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 dr inking water for 1 week and mated. Offspring were exposed via lactatio n and in their drinking water after weaning. At 13 weeks, a male and a female pup from each litter were anesthetized with urethane and prepa red for recording of CA3-evoked field potentials in the hippocampal CA 1 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 l ittle LTP, while those exposed to 500 ppm exhibited LTP initially but then failed to maintain it. Chronic developmental lead exposure preven ted the full expression of LTP in the CA1 region of the rat hippocampu s. (C) 1997 Elsevier Science Ireland Ltd.