UPTAKE OF INORGANIC MERCURY BY THE HUMAN BRAIN

A 24-year-old man injected himself intravenously with metallic mercury in a suicide attempt, and died 5 months later after cutting his wrist s. The brain was removed at postmortem and 7-mu m paraffin sections we re cut from representative blocks. Dense deposits of mercury were foun d on autometallography in large cortical motor neurons, but in no othe r cerebral neurons. Smaller mercury deposits were found in the brain s tem (in the mesencephalic trigeminal nucleus, noradrenergic neurons, a nd in neurons for extraocular muscles), the cerebellum (in the dentate nucleus) and in lateral motor neurons in the C2/3 spinal cord. Mercur y deposits were found in glial cells in all regions. The finding that elemental mercury enters human cortical motor neurons in preference to other cerebral neurons raises the possibility that this neurotoxin ma y play a part in the pathogenesis of some human motor neuron diseases.