Chronic imipramine diminishes the nuclear size of neurons in the locus coeruleus and cingular cortex but not in the hippocampus of the rat brain.

The effect of an antidepressant drug--imipramine--on the nuclear volume of the rat brain neurons was studied. Imipramine was administered per os, 10 mg/kg acutely or chronically (twice a day, for 14 days). A reduction in the nuclear volume was observed after chronic treatment in neurons of the locus coeruleus and cingular cortex, but not in the hippocampus. The diminution in the nuclear volume of the affected cells suggests a decrease in their activity.