Caffeine’s influence on object recognition and working-memory in prepubertal mice and its modulation by gender

ObjectiveThis study investigated the effects of intraperitoneal injection of caffeine on Y-maze working-memory and novel object recognition (NOR) in prepubertal mice.MethodologyY-maze spontaneous alternation and a novel object recognition test (consisting of acclimation, acquisition and test phases) were performed. Mice received a single dose of caffeine (10, 20, 40, 80 and 120 mg kg−1 i.p.) or vehicle, 30 min before Y-maze exploration. For the NOR test, caffeine was given 30 min before training and another dose 30 min before test phase.ResultsNOR time (acquisition phase) increased significantly in males at all doses of caffeine and decreased in females at 10, 20 and 40 mg/kg compared to vehicle; during the test phase, novel object exploration time decreased significantly in males and increased in females at 10 and 20 mg/kg only to decrease again at 120 mg/kg. Recognition index decreased in males and increased in females while, males showed poor discrimination between novel and familiar objects compared to vehicle; while females showed increased discrimination between novel and familiar object at 10, 20,40 and 80 mg/kg and a decrease at 120 mg/kg. Y-maze spontaneous alternation improved significantly in males at 10 and 40 mg/kg and decreased at 20 and 120 mg/kg in females.ConclusionThe findings suggest that acute caffeine injection improves non-spatial memory retention in female mice but not in males; spatial working-memory is however improved in males but not in females.