Adolescent and adult rats differ in the amnesic effects of acute ethanol in two hippocampus-dependent tasks: Trace and contextual fear conditioning.
Adolescent and adult rats differ in the amnesic effects of acute ethanol in two hippocampus-dependent tasks: Trace and contextual fear conditioning.
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DOI：
10.1016/j.bbr.2015.06.046
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发表时间：
2016-02-01
影响因子：
2.7
通讯作者：
Barnet RC
中科院分区：
文献类型：
--
作者：
Hunt PS;Barnet RC
经验产生的痕迹条件反射和背景条件反射的缺陷已经成为研究海马在学习中的作用的有用工具。也有人认为，在这些任务的学习是特别容易受到酒精的神经毒性作用在关键的发展时期，如青春期。在五个实验中，我们系统地研究了存在和来源的年龄依赖性的脆弱性的记忆破坏的影响，急性乙醇的痕迹条件和上下文的恐惧条件。在实验1中，训练前乙醇破坏痕迹条件更强烈的青少年（出生后一天，PD 30 -35）比成年大鼠（PD 65 -75）。在实验1b中，当预训练乙醇伴随着预测试乙醇没有赤字在跟踪条件下观察到青少年，这表明状态依赖性检索失败介导乙醇的破坏跟踪条件在这个年龄。实验2a和2b研究了乙醇预处理对情境条件反射的影响。在这里，成年而不是青少年大鼠在条件冻结上下文线索受损。实验2c探讨了这种效应的状态依赖性。训练前乙醇继续破坏成年人的情境条件反射，即使在测试前也给予乙醇。总的来说，这些发现揭示了乙醇对依赖于校园的记忆的破坏性影响中明显的年龄依赖性和任务依赖性漏洞。青少年被酒精干扰的痕迹比成年人，成年人被酒精干扰的背景条件比青少年。我们认为，青少年可能更容易受到内部状态的变化（状态依赖检索失败）比成年人和乙醇通过不同的机制破坏性能跟踪和上下文条件反射。这些研究结果的相关性海马功能的理论进行了讨论。
Experience-produced deficits in trace conditioning and context conditioning have been useful tools for examining the role of the hippocampus in learning. It has also been suggested that learning in these tasks is especially vulnerable to neurotoxic effects of alcohol during key developmental periods such as adolescence. In five experiments we systematically examined the presence and source of age-dependent vulnerability to the memory-disrupting effects of acute ethanol in trace conditioning and contextual fear conditioning. In Experiment 1a pre-training ethanol disrupted trace conditioning more strongly in adolescent (postnatal day, PD30-35) than adult rats (PD65-75). In Experiment 1b when pre-training ethanol was accompanied by pre-test ethanol no deficit in trace conditioning was observed in adolescents, suggesting that state-dependent retrieval failure mediated ethanol's disruption of trace conditioning at this age. Experiments 2a and 2b examined the effect of ethanol pretreatment on context conditioning. Here, adult but not adolescent rats were impaired in conditioned freezing to context cues. Experiment 2c explored state-dependency of this effect. Pre-training ethanol continued to disrupt context conditioning in adults even when ethanol was also administered prior to test. Collectively these findings reveal clear age-dependent and task-dependent vulnerabilities in ethanol's disruptive effects on hippocampus-dependent memory. Adolescents were more disrupted by ethanol in trace conditioning than adults, and adults were more disrupted by ethanol in context conditioning than adolescents. We suggest that adolescents may be more susceptible to changes in internal state (state-dependent retrieval failure) than adults and that ethanol disrupted performance in trace and context conditioning through different mechanisms. Relevance of these findings to theories of hippocampus function is discussed.