title: Uptake of inorganic mercury by human locus ceruleus and corticomotor neurons: implications for amyotrophic lateral sclerosis.
abstract: BACKGROUND
  Environmental toxins are suspected to play a role in the pathogenesis of amyotrophic lateral sclerosis (ALS). In an attempt to determine which pathways these toxins can use to enter motor neurons we compared the distribution of mercury in the CNS of a human and of mice that had been exposed to inorganic mercury.
  
  
  RESULTS
  In the human who had been exposed to metallic mercury, mercury was seen predominantly in the locus ceruleus and corticomotor neurons, as well as in scattered glial cells. In mice that had been exposed to mercury vapor or mercuric chloride, mercury was present in lower motor neurons in the spinal cord and brain stem.
  
  
  CONCLUSIONS
  In humans, inorganic mercury can be taken up predominantly by corticomotor neurons, possibly when the locus ceruleus is upregulated by stress. This toxin uptake into corticomotor neurons is in accord with the hypothesis that ALS originates in these upper motor neurons. In mice, inorganic mercury is taken up predominantly by lower motor neurons. The routes toxins use to enter motor neurons depends on the nature of the toxin, the duration of exposure, and possibly the amount of stress (for upper motor neuron uptake) and exercise (for lower motor neuron uptake) at the time of toxin exposure.
authors.affiliation: The Stacey Motor Neuron Disease Laboratory, Department of Pathology, Sydney Medical School, The University of Sydney, New South Wales, Australia. roger.pamphlett@sydney.edu.au.
authors.forename: Roger
authors.initials: R
authors.lastname: Pamphlett
authors.forename: Stephen
authors.initials: S
authors.lastname: Kum Jew
mesh_terms: D000328:Adult; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology; D000818:Animals; D001933:Brain Stem / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008125:Locus Coeruleus / Q000378:metabolism*; D008297:Male; D008627:Mercuric Chloride / Q000008:administration & dosage; D008628:Mercury / Q000378:metabolism*; D051379:Mice; D008875:Middle Aged; D008959:Models, Neurological; D009046:Motor Neurons / Q000378:metabolism*; D009457:Neuroglia / Q000378:metabolism; D013045:Species Specificity; D013116:Spinal Cord / Q000378:metabolism; D013315:Stress, Psychological
chemical_list: D008627:Mercuric Chloride; D008628:Mercury