Ultrastructural changes in the nervous system of rabbits poisoned with methyl mercury

Abstract

Rabbits were given methyl mercury acetate orally at a daily dose of 7.5 mg/kg for from 1 to 4 days. Although dorsal root and Vth cranial nerve ganglion cells were the most sensitive, certain special cell types within the central nervous system were also susceptible. These included granule, stellate, and basket cells of the cerebellum and small neurons of the cerebral cortex. The features common to them are their relatively small size and high nuclear to cytoplasmic volume ratio. Early degenerative changes in affected cells always appeared to involve ribosomes. The sensitivity of ganglion cells was attributed to the permeability of ganglionic blood vessels; that of small central nervous system nerve cells may be associated with their low content of protein-synthesizing organelles.