Mercury Toxicity and Neurogenesis in the Mammalian Brain

The mammalian brain is formed from billions of cells that include a wide array of neuronal and glial subtypes. Neural progenitor cells give rise to the vast majority of these cells during embryonic, fetal, and early postnatal developmental periods. The process of embryonic neurogenesis includes proliferation, differentiation, migration, the programmed death of some newly formed cells, and the final integration of differentiated neurons into neural networks. Adult neurogenesis also occurs in the mammalian brain, but adult neurogenesis is beyond the scope of this review. Developing embryonic neurons are particularly susceptible to neurotoxicants and especially mercury toxicity. This review focused on observations concerning how mercury, and in particular, methylmercury, affects neurogenesis in the developing mammalian brain. We summarized information on models used to study developmental mercury toxicity, theories of pathogenesis, and treatments that could be used to reduce the toxic effects of mercury on developing neurons.