Jf. Flood et Je. Morley, DOSE-RESPONSE DIFFERENCES IN THE ABILITY OF RAMIPRIL TO IMPROVE RETENTION IN DIABETIC MICE, European journal of pharmacology, 240(2-3), 1993, pp. 311-314
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.