The carbohydrate deposits detected by histochemical methods in the molecular layer of the dentate gyrus in the hippocampal formation of patients withschizophrenia, Down's syndrome and dementia, and aged person

Post-mortem brain tissue was obtained from 28 patients with brain disorders , of which 15 had clinically diagnosed schizophrenia, 6 Alzheimer type deme ntia, 5 dementia with tangles and 2 cases of Down's syndrome. The controls were 22 cases from autopsies without brain disorders or with no known episo des of brain disorder. The tissues were stained for the detection of carboh ydrate deposits in the hippocampal formation, using lectin, immunohistochem ical and conventional staining methods. The staining revealed the existence of spherical deposits in the inner and middle molecular layers of the dent ate gyrus in the hippocampal formation which contained fucose, galactose, N -acetyl galactosamine, N-acetyl glucosamine, sialic acid, mannose and chond roitin sulfate. The number of the deposits was higher in patients with brai n disorder such as schizophrenia, Alzheimer type dementia, dementia with ta ngles or Down's syndrome, and in some aged individuals, in comparison to th ose in younger individuals. No deposits were detected in a few younger or a ged individuals. Spherical deposits 3-10 mum in diameter may be an immature form of the corpora amylacea, since they were similar in the histochemical characteristics with lectin, immunohistochemical and conventional staining methods. However, differing staining ability by hematoxylin, periodic acid Schiff's reagent and antibodies against the intracellular degraded protein s such as ubiquitin and tau-protein was observed. The antibodies against ub iquitin and tau-protein showed clear reactivity with the corpora amylacea a nd no reactivity with spherical deposits, indicating that the corpora amyla cea has an intracellular origin and spherical deposits an extracellular mat rix origin. The results obtained in this study indicate that not only neuro nal degeneration but also unusual glycometabolism in neurons may disturb th e neuronal function and cause brain disorders, and that spherical deposits may cause dysfunction of the neuronal network in the dentate gyrus of the h ippocampus which is closely linked with recognition and memory functions.