The protective effect of curcumin on scopolamine induced spatial learning and memory deficits in rats

Background: The cholinergic system plays an important role in learning and memory. Administration of extracts of Curcuma longa or its constituent, curcumin, have some roles in cognitive function in animals. The aim of the present study was to investigate the effects of curcumin in preventing spatial performance impairment induced by scopolamine, a cholinergic receptor antagonist, in rats using Morris Water Maze (MWM).

Methods: Male Wistar rats (Razi Institute, Tehran, Iran) received curcumin (10, 30 or 60 mg/kg, i.p.) 30 min before injection of scopolamine (0.5 mg/kg, i.p.) for 6 consecutive days. Spatial learning and memory parameters in the same days were tested using MWM. For this purpose, escape latency and swim distance to hidden platform were tested for four consecutive days. In probe trials, percentage of time that animals spent in target quadrant was recorded. 24h later, visible version of MWM was performed in which escape latency to visible platform and swim speed were tested. 

Results: Administration of scopolamine impaired the formation of spatial learning and memory processes. Pre-injection of curcumin (60 mg/kg) prevented the effect of scopolamine on training days but had no significant effect on percentage of time that animals spent in target quadrant during probe trials. In the visible version of MWM, there was no any significant difference in spatial performance among studied groups.

Conclusion: Considering the protective effect of curcumin, it seems that higher dose of curcumin has an interaction with cholinergic system in the formation of spatial learning in rats.