ADP-RIBOSYLATION OF BRAIN NEURONAL PROTEINS IS ALTERED BY IN-VITRO AND IN-VIVO EXPOSURE TO INORGANIC MERCURY

ADP-ribosylation is an essential process in the metabolism of brain ne uronal proteins, including the regulation of assembly and disassembly of biological polymers. Here, we examine the effect of HgCl2 exposure on the ADP-ribosylation of tubulin and actin, both cytoskeletal protei ns also found in neurons, and B-50/43-kDa growth-associated protein (B -50/GAP-43), a neuronal tissue-specific phosphoprotein. In rats we dem onstrate, with both in vitro and in vivo experiments, that HgCl2 marke dly inhibits the ADP-ribosylation of tubulin and actin. This is direct quantitative evidence that HgCl2, a toxic xenobiotic, alters specific neurochemical reactions involved in maintaining brain neuron structur e.