Effects of chronic lithium treatment on limbic seizure generation in the cat.

The effect of chronic lithium administration (2.2-8.7 mEq/kg/day, 17 days) to the cat on seizure initiation in the amygdala and hippocampus was assessed by the low-frequency kindling technique. Lithium 4.3 mEq/kg/day PO, producing a serum lithium level between 1.2 and 1.6 mEq/l, caused an elevation of the amygdala seizure threshold on treatment days 5-9. In contrast, the same dosage caused a transient reduction of the hippocampus seizure threshold on treatment days 13-17 and on withdrawal days 21-25. Lithium 2.2 mEq/kg/day PO caused no significant effect on the parameters of the two types of seizure. Lithium 8.7 mEq/kg/day PO caused severe behavioral changes and did not permit chronic treatment. These results indicate that the effect of chronic lithium treatment on limbic seizures is dependent on the location of epileptic focus.