Effect of 6-hydroxydopamine-induced lesions of A10 dopaminergic neurons on aggressive behavior in rats.

The present study evaluated the effects of microinjections of 6-hydroxydopamine into the ventral mesencephalic tegmental area (nucleus A10) on aggressive behavior in rats. This treatment resulted in a reduction in foot-shock-induced fighting but failed to influence muricide (mouse-killing) behavior in chronically isolated rats. The general activity of animals tested in the open field was significantly increased two weeks after lesions. These behavioral changes were accompanied by a significant depletion of forebrain dopamine, with no difference between lesioned and sham-lesioned rats in norepinephrine and 5-hydroxyindole acetic acid levels.