急性恐惧应激对大鼠激素水平、空间学习记忆行为的影响

目的:观察急性应激对大鼠激素水平、空间学习记忆行为的影响,探讨恐惧应激对机体学习记忆能力的影响及其机制.方法:成年雄性Sprague-Dawley大鼠32只,体质量180～220 g.随机分成对照组(n=16)和应激组(n=16).用足电击 白噪声刺激方式建立急性恐惧应激大鼠模型,并进行空间觅向能力测试,以判断动物记忆储存及提取再现能力.放射免疫法及荧光分光光度法检测血浆和脑组织激素水平.结果:血浆及脑组织去甲肾上腺素、5-羟色胺、皮质醇水平增高,而肾上腺髓质素水平降低(P＜0.01);水迷宫实验结果显示急性恐惧应激后大鼠训练潜伏期(LP)与对照组相比延长(P＜0.05),在限定时间内穿过平台原位置的次数显著减少(P＜0.01).结论:急性恐惧应激可以显著影响大鼠的激素水平,对学习记忆能力造成损伤.

Effects of acute fear stress on hormone levels, abilities of spatial learning and memory of rats

AIM: To study the effects of acute fear stress on the hormone levels, and the abilities of spatial learning and memory of rats. METHODS: Thirty-two adult male SD rats weighing 180-220 g were randomly divided into control group (n=16) and stress group (n=16). Rats of stress group received 30-min acute stress including white noise, and foot shock, and then the spatial learning and memory performance was measured by Morris water maze. The hormone levels in plasma and brain were determined by spectrophotofluorometry and radioimmunoassay kit. RESULTS: In water maze task, the time taken for fear-stressed rats to find the platform (latency) for spatial bias was prolonged(P<0.05), and the frequency of crossing over the platform location was decreased in the probe trail (P<0.01). The stress also resulted in significantly higher plasmic and cerebral noradrenaline, corticosteroid, 5-hydroxytryptamine levels, and lower adrenomedulin level in comparison with the controls (P<0.01). CONCLUSION: Acute fear stress leads to abnormalities of learning and memory of rats, and the alteration of hormone levels in this process may be a significant mechanism underlying the effect.