link to epilepsy. Nicotine is also known to enhance cognition -- the basic brain function involved in learning and recognition. Jones and Yakel published their study in the Journal of Physiology. Copyright 1997 Nando.net Copyright 1997 Reuters http://www.nando.net/newsroom/ntn/health/110497/health4_29487_noframes.html ----------------------------------------------------------------------- janet [log in to unmask]