Distribution of lithium in the rat brain after a single administration known to elicit aversive effects.

In order to get insight into the brain areas involved in the initial unpleasant effects resulting from the administration of lithium (Li+), its distribution was mapped in the rat brain using the 6Li(n,alpha)3H nuclear reaction after a single injection of 6Li2SO4 at doses and latencies corresponding to the elicitation of such unpleasant effects. An improved method for visualization and measurement of local Li+ concentrations was used consisting in diffracting light along the tracks left by alpha particles in a dielectric detector. The distribution of Li+ was found less homogeneous than when Li+ was administered chronically. Periaqueductal and periventricular structures were the brain areas containing the highest concentrations of Li+.