Human cortical neuronal cell line: establishment from a patient with unilateral megalencephaly
Article Abstract:
Cells of the central nervous system (neurons) are difficult to characterize on the molecular level because they are so heterogeneous (consist of different cell types), unlike the cells of many other organs or systems. Characterization of other cell types is often done through the use of continuous cell cultures (cell lines grown under laboratory conditions) which allow many generations of cells to be collected and analyzed. Neurons, however, present special problems because they have limited life spans. Cells from malignant tumors of the nervous system, which often can be grown successfully in culture, may differ from normal neurons. These problems have been addressed through the use of a cell line from human neurons of the cortex, the surface layer of the brain. Cortical tissue was removed from an 18-month-old patient undergoing surgery for uncontrollable seizures, and the neurons within the sample were allowed to develop under laboratory conditions. After many generations, the properties of the resulting cell line, designated HCN-1A, were investigated. Application of a combination of nerve growth factor, 1-isobutyl-3-methylxanthine, and dibutyryl adenosine 3,5-monophosphate produced the greatest amount of cellular differentiation into a neuronal morphology. Use of markers for proteins known to be associated with neurons showed that all HCN-1A cells stained positively for neurofilament protein, neuron-specific enolase, tubulin, and vimentin. These cells also appeared positive for certain neurotransmitters, such as somatostatin, GABA, glutamate, cholecystokinin-8, and vasoactive intestinal polypeptide. Such transmitters are present in the cortex, and these cells did not stain with markers for catecholamines, known to be present at a low level in that region. Markers for glial or other nonneuronal cells did not stain HCN-1A cells. These findings indicate that this cell line is a neuronal line. While the patient's diagnosis (unilateral megalencephaly, a condition involving continued proliferation of immature neurons) may mean that the cells are abnormal, they should be useful in studies of neuronal function. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Science
Subject: Science and technology
ISSN: 0036-8075
Year: 1990
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Autoradiographic imaging of phosphoinositide turnover in the brain
Article Abstract:
Phosphoinositides are a class of compounds that function as second messengers in many cells of the body. Second messengers serve to carry along with the cell a sequence of events which begins by the binding of some molecule to a cell surface receptor. Phosphoinositides serve as second messengers in the brain, where the interaction of cells with glutamine or acetylcholine, two neurotransmitter substances, may initiate the phosphoinositide system. Previously such events could be measured by removing bits of brain tissue and performing a chemical analysis. Researchers have now devised a method for visualizing the areas of phosphoinositide activity on microscopic slides. The technique uses radioactively labelled cytidine, a precursor of phosphoinositide turnover. Since it is water-soluble and washes out, inositol itself proved useless as a labelled compound. However, the metabolic product of the labelled cytidine, cytidine diphosphate diacylglycerol, is not water soluble and remains bound to the cell membrane. It then becomes possible to process a microscopic slide and use photographic emulsion to localize the radioactive label within the tissue section. Using this method, researchers have identified particularly robust areas of phosphoinositide activity within the molecular layer of the cerebellum and within the hippocampus. In the hippocampus, the phosphoinositide second messenger system responds to acetylcholine in the regions called CA1, CA3, CA4, and the subiculum; the phosphoinositide system responds to glutamine only in the CA3 and subiculum regions. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: Science
Subject: Science and technology
ISSN: 0036-8075
Year: 1990
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Biological roles of nitric oxide
Article Abstract:
Nitric oxide provides significant physiological benefits that researchers did not believe existed until five years ago. The chemical is a molecular messenger, much like a neurotransmitter, that stimulates macrophage activity.
Publication Name: Scientific American
Subject: Science and technology
ISSN: 0036-8733
Year: 1992
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