Individual differences in anxiety trait are related to spatial learning abilities and hippocampal expression of mineralocorticoid receptors
Individual differences in anxiety trait are related to spatial learning abilities and hippocampal expression of mineralocorticoid receptors
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DOI：
10.1016/j.nlm.2006.02.001
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发表时间：
2006-09-01
影响因子：
2.7
通讯作者：
Venero, Cesar
中科院分区：
文献类型：
--
作者：
Herrero, Ana I.;Sandi, Carmen;Venero, Cesar
虽然高水平的焦虑可能会对学习和记忆产生负面影响，但焦虑的个体差异是否会影响远交大鼠群体的空间学习和记忆仍有待证明。我们已经研究了这种可能性，在雄性Wistar大鼠的焦虑水平的第一个特点是高（HA）或低（LA）根据他们的行为在高架十字迷宫或在开放领域的测试。随后，他们在Morris水迷宫中的表现进行了研究，这是一项依赖于海马活动的任务。有趣的是，与HA大鼠相比，LA大鼠在水迷宫中表现出更快的获得和更好的记忆。事实上，这种性能差异可能主要归因于HA大鼠在空间导航过程中表现出的趋触行为（靠近迷宫壁绕圈游泳）的增加。已知糖皮质激素会影响焦虑状态，海马是糖皮质激素在大脑中的主要靶点。因此，我们调查是否海马表达的两个经典的皮质类固醇受体，盐皮质激素（MR）和糖皮质激素（GR）在两组大鼠不同。我们发现LA大鼠海马MR的表达高于HA大鼠，但GR的表达低于HA大鼠。事实上，这些受体的表达水平与动物在高架十字迷宫的开放臂中所花费的时间呈正相关。此外，我们提出的证据表明，在我们研究的第一阶段量化的焦虑水平构成了一种特质，而不是一种状态。两者合计，这项研究产生的证据之间的焦虑特质，海马MR表达和学习能力的个人在紧张的空间定向任务的密切互动。(c)2006年爱思唯尔公司All rights reserved.
Although high levels of anxiety might be expected to negatively influence learning and memory, it remains to be shown whether individual differences in anxiety may influence spatial learning and memory in outbred rat populations. We have studied this possibility in male Wistar rats whose levels of anxiety were first characterized as either high (HA) or low (LA) according to their behavior in the elevated plus maze or in the open field test. Subsequently, their performance in the Morris water maze was studied, a task dependent on hippocampal activity. Interestingly, LA rats showed a faster acquisition and better memory in the water maze when compared to HA rats. Indeed, this difference in performance could mainly be attributed to the increase in thigmotactic behavior (swimming in circles close to the maze walls) displayed by HA rats during spatial navigation. Glucocorticoids are known to affect the state of anxiety and the hippocampus is the main target of glucocorticoids in the brain. Hence, we investigated whether the hippocampal expression of the two classical corticosteroid receptors, mineralocorticoid (MR) and glucocorticoid (GR) differed in the two groups of rats. We found that LA rats displayed higher hippocampal expression of MR but not GR than HA rats. Indeed, the expression levels for these receptors were positively correlated with the amount of time spent by the animals in the open arms of the elevated plus maze. Moreover, we present evidence that the levels of anxiety quantified in the first stages of our study constitute a trait rather than a state. Taken together, this study has generated evidence of a close interaction between the anxiety trait, hippocampal MR expression and the learning abilities of individuals in stressful spatial orientation tasks. (c) 2006 Elsevier Inc. All rights reserved.