A low dose of lithium chloride selectively induces Fos protein in the central nucleus of the amygdala of rat brain.

1. Lithium is a very effective treatment for mood disorders. To elucidate the neural substrates of the mood stabilizing actions of lithium, in the present study the authors investigated the effects of a low dose of lithium on regional expression of Fos protein. 2. The administrations of a high dose of lithium chloride (100 mg/kg) induced Fos in widespread areas of the rat brain. In contrast, administration of a low dose of lithium chloride, equivalent to a therapeutic dose in humans, induced Fos only in the central nucleus of the amygdala. 3. These results demonstrate that the central nucleus of the amygdala plays important role in the neural framework that is responsible for the mood-stabilizing effect of lithium.