A reward-reduction model of depression using self stimulating rats: an appraisal

A potential model of depression using a "reward reduction" technique with intracranial self-stimulation (ICSS) has been suggested. A number of rats with electrodes chronically implanted in the medial forebrain bundle were trained on this paradigm. The model involved the use of progressively increasing fixed ratio (IFR) schedules. Two tricyclic antidepressants, imipramine and protriptyline, were administered. Neither of these drugs resulted in the response enhancement which had been predicted. Only d-amphetamine (0.5 mg/kg) produced the predicted "antidepressant" action. It was concluded that response instability made this test difficult to operate and that even animals with adequately stable baselines did not produce a response pattern which could be categorised as specifically antidepressant.