Abstract: (15533 Views)
Introduction: The N-methyl-D-aspartate (NMDA) receptors, which have been implicated in memory formation,
could be noncompetitively blocked by ketamine. The present study examines the short term effect of ketamine on
induction of anterograde and retrograde amnesia in male rats using Morris water maze (MWM).
Methods: Male N-MRI rats were randomly divided into nine experimental groups. MWM studies were performed
to evaluate spatial learning and memory parameters. In order to examine the effect of ketamine on the induction of
anterograde amnesia, 4 groups of animals received daily injections of ketamine (1, 3, 6 or 12 mg/kg, i.p.) 10 min before
testing on training days. To examine the effect of drug on the induction of retrograde amnesia four other groups of rats
received daily injection of normal saline (on training days) and ketamine (1, 3, 6, or 12 mg/kg, i.p.) (in probe trial) 10
min before testing. Rats of the control group received normal saline on all days of experiments. Spatial learning and
memory parameters were recorded and subjected to the analysis of variance (ANOVA). Difference was considered
significant if p<0.05.
Results: Data showed that injection of ketamine at the dose of 3 mg/kg and higher inhibits spatial learning and
memory parameters and induces both anterograde and retrograde amnesia in rats.
Conclusion: It seems that ketamine induces inhibitory effects on spatial learning and memory via blocking the
NMDA receptors. On the other hand, ketamine induced dose dependent decrease in swim speed which was significant
at the dose of 12 mg/kg.