Mercury

Publisher Summary This chapter discusses mercury, which is a well-documented neurotoxicant. Human exposure to mercury is mainly in the form of methylmercury predominantly from the consumption of fish. This chapter aims to outline the kinetics of organic mercury (MeHg) in humans and the toxic effects of MeHg on the developing fetal central nervous system (CNS) as well as on other organ systems. MeHg has been found to bind to protein-SH groups of amino acids, such as cysteine. A brief review outlining the most critical features of the mechanisms involved in MeHg-induced neurotoxicity are explained in this chapter. This chapter describes the differences in MeHg-induced brain damage between the fetus and the adult and highlights several of the proposed mechanisms of MeHg toxicity in the developing organism. The brain is the primary target site for MeHg. Because the vulnerability to MeHg poisoning is age related, the symptoms of mercury poisoning and mercury deposits are quite different depending on the age at the time of exposure. In addition to its effects on brain structure and brain enzymes, MeHg exposure also affects synaptic transmission. The studies have established that prenatal MeHg exposure in both humans and laboratory animals leads to diffuse brain damage including reduced brain size, damage to the cortex and basal ganglia, loss of cells, ventricular dilation, ectopic cells, disorganized brain layers and gliosis. The risk and toxicity of MeHg have also been analyzed.