Chronic exposure to lead (Pb) or manganese (Mn) is known to alter variety of neurological and behavioral functions. In this study, we have examined the neuro-behavioral perturbations in rats exposed to both Pb and Mn, and the protective effect of calcium supplement. Rats (3 months old) were exposed to Pb (0.2% through drinking water) and Mn (intraperitonially daily at a concentration of 2.5 mg/kg body wt) for a period of 3 weeks.
A separate batch of animals received calcium (0.02%) in drinking water together with Pb and exposed to Mn. Following exposures, the neurochemical alterations were assessed by determining the activity changes in synaptosomal acetyl cholinesterase (AChE) and mitochondrial ATPases in different brain regions (cortex, hippocampus and cerebellum). Behavioral studies included both cognitive (water maze tasks) and non-cognitive (open field, exploratory and locomotory tasks). Combined exposure to Pb and Mn resulted in behavioral dysfunctions (decrease in latency, swim distance, swim speed in water maze task and decrease in open field behavior and locomotor activity). Similar to the changes observed in motor and cognitive behavior, decrease in the activity of both AChE and ATPases were also observed in the brain regionsof Pb+Mn exposed rats. However, the animals which received calcium together with Pb+Mn showed reversal effect in behavioral as well as the activity of the enzymes suggesting protective role of calcium supplementation against the Pb and Mn induced neurotoxicity. The results of this study support our earlier findings on the protective role of calcium and zinc against Pb and Mn induced neurotoxicity.
Behavioral perturbations, Water maze, Lead, Manganese, Locomotor activity, cholinergic system, Calcium protection
