Kutlu Munir G, Gould Thomas J
Department of Psychology, Neuroscience Program, Weiss Hall, Temple University, Philadelphia, PA 19122, USA.
Department of Psychology, Neuroscience Program, Weiss Hall, Temple University, Philadelphia, PA 19122, USA.
Behav Brain Res. 2014 Apr 15;263:133-7. doi: 10.1016/j.bbr.2014.01.031. Epub 2014 Jan 31.
Smoking is linked to post-traumatic stress disorder (PTSD) which suggests smoking is either a risk factor or an attempt at self-medication. The ability to reduce or extinguish fear-related memories may be altered in patients with PTSD and it is possible that nicotine modulates this. Although there are numerous studies examining the effects of nicotine on acquisition of fear learning, the effects of nicotine on extinction of contextual fear are not well understood. In the present study, we examined the effects of acute nicotine (0.18 mg/kg) on extinction of contextual fear in C57BL/6J mice. Animals were first trained in a background contextual fear conditioning paradigm using a white noise as a conditioned stimulus (CS), which co-terminated with a 2 s 0.57 mA unconditioned foot-shock stimulus (US). Animals were then administered either nicotine or saline and exposed to either the training context or a novel context in order to measure freezing to the context during extinction. Our results demonstrate that nicotine administration during extinction delays extinction of contextual freezing while nicotine did not affect cued freezing or freezing to the novel context.
吸烟与创伤后应激障碍（PTSD）有关，这表明吸烟要么是一个风险因素，要么是一种自我治疗的尝试。PTSD患者减少或消除恐惧相关记忆的能力可能会发生改变，尼古丁有可能对其产生调节作用。尽管有大量研究探讨了尼古丁对恐惧学习获得的影响，但尼古丁对情境性恐惧消退的影响尚不清楚。在本研究中，我们检测了急性尼古丁（0.18毫克/千克）对C57BL/6J小鼠情境性恐惧消退的影响。首先，动物在背景情境性恐惧条件反射范式中接受训练，使用白噪声作为条件刺激（CS），该刺激与持续2秒、强度为0.57毫安的非条件足部电击刺激（US）同时终止。然后给动物注射尼古丁或生理盐水，并将其置于训练情境或新情境中，以测量消退过程中对情境的僵立反应。我们的结果表明，在消退过程中给予尼古丁会延迟情境性僵立反应的消退，而尼古丁并不影响线索性僵立反应或对新情境的僵立反应。
