What are the elements of motivation for acquisition of conditioned taste aversion?
What are the elements of motivation for acquisition of conditioned taste aversion?
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DOI：
10.1016/j.nlm.2013.10.013
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发表时间：
2014-01-01
影响因子：
2.7
通讯作者：
Ito, Etsuro
中科院分区：
文献类型：
--
作者：
Mita, Koichi;Okuta, Akiko;Ito, Etsuro
静水椎实螺（Lymnaea stagnalis）能够通过经典条件反射学会避开食物，并将这种厌恶情绪巩固为长期记忆（LTM）。先前的研究表明，禁食时间长短对于味觉厌恶的习得及其巩固为长期记忆（即条件性味觉厌恶，CTA）都很重要。在此，我们验证了血淋巴葡萄糖浓度是CTA学习与记忆中的一个重要因素这一假设。禁食1天能带来最佳的学习与记忆效果，而禁食时间过长则效果递减。禁食5天会导致螺无法学习或记忆。在禁食期间，血淋巴葡萄糖浓度会下降。如果在禁食5天后再喂食螺2天，它们的葡萄糖水平会显著上升，且表现出学习与记忆能力，但无论是学习还是记忆效果都不如禁食1天的螺。给螺注射胰岛素以降低葡萄糖水平，会使它们的学习与记忆能力增强。已知胰岛素还会引起与进食相关神经元之间突触传递的长期增强。另一方面，给禁食5天的螺注射葡萄糖并不能改变它们无法学习和记忆的状况。然而，如果让这些螺食用蔗糖3分钟，它们随后就会表现出学习与记忆的形成。我们的数据表明，血淋巴葡萄糖浓度是推动静水椎实螺习得CTA的一个重要因素，胰岛素在大脑中的作用以及进食行为也是重要因素。（C）2013爱思唯尔公司版权所有。
The pond snail Lymnaea stagnalis is capable of being classically conditioned to avoid food and to consolidate this aversion into a long-term memory (LTM). Previous studies have shown that the length of food deprivation is important for both the acquisition of taste aversion and its consolidation into LTM, which is referred to as conditioned taste aversion (CTA). Here we tested the hypothesis that the hemolymph glucose concentration is an important factor in the learning and memory of CTA. One-day food deprivation resulted in the best learning and memory, whereas more prolonged food deprivation had diminishing effects. Five-day food deprivation resulted in snails incapable of learning or remembering. During this food deprivation period, the hemolymph glucose concentration decreased. If snails were fed for 2 days following the 5-day food deprivation, their glucose levels increased significantly and they exhibited both learning and memory, but neither learning nor memory was as good as with the 1-day food-deprived snails. Injection of the snails with insulin to reduce glucose levels resulted in better learning and memory. Insulin is also known to cause a long-term enhancement of synaptic transmission between the feeding-related neurons. On the other hand, injection of glucose into 5-day food-deprived snails did not alter their inability to learn and remember. However, if these snails were fed on sucrose for 3 min, they then exhibited learning and memory formation. Our data suggest that hemolymph glucose concentration is an important factor in motivating acquisition of CTA in Lymnaea and that the action of insulin in the brain and the feeding behavior are also important factors. (C) 2013 Elsevier Inc. All rights reserved.