Effects of Tube Feeding on Hippocampal Function in SAMP1 Mice

Objectives: It has been reported that a tube feeding, which reduces the ability of taking food orally and the deterioration of general conditions, results in the decrease of the levels of ADL in elderly patients. In recent years, a significant relationship between reduced mastication ability and senile dementia has been suggested. Methods: In order to evaluate the involvement of decreased ability to take food in hippocampal function, we examined the effect of tube feeding on hippocampal induction of the protein product, Fos of the immediate early gene, c-fos, on spatial learning ability in a water maze test and on dendritic spine density using Golgi-cox method in senescence-accelerated mice (SAMP1). Results: Tube feeding enhanced the deficits in spatial learning ability in SAMP1. Immunohistochemical and morphological studies also disclosed that the reduction both in the number of Fos-positive cells in hippocampal CA1 and in the dendritic spine density in hippocampal CA1 pyramidal cells was found. Conclusion: The present results suggest that a tube feeding probably reduces input activities in the hippocampus, thereby results in deficits in spatial memory.