DOSE-RESPONSE DIFFERENCES IN THE ABILITY OF RAMIPRIL TO IMPROVE RETENTION IN DIABETIC MICE

Ramipril blocks the conversion of angiotensin I to II. The literature indicates that diabetes is often associated with mild impairment of le arning and memory. The study reports the effects of ramipril on memory retention in diabetic and non-diabetic mice. Mice were made diabetic by an injection of streptozocin. After overt signs of diabetes were pr esent, diabetic or vehicle-treated mice were partially trained on a fo otshock active avoidance task. Immediately after training, ramipril (0 .5-1.5 mg/kg s.c.) was administered and retention was tested by contin uing training one week later until mice avoided footshock on five out of six trails. The results indicate that ramipril enhanced retention o f both diabetic and control mice but it required about 5 times as much ramipril in diabetic as control mice to achieve the same effect on re tention. Increased sensitivity to angiotensin II may play a role in co gnitive impairment in diabetes.