Some effects of methyl mercury salts on the rabbit nervous system.

Young adult rabbits have been given methyl mercury salts by subcutaneous injections or by gastric intubation. After 3 daily doses of 7.5 mg/kg by the 8th day moderate to severe ataxia developed, and after 4 doses, severe ataxia. Some of these latter animals might die. This species, therefore, seems to be about twice as sensitive to the neurotoxic properties of methyl mercury salts as the laboratory rat. With the light microscope extensive degenerative changes were seen in primary sensory ganglion cells, in both Purkinje and granule cells of the cerebellum, and in certain cells in several regions of the forebrain. The earliest changes became visible microscopically about the fourth day after commencing dosing, and reached a maximum of severity from the 7th to 10th day. The pattern of neuronal damage more closely resembled that found in the cat and in man than that seen in the rat. No evidence of changes vascular permeability was detected.