Stem cells isolated from the central nervous system of both embryonic and adult mice can generate neurons and glia through the activation of different patterns of differentiation in dependence of exposure to appropriate epigenetic signals. On the other hand, environmental conditions might affect the proliferation, migration, and differentiation of these cells. We report here, for the first time, that inorganic mercury affects the proliferative and differentiative capacity of adult neuronal stem cells (ANSCs). Actually, inorganic mercury increases apoptosis in ASNC. Furthermore, in stem cell-derived astrocytes, high levels of the 70 kDa heat shock protein (HSP-70) occur, while the levels of GTP-beta-tubulin activity dramatically decrease. Interestingly, when induced to differentiate, inorganic mercury modifies morphological proprieties of astrocytes, while the neuron population is reduced. These results demonstrate that inorganic mercury produces toxicity in the ANSC-derived neuronal population and affects the biological properties of the glial-derived population.