Nicotine produces a within-subject enhancement of contextual fear conditioning in C57BL/6 mice independent of sex
Nicotine produces a within-subject enhancement of contextual fear conditioning in C57BL/6 mice independent of sex
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DOI：
10.1007/bf02688830
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发表时间：
2003-04-01
期刊：
影响因子：
--
通讯作者：
Gould, TJ
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文献类型：
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作者：
Gould, TJ
尼古丁可以增强学习能力，包括情境恐惧条件反射。本研究扩展了先前关于尼古丁和条件恐惧的研究，使用受试者内设计来研究尼古丁增强C57BL/6小鼠情境恐惧条件反射的本质和情境恐惧条件反射的性别差异。实验采用80 dB， 6 cps的宽带滴答声条件刺激（CS）与2秒，0.35 mA的冲击非条件刺激（US）配对的方法对小鼠进行训练。24小时后，小鼠在原始环境中进行冻结测试，1小时后，小鼠在相同的环境中再次进行测试。在三种情况下给予0.5 mg/kg的尼古丁剂量：(1)在训练、测试和再测试之前；(2)培训和复试前；(3)仅在复测前。使用受试者内部设计允许测试尼古丁是否会在情境恐惧条件反射中产生状态依赖性缺陷。在接受尼古丁训练和测试的小组中，尼古丁确实增强了情境恐惧条件反射。然而，在训练而不是测试或测试而不是训练时，尼古丁并没有改变冻结。然而，对于条件反射或尼古丁对条件反射的影响，性别差异并不存在。这些结果表明，尼古丁增强了获取和恢复过程，但当仅用于训练或仅用于测试时，不会产生状态依赖性缺陷。
Nicotine enhances learning including contextual fear conditioning. The present study extends previous work on nicotine and conditioned fear to examine the nature of nicotine's enhancement of contextual fear conditioning and sex differences in contextual fear conditioning in C57BL/6 mice using a within-subjects design. Mice were trained by pairing of an auditory stimulus of 80 dB, 6 cps train of broad-band clicks conditioned stimulus (CS) with a 2 sec., 0.35 mA shock unconditioned stimulus (US). Twenty-four hours later mice were tested for freezing in the original context, and one hour later mice were retested in the same context. A 0.5 mg/kg dose of nicotine was given either for three conditions: (1) before training, testing, and retesting; (2) before training and retesting; and (3) before retesting only. The use of a within-subjects design allowed for testing if nicotine would produce state-dependent deficits in contextual fear conditioning. Nicotine did enhance contextual fear conditioning in the groups that received nicotine for both training and testing. Nicotine, however, did not alter freezing when given on training but not testing or testing but not training. No sex differences, however, existed for conditioning or for nicotine's effects on conditioning. These results suggest that nicotine enhanced acquisition and retrieval processes but did not produce state-dependent deficits when administered just for training or just for testing.