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), a n organic manganese-containing compound, on the mouse motor nerve was studi ed. The motor nerve conduction velocity was markedly decreased in MMT-treat ed mice. The Na+,K+-ATPase activity of sciatic nerve isolated from MMT-trea ted mice was decreased; however, the sciatic nerve Na+,K+-ATPase activity w as not affected by the in vitro treatment of MMT. Moreover, [H-3]ouabain bi nding of sciatic nerve isolated from MMT-treated mice was decreased. Using Western blot analysis, the amount of Na+,K+-ATPase catalytic alpha 1 subuni t polypeptide in sciatic nerve of MMT-treated mice was also decreased. Thes e results indicate that a causal relationship may exist between reduced ner ve Na+,K+-ATPase activity and motor nerve conduction velocity in MMT-treate d mice and that a measurable decrease in alpha 1 catalytic subunit isoform of Na+,K+ -ATPase may be necessary for the development of peripheral neurop athy by MMT. (C) 2000 Academic Press.