Changes in Acetylcholine Concentration in Mouse Brain Following Ingestion of Lead Acetate in Drinking Water

Abstract

To expose pups to lead, a concentration of 0.258, 0.5% and 1%lead acetate was administered through drinking water to Sprague-Dawley, ICR, lactating dams. After weaning, the pups were given the lead acetate in the drinking water. A significant decrease of 43%, 48% and 54% i n whole brain acetylcholine occurred after 21'days of treatment with 0.25%, 0.5% and 1.0% lead acetate, respectively. Similar treatment for 30 days caused a significant but lesser diminution at time of sacrifice of 37%, 38% and 34% i n whole brain acetylcholine content. Acetylcholine concentration, when measured in whole brain, returned to normal levels at the end of a GO-day exposure in all the treated groups. Treatment with 0.25% and 0.5% lead acetate solution did not have any adverse effect on the body weight of the growing mice, but treatment with 1%lead acetate in drinking water caused a significant decrease in body weight of mice. When mice were treated with 0.25%, 0.5% and 1%ead acetate for 30 days, the most pronounced decrease in acetylcholine content was observed in the corpus striatum. All other regions showed a lesser decrease with the exception of the hippocampus where treatment with 1% lead acetate for 30 days caused an increase in acetylcholine content by 15%. The lead induced decrease in acetylcholine content in the mouse brain returned to normal steady state levels under condition of continuous exposure. The data obtained from the regional study indicate that this adaptation probably occurred in brain regions at different rates.