Ameliorative effects of nucleosides on senescence acceleration and memory deterioration in senescence-accelerated mice

We investigated the effects of a mixture of dietary nucleosides and trucleotides (NS+NT) on memory in senescence-accelerated mice (SAM). Memory retention was studied with passive avoidance and active avoidance tests. In old mice, the time of passive avoidance was significantly higher in the NS+NT group than in the control group at days 1 and 7. However, such an effect of NS+NT was not observed in young mice. In the active avoidance test, the incidence of successful avoidance in old mice was significantly higher in the NS+NT group than in the control group at days 1 and 2. The percentages of specific brain cells containing lipofuscin were significantly lower in NS+NT groups than in the control groups in both young and old mice. The number of monovacuoles and multiple vacuoles in specific brain regions tended to be lower in NS+NT than in control groups, with significant differences in the microvacuoles of the middle cortex of young mice and in the multiple vacuoles in the hind cortex of old mice. These results suggest that increased dietary NS+NT may be associated with decreases in the age-induced deterioration of brain morphology and certain memory tasks. (C) 2003 Elsevier B.V. All rights reserved.