The antiaggressive effect of lithium is abolished by area postrema lesion.

Lithium (Li) suppresses intraspecific aggression in rats and other mammals. However, antiaggressive doses of Li have been shown to produce signs of illness and to serve as an unconditioned stimulus for conditioned taste aversions (CTA). Therefore, it is possible that the antiaggressive effects of Li result from Li-induced malaise. Malaise and CTA's produced by some drugs and toxins are mediated by chemoreceptors in the area postrema. In this paper we report [1] that thermal lesion of the area postrema abolishes Li's ability to condition taste aversions and [2] that area postrema lesion abolishes the antiaggressive effect of Li as measured by attack latency in a shock-induced aggression test. Taken together, these findings suggest that some or all of Li's antiaggressive action in rats may result from malaise attributable to Li's action on the area postrema.