Nicotine enhances contextual fear conditioning in C57BL/6J mice at 1 and 7 days post-training
Nicotine enhances contextual fear conditioning in C57BL/6J mice at 1 and 7 days post-training
复制标题
DOI：
10.1016/s1074-7427(03)00057-1
复制
发表时间：
2003-09-01
影响因子：
2.7
通讯作者：
Higgins, JS
中科院分区：
文献类型：
--
作者：
Gould, TJ;Higgins, JS
尼古丁已被证明可以增强学习过程。本实验扩展这些结果，检查尼古丁的影响收购和巩固的上下文和线索的恐惧条件，和尼古丁的增强条件恐惧的持续时间。C57 BL/6小鼠用两对听觉CS和足部电击US训练。在训练前或训练后立即和测试日给予多剂量尼古丁（0.0、0.050、0.125、0.250和0.375 mg/kg，i.p）。在训练后24小时和训练后1周再次测量背景和听觉CS的冻结。小鼠在1周复检中未接受尼古丁。在训练和测试日给予尼古丁（0.125和0.250 mg/kg），在24 h时增强了对环境的冻结。此外，在先前用0.125和0.250 mg/kg尼古丁处理的小鼠中，在训练后1周观察到对背景的冻结增加。因此，尼古丁处理的小鼠在1周后重新测试时确实显示出升高的冻结水平，即使在1周重新测试时没有给予尼古丁。仅在训练日或测试日接受尼古丁的小鼠和接受尼古丁与美加明（一种尼古丁受体拮抗剂）的小鼠与盐水处理的小鼠没有差异。此外，训练后给予尼古丁并没有增强恐惧条件反射。本研究结果表明，尼古丁增强的上下文恐惧条件依赖于管理尼古丁的训练和测试日，但结果在一个持久的增强记忆的上下文恐惧条件，仍然在没有尼古丁。(C)2003年由Elsevier Science（美国）出版。
Nicotine has been demonstrated to enhance learning processes. The present experiments extend these results to examine the effects of nicotine on acquisition and consolidation of contextual and cued fear conditioning, and the duration of nicotine's enhancement of conditioned fear. C57BL/6 mice were trained with two pairings of an auditory CS and a foot shock US. Multiple doses of nicotine were given before or immediately after training and on testing day (0.0, 0.050, 0.125, 0.250, and 0.375 mg/kg, i.p). Freezing to both the context and auditory CS was measured 24 h after training and again 1 week after training. Mice did not receive nicotine for the 1-week retest. Nicotine (0.125 and 0.250 mg/kg) given on both training and testing days enhanced freezing to the context at 24 h. In addition, elevated freezing to the context was seen 1 week post-training in mice previously treated with 0.125 and 0.250 mg/kg nicotine. Thus, nicotine-treated mice did show elevated levels of freezing when retested 1 week later, even though no nicotine was administered at the 1-week retest. Mice that received nicotine on training day or testing day only and mice that received nicotine with mecamylamine, a nicotinic receptor antagonist, were not different from saline-treated mice. In addition, post-training administration of nicotine did not enhance fear conditioning. The present results indicate that nicotine enhancement of contextual fear conditioning depends on administration of nicotine on training and test days but results in a long-lasting enhancement of memories of contextual fear conditioning that remains in the absence of nicotine. (C) 2003 Published by Elsevier Science (USA).