Comparison of Donepezil and Riluzole in Improving Spatial Memory of Male Wistar Rats

Purpose: Alzheimer’s disease (AD) is a degenerative brain disorder and the major cause of dementia and cognitive deficits in the elderly. Riluzole modulates glutamate concentration and improves memory performance in aged rats and may be of benefit in AD. Donepezil is a cholinesterase inhibitor that is used for the treatment of mild-to-moderate AD. In this study, we compared their effects on attenuation of learning and memory deficits in a rat model of AD. 
Materials and Methods: Scopolamine injection for 14 consecutive days induced memory impairment. Effect of riluzole on this impaired memory was evaluated by Morris water maze protocols: accusation phase and probe trial test. Adult male Wistar rats (250–300 g) were trained for 4 consecutive days, 24 hours after last scopolamine injection. Spatial memory and learning index (%) were measured depending on the time taken to find the platform and the time utilized in the target quadrant (Q2). The time/distance was measured by the computer. Results were analyzed by one-way analysis of variance and Tukey post hoc. 
Results: Riluzole was effective in the treatment of memory impairment of scopolamine-injected group. The riluzole-treated group, on test day, showed better spatial memory rather than scopolamine-treated group. Besides, learning index (%) improvement was significantly higher in the riluzole-treated group, rather than scopolamine-injected group. 
Conclusion: It can be concluded that riluzole administration at the same time with scopolamine injection or after it causes marked improvements in learning index during training days and the spatial memory on the test day. Therefore, this study strengthens the hypothesis that acute riluzole treatment is capable of treatment of diseases related to memory impairment such as AD.