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

在老年SAMP8小鼠中，通过检测切断上颌磨牙(无磨牙状态)对海马区蛋白产物Fos、即刻早期基因c-fos的诱导以及水迷宫中空间行为的影响，来评估功能障碍的牙齿在老年SAMP8小鼠中的作用。无磨牙状态下，大鼠海马CA1区Fos阳性细胞数量减少，Fos免疫反应定位于细胞核。无磨牙状态持续的时间越长，这种影响越明显。用人工牙冠修复缺失磨牙，可明显减轻无磨牙状态对CA1区学习能力和Fos诱导的抑制作用。综合来看，大量研究表明压力、衰老和海马体功能之间的关系，以及我们过去的发现[Brain Res.1999；826：148-53；Behavior。Brain Res.2000；108：145-55；Exp.老年学。2001；36：283-95]，目前的结果表明，减少咀嚼对老年SAMP8小鼠海马区加工的有害影响可能与无磨牙条件下诱导的压力有关。

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.