Effects of lithium on rat tail nerve conduction velocity.

Orthodromic and antidromic conduction velocities were measured in the tail nerve of rats given lithium throughout life. Lithium at nontoxic levels failed to influence nerve conduction velocities. Lithium at toxic levels (2 X 2.5 mmol/kg/day for 7 days) produced overt signs of lithium intoxication and reduced both orthodromic and antidromic nerve conduction velocities. The reductions in conduction velocities were related inversely to the level of lithium in serum and red blood cells. Conduction velocities returned to normal levels after cessation of the toxic lithium treatment. The findings show life-long administration of lithium at nontoxic levels to be without adverse effects on peripheral nerves in rats, while toxic lithium levels caused reversible impairment in conduction properties in peripheral nerves.