Acetylcholinesterase activity in the brain of rat pups and dams after exposure to lead via the maternal water supply.

Acetylcholinesterase (AChE) activity was measured in 11 brain areas of control and lead-exposed pups and dams. Lead exposure of pups was by way of the milk of dams drinking 0.2% lead acetate solution as drinking water starting at parturition. Of the brain areas studied, the cerebellum showed the greatest increase in weight (11-fold) and AChE activity per brain area (42-fold per cerebellum) from birth to 20 days, and was the only area in the pups in which AChE activity was consistently affected by the treatment. AChE activity in the cerebellum was 13% less at 10 days of age and 8% less at 20 days in lead-exposed than in control rats. This agrees with observations by others that the developing cerebellum is particularly sensitive to the effects of lead, and may be consistent with our previous report of an effect on motor coordination, i.e., slightly delayed appearance of the air righting reflex, in similarly treated pups. At weaning AChE activity in septum and olfactory tubercles was lower in lead-exposed than in control dams by 15% and 29%, respectively, and the increase in activity in the hypothalamus expected in lactating dams was attenuated by the lead exposure. Thus, lead exposure may affect AChE activity in brain areas of dams, as well as in pups, and so the potential for effects of lead exposure on the dam should not be discounted.