Prenatal and postnatal chronic exposure to low levels of inorganic lead attenuates long-term potentiation in the adult rat hippocampus in vivo.

Dams were exposed to 0, 100, 500, or 1000 ppm lead acetate in their drinking water for 1 week and mated. Offspring were exposed via lactation and in their drinking water after weaning. At 13 weeks, a male and a female pup from each litter were anesthetized with urethane and prepared for recording of CA3-evoked field potentials in the hippocampal CA1 region. In control and 100 ppm lead-treated animals, high-frequency stimulation (50 Hz) induced long-term potentiation (LTP) throughout a 4 h recording period. In contrast, 1000 ppm lead-treated pups showed little LTP, while those exposed to 500 ppm exhibited LTP initially but then failed to maintain it. Chronic developmental lead exposure prevented the full expression of LTP in the CA1 region of the rat hippocampus.