GANGLTOSIDES AND THE ARCHITECTURE OF HUMAN FRONTAL AND RAT SOMATOSENSORY ISOCORTEX |
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| Authors: | Helek H Hess N H Bass Carol Thalhhmer Rita Devarakonda |
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| Institution: | The Laboratory of Vision Research, National Eye Institute, National Institutes of Health, US. Department of Health, Education and Welfare. Bethesda, MD;University of Virginia School of Medicine, Charlottesville, VA, U.S.A. The McLean Hospital Biological Research Laboratory, Belmont, MA;University of Virginia School of Medicine, Charlottesville, VA, U.S.A. The Department of Neurology and Ncuropathology. Harvard Medical School, Boston, MA and the Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, U.S.A. |
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| Abstract: | Ganglioside sialic acid was determined in the layers of human frontal association cortex and rat somatosensory cortex by microchemical methods of sampling and analysis. In both cortices the distribution per unit dry weight showed three main peaks or inflections: (1) at the junction of layers II and III; (2) in the lower part of layer III at the junction with IV; and (3) at the junction of layers V and VI. These distributions parallel the occurrence of high concentrations of dendritic and axonal plexuses and their synaptic articulations. In human cortex, the concentration of ganglioside sialic acid per unit dry weight was slightly greater, the amount per cell was twice as great. and the amount per neuron present was 2- to 6-fold greater than in rat somatosensory cortex. The ganglioside sialic acid per cell was 120- to 200-fold greater in human association cortex than in rat retina, which is a CNS region with sparse neuropil. The results support the validity of ganglioside sialic acid as an index of the relative mass of neuronal plasma membranes in neural tissues and its usefulness in chemoanatomic quantitation of axodendritic interrelationships established by synaptic contacts with local and distant neurons. |
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