Relationship between lead-induced biochemical and behavioral changes with trace element concentrations in rat brain.

Lead has an obvious potential to disturb learning ability, adaptive responses, and other aspects of behavior and even personality in those who may appear healthy according to conventional medical criteria. These disturbances are shown to be associated with alterations in ionic, cholinergic, and dopaminergic neurotransmission in the central nervous system (CNS). The present experiment was designed to study the neurotoxic consequences of lead exposure on neurotransmitters like dopamine, serotonin, norepinephrine, and activity of acetylcholinestrase, as well as some ions like zinc, calcium, sodium, and potassium. The locomotory functions along with cognitive functions and memory loss were also studied at various dose levels. Lead was administrated orally in doses of 10 mg/kg, 50 mg/kg, and 200 mg/kg for a period of 12 wk and the study was done at the end of exposure. A dose-dependent decrease in the concentration of sodium, potassium, and zinc was observed; there was increase in the concentrations of lead and calcium. The most significant change noted was the decrease in activity of the acetylcholinestrase and other neurotransmitters. Lead exposure affected the locomotor and cognitive functions. Short-term memory remained unchanged at all lead exposure doses.