EFFECT OF CADMIUM EXPOSURE ON CHOLINERGIC SYSTEM AND ENERGY METABOLISM OF RAT BRAIN: REVERSAL EFFECT OF α-TOCOPHEROLAbstract
Cadmium (Cd) is a toxic heavy metal in the environment. The aim of this study was to investigate the potential effect of Cd on cholinergic and bioenergetic systems in three brain regions: cerebral cortex, cerebellum and hippocampus. The young albino rats (3 months) were exposed to low dose of Cd (1.5 mg/kg body weight) and high dose of Cd (3 mg/kg body weight) through intraperitoneal injection daily for a period of 3 weeks. A separate batch of rats were given α-tocopherol at a dose for a period of one week along with low and high dose of Cd. In this study, we observed that the AChE activity and ACh content in synaptosomal fractions and Mg2+-ATPase and Na+/K+-ATPase activities in mitochondrial fractions. We found the decrease in AChE, Mg2+-ATPase and Na+/K+-ATPase activities and increase in ACh content compared to control. The high dose of Cd treated rats showed maximal decrease in the AChE, Mg2+-ATPase and Na+/K+-ATPase activities and ACh content compared to low dose of Cd treated rats. The maximal alterations of these enzymes observed in hippocampus among three brain regions. Whereas, the rats supplemented with α-tocopherol along with Cd showed reversal effect with gradual increase in enzyme activities and decrease in ACh content. In addition to this, we found decrease in body weights in dose dependent manner upon Cd exposure. The above findings suggest Cd toxicity was reversed with α-tocopherol co-administration which could thus be considered for future applications as a neuroprotective agent against chronic exposure to Cd.