Retrograde axonal transport of mercury in primary sensory neurons innervating the tooth pulp in the rat.

The pulp cavity of the first upper molar was exposed unilaterally in adult rats with a dental drill and about 1 microliter of mercuric chloride was injected into the coronal pulp. The rats were killed after 1-24 days and frozen sections from the trigeminal ganglia were subjected to silver acetate autometallography for demonstration of mercury. Mercury was found to have accumulated in neurons of the ipsilateral trigeminal ganglion by retrograde axonal transport. The possible implications of this finding are discussed.