Modulation of working memory by mentat and donepezil using scopolamine induced amnesia in rats.

Nikhil Vijay1*, Abhijeet V. Tilak1, Pavitra Raj Dewda1, Rajesh Komma1, Mona A. Tilak1, Balaji More2

Abstract
To compare the effect of mentat and Donepezil was on working memory in rats. The rats were trained for conditioned avoidance response by using Cook‟s pole climbing apparatus. Rats trained for CAR received scopolamine (hydrobromide) in a dose of 0.5mg/kg by intraperitoneal route before administration of study drugs. This is known to produce amnesia which will be used to evaluate the effect on learning and memory of study drugs. Donepezil was given in a dose of 0.32mg/kg by intraperitoneal route and mentat was given in a dose of 200mg/kg by oral route for eight days in the animals after training for conditioned avoidance response. Data was analysed by the chi-square test. Findings show that administration of single dose of scopolamine 20 minutes before the test run on the apparatus causes transient amnesia daily for resulting in disruption of the retention of CAR. Mentat and donepezil significantly increased the retention of condition avoidance response in comparison to scopolamine. However there was no significant statistical difference in the increase in the retention of CAR in mentat or donepezil given alone, but the combination of the two drugs showed statistically significant increase in the retention of CAR than either of these drugs alone. Results from this study provide good platform to conduct clinical studies to assess the benefit of combining mentat with donepezil when given for a longer period of time.

Key words: Working memory, mentat, donepezil, scopolamine, conditioned avoidance response.