By Charles H. Ball News Office Researchers in an MIT laboratory have discovered chemical abnormalities in the brains of people with Alzheimer's disease that apparently do not occur in the brains of people with other neurologic diseases. While earlier research has established that two sets of chemical disturbances characterize the brains of those suffering from Alzheimer's, neither of these changes is exclusive to the disease. The abnormalities uncovered in the study involve the way that brain cells use the chemical choline. This chemical is an important building block both for the membranes in brain cells and a neurotransmitter, acetylcholine.
Neurotransmitters are the chemicals that carry signals from one nerve cell to another.
Choline normally is produced in the liver and obtained from the diet. The researchers' findings show that choline levels in the brains of Alzheimer's victims are much lower than normal, and the amounts of choline present in the membranes of brain cells are also diminished, partly because the membranes are broken down more rapidly than they should be to release the stored choline. These disturbances are found all over the brain-both in regions previously known to be involved in Alzheimer's disease and in other regions formerly thought to be normal. Moreover, unlike the other known chemical disturbances of Alzheimer's, they are not found in the brains of people with Down's Syndrome, nor in other neurological diseases like Parkinson's Disease and Huntington's Disease. Prior to the newly reported discoveries, two other chemical abnormalities had been observed in the brains of people with Alzheimer's.