Donepezil mitigates memory deficits in Siberian hamsters

The purpose of this study was to test the effect of donepezil (Aricept) on cognition in circadian arrhythmic Siberian hamsters, an animal model that mimics the breakdown of circadian rhythms in humans. This is because circadian dysfunction is known to accelerate cognitive impairment in not only Alzheimer’s disease, but adult- onset circadian dysfunction. Male Siberian hamsters were split into circadian-intact and circadian-arrhythmic groups and randomly assigned to either vehicle or donepezil treatment group. Animals in the donepezil treatment group received daily oral administration of 3.0mg/kg of donepezil dissolved in sugar water for 21 days. The vehicle group received the same amount of plain sugar water for the same amount of time. All animals were tested before and after treatment in a spontaneous alternation (SA) T-maze to measure cognition and spatial mapping. Surprisingly, the daily sugar water restored rhythms in all animals (vehicle and donepezil). Animals treated with donepezil performed significantly better in the alternation test than did the vehicle-treated group.