Zeid Dana, Gould Thomas J
Department of Biobehavioral Health.
Behav Neurosci. 2018 Aug;132(4):240-246. doi: 10.1037/bne0000247. Epub 2018 Jul 5.
Preadolescent mice have been shown to be differentially susceptible to the effects of both acute and chronic nicotine exposure on contextual fear learning relative to adults. For this study, we tested the effects of chronic nicotine exposure in preadolescence on adulthood extinction and spontaneous recovery of fear memory in a model in which contextual fear acquisition occurred prior to nicotine exposure. Preadolescent (postnatal day 23) and adult (postnatal day 53) male C57BL/6J mice underwent contextual fear conditioning and were then exposed to chronic nicotine at 12.6 mg/kg/day for 12 days via osmotic minipump. Eighteen days following the removal of nicotine, both groups of mice underwent fear extinction, followed by a spontaneous recovery session a week later. History of chronic nicotine did not affect later extinction of fear memory in adult-trained mice, whereas adolescent-trained mice exhibited a global impairment in retention of fear memory that precluded detection of effects of early nicotine on later fear extinction. However, it was found that adult spontaneous recovery of fear memory was impaired in mice exposed to nicotine as adults and enhanced in mice exposed to nicotine as preadolescents. These results may indicate greater vulnerability to recurrence of traumatic memory as well as compromised inhibitory control in young smokers. (PsycINFO Database Record
与成年小鼠相比，青春期前小鼠已被证明对急性和慢性尼古丁暴露对情境恐惧学习的影响具有不同的易感性。在本研究中，我们测试了青春期前慢性尼古丁暴露对成年期恐惧记忆消退和自发恢复的影响，该模型中情境恐惧习得发生在尼古丁暴露之前。青春期前（出生后第23天）和成年（出生后第53天）雄性C57BL/6J小鼠接受情境恐惧条件反射，然后通过渗透微型泵以12.6 mg/kg/天的剂量暴露于慢性尼古丁中12天。去除尼古丁18天后，两组小鼠都进行了恐惧消退，一周后进行了自发恢复实验。慢性尼古丁暴露史对成年期训练的小鼠后期恐惧记忆的消退没有影响，而青春期训练的小鼠在恐惧记忆保留方面表现出整体损伤，从而无法检测早期尼古丁对后期恐惧消退的影响。然而，研究发现，成年期暴露于尼古丁的小鼠成年期恐惧记忆的自发恢复受损，而青春期前暴露于尼古丁的小鼠则增强。这些结果可能表明年轻吸烟者更容易出现创伤性记忆复发以及抑制控制受损。（PsycINFO数据库记录）
