A single footshock causes long-lasting hypoactivity in unknown environments that is dependent on the development of contextual fear conditioning
A single footshock causes long-lasting hypoactivity in unknown environments that is dependent on the development of contextual fear conditioning
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DOI：
10.1016/j.nlm.2010.05.005
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发表时间：
2010-09-01
影响因子：
2.7
通讯作者：
Armario, Antonio
中科院分区：
文献类型：
--
作者：
Daviu, Nuria;Fuentes, Silvia;Armario, Antonio
暴露于一个单一的会议footshocks诱导长期持久的抑制活动在未知的环境中，显着不同的休克上下文。有趣的是，这些影响并不一定与焦虑增强有关，对这种活动减退的解释仍不清楚。在本实验中，我们进一步研究了雄性Sprague-Dawley大鼠的这种现象。在第一个实验中，在暴露于三种不同的未知环境6-12天后，三次电击导致活动减退。这种改变的行为并不伴随着更大的下丘脑-垂体-肾上腺（HPA）激活，虽然更大的HPA激活平行更高水平的冻结观察休克的背景下。在第二个实验中，我们使用了一个单一的冲击和两个程序，一个是在冲击前预先暴露于上下文，另一个是立即冲击，不会引起上下文恐惧条件反射。活动减退和一定程度的恐惧（冻结）的泛化到未知的环境中只出现在一组开发恐惧条件反射，但没有证据表明，在高架十字迷宫增强焦虑在任何组中被发现。结果表明，如果动物能够将厌恶体验与一个独特的未知环境联系起来，它们在任何未知环境中都会表现出更谨慎的行为，尽管在不同的环境中重复体验，这种策略仍然存在。这种持久的谨慎行为与HPA对未知环境的更大反应无关，但在休克背景下观察到这种反应。目前的研究结果提出了一些关注的解释持久的行为变化所造成的短暂的压力。(C)2010年爱思唯尔公司All rights reserved.
Exposure to a single session of footshocks induces long-lasting inhibition of activity in unknown environments that markedly differ from the shock context. Interestingly, these effects are not necessarily associated to an enhanced anxiety and interpretation of this hypoactivity remains unclear. In the present experiment we further studied this phenomenon in male Sprague-Dawley rats. In a first experiment, a session of three shocks resulted in hypoactivity during exposure, 6-12 days later, to three different unknown environments. This altered behaviour was not accompanied by a greater hypothalamic-pituitary-adrenal (HPA) activation, although greater HPA activation paralleling higher levels of freezing was observed in the shock context. In a second experiment we used a single shock and two procedures, one with pre-exposure to the context before the shock and another with immediate shock that did not induce contextual fear conditioning. Hypoactivity and a certain level of generalization of fear (freezing) to the unknown environments only appeared in the group that developed fear conditioning, but no evidence for enhanced anxiety in the elevated plus-maze was found in any group. The results suggest that if animals are able to associate an aversive experience with a distinct unknown environment, they would display more cautious behaviour in any unknown environment and such strategy persists despite repeated experience with different environments. This long-lasting cautious behaviour was not associated to greater HPA response to the unknown environment that was however observed in the shock context. The present findings raised some concerns about interpretation of long-lasting behavioural changes caused by brief stressors. (C) 2010 Elsevier Inc. All rights reserved.