心理应激对大鼠工作记忆影响及酪氨酸干预作用

The effect of psychological stress on working memory in rats and the intervention effect of tyrosine

目的 探讨心理应激对工作记忆 (workingmemory)的影响及中枢递质多巴胺 (dopamine,DA)的前体酪氨酸(tyrosine)的干预作用。方法 先用八臂放射状迷宫训练大鼠 ( 1次 /d、6d/周、连续10周)至学习记忆形成,再以CommunicationBox模型对大鼠进行连续 14d、30min/d的心理应激,并从0d起经饲料给予 250, 500和 1000mg/kg3个剂量的酪氨酸干预,观察第 1, 4, 7, 10, 13天的工作记忆错误(workingmemoryerror)及参考记忆错误(referencememoryerror)。结果 与对照组相比,心理应激组在第 1, 7, 10, 13天的工作记忆错误及所有时间测定的参考记忆错误皆高于对照组。与心理应激组相比,酪氨酸 1000mg/kg组在第 7天及第 13天出现工作记忆错误降低,在第 4天及第 10天出现参考记忆错误降低,酪氨酸 500mg/kg组在第 10天时也出现了工作记忆错误、参考记忆错误的降低,酪氨酸 250mg/kg组均未出现具有显著性统计学意义的变化。结论 急性和反复的心理应激能够损害大鼠的工作记忆,高剂量酪氨酸能在较早期降低心理应激对工作记忆的损害, 500mg/kg酪氨酸干预对降低较长期的心理应激造成的工作记忆损害也有一定的作用。

Objective To study the effects of psychological stress on working memory in rats, as well as the intervention effects of tyrosine, the precursor of central neurotransmitter dopamine. Methods SD rats trained by eight-arms maze (1 time/d, 6 d/w, continuously for 10 weeks) and formed the model of working memory, were exposed to stress continuously for 14 days (30 min/d) by Communication Box, and fed with tyrosine 250, 500 and 1000 mg/ kg respectively. Working memory error (WME) and reference memory error (RME) were observed.Results WME of stress treated group determined in 1, 7, 10 and 13 d were higher than that of control group, and RME of stress treated group determined in each time were obviously higher too.Compared with psychological stress group, WME of tyrosine 1000 mg/kg treated group was decreased in 7 and 13 d (P<0.05), and RME decreased in 4 and 10 d(P<0.05), WME and RME of tyrosine 500 mg/kg treated group determined in 10 d were lower than that of psychological stress group (P<0.05). No significant difference was found in tyrosine 250 mg/kg treated group. Conclusions The acute and repeated psychological stress could impair the performance of working memory, while high dose tyrosine obtained remarkable protection in early part of time. Mid-dose tyrosine also had protective effects to the injury of the performance of working memory induced by a long time and repeated psychological stress conditions.