Investigate a mystification function and life science of a person of advanced age aiming at the health science

通过检查老年SAMP 8小鼠切断上磨牙（无磨牙条件）对海马诱导即刻早期基因（c-fos）的蛋白产物Fos和水迷宫中空间表现的影响，评估了老年海马活动中功能障碍牙齿的参与。无磨牙条件下引起的Fos阳性细胞在海马CA 1区，其中Fos免疫反应位于细胞核中的数量减少。无磨牙状态持续的时间越长，这种影响就越明显。用人工冠修复丢失的磨牙，可以大大减少无磨牙条件下对CA 1区学习能力和Fos诱导的抑制。结合大量显示压力、衰老和海马功能之间关系的研究以及我们过去的发现[Brain Res. 1999 ; 826：148-53 ; Behave. Brain Res. 2000 ; 108：145-55 ; Exp.老年学二○ ○一年;三十六：283-95]，本结果表明咀嚼减少对老年SAMP 8小鼠海马加工的有害影响，这与无磨牙条件诱导的应激有关。

The involvement of dysfunctional teeth in senile hippocampal activity was evaluated by examining, in aged SAMP8 mice, the effect of cutting off the upper molars (molarless condition) on hippocampal induction of the protein product, Fos, of the immediate early gene, c-fos, and on spatial performance in a water maze. The molarless condition caused a reduction in the number of Fos-positive cells in the hippocampal CA1 region, in which Fos immunoreactivity was localized in the cell nuclei. This effect was more pronounced the longer the molarless condition persisted. The suppression of both learning ability and Fos induction in the CA1 induced by the molarless condition was considerably reduced by restoring the lost molars with artificial crowns. Taken together with the plethora of research showing a relationship between stress, aging and hippocampal function and our past findings [Brain Res. 1999 ; 826 : 148-53 ; Behave. Brain Res. 2000 ; 108 : 145-55 ; Exp. Gerontology. 2001 ; 36 : 283-95], the present results suggest the detrimental effects of a reduction in chewing on hippocampal processing in aged SAMP8 mice that would be linked with stress induced by the molarless condition.