Effects of ACE-inhibitors on learning and memory processes in rats.

Introduction: Besides their well known effect on systemic blood vessels and heart, ACE inhibitors are supposed to have an effect on CNS by changing the local peptide-protein system.

Aim: To study the effect of ACE-inhibitors on learning and memory processes using active and passive avoidance.

Material And Methods: Male Wistar rats were used; the animals were divided into 4 groups of 20 animals each. Distilled water (group C), captopril 1.5 mg/kg (group E1), trandolapril 2 mg/daily (group E2), and oxiracetam 0.1 mg/kg (group E3), respectively, were given orally 60 minutes before the test. Active (shuttle box) and passive (step-through) avoidance tests with standard configuration were used.

Results: The experimental and control animals increased the number of avoidances during the learning session of the active avoidance test; groups C, E1 and E2 showed no change in the number of escapes and intertrial crossings; in group E3 animals both variables were decreased. In memory retention test the experimental animals increased the number of avoidances in comparison to the controls. No difference was found in the number of escapes and intertrial crossings. In passive avoidance test all animals showed prolonged latencies during the learning session. In the early and late retention test prolonged latencies were found only in the experimental animals.

Conclusion: The ACE inhibitors captopril and trandolapril improve learning and memory in active and passive avoidance tests comparable to the effect of the nootropic drug oxiracetam.