Dose-Dependent Effect of Curcumin on Learning and Memory Deficit in Kainate-Epileptic Rats

Epileptic seizures accompany disturbances in learning, memory, and cognitive skills. With regard to antiepileptic potential of curcumin and its beneficial effect on memory, the effect of its administration on learning and memory in kainate-epileptic rats was investigated. Forty male rats were divided into sham, positive control (valproate-treated epileptic), epileptic, and two curcumin-treated epileptic groups. Rat model of epilepsy was induced by unilateral intrahippocampal administration of 4 μg of kainate per rat. Rats received intraperitoneal injection of curcumin (50 and 100 mg/kg) daily for 1 week before surgery. For evaluation of learning and memory, initial (IL) and step-through latencies (STL) were determined using passive avoidance test and alternation behavior percentage was obtained according to Y maze test. Regarding IL, there was no significant difference between the groups. In contrast, STL significantly decreased in curcumin-50-treated epileptic group (p<0.05) (a change from 263.1 to 184.5 s). However, this parameter significantly increased in curcumin-100-treated epileptic group as compared to epileptic group (p<0.01) (a change from 263.1 to 220.3 s). In addition, STL was also significantly higher in valproic acid-treated epileptic group versus epileptic group (p<0.05) (a change from 145.7 to 210.3 s). Alternation percentage was also significantly higher in curcumin-50- and curcumin-100-treated epileptic groups relative to epileptic group (p<0.05) (a change from 60.5 to 77.6 and 80.3%). Curcumin could dose-dependently enhance the consolidation and recall in epileptic animals and could improve spatial memory in such animals.