Age related changes in aminergic system and behavior following lead exposure: Protection with essential metal supplements

Age related impairments in behavioral functions following lead (Pb) exposure have been linked to changes in neurotransmitter levels in brain regions. In the present study, we have evaluated the protective effect of a mixture of essential elements containing calcium, zinc and iron against Pb-induced long-term effects on aminergic system and behavior of rats. Rats were lactationally exposed to Pb (0.2%) or Pb acetate together with nutrient metal mixture (0.02% Ca, Zn and Fe) in drinking water of the mother from postnatal day (PND) 1 to PND 21. Increases in synaptosomal dopamine, epinephrine, norepinephrine and serotonin levels and decrease in mitochondrial monoamine oxidase (MAO) in cortex, cerebellum, and hippocampus regions were observed following Pb exposure in different age groups (PND 45, 4, 12 and 18 months) of rats. The alterations were greater in hippocampus than cortex and cerebellum. Total locomotor activity, exploratory and open field behaviors were also altered following Pb exposure. However, the alterations were maximum in PND 45 coinciding with greater blood Pb levels observed in PND 45. These data suggest that, Pb exposure induced age dependent alterations in motor behavior and synaptosomal aminergic system were significantly reversed with the supplementation of nutrient metal mixture suggesting therapeutic nature of essential metal supplements against Pb-induced toxicity.