早期惨叫声音应激对雌鼠学习记忆能力的影响

目的：探讨早期惨叫声音应激对雌鼠成年后空间学习记忆能力、血清去甲肾上腺素(norepinephrine，NE)及皮质酮(corticosterone，CORT)水平和肾上腺形态的影响。方法：通过对新生Sprague-Dawley(SD)雌性大鼠施加惨叫声音应激(21 d)，建立SD雌性大鼠早期应激模型。成年后采用Morris水迷宫方法检测早期应激对其空间学习记忆能力的影响；分离血清，采用放射免疫法测定血清中NE和CORT的浓度；摘取肾上腺，以甲醛固定、石蜡包埋、切片后采用HE染色观察肾上腺形态变化。结果：早期惨叫应激后大鼠的逃离潜伏期明显变短(P<0.05)，穿越平台次数显著增多(P<0.05)；血清NE含量升高、CORT升高趋势明显(P<0.05)；肾上腺充血较为明显、细胞增大。结论：新生雌鼠早期惨叫声音应激增强了成年期的空间学习记忆能力，使下丘脑-垂体-肾上腺皮质轴和交感神经系统活化。

Effect of early scream sound stress on learning and memory in female rats

Objective: To investigate the effect of early scream sound stress on the ability of spatial learning and memory, the levels of norepinephrine (NE) and corticosterone (CORT) in serum, and the morphology of adrenal gland. Methods: Female Sprague-Dawley (SD) rats were treated daily with scream sound from postnatal day 1(P1) for 21d. Morris water maze was used to measure the spatial learning and memory ability. The levels of serum NE and CORT were determined by radioimmunoassay. Adrenal gland of SD rats was collected and fixed in formalin, and then embedded with paraffin. The morphology of adrenal gland was observed by HE staining. Results: Exposure to early scream sound decreased latency of escape and increased times to cross the platform in Morris water maze test (P<0.05). The levels of serum NE was significantly elevated, with an obvious tendency in the increase of CORT level (P<0.05). The morphology of adrenal gland was also influenced. Conclusion: Newborn female rats subjected to scream sound stress can enhance spatial learning and memory ability in adulthood, which is related to activation of the hypothalamo-pituitary-adrenal axis and sympathetic nervous system.