Alterations in the Properties and Isoforms of Sciatic Nerve Na+,K+-ATPase in Methylcyclopentadienyl Manganese Tricarbonyl-Treated Mice

The in vivo effect of methylcyclopentadienyl manganese tricarbonyl (MMT), an organic manganese-containing compound, on the mouse motor nerve was studied. The motor nerve conduction velocity was markedly decreased in MMT-treated mice. The Na+,K+-ATPase activity of sciatic nerve isolated from MMT-treated mice was decreased; however, the sciatic nerve Na+,K+-ATPase activity was not affected by the in vitro treatment of MMT. Moreover, [3H]ouabain binding of sciatic nerve isolated from MMT-treated mice was decreased. Using Western blot analysis, the amount of Na+,K+-ATPase catalytic α1 subunit polypeptide in sciatic nerve of MMT-treated mice was also decreased. These results indicate that a causal relationship may exist between reduced nerve Na+,K+-ATPase activity and motor nerve conduction velocity in MMT-treated mice and that a measurable decrease in α1 catalytic subunit isoform of Na+,K+-ATPase may be necessary for the development of peripheral neuropathy by MMT.