Postnatal lead exposure alters expression of forebrain p75 and TrkA nerve growth factor receptors.
Lead is a potent developmental neurotoxicant that affects many aspects of cognition and behavior. The hippocampus and striatum are among the areas particularly sensitive to the effects of lead and cholinergic neurons in both regions depend upon nerve growth factor (NGF) for their survival and maturation. The present study examined the extent to which postnatal lead exposure may affect the survival and expression of neuroptrophin receptors of septo-hippocampal cholinergic projection neurons in the medial septum/vertical limb of the diagonal band of Broca (MS/VDB) and cholinergic neurons of the striatum. Weanling rats were fed chow containing lead acetate for 30 days and effects on cholinergic cell number and the number of cells expressing neurotrophin receptors p75(NGFR) and trkA were assessed. A decrease in the number of cells expressing p75(NGFR) and an increase in the number of cells expressing trkA receptor was observed in the MS/VDB of lead-exposed rats, without a loss of cholinergic cell number or alteration in cell size. Lead-exposure resulted in a significant decrease in trkA-expressing cells in the striatum but no change in the number or size of cholinergic neurons. These results suggest that a brief postnatal lead exposure does not result in loss of MS/VDB or striatal cholinergic neurons but does modify the expression of neurotrophin receptors in these regions. The significance of these effects on the septo-hippocampal and striatal functioning remains to be studied.
Kidd
S K
SK
Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, JAH 521, Philadelphia, PA 19107, USA.
Anderson
D W
DW
Schneider
J S
JS
D000818:Animals; D002799:Cholinergic Fibers / Q000187:drug effects / Q000378:metabolism*; D020667:Diagonal Band of Broca / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007855:Lead Poisoning / Q000378:metabolism*; D008297:Male; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism*; D009434:Neural Pathways / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D020318:Rats, Long-Evans; D020800:Receptor, Nerve Growth Factor / Q000187:drug effects / Q000378:metabolism*; D020917:Receptor, trkA / Q000187:drug effects / Q000378:metabolism*
D020800:Receptor, Nerve Growth Factor; D020917:Receptor, trkA