各種形式的壓力會導致海馬齒狀回細胞增殖和神經新生迅速減少，從而損害海馬齒狀回相關的記憶表現和情緒表達。然而，幾乎沒有研究探討過之前的慢性壓力是否可能對現存的海馬齒狀回細胞的有絲分裂、神經新生和與海馬齒狀回相關的認知/情緒功能造成持久的破壞性影響。也幾乎沒有研究探索過在整個壽命過程中出現不同的壓力是否會導致較差的記憶表現。面對壓力時心理方面的控制感的存在是否可以緩衝由壓力引起的海馬齒狀回的細胞增殖和神經元分化的減少，這一點也是未知的。因此本研究探討面對慢性壓力有或沒有心理方面的控制感對繼發的海馬齒狀回神經新生和記憶/情緒反應的調節作用。本研究以10天的足部電擊作為長期壓源，並使用成對的小鼠[執行小鼠（足部電擊的終止取決於表現出特定之自發行為）與共軛小鼠（電擊終止與行為無關）]接受該壓力方案。另一批小鼠則不接受壓力方案做為對照組。在壓力方案下，執行小鼠、共軛小鼠和對照組小鼠接受腹腔注射溴脫氧尿苷（BrdU；100 mg / kg）。壓力方案結束後的第6週，利用物體位置和強迫游泳測試來評估小鼠空間記憶和情緒表現。結果顯示，在壓力方案結束後的第6週，執行小鼠的海馬齒狀回的BrdU+及（BrdU / NeuN+細胞數量大於共軛小鼠和對照組小鼠。為了評估這種壓力源是否可能對細胞週期產生長期影響，三組小鼠在同一時間點使用另一種細胞增殖標記物Ki67來進行確認三組間是否有存在著差異。結果顯示三組小鼠的Ki67+細胞的數量相當。而在物體位置和強制游泳測試方面的表現，執行小鼠表現比共軛小鼠要好。在接受完四個版本的物體位置測試後10天，將小鼠接受水中禁錮壓力，並用兩種Y字型迷宮測試其記憶力。接受不同的壓力並不會影響三組小鼠在Y字型迷宮的表現，而在細胞增殖的數量上可以看到受到不同壓力後與沒有受壓力的組別相比三組之間的細胞數量都有減少，但三組之間沒有差異。從此研究得知，小鼠受到壓力時有心理方面的控制感有較好的記憶表現並且神經新生增加，但是在整個生命過程中受到不同的應激挑戰，記憶的表現及細胞增殖的數量與沒有心理方面的控制感是一樣的。結果也顯示遠程神經新生與當前空間記憶表現之間可能相關。

Various forms of stress may cause rapid decreases in cell proliferation and neurogenesis in hippocampal dentate gyrus (DG) and subsequently impair the DG-related memory performance and emotion expression. Nonetheless, whether a previous chronic stress may cause long-lasting, devastating effects on the extant DG cell mitosis, neurogenesis and DG related cognitive/emotional function remains scarcely explored. Moreover, whether different stress across life span may worsen memory performance and emotional expression remains scarcely explored. Likewise, whether the presence of psychological aspect of control may buffer against the stress-induced decreases in DG cell proliferation and neuronal differentiation is still unknown. Thus, this study assessed the modulating effects of a longterm stress with or without the psychological aspect of control on the subsequent DG neurogenesis and memory/emotion responses. A 10-day footshock regimen was employed to serve as the long-term stress and pairs of dyads were used [the executive (termination of footshock was contingent on a specific spontaneous behavior) vs. yoked (termination of footshock was non-contingent on any behavior) mice]. Another batch of mice served as controls receiving no stress regimen. The executive, yoked, and control mice received an intraperitoneal bromodeoxyuridine (BrdU, 100 mg/kg) injection under the stress regimen. At 6 weeks after the conclusion of the stress regimen, mice received object location and forced swimming tests to assess their spatial memory and emotion performances. The results showed that the number of BrdU+ and BrdU+/NeuN+ cells of DG in the executive mice was greater than the yoked and control mice at 6 weeks after the conclusion of the stressor regimen. In an attempt to assess whether such stressor may cause long-lasting impact on the extant cell cycles, another cell proliferation marker, Ki67, was used to assess the cell number of the extant cell cycles in three groups of mice at the same time point. The result indicated that the number of the Ki67+ cells was comparable in the three groups. In contrast, the executive mice outperformed in the object location and forced swimming tests as compared to the yoked mice. Ten days after receiving the fourth version of object location task, mice were employed to water restraint stress and to assess their memory by two versions of Y maze. Receiving different stress did not affect the performance on Y maze and the number of newly proliferated cells in the three mouse groups. These results, taken together, suggest that mice received stress with the psychological aspect of control outperformed in memory and increased newly cell proliferation. However, different stress-challenged across life did not alter memory performance and cell proliferation between mice received stress with and without psychological aspect of control. The result also suggested a likely correlation of remote neurogenesis and present spatial memory performance.

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