LEAD AND MERCURY TOXICITY AND THE ROD LIGHT RESPONSE

  • 1 January 1985
    • journal article
    • research article
    • Vol. 26  (8) , 1117-1123
Abstract
Pb and Hg have been reported to alter selectivity the rod component of the electroretinogram, and to inhibit the phosphodiesterase in rod outer segments which may be responsible for generating the rod''s light response. The effect of Pb and Hg on the voltage response to light of rods are compared with those of the phosphodiesterase inhibitor papaverine. Pb and Hg, like papaverine, slow the light response. Papaverine increased the light response amplitude while Pb decreases it. Hg initially increases and then decreases the amplitude. The late decrease in amplitude produced by mercury is associated with rod degeneration; an effect which may mimic degenerative diseases in which the rod phosphodiesterase is insufficiently active. The changes of electroretinogram induced by Pb and mercury can be accounted for by the changes in receptor potential these heavy metals produce. The changes in receptor potential seen are consistent with Hg inhibiting the rod phosphodiesterase, and with Pb having an action in addition to phosphodiesterase inhibition.