A previously unknown role of cholesterol in the formation of contacts between nerve cells has been discovered by researchers at the Max-Delbrck-Center for Molecular Medicine in Berlin, Germany, and at the Centre de Neurochimie in Strasbourg in France (Science, November 09th, 2001). Their results suggest a link between brain cholesterol metabolism and nerve cell development, learning and memory and hint at new strategies to cure injury- or disease-induced brain lesions.

Brain function depends on the exchange of electrical signals between nerve cells that is mediated by highly specialized contact sites, the socalled synapses. Their formation is a decisive phase during brain development and plays an important role in learning and memory. So far, however, the mechanisms of this process are largely obscure and thus, their elucidation is therefore an important topic of neuroscience research. Moreover, the identification of "synaptogenic" factors is a fundamental prerequisite to repair synaptic connections that have been destroyed by injury, stroke or neurodegenerative diseases like Alzheimer's.

A clue to the existence of a synaptogenic factor came from a study that Dr. Frank Pfrieger, presently leader of a bilateral research group of the Max-Planck Society and the Centre National de Recherche Scientifique, conducted some years ago in the lab of Prof. B. Barres at Stanford University in the USA. The two researchers examined whether neurons can form contacts by themselves or whether they need help from socalled glial cells. Glial cells form a large part of the brain tissue and support its development and function in many different ways. By studying isolated nerve cells in culture dishes Pfrieger and Barres found that neurons survive and grow under glia-free conditions, but show only few of the electrical signals that are generated by
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Contact: Dr. Frank W. Pfrieger
fw-pfrieger@gmx.de
33-3-88-45-66-45
Max-Planck-Gesellschaft
9-Nov-2001