INVOLVEMENT OF ANGIOTENSIN-CONVERTING ENZYME-INHIBITION IN REVERSAL OF HELPLESS BEHAVIOR EVOKED BY PERINDOPRIL IN RATS

Several clinical investigations have suggested that captopril, an angiotensin-converting enzyme inhibitor (ACEI) currently used as an anti-hypertensive agent, exhibits antidepressant properties in humans. In the present study we evaluated the action of perindopril, another ACEI, and two of its metabolites, the di-acide form perindoprilat, which possesses ACE inhibitory properties, and BDM-4, an inactive metabolite, in the learned helplessness paradigm. In order to confirm a possible action of these drugs via dipeptidyl carboxypeptidase inhibition, we also investigated two inactive analogues of perindopril and perindoprilat. Perindopril (0.06-8 mg/kg per day) and perindoprilat (0.25-8 mg/kg per day) induced a reversal of escape deficits. BMD-4 and two analogues failed to reverse helpless behavior. These results support the hypothesis that ACE inhibition is a key factor in the behavioral antidepressant-like activity of perindopril and perindoprilat. © 1990.