THE CHOLINERGIC SYSTEM IN ALZHEIMERS-DISEASE

The past decade has witnessed an enormous increase in our knowledge of the variety and complexity of neuropathological and neurochemical cha nges in Alzheimer's disease. Although the disease is characterized by multiple deficits of neurotransmitters in the brain, this overview emp hasizes the structural and neurochemical localization of the elements of the acetylcholine system (choline acetyltransferase, acetylcholines terase, and muscarinic and nicotinic acetylcholine receptors) in the n on-demented brain and in Alzheimer's disease brain samples. The result s demonstrate a great variation in the distribution of acetylcholinest erase, choline acetyltransferase, and the nicotinic and muscarinic ace tyl choline receptors in the different brain areas, nuclei and subnucl ei. When stratification is present in certain brain regions (olfactory bulb, cortex, hippocampus. etc.), differences can be detected as rega rds the laminar distribution of the elements of the acetylcholine syst em. Alzheimer's disease involves a substantial loss of the elements of the cholinergic system. There is evidence that the most affected area s include the cortex, the entorhinal area, the hippocampus, the ventra l striatum and the basal part of the forebrain. Other brain areas are less affected. The fact that the acetylcholine system, which plays a s ignificant role in the memory function, is seriously impaired in Alzhe imer's disease has accelerated work on the development of new drugs fo r treatment of the disease of the 20th century. (C) 1997 Elsevier Scie nce Ltd.