Trandolapril attenuates acquisition of conditioned avoidance in rats

We have previously shown that angiotensin II (Ang II) improves cognitive performance of rats. In this study, behavioral effects of trandolapril, a highly lipophilic antihypertensive drug efficiently inhibiting brain angiotensin converting enzyme (ACE), were examined in rats. Single (0.1, 0.5, 1.0 mg/kg) or repetitive (0.1 mg/kg daily for 14 days) doses of trandolapril were given orally. The medium dose of the drug administered acutely as well as the chronic treatment significantly attenuated acquisition of conditioned avoidance responses. None of the three doses of trandolapril changed consolidation of memory and recall of the passive avoidance behavior, object recognition, and locomotor exploratory activity in open field. These data point to the psychoactive properties of trandolapril and suggest that physiological levels of the endogenous Ang II may be required for effective learning.