Abstract 120: Reduced Long Term Memory in Morris Water Maze in Rats Resuscitated From Ventricular Fibrillation Cardiac Arrest
Background: Rodent models of cardiac arrest (CA) help to investigate pathophysiologic mechanisms of cerebral ischemia and reperfusion. Sensitive neurologic tests would enhance the ability of such models to evaluate possible beneficial effects of protective therapies. The Morris Water Maze (MWM) is a procedure to test spatial learning and memory. The aim of this study was to investigate behavioral testing with the Morris Water Maze in rats resuscitated from ventricular fibrillation (VF) CA.
Methods: Sprague-Dawley rats (379±13g, male, anesthetized) were put into VF CA. After 8 min of CA the animals received mechanical chest compressions for 2 min and epinephrine 20 μg/kg. The animals were defibrillated thereafter every 2 min to achieve return of spontaneous circulation. Ten animals surviving with favorable neurologic recovery were compared to 10 naive rats. MWM testing was performed in each animal 3 times on 4 consecutive days for maximal 120 s with a hidden platform and on day 5 and day 12 with the platform removed.
Results: The latency time to find the hidden platform (reflecting spatial learning) decreased in the CPR group and the control group from 107±31 s and 75±42 s to 10±5 s and 17±14 s between day 1 and day 4 (p=0.11). After removal of the platform, the time within the target sector on day 5 (reflecting short term memory) in 60 s was 24±6 s and 25±8 s (p=0.87).Time within the target sector on day 12 (reflecting long term memory) was significantly reduced in the CPR group vs. naive rats with 15±3 s and 18±2 s (p=0.03)
Conclusions: Spatial learning and short-term memory in clinical neurologically intact animals resuscitated from an 8 min VF CA was comparable to normal healthy controls. Long term memory after a 7-day period without training was reduced. Memory retention rather than short term may prove valuable in this global ischemia model as behavioral testing strategy.
- © 2013 by American Heart Association, Inc.