Decreased disrupting effect of neuroleptics on conditioned avoidance in rats with lesions in the mid-brain raphe nuclei.

The present study evaluated the effects of some neuroleptics (Chlorpromazine, haloperidol, spiroperidol) on general activity and avoidance behavior (one-way and two-way) in rats with lesions in the midbrain raphe nuclei (the nucleus raphe medianus and nucleus raphe dorsalis). Animals with lesions showed reduced response to neuroleptics when compared with sham-operated animals. The resistance of raphe-lesioned rats to neuroleptics is discussed on the basis of possible interaction between catecholamine and serotonin brain neurons.