[Effect of lead exposure during pregnancy on hippocampal long-term potentiation and expression of NMDAR-2A mRNA in the off-spring rats].
Chronic lead exposure during brain development is known to affect cognitive and behavioral functions in children and animals. The lead exposure on pregnant rats was used as a model to examine the effects of lead on the long-term potentiation(LTP) in hippocampal dentate gyrus(DG) region in vivo and the expression of NMDAR-2A mRNA by in situ hybridization in the off-springs. Female rats were exposed to 0.5 g/L or 2 g/L lead acetate in drinking water since 10 days before mating to weaning. The filial rats of 70-90 days old with blood lead levels below 100 micrograms/L were prepared for recording their DG-evoked population spike(PS) in the hippocampal DG area in vivo. The results showed that the range of LTP were (136 +/- 31)% in low lead group, (145 +/- 30)% in high lead group, and (319 +/- 114)% in control group. The reduction of NMDAR-2A mRNA expression 34%-44% in the granule and pyramidal cell layers caused by lead were seen in 21 days old rats. It indicated that the cognitive deficits induced by low-level lead exposure in early stage of life may persist to adulthood, and the modified NMDAR gene expression may play a key role in the cognitive deficits associated with lead exposure during development.
Institute of Occupational Medicine, Chinese Academy of Preventive Medicine, Beijing 100050, China.
J
J
Zhang
J
J
Lü
T
T
Cui
G
G
Xie
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007854:Lead / Q000633:toxicity*; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000096:biosynthesis*
D007854:Lead; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate