D. Crespo, M. Megias, C. Fernandez-Viadero, R. Verduga

The hippocampal formation (HF) is a brain region that has been most implicated in the age-related memory dysfunction, and it is very vulnerable to the process of ageing. There is some controversy over the structural basis of memory in the hippocampus. The recent investigations reporting the involvement of NO in memory function have paved the way for the analyses of the relations between these NO-neurons and memory.

CDP-Choline is a well-known intermediate in the biosynthesis of phosphatidylcholine (PC). Previous studies suggested a repairing effect of CDP-Choline on brain membranes. Our aim was to study the effects of chronic administration of CDP-Choline on the morphology of HF. Furthermore, we performed cognitive test to evaluate any effect on memory acquisition and retrieval. Three groups of male mice were used. A group of 12 months old animals (ACG), a 24 months old mice (OCG) and a third group of mice administered orally a solution of CDP-choline (150mg/kr per day) from 12 months of age up to 24 months (OEG).

We used NADPH-diaphorase to examine variations in NO neuronal activity. Astrocytes were evaluated using GFAP. Electron microscopy was used to analyse the morphological and morphometric features of cells. The mossy fibres of the DG granule cells were visualised with the Timm technique. The cognitive study was performed in a radial plus maze, to test working (WM) and reference memories (RM). Comparisons among groups were performed using analysis of variance (ANOVA).

Our results revealed that the hippocampus of the OCG showed some morphological characteristics of ageing when compared to ACG. Those main features were a significant decrease in the number of NADPH-d neurons (p

The cognitive study showed that errors in WM and RM were increased in the ACG when compared to old animals. The OEG performed their task faster than any other group (p

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