Effects of chronic lead exposure on short-term and long-term depression inarea CA1 of the rat hippocampus in vivo

Chronic developmental lead (Pb) exposure to the rat has been reported to im pair the long-term potentiation (LTP) in area CAI and DG of the hippocampus . The present study was performed to investigate the effects of chronic Pb exposure on homosynaptic short-term depression (STD) and long-term depressi on (LTD) of population spikes (PS) in area CA1 of the rat hippocampus in vi vo. Neonatal Wistar rats were exposed to Pb from parturition to weaning via the milk of dams fed with 0.2% lead acetate solution. The input/output (I/ O) function, paired-pulse reaction (PPR), the PS were measured in the area CA1 in response to low frequency stimulation (LFS). The results showed that the home-STD amplitude of PS depotentiation in Pb-exposed rats (87.48 +/- 7.44%, n = 14) was less significant than that in control rats (72.34 +/- 6. 05%, n = 18, P < 0.05), and the home-LTD amplitude of PS depotentiation in Pb-exposed rats (72.80 +/- 5.86%, n = 14) was even less significant than th at in control rats (47.80 +/- 5.03%, n = 18, P < 0.01). The results suggest that chronic Pb exposure in neonatal rats caused impairments in the STD an d LTD of area CAI of hippocampus. (C) 2000 Elsevier Science Ltd. All rights reserved.