The Effects of Chronic Low-level Lead Exposure on the Early Structuring of the Central Nervous System
Chronic low-level lead exposure has been demonstrated to inhibit neural cell acquisition and impair early postnatal structuring of the central nervous system. Lead was demonstrated to have an anti-mitotic action both in vitro and in vivo, although the latter was confined to the cerebellum at blood lead threshold values of 30–40 µg/dl. Low-level lead exposure more potently affected in vivo cell positioning and fibre outgrowth, as judged by the impaired developmental desialylation of the D2-CAM/N-CAM protein, and these effects were seen at blood lead threshold values of 20–30 µg/dl. This inhibition of normal D2-CAM/N-CAM desialylation is attributed to improper guidance of neuronal cells and their fibres, as lead is demonstrated to specifically induce precocious differentiation of the glial cells.
KeywordsGlutamine Synthetase Lead Exposure Neural Cell Adhesion Molecule Blood Lead Level Glutamine Synthetase Activity
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- Averill, D. R. and Needleman, H. L. (1980) Neonatal lead exposure retards cortical synaptogenesis in the rat. In Needleman, H. (ed.), Low Level Lead Exposure: the Clinical Implications of Current Research, pp. 201 - 210 ( New York: Raven Press )Google Scholar
- Bjerrum, O. J. and Bog-Hansen, T. C. (1976) Immunochemical gel precipitation in membrane studies. In Maddy, A. H. (ed.), Biochemical Analysis of Membrane, pp. 378–427. ( London: Chapman & Hall )Google Scholar
- Brackenbury, R., Thiery, J.-P., Rutishauser, U. and Edelman, G. M. (1977) Adhesion among neural cells of the chick embryo. I. An immunological assay for molecules involved in cell- cell binding. J. Biol Chem., 253, 7314–7318Google Scholar
- Choung, C.-M. and Edelman, G. M. (1984). Alterations in neural cell adhesion molecules during development of different regions of the nervous system. J. Neurosci., 4, 2354–2368Google Scholar
- Jacobson, M. (1978) Developmental Neurobiology, 2nd edn ( New York and London: Plenum )Google Scholar
- Phelan, P. and Regan, C. M. (1982) Developmental expression of glutamine synthetase activity in rat brain. Ir. J. Med. Sci., 151, 403–404Google Scholar
- Rutter, M. (1980) Raised lead levels and impaired cognitive/behavioural functioning: a review of the evidence. Dev. Med. Child. Neurol, 22 (Suppl. 42), 1–26Google Scholar
- Wenzel, J., Kammerer, E., Joschko, R., Joschko, M., Kaufmann, W., Kirsche, W. and Matthies, H. (1977) The influence of a learning experience on synaptosomes in the rat hippocampus. Z. Mikrosk.-Anat. Forsch., Leipzig, 91, 57–73Google Scholar
- Winneke, G. (1986) Animal studies. In Lansdown, R. and Yule, W. (eds), The Lead Debate: the Environment, Toxicology and Child Health, pp. 217–234 ( London: Croom Helm )Google Scholar
- Yule, W. (1986) Methodological and statistical issues. In Lansdowne, R. and Yule, W. (eds), The Lead Debate: The Environment, Toxicology and Child Health, pp. 193–216 ( London: Croom Helm )Google Scholar