Lithium neurotoxicity. I. The concentration of lithium in dopaminergic systems of rat brain determined by flameless atomic absorption spectrophotometry.

Severe neurotoxicity has been reported in patients receiving combinations of lithium and butyrophenones and halogenated phenothiazines and the suggestion has been made that lithium is preferentially concentrated in dopamine systems in brain. Conventional flame atomic absorption spectrophotometry does not allow analysis of sufficiently small samples of brain tissue to allow accurate association with specific transmitter systems, although previous reports have suggested that lithium is concentrated in the striatum. A method has been developed using flameless atomic absorption spectrophotometry to allow accurate measurement of lithium concentrations in 10--100 ng fresh weight of brain tissue. Using this technique in experiments where rats were fed lithium over a period of three weeks, we could not confirm a direct association of lithium with an area predominetly served by dopamine transmitters.