Bilaterally olfactory bulbectomized rats were compared with intact rats in their responsiveness to the acute and chronic administration of nomifensine and trazodone in the learned immobility test of Porsolt. No difference in the duration of immobility was found between the bulbectomized and intact rats. The duration of immobility was significantly attenuated in both the bulbectomized and intact rats after nomifensine treatment, the effect on the bulbectomized rat being greater than in the intact animals. Trazodone significantly attenuated the duration of immobility of the intact rats only after chronic (14 days) administration. Both nomifensine and trazodone significantly affected the turnover of serotonin in the amygdaloid cortex following acute administration but no changes could be detected in the parameters after chronic drug treatment.