基底外侧杏仁核与海马CA3区参与应激所致大鼠学习记忆能力的降低

摘要

目的:观察应激大鼠的学习记忆和基底外侧杏仁核(basolateral amygdaloid nucleus,BL)与海马内的神经肽Y(NPY)、巢蛋白免疫阳性反应变化及它们的相关性.方法:运用SD大鼠的束缚并倒悬应激模型、Morris水迷宫和免疫组织化学方法,观察急、慢性应激(3d,21d)对大鼠学习记忆能力变化和BL、海马CA3区内NPY、巢蛋白免疫阳性反应的影响.结果:急、慢性应激组和对照组的逃避潜伏期分别为18.27±4.20、20.02±3.02、9.18±3.03,定向航行60s跨越平台次数分别为4.05±1.06、3.13 ±1.37、7.97±1.91;光镜下,急、慢性应激组脑内BL、CA3区的NPY/巢蛋白阳性神经元形态异常;急、慢性应激组和对照组脑内NPY、巢蛋白免疫阳性物积分光密度测定值,在BL内分别为1.07±0.53、1.01±0.46、2.77±0.83和1.13±0.42、0.94±0.50、2.89±0.48,在CA3区内分别为2.20±0.45、3.41±1.20、11.90±0.87和2.44±0.30、3.95±1.24、9.33±0.86.结论:急、慢性应激组大鼠的学习记忆能力降低,而且同BL和海马CA3区内的NPY/巢蛋白阳性神经元受到损害有关.%Objective:To observe changes of capability of learning and memory and nestin/NPY-ir positive response in amygdala and hippocampus in stressed rats.Methods: The capability of learning and memory was examined in Morris water maze, and the immunohistochemical stainings of nestin/NPY-ir positive response was observed in the basolateral amygdaloid nucleus (BL) and CA3 regions with a stressed model by restrained and hung head-downed Sprague-Dawley rats.Results:(1)The escape latency and crossing times in the acute/chronic stressed (3d or 21d) and control groups were 18.27±4.20,20.02±3.02, 9.18±3.03; 4.05±1.06, 3.13±1.37 and 7.97±1.91; respectively.(2)Under a light microscope, there were morphological changes of nestin/NPY-ir positive cells in BL and CA3 regions between the stressed and control groups.(3)The integral optical densities on immunohistochemical stainings of NPY/nestin-ir positive response in the acute/chronic stressed and control groups were 1.07±0.53, 1.01±0.46 and 2.77±0.83; 1.13±0.42, 0.94±0.50 and 2.89±0.48 in BL, respectively; and 2.20±0.45, 3.41±1.20 and 11.90±0.87; 2.44±0.30, 3.95±1.24 and 9.33±0.86 in CA3 regions, respectively.Conclusion: The decrement of capability in learning and memory is involved in the damages of NPY/nestin-ir positive cells in BL and CA3 regions in acute/chronic stressed rats.