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CHRONIC DEVELOPMENTAL LEAD EXPOSURE REDUCES NEUROGENESIS IN ADULT RAT HIPPOCAMPUS BUT DOES NOT IMPAIR SPATIAL LEARNING.
Citation:
GILBERT, M. E., M. E. KELLY, T. E. SAMSAM, AND J. H. GOODMAN. CHRONIC DEVELOPMENTAL LEAD EXPOSURE REDUCES NEUROGENESIS IN ADULT RAT HIPPOCAMPUS BUT DOES NOT IMPAIR SPATIAL LEARNING. . TOXICOLOGICAL SCIENCES. Society of Toxicology, RESTON, VA, 86(2):365-374, (2005).
Description:
It has long been heralded that the mature brain does not generate new neurons, it only loses them as a function of injury, disease and age. An exciting recent finding in neuroscience has been that the dentate granule cell layer of the hippocampus has the distinctive property of ongoing cell birth of neurons that continues throughout adult life, a process called neurogenesis. Although mechanisms controlling birth of neurons in the adult brain are unknown, age, activity, diet and psychosocial stress have all been demonstrated to regulate this type of neurogenesis. Little information is available on the impact of environmental insults on this process. This study investigated the effects of a classic developmental neurotoxicant, lead (Pb), on this type of structural plasticity in the adult brain. We report that Pb exposure reduces the survival of newly generated neurons in the adult brain. Although the function of these newly generated neurons has not been clearly defined, information is accumulating to indicate a crucial role of these cells in some types of learning and in disorders of affect and mood. Both cognitive function and affective behaviors are altered by Pb exposure. Thus, interference with this type of structural plasticity in the adult nervous system by environmental chemicals may contribute to functional deficits associated with exposure to pollutants. These findings are the first to reveal that environmental chemicals can interfere with structural plasticity and may provide a model system for investigating subtle alterations in brain structure that result from exposure to toxicants.